Heredity - Unit 6

Question 1

What are homologous chromosomes?

Answer 1

The two copies of each autosome. (any chromosome that is not a sex chromosome.)

Question 2

What is a diploid?

Answer 2

Cells with two copies of each chromosomes are diploid.

Question 3

What is the abbreviation of Diploid?

Answer 3

Diploid is abbreviated as 2n.

Question 4

In humans what is the 2n number?

Answer 4

In humans, the 2n number is 46.

Question 5

What cells are haploid?

Answer 5

Sperm and egg cells are haploid.

Question 6

What is the abbreviation of Haploid?

Answer 6

Haploid is abbreviated to n

Question 7

What is the Haploid number in humans?

Answer 7

In humans, the n number is 23.

Question 8

What results in a 2n new organism?

Answer 8

When a n sperm cell unites with a n egg cell, a 2n new organism results.

Question 9

When does Meiosis occur?

Answer 9

Occurs during the formation of gametes(sperm and egg cells).

Question 10

What happens during Meiosis?

Answer 10

The number of chromosomes is reduced by 1/2.

Diploid cell —> 4 haploid cells

Question 11

How many steps does Meiosis occur in?

Answer 11

Meiosis occurs in 2 steps:

1. Meiosis I
2. Meiosis 2

Question 12

What does Meiosis 1 result in?

Answer 12

Meiosis 1 results in 2 haploid daughter cells with duplicated chromosomes

Question 13

What happens in Meiosis 2?

Answer 13

Haploid daughter cells from Meiosis I divide, resulting in 4 haploid gametes with un-doubled chromosomes.

Question 14

What happens before Meiosis 1?

Answer 14

Interphase

Question 15

What 3 things happen during Interphase?

Answer 15

1. Cells increase in size
2. Cells synthesize (make) proteins
3. Cells replicate DNA

Question 16

What are the 4 stages of Meiosis 1? (PMAT)

Answer 16

1. Prophase 1
2. Metaphase 1
3. Anaphase 1
4. Telophase 1

Question 17

What happens during prophase 1?

Answer 17

Chromosomes condense, nuclear envelope breaks down, spindle forms.

Question 18

When does Synapsis occur?

Answer 18

Prophase 1

Question 19

What happens during Synapsis?

Answer 19

Homologous chromosomes come together to form a tetrad.

Question 20

What is a Tetrad?

Answer 20

Tetrad is two chromosomes or four chromatids (sister and non-sister chromatids).

Question 21

What happens during cross over?

Answer 21

Portions of chromatids break off and exchange places with corresponding portions of adjacent chromosomes.

Question 22

What is mixed during cross over?

Answer 22

Mixes DNA from maternal and paternal chromosomes.

Question 23

What happens during Metaphase 1?

Answer 23

Tetrads align on the metaphase plate.

Question 24

What happens during Anaphase 1?

Answer 24

Homologous chromosomes separate and move towards the poles.

Sister chromatids remain attached at their centromeres.

Question 25

What happens in Telophase 1?

Answer 25

New nuclear membranes are formed, chromosomes uncoil, and spindle breaks down.

Question 26

What happens during Cytokinesis?

Answer 26

During Cytokinesis two haploid daughter cells are formed. (But they have duplicated chromosomes)

Question 27

What happens during Anaphase 1?

Answer 27

Sister chromatids separate and they move towards the poles

Question 28

What 3 things happen during telophase 2?

Answer 28

1. Nuclei form
2. Nucleolus reappears
3. Spindle disappears

Question 29

How many haploid daughter cells are produced during telophase 2?

Answer 29

Four haploid daughter cells are produced.