8.1 Mitosis & Cell Division

Question 1

Nucleosome:

Answer 1

DNA wrapped around histones

Question 2

Nucleic acid:

Answer 2

Chain of nucleotides

Question 3

Cells need to divide for:

Answer 3

Growth

Tissue repair

Question 4

When a cell divides it is important that the daughter cells receive…

Answer 4

Exactly the same genetic information as the parent cell

Question 5

Cells divide to give exact copies of themselves by a process called…

Answer 5

Mitosis

Question 6

Division of somatic cells produces…

Answer 6

Daughter cells

Question 7

DNA is organised into…

Answer 7

Chromosomes

Question 8

A cell that is not dividing is said to be in…

Answer 8

Interphase

Question 9

Complex chromatin is…

Answer 9

Long threads of DNA wound around histones (protein molecules)

Question 10

DNA replicates during…

Answer 10

Interphase (cannot see anything happening in the cell at this stage)

Question 11

Chromosome is made up of…

Answer 11

Two chromatids held together by a centromere

Question 12

Chromosomes consist of two chromatids as the DNA

Answer 12

Replicates during interphase - one of the chromatids is the exact same copy of the one joined to it

Question 13

Uncoiled DNA is called…

Answer 13

Chromatin (between cell divisions)

Question 14

Coiling happens during…

Answer 14

Cell division

Question 15

Coiling is when…

Answer 15

DNA wraps tightly around proteins called histones

Question 16

Chromosome consist of two..

Answer 16

Identical halves (chromatids) connected together by a centromere
23 pairs one from mother other from father

Question 17

Chromatid is…

Answer 17

Half of one chromosome
Contains one complete set of info
Copies itself to make the other chromatid
2 chromatids = 1 chromosome
Sister chromatids (identical) formed prior to mitosis - DNA replication (S)

Question 18

Human diploid (2n) has…

Answer 18

46 chromosomes

23 identical pairs - homologous chromosomes (carry the same traits)

Question 19

Mitosis - first you duplicate DNA: why?

Answer 19

Have 2 pairs of 23 chromosomes
If cell splits, you will only have 1 pair
Duplicate DNA - if cell splits - still have 2 pairs

Question 20

Importance of mitosis for growth?

Answer 20

Sperm and ovum fuse together = Zygote
Cell is diploid (46chromosomes - one set from each parent)
Zygote then divides by mitosis so that ALL the cells in the new organism have exactly the same information
So all the new cells contain exactly the same alleles

Question 21

Importance of mitosis for repair:

Answer 21

If cells die or are damaged new cells need to be produced

It is important that the new are genetically identical as the cells they are replacing

Question 22

Importance of mitosis for asexual reproduction:

Answer 22

Only requires one parent
All the offspring produced are identical to the parent
Can be an advantage when the environmental conditions are not changing
Enables an organism to produce many offspring very quickly
Examples of vegetative propagation are growing new plants from bulbs, tubers or cuttings