Genetic Variation 1

Question 1

What are gametes?

Answer 1

Sex cells with half the number of chromosomes.

Question 2

What phase does crossing over happen?

Answer 2

Prophase 1

Question 3

What is a haploid cell?

Answer 3

A cell with n chromosomes (half)

Question 4

What is a diploid cell?

Answer 4

A cell with 2n chromosomes (whole)

Question 5

What happens during prophase I?

Answer 5

Pairing of homologous chromosomes, homologous chromosomes condense

Question 6

What is synapsis?

Answer 6

Binds homologous chromosomes together

Question 7

What happens during metaphase I?

Answer 7

Chromosome centromeres attach to spindle fibers, homologous chromosomes line up as a pair at the equator

Question 8

What happens during anaphase I?

Answer 8

Homologous chromosomes separate and move to opposite poles of the cell, 2n to n

Question 9

What are homologous chromosomes?

Answer 9

Same length,same centromere position, genes for same traits

Question 10

What happens during telophase I?

Answer 10

Chromosomes reach the cell’s opposite poles, cytokinesis occurs

Question 11

How many cells result from cytokinesis in meiosis?

Answer 11

4

Question 12

Why is meiosis important?

Answer 12

Provides variation

Question 13

When is genetic variation produced?

Answer 13

Crossing over, fertilization

Question 14

How is asexual reproduction different from sexual reproduction?

Answer 14

The organism inherits all of its chromosomes from one parent and is genetically identical.

Question 15

Why is sexual reproduction beneficial?

Answer 15

• Rate of good mutations is faster

- Progressive genes multiply faster over times than they do for asexual organisms

Question 16

What is one simularity between meoisis and mitosis?

Answer 16

They start with a diploid number of cells.

Question 17

What is the difference between somatic and stem cells?

Answer 17

Somatic: developed, might be used to maintain and repair tissue.
Stem: Have the potential to become any type of cell.

Question 18

True or false: is meiosis a cycle?

Answer 18

False

Question 19

What are cyclins?

Answer 19

Proteins that bind to CDKs

Question 20

What are sister chromatids?

Answer 20

Two halves of a duplicated chromosome

Question 21

During meiosis, when does the ploidy (number of sets of chromosomes) get reduced from diploid (2n) to haploid (n)?

Answer 21

Once telophase I of meiosis I is complete

Question 22

The somatic cells of a cat contain 38 chromosomes.

If a cat cell undergoes meiosis, how many chromosomes will be in the resulting cell?

Answer 22

19

Question 23

What occurs during meiosis II?

Answer 23

Separation of sister chromatids

Question 24

How many cells does mitosis yield?

Answer 24

2

Question 25

What are two things that make meiosis and mitosis different?

Answer 25

• mitosis is a cycle, meiosis is not.

- mitosis replaces damaged cells, meiosis produces gametes

Question 26

What is crossing over?

Answer 26

The exchange of genetic information between homologous chromosomes.

Question 27

Down syndrome occurs when there’s an extra chromosome at the chromosome 21 pair. How might Down Syndrome occur?

Answer 27

Sister chromatids fail to separate at chromosome 21 during anaphase II in a parent’s gamete.

Question 28

What is the order of mitosis?

Answer 28

Interphase, Prophase, Metaphase, Anaphase, Telophase

Question 29

What is the purpose of mitosis?

Answer 29

• replace damaged cells

- separate replicated DNA

Question 30

What happens when cells divide uncontrollably?

Answer 30

They are at risk of becoming cancerous