Cell Division (chpt. 14)

Question 1

Cell continuity

Answer 1

All cells develop from pre existing cells

Question 2

Chromosome

Answer 2

A thread-like structure found in the nucleus made of DNA (which forms genes) and proteins

Question 3

Gene

Answer 3

A gene is a section of DNA that contains the instructions to make a protein

Question 4

Chromatin

Answer 4

Chromosomes that are not dividing

Question 5

How many chromosomes do humans have

Answer 5

46 chromosomes or 23 pairs

Question 6

Haploid cell

Answer 6

(n)
Has one set of chromosomes e.g. gametes

Question 7

Diploid cell

Answer 7

(2n)
Has two sets of chromosomes

Question 8

Homologous pairs

Answer 8

Two chromosomes of similar size with the same sequence of genes

Question 9

Cell cycle

Answer 9

The changes that take place in a cell during the period between one cell division and the next

Question 10

Interphase

Answer 10

• The phase in the cell cycle where it is not dividing
• Longest (90%)
• Makes new organelles
• Forms chemicals (enzymes, hormones)
• Chromosomes replicate

Question 11

Mitosis

Answer 11

Cell division where the parent cell divides to produce two daughter cells, each with the same number of chromosomes and identical to each other

Question 12

Mitosis

Answer 12

Cell division where the parent cell divides to produce two daughter cells, each with the same number of chromosomes and identical to each other

Question 13

Use of mitosis in single-cellular organisms

Answer 13

Asexual reproduction

Question 14

Use of mitosis in multi-cellular organisms

Answer 14

Growth & repair

Question 15

4 phases of mitosis

Answer 15

Prophase
Metaphase
Anaphase
Telophase

Question 16

Prophase of mitosis

Answer 16

Nuclear membrane starts to break down
Chromosomes contract and become visible
Spindle fibres start to form
DIAGRAM

Question 17

Metaphase of mitosis

Answer 17

Nuclear membrane is fully broken down
Chromosomes line up along the equator
Spindle fibres attach to the centromere
DIAGRAM

Question 18

Anaphase of mitosis

Answer 18

Spindle fibres contract pulling one chromosome to each pole of the cell
Cell elongates
Chromosomes become single stranded
DIAGRAM

Question 19

Telophase of mitosis

Answer 19

Nuclear membrane forms around the chromatin
Chromatin forms
Spindle fibres break down
Cleavage furrow forms in animal cells
Cell plate forms in plant cells
DIAGRAM:

Question 20

DRAW stages of mitosis (x4)

Question 21

Cleavage furrow

Answer 21

Forms in animal cells
Telophase (final stage of mitosis)

Question 22

Cell plate

Answer 22

Forms in plant cells
Telophase (final stage of mitosis)

Question 23

Meiosis

Answer 23

A form of cell division in which the daughter nuclei contain half the number of chromosomes of the parent nucleus
Usually gametes

Question 24

Functions of meiosis

Answer 24

Sexual reproduction
Allows for genetic variation

Question 25

Cancer

Answer 25

A group of disorders in which certain cells lose control over both the rate of mitosis and the number of divisions

Question 26

Carcinogen

Answer 26

Any environmental factor that mutates DNA
Carcinogen = cancer causing
E.g. tobacco smoke, radiation, viruses

Question 27

Examples of carcinogens

Answer 27

Tobacco smoke
Radiation
Viruses

Question 28

Benign tumour

Answer 28

A tumour that grows slowly and the adverse affects are usually to simply apply physical pressure to surrounding tissues
E.g warts, skin tags

Question 29

Malignant tumour

Answer 29

A tumour that consists of rapidly growing cells that invade and can destroy other tissues.

Question 30

Metastasis

Answer 30

Movement of malignant cells

Question 31

Name two types of biomolecules produced during interphase

Answer 31

• protein
• fat
• DNA or RNA (nucleic acid)
• carbohydrates

Question 32

Why do mature human blood cells not undergo cell division?

Answer 32

They have no nucleus