Chapter 13

Question 1

Genetics

Answer 1

Study of heredity and variation

Question 2

Heredity

Answer 2

Transmission of traits from one generation to next

Question 3

What are genes composed of?

Answer 3

DNA

Question 4

Somatic cells have how many pairs of chromosomes?

Answer 4

23

Question 5

What do somatic cells consist of?

Answer 5

22 autosomes, 1 sex chromosome

Question 6

A diploid cell has how many sets of chromosomes?

Answer 6

2

Question 7

Why do homologs separate in meiosis I?

Answer 7

So 2 of the same chromosome don’t go to same cell

Question 8

What does fertilization form?

Answer 8

Zygote

Question 9

Why does meiosis create haploid cells?

Answer 9

So a zygote can have 1 pair from mom and another from dad

Question 10

What separates in meiosis I? Meiosis II?

Answer 10

I - homologous chromosomes

II - sister chromatids

Question 11

In which process do diploid cells become haploid?

Answer 11

Meiosis I

Question 12

Why does chromatin coil up?

Answer 12

So not to tangle and break and so each cell receives the correct amount of genetic information

Question 13

What occurs in synapsis? What follows this process?

Answer 13

• Homologous chromosomes align gene to gene

- Crossing over, where nonsister chromatids exchange alleles of similar gene

Question 14

What is chiasmata?

Answer 14

Region where crossing over has occurred and that keeps the tetrad together

Question 15

How many times are cohesins cleaved?

Answer 15

Twice, one to separate homologs, another to separate sister chromatids

Question 16

What is the original source of genetic diversity?

Answer 16

Mutations

Question 17

What three mechanisms contribute to genetic variation?

Answer 17

• Independent assortment
• Crossing over
• Random fertilization

Question 18

What is independent assortment?

Answer 18

That there is a 50% chance that haploid cells after meiosis I receives either a maternal or paternal chromosomes due to the tetrads’ random assortment at the metaphase plate

Question 19

What does crossing over create?

Answer 19

Recombinant chromosomes, which combine genes inherited from each parent

Question 20

What is random fertilization?

Answer 20

Fact that any sperm can fuse with any ovum