Sci 30 Chapter 2.1 a genetics defined INTRO

(1)

Genetics

• The last time you dealt with

genetics will have been in

Science 9 (unless you have

taken Bio 30) … so before

we begin let’s try some

Science 9 questions …

(2)

Q # 1

Labrador retrievers have 78 chromosomes in

each of their muscle cells.

Which biological process ensures that a male

Labrador retriever’s sperm cells will each have

39 chromosomes?

A. Mitosis

B. Meiosis

C. Selective breeding

D. Artificial selection

(3)

Q # 2

A benefit of asexual reproduction is that

it

A. produces many offspring

B. increases genetic diversity

C. increases species diversity

D. requires specialized structures

(4)

Q # 3

Physical Adaptations Observed in Four Organisms

I.Durum wheat is high in protein and gluten, which makes it suitable for use in pasta and bread.

II.The beak of a golden eagle is sharp and strong, which makes it useful for ripping and tearing meat.

III.The broad leaves on a maple tree make it efficient at gathering sunlight for photosynthesis.

IV.Wolves have large ridges of bone on the back of their skulls that allow the anchoring of strong jaw muscles.

Which physical adaptation is a result of artificial

selection?

A. I B. II C. III D. IV

(5)

Q # 4

Gregor Mendel, an Austrian monk, experimented with pea plants. He observed that when a plant that

produced round seeds was mated with a plant that produced wrinkled seeds, the resulting offspring produced only round seeds.

A conclusion that can be drawn from

Mendel’s experiment is that the

wrinkled-seed trait is

A. dominant and no longer part of the offspring’s DNA B. recessive and no longer part of the offspring’s DNA C. dominant and still part of the offspring’s DNA

D. recessive and still part of the offspring’s DNA

(6)

Q # 5

Which of the following heritable

human traits cannot be

influenced by the environment?

A. Height

B. Weight

C. Skin colour

D. Earlobe attachment

(7)

Q # 6

(8)

Q # 7

8

In the flowchart above, the stage at which

fertilization takes place is labeled

(9)

Q # 8

Which of the following human traits

is influenced by environmental

factors?

A. Mass

B. Blood type

C. Colour-blindness

D. Ability to roll tongue

(10)

Q # 9

A man and a woman who both have brown hair

have three children. Two of the children have brown hair and one child has blonde hair.

The gene that codes for brown hair (B) is dominant to the gene that codes for blonde hair (b).

The gene pair combinations of the

man and the woman are most likely

A. bb and bb B. Bb and Bb C. BB and Bb D. BB and BB

(11)

Q # 10

Which part of a cell carries

information about heritable traits?

A. A cell wall

B. A chloroplast

C. A chromosome

D. A cell membrane

(12)

Q # 11

Human cells normally have 46 chromosomes. Klinefelter syndrome results when human cells have 47 chromosomes.

Klinefelter syndrome is the result of a defect that occurs during

A. mitosis B. meiosis

C. artificial selection D. asexual reproduction

(13)

So … how did you do?

• We will be re-examining

these topics and expanding

on them in this Unit!

(14)

Genetics

Chapter 2 Page 77 Science 30

Wednesday, October 7, 2020

(15)

All the biodiversity in the world!

(16)

(17)

17

(18)

And if that’s not enough to make

you think about biodiversity …

(19)

And one more …

(20)

Locating Genetic Information Within the Cell

• Genetics is the science of gene function

and

inheritance

• Genetic information is found in the

nucleus

– the command centre in every cell to direct cellular activities

• Inside the nucleus we would find

chromosomes

– one DNA molecule wrapped around protein beads

(21)

DNA is made up of Genes

• a segment of DNA, recipe, template or pattern

• DEOXYRIBONUCLEIC ACID

• _{Universal molecule}_{: stores genetic information for}

all organisms

• Molecular fingerprint: unique to each individual (except identical twins)

(22)

How far along are we with

technology?

(23)

(24)

Analogy

Library

Cell with chromosomes with a

_{complete set of instructions}

(23)

Cookbook

One chromosome with different

_recipes

Recipe

1 gene = 1 template for protein

Language

DNA

_{make product = PROTEINS}

–

base pairs read by cell to

(25)

In picture form!

25

(26)

• DNA sometimes winds up and condenses making distinct

chromosomes visible under a microscope

(27)

(28)

Role of Protein (page

82-83)

• _{Humans have}

46 ₄₆

_{chromosomes and} 25,000 genes

– Therefore each chromosome has many genes.

– Each gene is the

recipe

for one protein

• The information encoded in the DNA is used to control cellular processes by

directing

the synthesis of proteins that carry out many functions

– Enzymes, antibodies, transporters such as hemoglobin, hormones, and some

structural components of cells and tissue.

(29)

Role of Protein

• Proteins made in a living cell determine

what the cell looks like and how it functions.

• All the proteins made in the cells of a

multicellular organism determine the

characteristics

of the organism.

