Cell Division

Question 1

What is a homologous pair of chromosomes?

Answer 1

Two chromosomes that carry the same genes in the same loci

Question 2

What do two chromosomes that carry the same genes in the same loci form?

Answer 2

Homologous pair of chromosomes

Question 3

What begins to breakdown in prophase?

Answer 3

Nuclear membrane

Question 4

What does the nuclear membrane do in prophase?

Answer 4

Begins to breakdown

Question 5

Where do centrioles move to in prophase?

Answer 5

Poles of the cell

Question 6

What happens to chromatin in prophase?

Answer 6

Chromatin supercoils and condense in chromosomes

Question 7

What forms in metaphase?

Answer 7

Spindle fibres

Question 8

Where do spindle fibres attach in metaphase?

Answer 8

To the centromere of chromosomes

Question 9

Where do chromosomes align in metaphase?

Answer 9

At the equator

Question 10

What happens to spindle fibres in anaphase?

Answer 10

Spindle fibres shorten

Question 11

What splits in anaphase?

Answer 11

Centromere

Question 12

What is separated in anaphase?

Answer 12

Sister chromatids

Question 13

Where are chromatids pulled in anaphase?

Answer 13

To opposite poles of the cell

Question 14

What begins to reform in telophase?

Answer 14

Nuclear membrane

Question 15

What happens to chromosomes in telophase?

Answer 15

Chromosomes unwind

Question 16

What is a tumour?

Answer 16

Mass of cells/tissue OR Abnormal cells/tissue

Question 17

What causes a tumour?

Answer 17

Uncontrolled mitosis/cell division

Question 18

How do you determine a mitotic index from tissue observed with an optical microscope?

Answer 18

Count cells in mitosis in field of view; Divide this by total number of cells in field of view; Repeat many/at least 5 times

Question 19

How can fields of view be selected when determining mitotic index?

Answer 19

Select (fields of view) at random

Question 20

What should a student do to ensure mitotic index accuracy?

Answer 20

Examine large number of fields of view / many cells

Question 21

Why examine a large number of fields of view?

Answer 21

To ensure representative sample

Question 22

What else should a student do to ensure accurate mitotic index?

Answer 22

Repeat count

Question 23

Why repeat the count?

Answer 23

To ensure figures are correct

Question 24

How should part cells at the edge be counted?

Answer 24

Method to deal with part cells shown at edge / count only whole cells

Question 25

Why count only whole cells?

Answer 25

To standardise counting

Question 26

What is replicated in binary fission?

Answer 26

Replication of (circular) DNA; Replication of plasmids

Question 27

What divides in binary fission?

Answer 27

Division of cytoplasm (to produce daughter cells)

Question 28

How does viral replication start?

Answer 28

Attachment proteins attach to receptors

Question 29

What enters the cell in viral replication?

Answer 29

(Viral) nucleic acid enters cell

Question 30

What happens to viral nucleic acid in the cell?

Answer 30

Nucleic acid replicated in cell OR Reverse transcriptase makes DNA from RNA

Question 31

What does the cell produce during viral replication?

Answer 31

Cell produces (viral) protein/capsid/enzymes

Question 32

What happens after viral proteins are produced?

Answer 32

Virus assembled and released (from cell)

Question 33

What happens to DNA during late interphase before meiosis?

Answer 33

DNA replication

Question 34

How many divisions occur in meiosis?

Answer 34

Two divisions

Question 35

What separates in the first division of meiosis?

Answer 35

Separation of homologous chromosomes

Question 36

What separates in the second division of meiosis?

Answer 36

Separation of (sister) chromatids

Question 37

How many cells/nuclei does meiosis produce?

Answer 37

4 (haploid) cells/nuclei

Question 38

What do homologous chromosomes do in crossing over?

Answer 38

Pair up

Question 39

How are maternal and paternal chromosomes arranged?

Answer 39

In any order

Question 40

What process involves swapping portions of chromatids?

Answer 40

Crossing over

Question 41

What is exchanged in crossing over?

Answer 41

(Equal) portions of chromatids are swapped between chromosomes

Question 42

What does crossing over produce?

Answer 42

New combination of alleles

Question 43

When are chromatids separated after crossing over?

Answer 43

At meiosis II / later

Question 44

What do homologous pairs of chromosomes form during crossing over?

Answer 44

Bivalent

Question 45

What forms at the points of crossing over?

Answer 45

Chiasma(ta)

Question 46

What lengths are exchanged in crossing over?

Answer 46

(Equal) lengths of (non-sister) chromatids / alleles

Question 47

What does exchanging alleles produce?

Answer 47

New combinations of alleles

Question 48

How many divisions occur in mitosis vs meiosis?

Answer 48

One division in mitosis, two divisions in meiosis

Question 49

Are daughter cells genetically identical or different?

Answer 49

Daughter cells genetically identical in mitosis; genetically different in meiosis

Question 50

How many cells are produced in mitosis vs meiosis?

Answer 50

Two cells produced in mitosis; (usually) four cells produced in meiosis

Question 51

What happens to chromosome number in mitosis vs meiosis?

Answer 51

Diploid to diploid/haploid to haploid in mitosis; diploid to haploid in meiosis

Question 52

When are homologous chromosomes separated?

Answer 52

Only in meiosis

Question 53

Which process involves crossing over?

Answer 53

Only in meiosis

Question 54

Which process involves independent segregation?

Answer 54

Only in meiosis