Your Test is: ___________________________________________________
Go to mdk12.org, click on instruction, click on tool kit, click on biology, click on biology goal 3.0 concepts of biology: the indicators below are what you will be tested on, and on this review sheet is all review material
for the test. You should click on each indicator below, then click the PUBLIC RELEASE and PDF to see practice type questions
3.1.1 3.2.1 3.3.1 3.3.2 3.3.3 3.3.4
Unit 6 Review: Life is a Cycle, Family Tree, and All in the Family Review
DNA Structure and Function
-Recognize that DNA is a double helix that stores genetic information for assembling proteins and passing on genetic information.
-Recognize that DNA is an organic molecule classified as nucleic acids
-Identify nucleotides as the building blocks of DNA (three parts of nucleotide - sugar, phosphate, & nitrogen bases): the repeating units to form a DNA molecule
-The sugar in DNA is (deoxyribose)
-The bases are A,T,C,G
Remember Adenine pairs with Thymine and Cytosine pairs with Guanine
Know this picture of DNA
1=nitrogenous base 2=deoxyribose sugar 3=phosphate 4=nucleotide
DNA Replication
Recognize that the structure of the DNA molecule helps to ensure that genetic information is replicated exactly
Recognize that DNA must be duplicated before cell division to ensure each daughter cell receives its own genetic information
Results in two genetically identical molecules
Write out the complementary DNA strand: TTAACGTAT AATTGCATA
Interphase=Cell growth, DNA replication, Preparation for Mitosis
Cell division is a multistep process that involves preparation before the cell can divide. Every cell must first copy its DNA before cell division.
-Cancer is uncontrollable cell growth during interphase of the cell cycle
Mitosis:
Explain why cells produced through mitosis contain identical genetic information (chromosome number remains the same)
In order for a cell to undergo mitosis DNA must be copied
Recognize that repeated division of cells (mitosis) enables organisms to grow and make repairs
Results in to cells with the same number of chromosomes
-Cancer is uncontrollable cell growth during mitosis
Cancer and its relation to the Cell Cycle
-define cancer in order to explain how cancer is related to the cell cycle
-analyze the link between cancer and the cell cycle in order to explain how mutations can lead to cancer.
Cancer
Cancer cells do not respond to the signals that regulate the growth of most cells.
Cancer is unregulated cell growth.
Cancer occurs in cells with uncontrolled mitosis.
Cancer can affect all cell types.
-Interpret how the effects of DNA alteration can be harmful to the individual and/or society
-Recognize that cells exist within a narrow range of environmental conditions and changes to that environment, either naturally occurring or induced, may cause
Asexual Reproduction
-Analyze how traits are inherited and passed on from one generation to another in asexual organisms
-Explain that in asexually reproducing organism all the genes come from one parent (genetically identical)
-Investigate organisms that reproduce asexually to identify what traits they receive from the parent (binary fission, budding, vegetative, mitosis)
Key points for asexual reproduction
-Binary fission is a form of asexual reproduction that occurs in bacteria -Budding is a form of asexual reproduction that occurs in hydra and yeast
-Vegetative reproduction is a form of asexual reproduction that occurs plants like
strawberries and potatoes
Sexual reproduction
-Analyze how traits are inherited and passed on from one generation to another in sexual reproducing organisms
fertilization-restore chromosome number
-Explain that in sexually reproducing organism half of the genes come from each parent (variety of parent and offspring likeliness and differences)
Meiosis -Meiosis: process that forms gametes female (egg), single specialized cell form male (sperm)
- Chromosome number: reduced by half, so results in a haploid cell (n);
Meiosis Crossing Over
-results in 4 genetically different cells, new gene combinations
-Variety is generated by meiosis with the process of crossing over of the alleles
-Recognize that meiosis is the process that forms gametes
-meiosis produces four unique gametes, cro
fertilization -Investigate and explain how fertilization combines genetic material from two parents
-Identify male (sperm) and female (egg) gametes (1N)
-Recognize that gametes combine to form a zygote (1N +1N =2N)
-A zygote has twice the number of chromosomes as a gamete
-Recognize that the zygote is a genetically unique individual (genetic variation)
Vocabulary -Alleles: a gene that controls a characteristic
-Genes: chemical factor that determines traits
-Phenotypes: expression of inherited characteristics, organism’s appearance. ex(Blue Eyes)
-Genotype: genes or alleles carried on a chromosome Dominant: expressed form of characteristic ex)BB
Recessive: trait only expressed when to recessive alleles for same trait are inherited
Heterozygous: individual has 2 different alleles for a trait ex) Bb
Mendelian Genetics
-Explore evidence and describe how traits are hidden in one generation can be expressed in the next because cells contain two alleles of each genes
-Mendel discovered that each trait is controlled by two factors (alleles)
-Gregor Mendel’s Principle of Genetics applies to all organisms
Genes – factors that determine your traits
Phenotypes: expression of inherited characteristics, organism’s appearance. ex(Blue Eyes)
-Genotype: genes or alleles carried on a chromosome
Dominant: expressed form of characteristic
Recessive: trait only expressed when two recessive alleles for same trait are inherited ex) bb Homozygous: individual has two identical alleles for a particular trait
Heterozygous: (aka hybrid) individual has 2 different alleles for a trait ex) Bb
The principle of dominance states that some alleles are dominant and others are recessive. In complete dominance, dominant alleles are always expressed while recessive alleles can be hidden or masked.