• The major role of proteins in the human

body:

–

regulatory molecules (

_{regulatory molecules (}

ENZYMES

_ENZYMES

)

₎

–

_{structural molecules}

–

_{source of}

_ENERGY

(30)

Protein =

• long chain of amino

_{long chain of amino}

acids (polypeptide chain)

in a 3D shape which

determines its function

• Relationship between Proteins _{Relationship between Proteins}

and DNA

and DNA::

One Gene



One Protein

(31)

Summarizing the Roles of Proteins

Type

Role of Protein

Sample

Enzyme

_{Speeds up chemical}

reaction

Breaks something apart or

puts pieces together

Amylase

–

digestion

(starch)

Structural

_{Support and framework to}

attach to other proteins

Keratin (hair)

_{Collagen (skin)}

Transport

_{Materials moved within a}

cell or body

Channel

_{proteins in}

membranes

(32)

Summarizing the Roles of Proteins

Type Role of Protein Sample

Hormone

Signals to coordinate

activities

Insulin

–

regulates

blood sugar

Contractile

Contractile Changes shape – Larger movements if

proteins work together

Actin and Myosin in

muscles

Defensive

Protect body against

disease

Antibodies

Energy

Decomposition releases

energy

Casein in milk

(33)

Question … ?

• Why do we (humans) have different coloured

hair?

– Hair colour is determined by the amount of

pigment, (melanin – 2 types), that is present in your hair follicles

– The more you have… the darker your hair colour!

– As we age these pigments are no longer

produced in large quantities – gray / white hair – Your DNA determines what types of pigments

your hair follicles produce which determines you hair colour!

(34)

Genetic Diagnostic Technologies:

• Karyotype (page 80)

• _{Computer image of organized}

_{Computer image of organized}

chromosomes from one nucleus by

number, shape and size

• Genetics use three features to identify and

match up chromosomes:

–

_LENGTH

– Longest to shortest

–

PATTERN

_PATTERN

– when stained bands on chromosomes are in different places

–

CENTROMERE

_CENTROMERE

– position of constricted part

(35)

Karyotype

(36)

So what do you think?

(37)

Karyotype

• Each cell of the human body has 23 pairs

of chromosomes

– 22 of the pairs are called autosomes – Last pair are sex chromosomes:

• XX: female

• XY: male

(38)

Sex Chromosomes

Females have two

homologous

X-chromosomes

(39)

Males have only one

X-chromosome and a

Y-chromosome

MOM X X DAD

X XX XX Y XY XY

(40)

• The SRY gene is located on the Y-chromosome

• Around the 6th_week, the gene starts making SRY protein, which turn on other genes which produce other proteins, such as testosterone – a hormone which

stimulates the

development of male sex organs

(41)

X- chromosome inheritance

(42)

Amniocentesis (page 83)

• _Prenatal

_Prenatal

( before birth) test to look at the Karyotype of the fetus

• _{Purpose: to determine}

chromosomal

_chromosomal

abnormalities

and gender

• _{Factors that increase genetic abnormalities or} disease include

–

Mother

_Mother

’

s

age

–

History

_History

of

genetic diseases

(43)

New Technologies!

• New technologies are emerging and there are options to amniocentesis now

• Noninvasive prenatal test (NIPT)

(44)

Ultra sounds

• SOUND waves sent straight back down and

reflected back to produce an image of the fetus

(45)

New technologies! 3D ultrasounds

• Many sound waves sent at different angles to produce a 3D image of the fetus

• See surface and internal structures

45

(46)

Let’s look at some karyotypes!

(47)

Abnormal karyotypes: Klinefelter’s male

• _XXY

• 1 : 500 births

• Diagnosed through karyotyping

• XX chromosome fails to separate during meiosis in egg

• May not show any symptoms

– Reduced fertility

– Lower muscle mass – Less testosterone

(48)

Abnormal karyotypes: XYY male

• _{Extra Y}

chromosome

• 1:1000 births

• Increased growth rate



taller

• Normal development

• Diagnosed through

karyotyping

• YY chromosome fails

to separate during

meiosis in sperm

(49)

Abnormal karyotypes: Turner’s Female

• _XO

• 1:2000 births • Physical

abnormalities

– Short stature – Broad chest – Limb swelling – Sterile

– Webbed neck

(50)

Abnormal karyotypes: XXX syndrome

• _XXX

• 1:1000 births

• No symptoms or mild effects

– Tall stature

– Delayed speech and language

(51)

Abnormal karyotypes: Cri du Chat

• _{Chromosome #5}

defect

• 1: 50 000 births

• Due to problems with larynx and nervous system infants have a cry like a meowing infant which they grow out of by age 2

• Symptoms

– Severe cognitive delays – Low birth weight

– Poor growth

– Cardiac defects are common

(52)

Abnormal karyotypes: Patau’s Syndrome

• Extra

chromosome #13

• 1: 10 000 births

• Errors during cell division • Symptoms

– Severe problems to nervous system

– Polydactyly (extra digits) – Heart defects

– Kidney defects

– Low survival rate past infancy (80% die within first year of life)

(53)

Abnormal karyotypes: Edward’s Syndrome

• _{Extra chromosome}

#18

• 1:6000 births; 80% female

• Second most common trisomy after Down’s Syndrome

• Low rate of survival (few live births)

– Miscarriages/still births

– Days to 1 year, survival after 5 years is very rare

• heart, kidney malformations

(54)

Abnormal karyotypes: Down’s Syndrome

• _Extra

chromosome #21

• Trisomy 21 • 1:700 births

• Most common chromosomal abnormality

• Delayed cognitive ability • Facial characteristics

• Wide gap between first and second toes

• Short stature

(55)

Chromosomal abnormalities

• https://www.youtube.com/watch?v=YUPZzJ6Pe64

(56)