4.1 gamete formation
No Marking Criteria Marks
(a) There are two type of reproduction: sexual and asexual. state four differences between these two types of reproduction
Sexual Asexual
D1-Sexual reproduction involving gametes Asexual reproduction not involving gametes D2-It involves two individual It involves only one individual
D3-Gamete formed in meiotic division The process relies on mitotic division D4-The offspring are genetically different
form parents
The offspring are genetically identical with parent
1
1
1
1 4
(b) Diagram shows the reproductive structures of a flower
Based on diagram, name the type of reproduction carried out by this plant
Sexual reproduction 1 1
(c) What is the importance of the type of reproduction mentioned in (a) (i).explain your answer3
F1-there is variation /diversity (in gene composition of the offspring) F2-When conditions become unfavorable some individual may survive F3-and able to reproduce
F4-this will prevent the extinction of the species
1
1 1 1 4 Ovary
The male reproductive system
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(a) In which organ does cell R is formed
Testis 1 1
(b) Name the process of the formation of cell R
Spermatogenesis 1 1
(c) Name the organelle M which is found abundantly in Part A
Mitochondria 1 1
(d) What is role Organelle M?
To produce energy through cellular respiration for the sperm to swim to the ovum 1 1
(e) State the function of the tail
To propel the sperm forward when swimming toward the ovum 1 1
(f) Explain the importance of both the process of W (mitosis) and X (meiosis) in sperm formation F1-to produce haploid sperm /gamete
F2-To ensure continuous species //to ensure the zygote formed through fertilization is diploid F3-Form genetic variation
1 1 1 3
(g) What are the main function of male gonad,testes? P1- testes produce male gamete
E1-and male hormone
1 1 2
(h) In which part of testes does spermatogenesis occur?
Seminiferous tubules 1 1
(i) Explain the function of scortum? F-to provide optimum temperature
E-which is 2-3oC lower than normal body temperature
1 1 2
Diagram shows a portion of the schematic diagram of formation of sperms
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(a) State the chromosome numbers of cells P, Q and R P: 2n Q: n R: n 1 1 1 3 (b) Name the cell division at W and X
W: Meiosis I X: Meiosis II
1 1 2
(c) The female reproductive system
(d) Name the structure labeled P,Y and R P:Ovary R:Corpus luteum Y :Secondary oocyte 1 1 1 3
No Marking Criteria Marks
(a) Name the hormone released by pituitary gland stimulates the development of follicles in P
Follicle-stimulating hormone(FSH) 1 1
(b) Write the sequence of development of follicle P
Ooogenium Primary follicle Graafian follicle Secondary oocytes 3 3
(c) Name the process that occurs in P that produces secondary oocyte
Oogenesis 1 1
(d) What is process X?
Ovulation 1 1
(e) What is ovulation ?
Ovulation is a process of the releasing of secondary oocyte form ovary 1 1
(f) In human, explain when the secondary oocyte will change into ovum
Secondary oocyte will change into ovum if a sperm penetrate /fertilizes it 1 1
(g) State the process occurs in Y
Fertilization 1 1
(h) What would happen if structure R is degenerated immediately after zygote is formed? P1-Level of progesterone will decrease
P2-Endometrium will break down
P3-Fertilised egg would not implant in endomentrium and wound be aborted
1 1 1 3
(i) Formation of primary oocyte takes place during development of a female foetus ,at stage of cell division events does the development stops?
Prophase I of meiosis
No Marking Criteria Marks
(a) Diagram shows the fanges of four types of hormones which control the menstrual cycle follicle development in the ovaries
Figure shows follicle development in an ovary. A woman has a problem conceiving due to the failure of process Z.A doctor advises her to take Human chorionic gonadothrophin Hormone (HCG) that has similar function to hormone P
Based on the above situation, explain how the HCG injection enables the pregnancy to occur F1-The HCG hormone stimulates ovulation //causing the graafian follicle to release secondary oocyte
F2-Corpus luteum secretes progesterone to maintain the thickness of the endomantrium F3-Thus enables implantation to occur
F1and any F2&F3
1 1 1 1 2
(b) Explain what happen if the woman fail to produce hormone Q?
F1-did not stimulates growth of follicle in the ovary//follicle does not develop into graafian (in the ovary)
F2-Primary occyte does not develop into secondary oocyte F3-did not stimulate the production of oestrogen
1
1 1 2
(c) What are the functions of Q in the process showed in figure above? F-Graafian follicle will release secondary follicle and develop into corpus E-Which will secrete progesterone and oestrogen if pregnancy happen
1 1 2
(d) Explain how the intake of contraceptive pill affects the development of follicles E1-Contraceptive pill contain oestrogen and progesterone hormone
E2-High level of oestrogen inhibit secretion of FSH//inhibit development of occyte E3-No ovulation occur
E4-Highh level of progesterone inhibit secretion of FSH//inhibit development of occyte Any 3 1 1 1 1 3 Z Q
Essay enhancement corner
No Marking Criteria Marks
Diagram shows a physiological process in a human
Based on the diagram above ,describe the physiological process P1-the process is oogenesis
P2-germinal epithelial cells undergoes mitosis to form diploid oogonia P3-oogonia grow to form diploid primary oocytes
P4-the primary oocytes undergoes meiosis I to form haploid secondary oocyte and first polar body
P5-secondary oocyte undergo meiosis II and form ovum and (second) polar body any 4P 1 1 1 1 1 4
4.2 The role of hormones in the menstrual cycle
No Marking Criteria Marks
(a) What is the menstrual cycle?
F1: Monthly reproductive cycle controlled by hormones
F2: consist of follicle development, ovulation, thickening of endometrium and menstruation
1 1 2
(b)
Based on diagram, state the meaning of menstrual cycle? 2 P1-The production of ovum by the ovary of female
P2-follow by a cycle in 28 days
1 1 2 (c) Secondary oocyte,copus lutuem,ovulation ,graafian follicle, primary oocyte
Using the term given ,write the correct sequence of a complete menstrual cycle
Primary occyte ,secondary occyte ,graffian follicle ,ovulation, corpus luteum 1 1 (d) Pituitary gland is important in the regulation of hormones in the menstrual cycle.
Explain its important
P1: The pituitary gland produces FSH to stimulate the development of follicles in the ovary. P2 : The follicle secretes oestrogen to repair the uterine Wall
P3 : After the 14th day, the pituitary produces LH that causes ovulation.
1
1 1 3 (e) Menstrual cycle is a monthly reproductive cycle consisting of follicle
development2ovulation ,the changes of the thickness of the endomentrium ,and menstruation .State its importance2
P1-Produce female gamete (Ovum for fertilization)
P2-Thickening endomentrium –prepared for implantation of the embryo
1 1
Days Marking Criteria Marks 0-7
What is hormone X and Y/P and Q X/P: Follicle stimulating hormone / FSH Y/Q:LH
1 1 2
Give a reason for your answer
P:On day 13, the hormone is highest/at the peak/maximum level (to stimulate ovulation ) Q:Increase in level form day 1 to day 7/8
1 1 2
State its function of hormone X
To stimulate the formation of follicles in the ovary 1 1
Explain the effect of follicle stimulating hormones (FSH) on structure P(Primary follicle) P1- (FSH) stimulates the growth / development of the primary follicle
P2-Structure P will grow / develop / becomes secondary follicle / Grafiaan follicle.
