4.1. Meiosis (Meiosis I and Meiosis II)

Question 1

• The form of cell division by which gametes, with half the

number of chromosomes, are produced.

Answer 1

Meiosis

Question 2

The fusion of a sperm and egg to form a zygote.

Answer 2

Fertilization

Question 3

Sex cells divide to produce _____

• Gametes have ____ the # of chromosomes.

Answer 3

gametes (sperm or egg); half

Question 4

Meiosis occurs only in ___ (testes or ovaries).
Male: spermatogenesis
Female: ___

Answer 4

gonads; oogenesis

Question 5

What phase??

• Similar to mitosis interphase.
• Chromosomes replicate (S phase).
• Each duplicated chromosome consist of two identical sister
chromatids attached at their centromeres.
• Centriole pairs also replicate.

Answer 5

Interphase I

Question 6

What phase???

• Nucleus and nucleolus visible.

Answer 6

Interphase I

Question 7

• Cell division that reduces the chromosome number by one-

half.

Answer 7

Meiosis I

Question 8

What phase??

• Longest and most complex phase (90%).
• Chromosomes condense.
• ___ occurs: homologous chromosomes come together to
form a tetrad.
• ___ is two chromosomes or four chromatids (sister and
nonsister chromatids).

Answer 8

Prophase I; Synapsis; Tetrad

Question 9

• Pair of chromosomes (maternal and paternal) that are

similar in shape and size.

Answer 9

Homologous Chromosomes

Question 10

Homologous pairs (\_\_\_) carry genes controlling the
same inherited traits.

Answer 10

tetrads

Question 11

Each \_\_\_\_ (position of a gene) is in the same position on
homologues.

Answer 11

locus

Question 12

Humans have 23 pairs of ______.

Answer 12

homologous chromosomes

Question 13

22 pairs of ____

01 pair of sex chromosomes

Answer 13

autosomes

Question 14

• A method of organizing the chromosomes of a

cell in relation to number, size, and type.

Answer 14

Karyotype

Question 15

Humans have 23 Sets of Homologous Chromosomes

Each Homologous set is made up of _____

Answer 15

2 Homologues.

Question 16

The ____ code for most of the offspring’s traits

Answer 16

Autosomes

Question 17

The ____ code for the sex of the offspring.

Answer 17

Sex Chromosomes

Question 18

If the offspring has two “X” chromosomes it will be a ____
If the offspring has one “X” chromosome and one “Y”
chromosome it will be a ___.

Answer 18

female; male

Question 19

are the sites of crossing

over.

Answer 19

Chiasmata (chiasma)

Question 20

this variation called ______ may occur between

nonsister chromatids at the chiasmata.

Answer 20

Crossing over (variation)

Question 21

: segments of nonsister chromatids break and reattach to the other
chromatid.

Answer 21

Crossing over

Question 22

• Shortest phase

* Tetrads align on the _____

Answer 22

Metaphase I; metaphase plate.

Question 23

phase where INDEPENDENT ASSORTMENT OCCURS

Answer 23

metaphase I

Question 24

What is the formula for combination?

Answer 24

“2^n”

Question 25

What phase??

• Homologous chromosomes separate and move towards the
poles.
• Sister chromatids remain attached at their centromeres.

Answer 25

Anaphase I

Question 26

What phase??

• Each pole now has haploid set of
chromosomes.
• Cytokinesis occurs and two haploid daughter
cells are formed.

Answer 26

Telophase I

Question 27

• No interphase II

or very short - no more DNA replication

Answer 27

Meiosis II

Question 28

All phases in meiosis are the same with mitosis. True or false??

Answer 28

True

Question 29

What separates during anaphase II?

Answer 29

sister chromatids

Question 30

How many haploid daughter cells are produced in Telophase II?

Answer 30

four haploid daughter cells

produced.

Question 31

• Important to population as the raw material for natural

selection.

Answer 31

Variation

Question 32

What are the three sexual sources of

genetic variation?

Answer 32

1. crossing over (prophase I)
2. independent assortment (metaphase I)
3. random fertilization

Question 33

A cell containing 20 chromosomes (diploid)
at the beginning of meiosis would, at its
completion, produce cells containing how
many chromosomes?

Answer 33

10 chromosomes (haploid)

Question 34

A cell containing 40 chromatids at the
beginning of meiosis would, at its completion,
produce cells containing how many
chromosomes?

Answer 34

10 chromosomes