Interim 2 review. Meiosis- forming sex cells Process in which haploid cells are formed from diploid cells In humans: Parent 4646 ParentDiploid (2N) Ovum2323.

Interim 2 review

Meiosis- forming sex cells

• Process in which haploid cells are formed from diploid cells• In humans:Parent 46 46 ParentDiploid (2N) Diploid

(2N)

Ovum 23 23 Sperm Haploid (N) Haploid (N)

Zygote 46 Diploid (2N)

Chromosome number cut in half

Fertilization

Mitosis vs Meiosis

Characteristic

Mitosis Meiosis

Cells produced

Body cells (somatic cells)

Sex cells (gametes)

Chromosome number

Same as parent cellDiploid 2N

Half number of parent cellHaploid N

Number of divisions

1 2

Number of cells produced

2 4

Meiosis

Meiosis I

Meiosis II

Meiosis

• During meiosis I, the ______________________ chromosomes separate.– What does this do to the chromosome number?

• During meiosis II, the sister ____________________ separate.

homologous

chromatids

Cut in ½

Meiosis I

Meiosis II

Prophase II Metaphase II Anaphase & Telophase II

Meiosis in Males and Females

• Males- results in 4 sperm cells• Females- results in one ovum (egg) and 3

polar bodies MALES FEMALES

4 Sperm cells 3 polar bodies 1 ovum

1st cell division

2nd cell division

• If three cells undergo meiosis in males, how many sperm cells will be produced? _____________

• If four cells undergo meiosis in females, how many ova (eggs) will be produced? _____________

• How many polar bodies would be produced for the same 4 cells? __________________

12

4

12

• If the 2N number of an organism is 32;• how many chromosomes are found in

a sperm cell? _______• how many chromosomes are found in

a diploid cell? _______• how many chromosomes are found in

an ovum? _______• how many chromosomes are found in

a haploid cell? _______• how many chromosomes are found in

a skin cell?________

16

32

16

16

32

• Sexual reproduction is important to the survival of the species because it adds genetic _________________________ to the population.

.

variation

Genetic variation

• Crossing Over- exchange of genetic information by non- sister chromatids during meiosis.

Mistakes in the Meiosis Nondisjunction- failure of chromosomes to

separate properly

Genetics Vocabulary

• ________________- the passing of traits from parents to offspring

• ________________- the study of heredity• _________________- rod-shaped structures

in the nucleus that transmits genetic information

• _________________- units of hereditary information found on the chromosomes

heredity

genetics

chromosomes

genes

Genetics Vocabulary• __________________- a gene that masks the

expression of another gene in a pair ( Symbol- capital letter)

• __________________- a gene in a pair that is hidden by the dominant gene (Symbol- lower case letter)

• ___________________- two genes in a pair that are identical. (RR or rr)

• _____________________- individual with one dominant and one recessive gene in a pair. (Rr)

dominant

recessive

homozygous

heterozygous

Genetics Vocabulary

• ______________________- either member of a pair of genes that determines a single trait.

• ____________________- the pair of alleles represented by the capital and lower case letters.

• ______________________- the trait that is actually expressed in an organism

allele

genotype

phenotype

• Immunity to poison ivy is a dominant trait while those people who get poison ivy show the recessive trait. Diagram a Punnett Square for a man who is heterozygous and a woman who get poison ivy.

1. What is the man’s genotype? ___________2. What is the woman’s genotype? ____________3. What is the probability of producing a child who gets poison ivy? __________4. What is the genotypic ratio?___________

Ii

ii

50%

1:1

I i

i

i

Ii

Ii

ii

ii

• Feather color in birds is an incomplete dominant trait. Genes for blue feathers and genes for white feathers combine to form birds with silver feathers. Diagram a cross for two silver feathered birds.

1. What is the parent’s genotype? ___________2. What is the phenotypic ratio? ____________3. What is the probability of producing bird with blue feathers? __________4. What is the probability of producing a bird with silver feathers?___________

BW

1:2:1

25%

50%

B W

B

W

BB

BW

BW

WW

• Blood type is a codominant trait. A man with blood type AO marries a female with blood type AB. 1. What are the genotypes

in the offspring? ___________________2. What is the genotypic ratio? ____________3. What is the phenotypic ratio? __________4. What is the probability of producing a child with blood type A? _______5. What is the probability of producing a child with blood type O? ______

AA, AO, AB, BO

1:1:1:1

2:1:1

50%

A O

A

B

AA

AB

AO

BO

0

• Eye color in canaries is a sex-linked trait. Black eyes are dominant and red eyes are recessive. A red-eyed female is crossed with a black-eyed male.

1. What is the male’s genotype? __________2. What is the female’s

genotype? _________What is the probability of

producing a 3. black-eyed female? _______4. black –eyed male? _______5. red-eyed female? ________6. red-eyed male? __________

XBY

Xb Xb

50%0

Xb Xb

XB

Y

XBXb

XbY

XBXb

XbY 050%

• Label the three parts of the nucleotide below.

A.______________

B.______________

C.______________

phosphate

sugar

base

In DNA, how do the bases bond?_____________ bonds with ____________

and_____________ bonds with ____________

Adenine Thymine

Cytosine Guanine

What is the name of the process in which DNA makes an exact copy of itself? __________________________Replication

Put the steps of DNA replication below in order.• 1. Free floating nucleotides attach to complementary

bases on both sides • 2. Sugars and phosphates join together on the new

strands• 3. DNA molecule unzips• 4. Two DNA molecules are produced each made of one

new strand and one template

________→ ________→ ________→ ________

3 1 2 4

Comparison of DNA and RNA

DNA RNA

Strands

Sugar

Base PairsLocation

2 1

deoxyribose ribose

A with T C with G

A with U C with G

nucleus Nucleus to cytoplasm

• Protein Synthesis is divided into two processes.

• Process 1- _____________________________-mRNA is made by copying the code from a DNA molecule.

This process occurs in the __________.

• Process 2-_____________________________- a protein is assembled from amino acids.

• This process occurs in the _______________ at a _____________________.

Transcription

nucleus

Translation

cytoplasmribosome

• Genetic information usually follows in one specific direction (Central dogma of biology). Which of the following BEST represents this flow?

• A.) DNA-->Protein-->RNA• B.) Protein-->RNA-->DNA• C.) RNA-->Protein-->DNA• D.) DNA-->RNA-->Protein

• Three bases on the mRNA molecule that code for one amino acid is a(n)

• A.) anti-codon.• B.) codon.• C.) tRNA.• D.) protein.

• Transcribe the section of DNA below.

G A C T T A C A G

C U G A A U G U C

• Label parts 1 through 5 in the diagram.

• 1. _______________ 4. _______________• 2. _______________ 5. _______________• 3. _______________

1

2

5

3

4

Amino acid

ribosome

tRNA

mRNA Protein

What is the name of the process in the picture?

_____________________

1

2

5

3

4

Translation

• A mistake in the genetic code is called a ____________________.

• Name the type of mutation in the DNA sequences below. Use these choices

Substitution Insertion Deletion• Original strand – CTGACT• New strand CTAGACT ___________________• New strand CTGCT ___________________• New strand CTGAGT ___________________

Mutation

Insertion

Deletion

Substitution

• ___________ ____________________ is a method used to separate and analyze DNA fragments.

• __________ ____________________ is the analysis of DNA fragments to identify an individual.

Gel Electrophoresis

DNA fingerprinting

s3cs s2s1 s5s4CS= crime scene DNAs1= suspect 1s2= suspect 2s3= suspect 3s4= suspect 4s5= suspect 5