1 1 2 Name hormone P and Q
Hormone P:Oestrogen Hormone Q:Progesterone
1 1 2 State the function of hormone X(FSH) and Y(LH)
Hormone X: stimulate growth and development of several primary follicle (in the ovary to become a Graafian follicle)
Hormone Y: Cause ovulation to occur//
Promotes development of the corpus luteum to produce progesterone and oestrogen// Stimulate completion of meiosis I by changing primary oocytes into a secondary oocyte
1
1 2
State the process which took place at X
Menstruation 1 1
Based on diagram above ,State one reason to support your answer
Days Marking Criteria Marks 0-7
An imbalance of hormones P (Oestrogen) and Y (LH) causes the disruption of the ovulation process. Explain.
Pt. 1 : If P secretion is reduced, Y is inhibited. Pt. 2 : Ovulation is delayed / does not occur
Pt. 3 : If P secretion is excessive, secretion of Y is stimulated. Pt. 4 : Inhibits X, no follicle development / ovulation is hastened Pt 5.The size of structure T is smaller than its size on 20th day
1 1 1 1 1 4 Explain why an imbalance of hormones P and Y causes the disruption of the ovulation
process.
F1: Hormone P is oestrogen and hormone Y is luteinizing hormone
F2: undersecretion of hormone P( oestrogen )inhibits secretion of Follicle stimulating hormone from pituitary gland
F3: No development of Graafian follicles so no ovulation occur// no secretion of luteinising hormone from pituitary gland so no ovulation occur
F4: Oversecretion of hormone P stimulates secretion of hormone Y from pituitary gland F5-Ovulation occur early
1 1
1
1 2
Name hormone Q and structure T. Hormone Q : Progesterone Structure T : Corpus luteum
1 1 2
Days Marking Criteria Marks 0-7
Based on the graph in diagram ,Name the hormone 2 P:LH
Q:FSH
1 1 2 Give a reason for your answer
P:On day 13, the hormone is highest/at the peak/maximum level (to stimulate ovulation ) Q:Increase in level form day 1 to day 7/8
1 1 2 8-14
State the function of hormone Y Hormone Y:Cause ovulation to occur//
Promotes development of the corpus luteum to produce progesterone and oestrogen// Stimulate completion of meiosis I by changing primary oocytes into a secondary oocyte
1 1
Explain the effect if the level of hormone Y is low P1- Ovulation will not occur
P2-Grafiaan follicle will not release the secondary oocyte (into the Fallopian tube).
1 1 2 Explain one difference between primary oocyte and secondary oocyte
Difference: primary oocyte is diploid while secondary oocyte is haploid. Explanation : Primary oocyte has undergo meiosis (I)
1 1 2
Days Marking Criteria Marks 15-21 Explain the importance of structure Q (corpus luteum)during development
F- Q secrete progesterone
P1-(progesterone will thickened and) maintained the endometrium wall
P2-Endometrium wall ready for implantation of embryo // prevent misscarriage / abortion. 1 1 1 3
Complete the follicle development in boxes M and N
2 2
Based on the diagram ,explain the relationship between the P1-After ovulation /corpus luteum secretes S /Progestrone
P2-The level of S /progrestrone increase to maintain the thickness of the endomentrium P3-When the M /corpus luteum degenerates, the level of S progesterone decreases, the endomentrium begi to disintegrates
1 1 1 3
If the fertilization occurred, the level of hormones S is maintained and the pregnancy is proceed
Explain the important of hormone S[GnRH]
P1-To inhibit the secretion of FSH of LH form pituitary gland P2-no development of follicle /secondary oocyte
P3-then the secretion of oestrogen is reduced
P4-Repair rejuvenation of endomentrium is not happened P5-Hence no new early embryo develops
1 1 1 1 1 3 Explain the relationship between structure Y and the level of hormone X form 16th day to
28th day
P1-16th day to 28th day: Y is formed ,hormone X is secreted,endometrium thickens P2-23th -28th days: Y degenerated, the level of hormone x declines resulting in the foetus
1 1 2 Hormone X
Days Marking Criteria Marks 22-28
Complete the graph starting for point X in diagram to show the change in the thickness of endometrium wall if fertilization does not occur
wall is decreasing / thinning. 1 1
Explain the graph that you draw in above P1- Corpus luteum degenerate
P2-No progesterone is secreted (to thicken the endometrium wall).
1 1 2 Draw in Diagram 6, structure T on the 26th day if fertilization did not take place.
The structure T shrinks. 1 1
Draw in Diagram 4, structure T on the 26" day if fertilization did not occur.1
Corpus luteum had shrunken/ become smaller in size 1 1
Give the relationship between the structure Q and the level of hormone Q(Progesterone) from the 16th to 28th day2
Pt.1 : On the 16th day, T is formed, hormone Q is secreted.
Pt 2 : On the 24th day, T degenerates, the level of hormoneQ declines.
1 1 2
Days Marking Criteria Marks 22-28
Explain the relationship between the structure T and the level of hormone Q from the 16" to 28" day.2
16" to 28"
F1: hormone Q( progesterone) rises to a high level to induce endomentrium to thicken and vascuiarised
E1-stucture T (corpus luteum) developed and become active
F2: hormone Q decreases to a very low level resulting in menstruation E2: Structure T degenerated and not active
1
1 1 1 2
Essay Enchancement Corner
No Marking Criteria Marks
(a)
Based on diagram, state the meaning of menstrual cycle?2 P1-The production of ovum by the ovary of female P2-follow by a cycle in 28 days
Starting with hormone produced by pituitary gland and ovary, describe how the hormone regulate the menstrual cycle and an ovary produced an ovum8
F1-What FSH/hormone P does
it stimulates the development of the follicle in the ovariesUsually one follicle ripens to become the graafina follicle in one of the ovaries during each cycle
It also stimulates the follicle in the ovary to secrete oestrogen F2-Effects of oestrogen /hormone X
After menstruation ,it causes the repair and growth of the uterine lining(endomentrium)
The urine lining become thick and spongy with blood vessels
A high concentration of oestrogen in the blood inhibitsFSH production ,preventing the ripening and growth of more follicles
It stimulates the pituitary gland to secrete luteinizing hormone(LH) F3-Function of LH/Hormone R
It causes ovulation
It also causes the formation of the corpus F4-Corpus luteum 1 1 1 1 1 1 1 1 1 1 1
The corpus luteum secretes progesterone and also some oestrogen F5-Function of progesterone /Hormone Y
It keeps the uterine lining thick and well supplied wiuth blood
Preparing it for implantation of the embryo
It inhibit both FSH and LH production
1
1 1 1 1 10
No Marking Criteria Marks
(b)
Explain the relationship between development of the follicle , changing of the respective hormonal level in the blood and the thickening of the uterine endometrium in a female.10 Day 0 – 7
Follicle – very small
– start to develop when receive FSH from pituitary – the wall of follicle will produce estrogen
FSH
- pituitary start to release FSH, FSH will go to the ovary - FSH stimulate development of follicle Endometrium - stimulate by estrogen; undergo thickening / repairing Day 8 – 14
Follicle
- become larger, develop to form follicle Graaf FSH / LH/ Estrogen/progesterone - FSH decrease, LH at maximum level , estrogen at maximum level
1 1 1 1 1 1 1 1
- LH stimulate ovulation / completion of meiosis I, estrogen stimulate the thickening of endometrium
- Progesterone level very low Endometrium
- endometrium become very thick (ready to implantation (of embryo)) -
Day 15 – 21 Follicle
- Follicle undergoes ovulation/ released oocyte II
- The remaining follicle tissue / corpus luteum secreted small amount of estrogen but large amount of progesterone
FSH/ LH/ Estrogen/ Progesterone
- Progesterone stimulated the thickening of endometrium , halted the secretion of FSH/LH - Development of new follicle and ovulation stop. Endometrium
- more thicker and highly vascular - ready for implantation of embryo
Day 22 – 28 Corpus luteum
- if no fertilisation, corpus luteum become disintegrate FSH/ LH/ Estrogen / Progesterone - FSH, LH and estrogen at minimum level; progesterone level also drop Endometrium - endometrium become breakdown & disintegrate
- blood and tissue are shed / lining of uterus discharge through vagina as menstrual flow.
