mitosis

Question 1

what structure do we find in the nucleus?

what molecule are these made from?

Answer 1

chromosomes which are made of the molecule DNA

Question 2

describe how chromosomes are contained in a body cell

Answer 2

Body cells contain 2 of each chromosome. they are paired.

Question 3

how many pairs of chromosomes do human body cells contain?

Answer 3

23 pairs of chromosomes

46 chromosomes in total

Question 4

the chromosomes of a gamete are…

Answer 4

certain cells called gametes have chromosomes which are not paired
(e.g human gametes have 23 single chromosomes)

Question 5

what do Chromosomes carry?

Answer 5

a large number of genes which determine many of our features

most human chromosomes contain hundreds of genes

Question 6

what is the cell cycle

Answer 6

where cells must be able to divide.

Question 7

what happens in the first stage of the cycle?

Answer 7

the DNA replicates to form 2 copies of each chromosome

Question 8

what happens during cell division

Answer 8

the cell grows and copies it’s internal structures such as mitochondria and ribosomes.

Question 9

what happens in the second stage of the cell cycle?

Answer 9

mitosis takes place

Question 10

when mitosis takes place, what happens to a cell dividing?

Answer 10

one set of chromosomes is pulled to each end of the cell. the nucleus also divides.

Question 11

what happens in the final stage of the cell cycle?

Answer 11

the cytoplasm and the cell membrane divide to form two identical cells.

Question 12

what is cell division by mitosis?

Answer 12

where we start with 1 cell which had 2 present chromosomes and at the end we got 2 identical cells, again, each with 2 chromosomes

Question 13

what does mitosis do?

Answer 13

it copies 1 cell into 2

Question 14

what are the functions of mitosis?

Answer 14

1. mitosis is essential for growth and development of multicellular (multicellular means a more than one cell) organisms (eg plants and animals).
2. when an organism repairs itself (eg when a broken bone heals).
3. for asexual reproduction

Question 15

what type of cells divide in mitosis?

Answer 15

eukaryotes

Question 16

why might mitosis occur in a body of a multicellular organism?

Answer 16

to repair and replace old worn-out cells with new ones

Question 17

what might a eukaryotic cell need to do during mitosis?

Answer 17

copy it’s own DNA when dividing

Question 18

what is produced when a cell divides by mitosis ?

Answer 18

2 genetically identical diploid daughter cells

Question 19

describe the relative mass of the DNA during mitosis

Answer 19

relative mass of DNA in nucleus increases as chromosomes are being copied

relative mass of DNA in nucleus rapidly decreases as cell is divided

Question 20

describe fully the steps of mitosis in order and names of each step

Answer 20

Interphase- the cell grows, performs routine life processes, and prepares to divide

Prophase - chromosomes are visible, nuclear membrane breaks down, spindle divers begin to form

Metaphase - sister chromatids line up at the centre of the cell

Anaphase - sister chromatids are pulled apart and move to opposite poles of the cell

Telophase - spindle fibres break down, nuclear membrane forms and chromosomes begin to uncoil and form chromatin

Cytokinesis - cytoplasm splits in 2 and cell divides

Question 21

what happens to the chromosomes at the telophase

Answer 21

they uncoil and form chromatin