Module: Herdity and Variation

Question 1

what is heredity?

Answer 1

the transfer of traits or characteristics from both parents to the offspring.

Question 2

what are chromosomes?

Answer 2

thread-like structures that are found in the nucleus of cells, made up of 2 chromotids, and contain DNA.

Question 3

list the 2 parts of the chromosome

Answer 3

• chromotid
• centromere

Question 4

explain what is meant by haploid and diploid chromosomes

Answer 4

• body cells that contain 46 (2n) chromosomes are called diploids
• body cells that contain 23 (half of 2n= n) are called haploids

Question 5

what are genes?

Answer 5

a part of a chromosome that determines a particular characteristic of an individual.

Question 6

list the main function of genes

Answer 6

to control many characteristics such as hair colour, skin colour, eye colour, blood type, gender, and face shape.

Question 7

what are homologoues chromosomes?

Answer 7

(2) chromosomes that contain the same genetic sequencing

Question 8

what is the cell cycle?

Answer 8

the sequence of events that occur when a new cell is being created

Question 9

what are the 2 type of cell division

Answer 9

• mitosis
• meiosis

Question 10

what is mitosis?

Answer 10

the creation of 2 daughter cells from one parent cell

Question 11

list the 5 stages of mitosis

Answer 11

1. interphase
2. prophase
3. metaphase
4. anaphase
5. telophase

Question 12

what are the 3 things that happen during interphase? [mitosis]

Answer 12

• DNA is replicated
• the cell receives nutrients
• organelles synthesize and allow the cell to grow

Question 13

what 3 things happen to the cell during prophase? [mitosis]

Answer 13

• chromatin threads condense to form chromosomes
• the nucleus surrounding the chromosomes will disappear
• centrioles appear and start producing rod-like structures called spindle fibers

Question 14

what 2 things occur in the cell during metaphase? [mitosis]

Answer 14

• the chromosomes align themselves in a vertical line- in the center of the cell
• the centrioles travel to opposite poles and emit spindle fibers to the centromeres of the chromosomes

Question 15

what 3 things occur during anaphase? [mitosis]

Answer 15

• the spindle fibers are retracted by the centrioles
• the chromosomes split/are torn apart leaving each chromatid to each centriole
• the cell elongates

Question 16

what 4 things occur during telophase? [mitosis]

Answer 16

-the spindle fibers disintegrate
- the nuclear membrane reforms around each chromosome- reforming the nucleus
- the chromosomes uncoil and reform chromatins (thin thread-like structures)
- a cleavage forms between both nuclei and splits into 2 daughter cells - containing the same DNA

Question 17

list the 2 advantages of mitosis

Answer 17

• provides growth and repair for tissues
• important to organisms that can only produce asexually.