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Flashcards in Chapter 13 Deck (20):
1

Genetics

Study of heredity and variation

2

Heredity

Transmission of traits from one generation to next

3

What are genes composed of?

DNA

4

Somatic cells have how many pairs of chromosomes?

23

5

What do somatic cells consist of?

22 autosomes, 1 sex chromosome

6

A diploid cell has how many sets of chromosomes?

2

7

Why do homologs separate in meiosis I?

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

8

What does fertilization form?

Zygote

9

Why does meiosis create haploid cells?

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

10

What separates in meiosis I? Meiosis II?

I - homologous chromosomes
II - sister chromatids

11

In which process do diploid cells become haploid?

Meiosis I

12

Why does chromatin coil up?

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

13

What occurs in synapsis? What follows this process?

-Homologous chromosomes align gene to gene
-Crossing over, where nonsister chromatids exchange alleles of similar gene

14

What is chiasmata?

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

15

How many times are cohesins cleaved?

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

16

What is the original source of genetic diversity?

Mutations

17

What three mechanisms contribute to genetic variation?

-Independent assortment
-Crossing over
-Random fertilization

18

What is independent assortment?

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

19

What does crossing over create?

Recombinant chromosomes, which combine genes inherited from each parent

20

What is random fertilization?

Fact that any sperm can fuse with any ovum