1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (c)
Based on the above diagram, explain how pituitary hormones and sex hormones control the menstrual cycle
F1-During day 1 to day 5, endopsperm wall break down and slough off F2-Pituitary land starts secreting FSH
E1-FSH causes a Graafian follicle to develop in the ovary
E2-during day 5 to day 10 FAH stimulate the wall of follicle and the tissue of the ovary to secrete oestrogen
E3-Oestrogen starts to repair of the uterine wall
F3-Ion day 12 to day 14 Oestrogen inhibits pituitary gland form secreting FSH E4-and stimulates pituitary glands to produce LH
F4-Lh causes ovulation to occur on day 14
E5-After day 14,the graafian follicle to change into corpus luteum F5-Corpus luteum secretes progesterone
E5-Progresteron make up the endometruim become thicken and filled with numerous blood vessel for implantation
E6-Increase in the concentration of progesterone will inhibit the production of FSH and LH
1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks
Digram shows the hormonal secretion and regilaiton the menstraul cycle .Based on the diagram dicuss the relationship between the following
i. hormonal level and the development of follicles P1- Pituitary secrete more FSH
P2- FSH reansport to the ovary by blood P3- FSH stimulate development of the follicle
P4- When the follicle dvelops into graafian follicle ,level if FAH will reduce
ii. Ovulation and formaiton of the luteum
P1- When graafian follicle form ,LH will secreted by pituirary
P2- Level of LH become maximum at day 10-14/fertile time form women P3- LH will stimulate the ovulaiton
P4- When follicle release the secondary oocyte into fallopian tube ,the folliucle withoutsecondaryoocyte called carpos luteum
iii. Homonal levels and changes in thickness of the endomantrium P1- Wall of the follicel secretes oestrogen
P2- It wil stimulate the thickening of endomentrium for implatation P3- When ovulaiton ovvurs,the secretion of oestrogen stops
P4- Corpus luteum will secretes progestron to continue the funciton of oestrogen P5- When menstrual occur ,oestrogen and progesterone level will decreas
1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks
Explain the changes and the functions of each type of hormone produced by Pituitary and ovary.
FSH (Follicle – stimulating hormone)
P1 - From day 1 to day 5, pituitary gland stars to secrete FSH P2 - FSH stimulates the development of follicle
P3 - And stimulates the tissue of ovary to secrete oestrogen Oestrogen
P4 - From day 5 to day 13, concentration of oestrogen continue to increase P5 - Oestrogen causes the repair and heal of the endometrium lining P6 - Endometrium lining becomes thicker and ( filled with blood vessels) LH (Luteinising Hormone)
P7 - On day 13, the LH level increases
P8 - Causing ovulation / Graafian follicle releases secondary oocyte. P9 - LH causes the formation of corpus luteum
P10 - Corpus luteum secretes progesterone Progesterone
P11 - Progesterone maintains the thickening of endometrium for implantation P12 - Progesterone inhibits the secretion of FSH and LH
P13 - If the secondary oocyte is not fertilised by a sperm, corpus luteum disintegrate / progesterone decreases
P14 - Endometrium lining begins to breakdown and menstruation starts Any 8 P 1 1 1 1 1 1 1 1 1 1 1 1 1 1 8
No Marking Criteria Marks
Based on the diagram state the meaning of menstuaration F1-breakdown of the lining of the uterus
P1-diacharge through the vagina
P2-small amount of blood and some cell
1 1 1 3
Describe how the menstrual cycle is affected if the pituitary hormones peak up seven days later. F1 - Menstruation / menses will occur a week later (than usual) // on the 7th day of the following cycle / month.
E1 - FSH peaks up on day-20 / a week later / just before day-21. E2 - LH peaks up on day 20 / a week later / just before day-21. F2 - ovulation only occur a week later / day-21
E3 - due to stimulation / from a rise of LH
F3 - level of estrogen remains high until day-21 because
E4 - graafian follicle that release estrogen remains intact / due tono LH F4 - corpus luteum will only be formed on day-21 / a week later
E5 - this causes level of progesterone to increase after day 21 andremains high
E6 - as level of progesterone high, the lining of uterine wall / endometrium will remains thick longer
E7 - when corpus luteum degenerate, level of progesterone drops
E8 - this causes the lining of endometrium to disintegrate causing menses which occurs a week later than usual Any 10
1 1 1 1 1 1 1 1 1 1 1 10
4.3 Early Development of human zygote
Diagram 1 shows the development of a human zygote .
Label the diagram
Stage Name of the stage / process
X Ovulation Y Fertilisation P Zygote Q Morula Z Implantation Q P P Q
Early Development of human zygote SPM 2012
No Marking Criteria Marks
(a)
Describe the development in detail 8
P1-A fertilization ovum is known as a zygote P2-Zygote divides repeatly by mitois
P3-Morula develops into balstula/blastocytst P4-It is a hollow ball of cells
P6-Blastocyst forms inner mass cells and trophoblast P7-Blastocyst implants at the endomentrium /uterus P8-Inner mass cells /zygotes develops into embryo P9-trophoblast will form villi of placenta any 8P
1 1 1 1 1 1 1 1 1 8 (b)
Describe the process which occurred form P and Q 4
P1 – Ovulation releases a secondary oocyte , which enters the oviduct.
P2 – The secondary oocyte starts meiosis II which progresses until metaphase II.
P3 – The nuclei of a sperm cell (n) and the ovum (n) fuse and form a diploid zygote (2n). // A sperm fertilize the ovum to form a zygote.
P4 –Zygote begins to divide repeatedly by mitosis as it travels along the fallopian tube towards the uterus.
P5 – Morula is form followed by blastula.
P6 – Implantation occur / The blastocyst attaches itself to the endometrium.
1 1 1 1 1 1 4
No Marking Criteria Marks (c)
Based on the diagram above (i) Explain briefly process A F1-ovulaiton
P1-he release of secondary oocyte form the ovary
(ii) Describe the early development of a zygote form process B until process C P1-after fertilization the zygoite divide repeatly/undergoes mitosis
P2-as its travel along the (fallopian) tube toward uterus P3-first division form two-celled embryo
P4-further division formed a solid mass of cells called morula P5-then morula is ball of about 100 cells called blastocyts/blastula
P6-Blastocyst/blastula is a fluid filled sphere with outer layer of cells and inner cell mass P7-The cilia in the (fallopian ) tube helps developing embryo to reach the uterus
P8-Blascocyts/blastula undergoes implantation to attach itself to the endomentrium P9-The inner cell mass becomes firmly embedded in the endomentrium
1 1 1 1 1 1 1 1 1 1 1 2 8 The formation of twins
No Marking Criteria Marks
(a) Diagram shows the formation of two pairs of twins
Based on the diagram ,explain how the formation of twin occurs6 F-Siamese twin
P1-One sperm and one ovum are involve in fertilization P2-to produce one /single zygote
P3-Zygote undergoes mitosis repeatly to form blastocyst P4-Blastocyts does not divide completely
P5-the blastocyt does not dvide completely
P6-The two blastocyst implant/embedded into endomentrium wall and develop to embryo) P6-The are joined at certainly part of body
1 1 1 1 1 1 1 1 8
Comparison of the twins
Refer to SPM 2005 Q7 Pg 312-314
No Marking Criteria Marks
(b)
Based on diagram ,explain the role of placenta as endocrine gland P1 : After the placenta is formed, it secretes progesterone
P2 : The level of progesterone continues to increase
P3: The hormone maintains the thickness of the uterus lining
1 1 1 3
No Marking Criteria Marks (a) Diagram 4.1 shows a graph on how the endometrium in the human uterus varies in thickness
with time. Fertilization took place on the 16th day of the second month.