The only combination of alleles that produces a recessive phenotype is homozygous recessive
Punnett Squares
Punnett Squares
-Explore the transmission of a single trait from one generation to the next generation -Used to predict and/or interpret the results of a genetic cross; translate genotypes in to
phenotypes T T (Parents TT* tt)
T t Tt
Tt Tt
-In the Parent generation, a true breeding tall plant is crossed with a true breeding short plant -Result is Offspring (F1) generation has Genotype: 100% Tt heterozygous and
Phenotype: 100% Tall
Punnett squares can be used to predict and compare genetic variations that results from a cross between two parents.
Punnett squares show the possible allele combinations that occur during fertilization between two parents’ gametes.
Each parent contributes one allele to an individual’s genotype. The alleles are sorted during meiosis when homologous chromosomes containing the same genes are separated into different gametes.
Punnett Squares Cross Two heterozygotes from cross above (aka F1 pea plants are crossed with each other or self-fertilized)
T T Tt
Tt tt
- Inside the 4 boxes are the possible genotypes (with respect to plant height) of the offspring from the F1 generation. Result is Offspring (F2) generation has
Genotype:
25% TT homozygous dominant 50% Tt heterozygous and 25% tt homozygous recessive Phenotype: 75% Tall and 25% short aka 3:1
-A punnett square shows possible results of a genetic cross, the genotypes of the offspring, and the alleles of gametes of each parent
Sex-Linked
X-Linked
--A trait carried by a gene on the sex chromosome, usually the x chromosome
-Most sex-linked traits are x-linked and recessive
-Recall sex chromosomes determine the individual’s sex; males have one X and one
Y(46, XY) and females have two copies of the X 46, XX) -Genes located on the X and The Y chromosomes are said to be sex-linked
-The human Y chromosome is much smaller than the human X chromosome. Thus the X
chromosome contains more genetic information than the Y chromosome. As a result X-linked genes are inherited in a different pattern than genes on autosomes.
-Males have just one X chromosome. Thus all recessive alleles are expressed in males. On the other hand, females have two X chromosomes. Thus recessive alleles are only expressed when she inherits two copies of the recessive alleles.
Recessive X-linked disorders, like colorblindness and hemophilia are more often expressed in males than females
Pedigrees -A pedigree is a chart used to analyze the pattern of inheritance of a trait across several generations
Only one trait is studied on each pedigree
Pedigrees are used to help parents understand the probability of having a child with a genetic disorder or specific trait
To Study Human heredity scientists use a pedigree chart. Pedigree Charts show relationships within a family so that inheritance of a trait can be traced though the generation. From this scientists can determine the genotype of most family members
-In order to read a pedigree it is important to know the symbols and what they represent
Male female marriage offspring
-In order to identify patterns of inheritance it is important to look for and identify specific trends:
Sheet to work out practice problems for our review
Use the pedigree below to answer the following question. In humans, the allele for having feet with normal arches is dominant (A). The allele for flat feet is recessive (a). The pedigree below shows the occurrence of normal arches and flat feet in four generations of a family.
1. What is the genotype of the Generation I parents? How do you know?
2. Create a punnet square of the cross
Between the generation 1 parents
Sex-linked Traits
1. Which sex is more likely have a recessive, sex-linked trait? Male or Female
2. Which parent do sons inherit recessive, sex-linked traits from? Mother or Father
