Cell Division

Question 1

Cells produced by mitosis are genetically ____ and cells produced by meiosis are genetically ____

Answer 1

Cells produced by mitosis are genetically identical and cells produced by meiosis are genetically different

Question 2

What is mitosis used for?

Answer 2

Growth, Repair and replacement of damaged cells, Asexual reproduction

Question 3

What happens in interphase?

Answer 3

Protein synthesis, DNA replication, organelles are made

Question 4

What happens in prophase?

Answer 4

Centrioles move to poles, chromosomes condense, nucleolus and nuclear membrane disintegrate

Question 5

What happens in metaphase?

Answer 5

Chromosomes line up on the equator, spindle fibres attach to centromeres

Question 6

What happens in anaphase?

Answer 6

Chromatids are pulled to the poles, centromere first

Question 7

What happens in telophase?

Answer 7

Chromosomes uncondense, spindle disintegrates, nuclear membrane and nucleolus reform

Question 8

How does cytokinesis differ in plant and animal cells?

Answer 8

In an animal cell the cytoplasm pinches inwards, in a plant cell a cell plate forms

Question 9

Uncontrolled mitosis leads to

Answer 9

Cancer/tumour formation

Question 10

What do haploid and diploid mean?

Answer 10

Haploid cells have no homologous pairs, diploid cells have homologous pairs

Question 11

Describe what happens in prophase 1 of meiosis

Answer 11

Same as in prophase mitosis, also homologous pairs come together to form bivalents and crossing over occurs at the chiasmata

Question 12

Describe what happens in metaphase 1 of meiosis

Answer 12

Bivalents line up on the equator, spindle fibres attach to centromeres. Random/independent assortment

Question 13

Describe what happens in anaphase 1 of meiosis

Answer 13

Whole chromosomes are pulled to the poles

Question 14

Describe what happens in telophase 1 of meiosis

Answer 14

In animal cells nuclear envelope reforms and cytokinesis occurs. There are two haploid cells

Question 15

Describe what happens in prophase 2 of meiosis

Answer 15

Centrioles replicate, new spindle formed at right angle to first

Question 16

Describe what happens in metaphase 2 of meiosis

Answer 16

Chromosomes line up on the equator, spindle fibres attach to centromeres. Random/ independent assortment

Question 17

Describe what happens in anaphase 2 of meiosis

Answer 17

Chromatids are pulled to the poles, centromere first

Question 18

Describe what happens in telophase 2 of meiosis

Answer 18

Chromosomes uncondense, spindle disintegrates, nuclear membrane and nucleolus reform. Four haploid cells produced.

Question 19

What three things cause variation during meiosis?

Answer 19

Crossing over in prophase 1, random/independent assortment in metaphase 1 and 2

Question 20

What is a homologous pair?

Answer 20

One chromosome from the mother, one from the father. They contain the same genes but may have different alleles

Question 21

What are centrioles, centromeres, chromatids and chromosomes?

Answer 21

Centrioles-organelle that forms spindle, Centromere- holds together chromatids to form chromosomes, Chromatids- Identical strands of DNA formed by replication, held together at the centromere to form chromosomes, Chromosomes- DNA wrapped around histone proteins.

Question 22

What are the three stages of interphase?

Answer 22

G1, S, G2