State the process which took place at X.1 Menstruation
1 1
(b) Based on the Diagram 4.1, state one reason to support your answer in (i)1
The endometrium begins to break down 1 1
(c) Complete the graph in Diagram 4.1 to show the changes in the thickness of the endometrium
after day 22 in the second month until day 28 of the third month.1 1 1 (d) Explain why the thickness of the endometrium changes in the way shown in (b) (i).2
P1 : The endometrium begin to became thicker, for preparation for the implantation of a fertilized ovum
P2 : The endometrium keep thickening due to the level of progesterone and oestrogen continue to rise because fertilization occurs.
P3 : The corpus luteum continues to secrete oestrogen and Progesterone
1
1
1 3
(e) Based on the changes in Diagram 3.1, complete Diagram 3.2 to indicate the level of the hormone progesterone from the first to the third months.2
Explain the changes in the level of progesterone in the three months as shown in Diagram P1 : Increasing in progesterone level will stimulate the uterine wall to became thicker
P2 :When the fertilization occur, the level of progesterone continue to rise to ensure the uterine walls continue to grow and nourish the embryo
1
No Marking Criteria Marks (f) Explain the changes in the level of progesterone when the women faces menopause.
P1 :The level of progesterone become lower P2: Ovaries are less stimulated by FSH and LH
P3: lead to inhibits the development of the follicles and ovulation
1 1 1 3 (g)
Diagram 4.3 shows the process of sperm formation in the human testis.2 Are cells V, cell W and cell X genetically identical? Explain.
F : Cell V is similar to cell W but is different from cell X.
P : Cell V and cell W are products of mitosis whereas cell X is a product of meiosis.
1 1 2
The function of the placenta in foetal development
No Marking Criteria Marks
(a)
Name two materials that pass via R(Placenta) form mother to the foetus
Water/amino acid/glucose/nutrient/oxygen /antibodies 1 1
(b) (i)
Name M
Amniotic fluid 1 1
(ii) State the importance in fluid M
P1-Protect the foetus by absorbing shock P2-Protects foetus form physical damage P3-Allow movement of the foetus any one
1 1 1 2
R
No Marking Criteria Marks (c) Explain how the structure R (Placenta) enable exchange of material to take place 2
F1-Placenta has a large surface area to volume ratio P1-to increase exchange rate
OR
F2-Material and embryonic bloods are brought into close contact P2-Diffusion can take place efficiently
OR
F3-Seperated only by a thin membrane P3-Diffusion can take place efficiently
1 1 1 1 1 1 2 (d)
Structure P consists of two type of blood vessels. Name both vessels 1. Umbilical artery 2. Umbilical vein 1 1 2 (e) (i)
State the function of each blood vessel named in above/ Give the diference between both blood vessel
1. Carry waste product/deoxygenated blood form the foetus to the placenta 2. Carry oxygenated blood form placenta to the foetus
1 1 2
(ii) State two substances which are carried by the blood in Y, in the direction of the arrow 1. Carbon dioxide
2. Nitrogenous waste products
1 1 2
(f) A pregnant woman of blood group A is having a foetus of blood group B. Based on diagram 5.1 and the statement above , state whether agglutination will occur in the foetal blood or not. Explain your answer.
F- No
E- The foetal circulatory system and the maternal circulatory system are separated // not directly connected (due to the presence of the placenta)
1 1 2
(g) Placenta also involved in endocrine system ,discuss how placenta act as endocrine system P1-placenta secretes oestrogen and progesterone
P2-helps maintain a thicked ,blood enriched endomentrium during pregnancy
1 1 2 P
No Marking Criteria Marks (a) State the differences between the content of R (placenta) and foetal blood
R (placenta) Foetal blood
Oxygen High Low
Nutrient High Low
Carbon dioxide Low High
Waste /example Low High
1 1 1 1 4
(b) Diagram 5.2 shows a negative habit of a pregnant mother. . Explain the effect of this habit to the foetus3
P1 : Cigarette contain nicotine / DDT / lead particles.
P2 : Nicotine are small in sizes so it can diffuse from maternal blood capillaries to foetal blood capillaries through the placenta
P3 : The substances are carried by umbilical vein to the foetus.
P4 : The substances can cause miscarriage // birth defect // illness in the resulting baby
1 1
1 1 4 (c) In the 16th week, pregnant mother was infected with disease .the infection caused structure n to
stop functioning the mother miscarriage, explain the statement
F1-N secrete progesterone to stimulate/induce the thickening endomentruim E1-Infection caused N not to secrete progesterone
E2-Endometrium are no longer thicken //endometrium break down o foetus is aborted
1 1 1 3
(d) Human chorionic gonadtrophin hormones (HCG) has a similar role to luteinizing hormone(LH).A wife .A wife has a problem conceiving due to the failure in ovulation . The wife becomes after doctors has given her injections of HCG
Based on above statement, explain how HCG injection enable the process of pregnancy. P1-HCG stimulates ovulation
P2-ovum/secondary oocytes is released form the ovary to the fallopian tube P3-Ovum fuses with sperm in fallopian tube forming a zygote
P4-corpus luteum secretes progesterone
P5-progesterone maintains the thickeness of the uterine wall /endometrium P6-the thickness of the uterine wall enables implantation to occur any three
1 1 1 1 1 1 4
Essay Enhancement corner
No Marking Criteria Marks
(a) Diagram shows the structure of placenta
Explain the function of placenta in foetal development 6 P1-Seperates foetal blood form maternal blood
P2-Exchange of substances between foetus and mother
P3-Oxygen and nutrient diffuse form the maternal blood to the foetal blood
P4-Carbon dioxide and nitrogenous waste products diffuse form the feotal blood into the maternal blood
P4-Carbon dioxide and( nitrogenous) waste products diffuses form the foetal blood into the maternal blood
P5-Some antibodies diffuse for the maternal blood into the foetal blood P6-Protect the feotus form the high pressure of maternal blood
P7-Prevents large organism like bacteria form entering the foetal blood P8-Prevents mixing of foetal blood with maternal blood/agglutination any 6P
1 1 1 1 1 1 1 1 1 6
(b) The developing foetus is nourish and protected in the mother‟s uterus Explain the above statement10
N1-Nutrients/oxygen/antibodies /hormones/any 2 example
N2-Form maternal are transported to the foetus through umbilical vein
N3-Carbon dioxide and nitrogenous waste products form the foetus are transported to the maternal (vein)through umbilical arteries
N4-The numerous blood capillaries ( in the chorionic villi provide a large surface area fro diffusion of materials
P1-The foetal circulatory system and the maternal circulatory system are separated P2-Prevents certain harmful bacteria and their toxins form entering the foetus
P3-Prebents the action of meternl hormones/chemical in mother‟s blood that could harm the developing foetus
P4-Prevents the mixing of blood groups of mother and the foetus P5-Which cause Aggulutination
P5-Prevents the fine blood vessel of the foetus di not burst P7-Due to blood pressure of the maternal circulation 4N +6P
1 1 1 1 1 1 1 1 1 1 10 Foetal blood Umbilical artery Umbilical vein Placenta
The advantage of having separate foetal and maternal circulatory system
No Marking Criteria Marks
(a) Explain why the foetus has a separate blood circulatory system form his mother2
F-Prevent the mixing of blood groups of the mother and the foetus which may be incompatibles E1-If incompatible bloods mix, they clot agglutinate
E2-and cause blockage in important organs/death Or
F-Protect the foetus form the high blood pressure of the mother E1-Foetus has fine and delicate blood vessel
E2-high blood pressure of mother„s blood will cause the feotl blood vessel burst and damage Or
F-Prevent the action of maternal hormone /chemical /harmful bacteria E1-From crossing the foetal blood
E2-which could harm the development of the foetus any two
1 1 1 1 1 1 1 1 1 3 (b) Name two the materials that partially prevented by placenta form entering the blood of foetus
Drug/alcohol/caffeine/nicotine /HIV/rubella virus 1 1
(c) R regresses and cause miscarriage Explain the above statement
F-Placenta acts as an endocrine gland//secreting
E-(these hormone) help to maintain a thickened /blood enriched endomentrium throughout the pregnancy
1 1 2
(d) Explain why colostrums valuable to the baby immediately after birth 2 F-Colostrums contain antibodies
P-To help/baby survive form pathogen
1 1 2
Essay enchancement corner
No Marking Criteria Marks
(a) Diagram 9 shows relationship between K and L of placental blood circulatory system.
