Mitosis + Meiosis

Question 1

What are the four stages of the cell cycle?
Summary of what happens in each

Answer 1

Growth 1 - cell grows
S phase - chromosomes replicate
Growth 2 - cell prepares for cell divison
Cell division - mitosis or meiosis

Question 2

What does diploid mean?
Where are they from?

Answer 2

Two copies of each chromosome
One maternal and one paternal

Question 3

What are the two arms of a chromosome?

Answer 3

P - short
Q - long

Question 4

What is at the end of each chromosome?
What are they?

Answer 4

Telomere
Repeat sequences

Question 5

Name the four types of centromere from the central to close to the top

Answer 5

Metacentric
Submetacentric
Acrocentric
Telocentric

Question 6

What is the appearance of chromosomes during metaphase?

Answer 6

Condensed
Different shapes and sizes

Question 7

How are chromosomes grouped? (3)
How many groups are there?

Answer 7

Size, position of centromere, local differences

7

Question 8

What groups are X and Y in?

Answer 8

C

G

Question 9

What type of banding is used to stain chromosomes?

Answer 9

G staining (giema staining)

Question 10

What occurs before a G stain is added?

Answer 10

Enzymatic digestion

Question 11

What is G banding used to identify? (3)

Answer 11

Translocations
Duplications
Loss of Y chromosomes

Question 12

What is turners syndrome?

Answer 12

One X chromosome missing

Question 13

How are chromosomes occupied in the nucleus?

Answer 13

Occupy distinct territories

Question 14

What do homologous chromosomes have the same of?

Answer 14

Same genes

Question 15

What are alleles?

Answer 15

Variants of the same gene

Question 16

How do sister chromatids and non sister chromatids compare?

Answer 16

Sister chomatids - same alleles
Non sister chromatids - different alleles

Question 17

What are somatic cells?

Answer 17

Cells of the body

Question 18

What happens in G1 phase?

Answer 18

Metabolic changes in preparation for cell division

Question 19

What happens in S phase?

Answer 19

DNA synthesis replicates the genetic material

Question 20

What happens in G2 phase?

Answer 20

Metabolic changes - assemble cytoplasmic materials for mitosis

Question 21

What happens in G0 phase?

Answer 21

Cell is not growing or dividing

Question 22

What happens in prophase?

Answer 22

Nuclear envelope dissolves
Nucleolus goes
Chromosomes condense
Spindle fibres form

Question 23

What happens in metaphase?

Answer 23

Spindle fibres attach to chromosomes
Chromosomes align

Question 24

What happens in anaphase?

Answer 24

Centromeres divide
Sister chromatids move to opposite sides

Question 25

What happens in telophase?

Answer 25

Nuclear envelope forms Chromosomes decondense Spindle fibres disappear

Question 26

What type of cells undergo meiosis?

Answer 26

Germline

Question 27

What type of cells are the start and end of meiosis?

Answer 27

Diploid Haploid

Question 28

What happens in prophase 1?

Answer 28

Nuclear membrane dissolves Chromosomes condense Homologous chromosomes pair up Crossing over occurs

Question 29

What type of chromosomes are formed after crossing over occurs?

Answer 29

Recombinant chromosomes

Question 30

What happens in metaphase 1?

Answer 30

Spindle fibres form Chromosomes line up in the centre

Question 31

What happens in anaphase 1?

Answer 31

Chromosomes migrate to opposite poles

Question 32

What happens in telophase 1?

Answer 32

Nuclear membrane reforms Chromosomes decondense Cytokinesis occurs

Question 33

What is the difference between meiosis 1 and 2?

Answer 33

No DNA replication in meiosis 2

Question 34

What happens before meiosis 1?

Answer 34

DNA replication

Question 35

What are the products of meiosis?

Answer 35

Four haploid daughter cells

Question 36

What does meiosis ensure/why is it important? How does this happen? (2)

Answer 36

Genetic diversity Random assortment of chromosome Crossing over

Question 37

What is meiosis in sperm cells called?

Answer 37

Spermatogenesis

Question 38

What are the four stages sperm cell in spermatogenesis?

Answer 38

Spermatogonium Primary spermatocyte Spermatids Mature sperm

Question 39

What is the process of meiosis in oocytes?

Answer 39

Oogonium Primary oocyte Polar bodies Mature ovum

Question 40

What is the condition in which a haploid organism has an abnormal number of chromosomes?

Answer 40

Aneuploidy

Question 41

What causes aneuploidy?

Answer 41

Non-disjunction - failure to separate pairs of chromosomes lined up at the metaphase

Question 42

What causes Down syndrome?

Answer 42

Non-disjunction Trisomy of chromosome 21 (3)