Explain why K and L circulatory system are not directly connected to each other. F1 both system separated
E1 blood of both not mixing E2 permits exchange of gases/food E3 waste product
E4 between the foetus and the mother
F2 prevent the action of maternal hormone/other chemical E5 in mothers blood
E6 which could harm the development of the foetus E7 but the protection is incomplete.
E8 Harmful chemical/alcohol/nicotine/morphine/bacteria/toxine/viruses E9 can enter the foetus from mothers blood
E10 cause permanent damage
F3 (protect foetus) from high blood pressure of maternal circulation. Any ten 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10
4.4Appreciating the contribution of science and technology t human reproduction
No Marking Criteria Marks
(a) A married couple, who has been married for 10 years, fail to have baby. Examination by a doctor revealed that the husband has a low sperm count. Describe one method that would help the couple to have a child
F1-Artificial insemination
E1-Sperm form a donor can be obtained form a sperm bank
E2-Sperm is injected into the uterus of a woman during ovulation any two
1 1 1 2 (b) If the sperm counts of a husband are too low, artificially insemination can be carries out to
overcome this infertility problem. Discuss the appropriate technique should be used P1-the sperm are collected for the husband/taken form sperm banks
P2-An inserted directly into the fallopian tube of the wife during ovulation phase
1 1 2
Essay enhancement corner
Refer to: SPM 2011 State two infertility problem and explain the various method to overcome infertility problem [6m] Pg 316
No Marking Criteria Marks
(a) A married want to have a baby. But he‟s wife has fallopian tubes blocked problem.it make impossible for her to conceive through the natural process.They insist to have their own child. Describe one modern technique that may be able to help this couple to have their own child. Explain the moral issues related to the suggested technique10
F-The couple can use the intro-vitro fertilization (IVF) method
P1-Mother undergoes hormonal treatment to produce more secondary oocyte P2-A fine laparoscope is used to remove the secondary oocyte form her ovary P3-the secondary ooctye are placed in a Petri dish of culture solution
P4-then, sperm form the husband are added to secondary oocyte
P5-the sperm and ova fused and become zygote//fertilization is occurred to form zygote P6-The zygote undergoes mitosis to become embryo/eight-cell stage
P7-The embryo formed is implanted in the wife uterus P8-A baby born is called as a test-tube baby
(f+any7P)
Able to explain the moral issues related to the suggested technique of reproductive technology
M1-Frezzing and destroying living embryo M2-Vitro fertilization morally acceptable
1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (b) Preventing pregnancy and difficulty in having children are two main problems in human
reproduction.
Based on the statement, discuss the moral issues related to applicationof Science and Technology in overcoming human reproduction‟s problems.
Preventing pregnancy F1 Contraceptive method
P1 stop ovum from being formed
P2 stop the fertilize ovum from developing in the uterus. P3 stop sperm from reaching ovum.
F2 Could harm the foetus when a women has the ability to bear a child. F3 Only use contraception for health
P4 for health P5 financial reason
F4 (Prevention of fertilize egg from developing) is an act of killing. F5 The use of spermicides kills life
F6 Religious believe there is only accept natural method of contraception. Overcoming infertility
F7 Infertility is the failure of the couple to have a baby P6 due to block fallopian tubes.
P7 low sperm count F8 Sperm bank
P8 not allowed (religion) if used sperm not from husband, F9 In-vitro fertilization IVF
P9 it is wrong to destroy extra embryos
P10 abuse the technique to select the sex /zygote P11 to produce perfect offspring
F10 Surrogate mother
P12 Life of surrogate mother is threatened.
Many women assume that as long as they are still getting their menstruations , they have plenty of healthy eggs left. But this is not quite true.
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (c) Explain the contribution of science and technology to human reproduction
F-name the methods to overcome infertility E- give explanations
F-Artificial insemination
E1-Impotence in the husband/ erectile dysfunction requirethe sperm to be collected and then injected into the cervixof the wife time of the woman's ovulation.
E2-Low sperm count /immobile sperms/ abnormal sperms of the Husband to be overcomed by obtaining healthy sperms form suitable donor in a sperms bank and then inject into the fallopian tubes of the wife during ovulation.
F-In vitro fertilisation ( inoperable blocked fallopian tubes)
El: Permanent blocked oviducts in the wife prevent Secondary occytes from being fertilized by the sperms.
E2: Wife treated with follicle – stimulating Hormone (FSH) and luteinising hormone (LH) to increase the oocyte production.
E3: Oocytes collected and placed in a Petri dish containing a suitable medium similar to the fallopian tubes.
E4: The oocytes are mixed with the husband's sperms.
E5: 2 days old embryos are transferred into the wife's uterus for implantation. F: In vitro fertilization ( Postponement of motherhood ) /
having children later in life.
El : Eggs / oocytes of women are collected , frozen and stored when less than 34 years old. E2: Oocytes are used: later when the women decide to stad a family.
F: Surrogate mother
El : Wife unable to have babies herself. And need another younger , healthier woman to bear her child.
E2: Woman become pregnant by artificial insemination or by in vitro fertilization. Any 9 correct
KS: Ability to describe one treatment method correctly
1 1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (d) Pregnant woman are advised not to smoke and avoid form drugs and alcohol
Explain this statement
- Cigarette contain nicotine / DDT / lead particles.
- The wall of maternal blood capillaries and the wall of foetal blood capillaries are semi-permeable.
- Nicotine, drugs and alcohol are small in size.
- Nicotine, drugs and alcohol can diffuse from maternal blood capillaries to foetal blood capillaries
- through the placenta
- The substances carried by umbilical vein to the foetus.
- Nicotine, drugs or alcohol can affect the development of foetus
- (example) cause disable / miscarriage . birth defect/ illness in the resulting baby.
1 1 1 1 1 1 1 1 6
(e) Mrs. Ali is a married woman, she has a problem to get pregnant
Explian under what type of condition Method A can be used to help Mr. and Mrs. Ali 5 - Method A is known as in-vitro fertilization (IVF)
- Method A is use if the fallopian tubes of Mrs. Ali are blocked. - sperm cannot reach the ovum, fertilization fail to occur. - fertilization has to be done outside the body.
- developed zygote/embryo then retransfer and implant in the uterus of Mrs. Ali.
- the embryo then undergo normal development in the uterus of Mrs. Ali as normal pregnancy. 1 1 1 1 1 1 5
No Marking Criteria Marks (f) Discuss the role of Madam X in Method B and issue may arise
- Method B is used if the uterus of Mrs. Ali fail to carry the implanted embryo because of damaged or abnormal uterus.
- Madam X is the woman who is willing / hired to carry the implanted embryo to full term. - Madam X is known as surrogated mother.
- Genetically the baby belongs to Mr. and Mrs. Ali.
- Who is the real biological mother of the baby, Mrs. Ali or Madam X
- There are cases that the surrogated mother refuse to return the baby to the couple after giving birth 1 1 1 1 1 1 5
(g) A married do not wish to start a family soon after marriage. Explain the following methods of contraception
(i) Natural method
F1-avoid sex during fertile period/after ovulation /around day 14 ( to prevent conception) P1-Detect ovulation by measuring body‟s temperature daily/rise in body temperature
(ii) Mechanical methods
F2-Using intrauterine device(IUD) P2-Prevents implantation of embryo F3-Using diaphragm
P3-Prevnts sperm form entering uterus F4-Using condom
P4-Prevent sperm form entering uterus
(iii) Chemical method
F5-Taking oral contraceptive pills
P5-Prevent formation of foliciles in the ovaries F6-Using spermicides P6-Kill sperm Any F corresponding P 1 1 1 1 1 1 1 1 1 1 1 6
No Marking Criteria Marks (h) A husband and wife with seven children plan not to have anymore child. Based on your
biological knowledge, explain the method that can be recommended to them 6 F1-Diaphragm
P1-Inserted into vagina to cover the cervix to stop sperm ofmr entering the uterus F2-IUD
P2-Fitted into uterus by doctor and can be left in the uterus (2 years) and prevent implantation F3-Spermicide
P3-Chemical cream /gel /foam is applied to vaginal walls before copulation and kill the sperm ejaculated into vagina
F4-Contraceptive pills
P4-Prevents ovulation (by inhibiting the secretion of FSH and LH)
P5-noth the fallopian tubes are cut and tied ( in an operation ) causes the ovum cannot reach the part of fallopian tube ,fertilization is not occurred
1 1 1 1 1 1 1 1 1 5 (i)
Explain the advantages of the following birth control methods family planning (i) Contraceptive pill
P1-Contains oestrogen /progesterone
P2-(oestrogen/progesterone hormone) can prevent the formation of follicle in the ovary
P3-Prevents ovulation //inhibits the secretion of follicle stimulating Hormone/FSH /Luteinizing hormone/LH
P4-No fertilization occur//the woman is not pregnant P5-Effeceint /safe method (of birth control)
(ii) Intrauterine device (IUC)
P6-(intrauterine) device is inserted into the uterus (by doctors) P6-Left in the uterus (for approximately two, three and five years) P8-irritates the endomtrium /prevents the thickening of the uterine wall P9-Prevent the implantation of embryo
P10-No development of zygote /no pregnancy P11-effeicent/safe method (of birth control)
(iii) Vasectomy
P12-the vas deferens are tied cut in a surgical operation
P13-The sperm re still produced but cannot be transferred out/reach the uterus/fallopian tube P14-No fertilization
P15-effeceint/safe method (of birth control) (P5, P11 and P15, mark awarded once only)
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10 Technology in human reproduction has given great contribution to
family planning .contraceptive pills, intrauterine deceive (IUD) and vasectomy are example of birth control method in family planning
No Marking Criteria Marks (g) Reproduction technology has contributed a lot to human health and population growth.
Describe how infertility is overcome in humans using the following methods:
Sperm banking [Bank sperma]
Artificial insemination [Permanian beradas]
In vitro fertilization [Persenyawaan in vitro]
Surrogate mother [Ibu tumpang] Sperm bank
Used when the man/spouse/male suffers from low sperm count/production of weak/unhealthy sperms
Sperms are donated and donor‟s identity is recorded/secret
Genetic biodata of donor and the woman recipient should match for successful fertilization Artificial insemination
Practiced by a couple when the man is sterile
Donor‟s sperm are injected into the womans uterus during ovulation
No sexual intercourse is involved
The genetic background and health of donor is screenned before acceptance In vitro fertilization
Practiced when the woman‟s ovum cannot be fertilized due to blockage of fallopian tube
Ovum is extracted (from the woman) and fertilized outside the body/in Petri dish/test tube
Fertilized ovum/zygote grows in culture medium
Than it is implanted into the woman‟s uterus Surrogate mother
Method practiced when a woman cannot be pregnant in normal way
The zygote is obtained by invitro fertilization
Another woman is implanted with the couple zygote
(Surrogate mother) carries the baby only until it is born
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (h) Menstrual cycle is regulated by hormone which is secreted by pituitary gland and ovary.
Married woman usually plans their families by taking contraceptive pill.
Based on your knowledge in biology, explain how this pills react as with negative feedback to prevent pregnancy.
P1–Contraceptive pills contain (a combination of low) oestrogen and (high) progestron hormone
P2 – the pills should be taken between any day from the 1st -5th day of the menstrual cycle, for a duration of 21 days
P3–Oestrogen promotes/causes repair / growth of the endometrium (in preparation for implantation)
P4- Progestrone maintain the thickness of uterus lining
P5 –High level of progesterone inhibit the pituitary‟s production P6- no secretion of FSH / follicle-stimulating hormone
P7–no follicle develops in the ovary P8 –no Graafian follicle
P9 – less / no secretion of LH by the pituitary gland P10 – Ovulation is low / does not occur
P11 – no fertilisation occur 1 1 1 1 1 1 1 1 1 1 1 10 (i) Describe briefly the method of in vitro fertilization (IVF) in human.
P1 - Woman is injected with FSH hormone
P2 - stimulates growth / developments of follicle in the ovary
P3 – (A laparoscope is inserted at the navel to) collect immature ova /ovum from the ovaries // the immature ova/ovum are harvested from the ovaries
P4 - then, the ova are placed in (glassware with) culture solution to mature
P5 – Sperms are collected and placed in the culture solution . Fertilisation occurs. // the ova then, fertilised with the sperm
P6 – leave it within 2 days (48 hours) to enable the zygote to develops/ divide themselves into eight cells
P7 – the zygote / embrsyos are placed into the woman/mother uterus (by using a catheter) P8 – the embryos/zygotes are allowed to develop in her uterus until birth
1 1 1 1 1 1 1 1 6 (j) Based on your knowledge in biology, what are the moral issues related to this method?
M1 – Storage techniques used in IVF produces more than one zygote. What will happen to this zygote
M2 – If the uterus of the mother is not strong/ healthy, who is going to accept the zygote? What is the relationship between zygote/child with the surrogate mother
M3 – If the husband is infertile, who is going to donate the sperm? What is the relationship between zygote/child with the father
M4 – Unmarried women can have their own children / can get pregnant M5 – Tendency of choosing the children gender
M6 – There were cases where the surrogate mother develop emotional ties and refuse to be separated from their babies REJECT – RELIGIOUS ORDERS
1 1 1 1 1 1 6
No Marking Criteria Marks (l)
Based on your biological knowledge in reproduction technology, explain how the couple can have children
F : In-vitro technique
P1 : means fertilization occurs outside of the body
P2 : the wife injected with hormone to fasten the development of the secondary oocyte / ovum in ovary
P3 : secondary oocyte / ovum release out by using laparoscope (from ovary before ovulation)
P4 : sperms from husband fertilize with the secondary oocyte in a Petri dish (contains culture medium)
P5 : (after fertilization) zygote will divide by mitosis P6 : (after 2 days) formed embryo until eight cells stage
P7 : embryo transferred to the endometrium of the uterus wall through cervix (using pippet) P8 : embryo implant at the endometrium of uterus wall and develop
P9 : baby that is delivered is called test tube baby P10 : This technique is complicate
1 1 1 1 1 1 1 1 1 1 1 10 A couple, Mr Zafrie and Mrs Munirah had married almost ten years but still do not have
any child. After undergone an inspection, they found that the husband does not have any problem but the Fallopian tube of Mrs Munirah is blocked.
No Marking Criteria Marks (m) “In Malaysia, it is estimated that one baby is abandoned every 10 days in the
Klang Valley, and 100 babies abandoned every year nationwide.”
The Star Online, September 27, 2008 Discuss the advantages and the disadvantages in the application of science and technology in human reproduction in handling the issue.
Advantages:
F1 - Sterilise method; vasectomy / by cutting the vas deferens intestes
E1 - to prevent the sperms from going to prostate glands// ejaculation does not contain sperms F2 - use of (male) condoms
E2 - prevent / reduce chances of sperms from going into cervix / uterus
F3 - Use female diaphragm that covers the cervix // Use of female condom which is fitted inside vagina
E3 - Block entrance of sperms into the uterus // Prevent entrance of sperms into uterus // sexually transmitted disease
F4 - Contraceptive pills // Contraceptive implant// Depo-vera injection
E4 - prevent development of follicle // inhibit ovulation // difficulties in implantation of zygote F5- Morning after pill
E5- Prevent fertilization/
F6- Sterilization by cutting and tying the fallopian tube
E6- Prevent the egg travelling along the fallopian tube / sperms reaching the ovum. Any 8
Disadvantages:
B1 - Sterilising method cause permanent disabilities to produce sperm / ovum hence the person is not able to produce off springs anymore
B2 – Condoms; sometimes sperms can still penetrate therefore chances of getting pregnant is still there
B3 - Pills are unreliable because they have to be taken consistently
B4 - All these methods will cause teenages / unmarried adults to increase their sexual activities (because they are not afraid to get pregnant thus increasing the moral issues in the societies).
Any 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 6
A married woman has her uterus removed ,making it impossible for her to conceiving the natural process, If she still wants to have a baby with her husband, suggest what she can do. Justify the technique that can ba used by the couple to conceive 6
F-surrogate mother
P1-Another woman is utilized as a surrogate mother P2-the sperm and ovum are contribute by the couple P3-Ovum are fertilized in a petri dish /in-vitro
P4-Fertilized egg are allowed to develop to become embryo P5-embryo are transferred to the surrogate mother‟s uterus
P6-the surrogate mother become pregnant and the foetus develop in her uterus until birth Any 5 1 1 1 1 1 1 5
No Marking Criteria Marks (n) Diagram, 8.3(i) and (ii) show the methods related to human reproduction
Based on the diagram ,describe the method M1-IVF/In vitro fertilization
P1-a laparoscope is inserted at the navel to collected immature ovum form ovary P2-The ovum is placed in cultured solution to mature
P3-sperm are collected and added to the culture
P4-Fertilization occurs//sperms and ovum fused and develop into embryo P5-(after 2-4days) the embryo si transferred/inserted into uterus (through cervix)
M2-Diaphragm
P6-For female contraceptive method P7-inserted into vagina to cover the cervix P8-to stop sperm entering the uterus
M1+4P=5 M2+2P=3 1 1 1 1 1 1 1 1 1 8
4.5 Sexual reproduction in Flowering plants
No Marking Criteria Marks
(a) What is fertilization ?2
P1-Process where nucleus o f male gamete fuse with nucleus of female gamete P2-Both gametes are haploid
P3-Zygote diploid will form
4.5.1 The formation of pollen grains in the anther
No Marking Criteria Marks
(a) Diagram shows the formation of Y through process X in a typical plant
Name X and Y X:Meiosis Y:Pollen grains
1 1 2 (b) State two characteristic of Y
F1-Have 2 nuclei I.e. tube nucleus and generative nucleus F2-Hapliod
F3-Have very rough surface
1 1 1 3
(c) Name the process when Y is transferred to stigma
Pollination 1 1
(d) Explain how the process you named in (b) take place P1-Pollinating agent (wind/water/animal)
P2-transfer the pollen onto the stigma
P3-pollen grain will stick onto the surface of the stigma
1 1 1 2
(e) Based on the diagram, explain the formation of pollen grain F-Pollen grains are formed in anther, an anther has four pollen sacs
E1-Each pollen sac contains hundreds f cells called pollen mother cells (2n)
E2-Each pollen mother cell undergoes meiosis to produces four haploid pollen cells/micro pores (n)
E4-The nucleus of each microspores then divided by mitosis to form a tube nucleus and generative nucleus
1 1 1
Essay enhancement corner
No Marking Criteria Marks
(a) Diagram shows the transferring of pollen grains onto the stigma and fertilization between male and female gamete
Describe the process that take place in diagram 8
P1- Pollen grains transfer onto stigma
P2- By pollinating agent e.g. animal /water/wind
P3- Pollen grain will stick onto the stigma because stigma is sticky//pollen grain have rough surface
P4- The sucrose solution on the stigma stimulate pollen grain to germinate P5- Pollen tube will grow until it reaches the pore at the embryo sac /microphyll P6- Nucleus tube lead the elongation of pollen tube
P7- As nucleus tube moved forward ,generative nucleus followed behind P8- Generative nucleus undergoes mitosis to form 2 male gamete
P9- One of the gamete fertilized the egg cell in the embryo sac to form diploid zygote P10- The other male gamete fertilized 2 polar nuclei to form triploid endosperm P11- Both processes take place at the same time ,so it called double fertilization
1 1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (b) Sexual reproduction in plants involve the production of pollen grains and ovules
(a) By using a flow chart describe how pollen grains are formed in plants.
C1 C2 C3 C4
Able to describe how pollen grains are formed in plants
Pollen grains are male gametes (produced in the anther/pollen sac
(pollen sac) contains diploid pollen parental cell/ pollen mother cell/ microspore mother cell
(each pollen mother cell) undergoes meiosis
Producing 4 haploid microspores(n)
nucleus of (every) microspore undergoes mitosis forming two nuclei
The generative nucleus and the tube nucleus
Microspore with surfaces adapted for dispersion and is now called pollen
1 1 1 1 1 1 1 6
Pollen sac Pollen parental
cell
Meiosis
microspores
No Marking Criteria Marks (c)
Diagram (i) and (ii) shows the formation of pollen grain and development of the embyo sac .Describe both processes 8
Pollen grains
G1-Pollen is produced in the anther (which consists of four pollen sacs) G2-each pollen sac contain hundred of pollen mother cells which is diploid
G3-each mother cells undergoes meiosis to form four haploid microspores/cells/tetrad
G4-The nucleus of each cell/microspore/tetrad indergoes mitosis to form (pollen )tube and a generative nucleus
Embryo sacs
E1-Embryo sac mother cell (diploid /2n)undergoes meiosis to form four haploid cells /megaspores
E2-three of the/megaspores degenerate, leaving only one (in the ovule)
E3-Nuclues of megaspores undergoes mitosis three times to form eight haploid bnuclei E4-Three of eight nuclei migrate to one end of the cell to form antipodal cells
E5-Another two nuclei/polar nuclei move to the centre
E6-(near the opening of ovule /micropyle) one of three nuclei develops into egg cell/female flanked by two synergid cells
E7-The structure is known as embryo sac
1 1 1 1 1 1 1 1 1 1 1 10
No Marking Criteria Marks (d)
Based on diagram ,Describe the process that occurs in the anther P1 Pollen mother cells in the pollen sac are diploid cells
P2 These cells undergoes meiosis
P3 to produce four haploid microspores/ tetrad P4 Nucleus of each microspore divides by mitosis P5 Forming haploid tube nucleus and generative nucleus P6 These microspores develop into pollen grains
1 1 1 1 1 1 1 6 (e) Diagram shows the formation of pollen grain in anther of a plant
Based on the diagram, explain the formation of pollen grain F-Pollen grains are formed in anther, an anther has four pollen sacs
E1-Each pollen sac contains hundreds f cells called pollen mother cells (2n)
E2-Each pollen mother cell undergoes meiosis to produces four haploid pollen cells/micro pores (n)
E4-The nucleus of each microspores then divided by mitosis to form a tube nucleus and generative nucleus
1 1 1
4.5.2The formaiton of the embyyo sac in the ovule
No Marking Criteria Marks
(a)
Name the structure Y Mega spore/Embryo
1 1 2 (b) In diagram, complete and label the mature embryo sac
Based in diagram, Explain the formation of a mature embryo sac P1-Embryo sac mother cell divides by meiosis to form haploid cells
P2-(three haploid cell degenerate,while one haploid cell develop into a haploid megaspore P3-The nucleus in the mega spores divides 3 times mitotically ) to produce 8 haploid cells P4-One cell form the egg cell,2 cell form the polar nuclei.3 cells form the anti podal cells and 2 cells form the synergid cells
1 1 1
1 4
Fertilization in plant occurs when receive nucleus in pollen grain fused with the nucleus in embryo sac in ovule .Based on your biology knowledge ,explain the development of ovule to form mature embryo sac
F-The ovule develops form the ovarian tissue
E1-Inside the ovule is a central mass of parenchyma tissue/nucellus E2-only one diploid cell megaspores /embryo sac mother cell(2n) enlarges
E3-Embryo sac mother cell undergoes meiosis to form a row of four haploid/megaspores E4-three of the four megaspore enlarges and nucleus undergoes mitosis three times to form eight haploid nuclei
E5-The left megaspore enlarges and nucleus undergoes mitosis three times to form eight haploid nuclei
E6-Three of the eight (migrate to one end of the cell) to form antipodal cells, another two nuclei to form polar nuclei develops into an egg cell/female gamete/ovum and to synergids cell any 6 1 1 1 1 1 1 1 1 6
4.5.3Formation of the pollen tube, zygote and triploid
No Marking Criteria Marks
(a) Diagram shows the germination of pollen tube towards the embryo sac in flowering plants
Based on diagram 5.2, explain the fertilization process in embryo sac P1-One male gamete will fuse the egg cell to form a diploid zygote
P2-Another male gamete will fuse with 2 polar nuclei to form triploid nucleus P3-Both process take place at the same time //double fertilization occurs
1 1 1 3
(b) Reproduction in plants involves the fusion of male gamete and female gamete.diagram 4.2 shows a male gamete 4.3 shows the early stage of double fertilization in flowering
Based on the diagram name the structure S
Polen grain 1 1
(c) Explain what happen to structure S when it land on structure T F1-Sucrose solution /sugar on structure T stimulate germination of S F2-Pollen tube grows out the ovary
F3-It grows down (the style) into ovary F4-enter ovule through microphyle
1 1 1 1 3 T
No Marking Criteria Marks (e) Complete diagram 4.4 below to shows how double fertilization occurs
The diagram 4 shows the process of double fertilization in a flowering plants Criteria of the diagram :
Correct drawing with pollen tube enter through the microphyle end -1 Correct drawing of embryo sac with 2 polar nuclei and egg nucleus inside- 1 Correct drawing of pollen tube with 2 male nuclei with correct labels -1
1 1 1 3 (f)
Name the cells contains in Y that involves in double fertilization process
2 polar nuclei//1 egg cell 1 1
(g) How structure W cause the formation of structure X F-W rough sticky wall
E1-(sticky wall)stimulate the germination /elongation of structure X to embryo sac
1 1 2
(h) State the two nuclei found in the structure X
No Marking Criteria Marks (i) Describe briefly the movement of structure X
P1-X secretes enzymes to digest the surrounding tissue as it grows downward
P2-the direction of growth of structure X is controlled by the nucleus tube which at the tip of the structure
1 1 2
(j) Explain why the fertilization process is process is known double fertilization P1-because there are two fertilization
P2-First fertilization happen when one of the male gamete fuses with the egg to form zygote P3-The second fertilization happens when the other male gamete fuses with the two polar nuclei to form a triploid nucleus (3n)/endosperm
1
1 1 3
(k) Explain what happen happens to the structure Y after double fertilization? P1-Nuclues triploid /zygote triploid undergoes mitosis
P2-Then develop to endosperm P3-Zygote develop to embryo
P4-(endosperm) store the food for the development of embryo/seed germination
1 1 1 1 3
Essay enhancement corner
No Marking Criteria Marks
(a) The product form the process in (a) is transferred onto the stigma through pollination Explain the process that will occur in the style and ovary after pollination
P1 On the stigma, sugar stimulates pollen grains to germinate P2 Form pollen tube
P3 Pollen tubes grows into the style and towards the ovule, led by tube nucleus P4 Generative nucleus undergoes mitosis and form two male gamete nuclei P5 Pollen tube penetrates the ovule through micropyle
P6 Tube nucleus disintegrates
P7 One male nuclei fuses with the egg cells to form diploid zygote
P8 Another male nucleus fuses with the two polar nuclei to form triploid zygote P9 This process is known as double fertilization
P10 Triploid nucleus divide to form endosperm (ie nutritive tissues) P11 Diploid zygote divides and grows into embryo
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No Marking Criteria Marks (b) Diagram shows the proves of fertilization in flowering plants
Based on diagram describe how this process occurs 10
P1-Pollen grains have been released form the anther to the stigma for pollination by insect to wind
P2-When pollen grain lands on stigma, epidermal cell secrete sucrose solution P3-(sucrose solution) stimulates the pollen grain to germinate and pollen tube P4-the pollen tube grows down the style to ward th ovule
P5-it secretes enzyme to digest surrounding tissues as it grow downward
P6-The generative nucleus (follows behind it) divides by mitosis to form two male gamete nuclei
P7-the male gamete nuclei move down the pollen tube lead by the tube nucleus
P8-when the pollen tube reaches the ovary, it penetrates the ovule through the microphyle P9-The tube nucleus degenerates, leaving a clear passage for the male nuclei to enter the embryo sac
P10-one male gamete fuses with two polar nuclei to form triploid nucleus which divide by mitosis to form endosperm tissue
P12-this fertilization is called double fertilization any 10 point
1 1 1 1 1 1 1 1 1 1 1 10 Mature embryo sac
Ovary Pollen grains
No Marking Criteria Marks (c)
Based on the diagram ,explain how double fertilization occurs in the plant10
P1-Anther produces pollen grains .male gamete
P2-Polen mother cell (in the anther) undergoes meiosis to produce (four) megaspores (n)/haploid cells /tetrad
P3-Megaspores (n)/haploid cells /tetrad develop into pollen grains
P4-The nucleus of each megaspores (n)/haploid cell /divides by mitosis
P5-to form one tube nucleus and one generative nucleus
P6-When a pollen grain falls on the stigma
P7-Stimulates (the pollen grain to germinate to) form pollen tube
P8-(during the growth of pollen tube) the generative nucleus divides mitotically
P9-to produce two male gametes
P10- to the male gametes move/follow behind the tube nucleus (down the pollen tube until they reach the microphyle
P11-The tube nucleus disintegrates and the two male gametes enter the embryo sac
P12-(during double fertilization ), one male gamete fuses with the egg cell/ovum to form a diploid zygote and
P13-The other male gamete fuses with two polar nuclei to form a triploid nucleus (so double fertilization occurs) any 10
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