A1 Cell Cycle

Question 1

How many stages of the cell cycle are there?

Answer 1

3.

Question 2

What are the three stages of the cell cycle?

Answer 2

Interphase, mitosis and cytokinesis

Question 3

What is the cell cycle?

Answer 3

The sequence of events that take place in a cell to prepare for cell divison

Question 4

What is interphase and its three phases?

Answer 4

The phase of the cell cycle in which the cell is preparing for divison
G1, S and G2

Question 5

What happens during G1?

Answer 5

Cell grows and increases in size, protein synthesis and energy is released

Question 6

What is mitosis and what happens during it?

Answer 6

Cell division in which the nucleus divides into nuclei containing the same number of chromosomes, two genetically identical daughter cells are produced

Question 7

What happens during G2?

Answer 7

A stage of interphase where the cell continues to grow and replicate organelles.

Question 8

What happens during S phase?

Answer 8

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated

Question 9

What is cytokinesis?

Answer 9

The division of cytoplasm and organelles to produce two genetically identical daughter cells

Question 10

What is cell potency?

Answer 10

A stem cell’s ability to differentiate specialised cell types.

Question 11

What are three types of potency levels?

Answer 11

Totipotent, pluripotent and multipotent

Question 12

What are totipotent cells?

Answer 12

Cells that can develop into any cell type including the placenta. They have a very high potency.

Question 13

What is a haploid?

Answer 13

A organism or cell that has only one complete set of chromosomes

Question 14

What is a diploid?

Answer 14

An organism or cell that has two sets of chromosomes

Question 15

What is a somatic cell?

Answer 15

A cell in the body which is not a gamete or undifferentiated cell

Question 16

What is a pluripotent cell?

Answer 16

Cells that can develop into any cell type not the placenta. It has a low potency.

Question 17

What is a multipotent cell?

Answer 17

Cells that can develop into multiple but limited cell types. They have a low potency.

Question 18

What are unipotent cells?

Answer 18

Cells that can only develop into one cell type

Question 19

What is a gamete?

Answer 19

A mature haploid male or female germ cell that is able to unite with another of the opposite sex in a sexual reproduction to form a zygote

Question 20

What is a gene?

Answer 20

A segment of DNA on a chromosome that codes for a particular polypeptide

Question 21

What is a locus?

Answer 21

Location of a gene on a chromosome

Question 22

What happens during cell cycle checkpoints and what is it?

Answer 22

Mechanisms that monitor the preparedness of a eukaryotic cell to advance through the various cell cycle stages

Question 23

What is a centromere?

Answer 23

An area where the chromatids of a chromosome are attached

Question 24

What are sister chromatids and what part of the cell cycle are they made?

Answer 24

Identical copies of a chromosome; full sets of these are created during the S sub-phase of interphase

Question 25

What does it mean when chromosomes are bivalent?

Answer 25

A pair of homologous chromosomes

Question 26

What does mitosis use?

Answer 26

Growth, repair and asexual reproduction

Question 27

What are the stages of mitosis?

Answer 27

Prophase, metaphase, anaphase and telophase (PMAT)

Question 28

What happens during prophase?

Answer 28

Chromosomes condense and become visible, nuclear envelope dissolves

Question 29

What happens during metaphase?

Answer 29

Chromosomes line up in the middle of the cell. Spindle fibres start to form.

Question 30

What happens during anaphase?

Answer 30

Sister chromatids separate and move to opposite ends of the cell

Question 31

What happens during telophase?

Answer 31

Chromosomes unwind and the nucleus starts to reform

Question 32

What is meiosis and what happens during it?

Answer 32

Nuclear division that produces gametes, 4 genetically different haploid daughter cells are produced. There are two nuclear divisions.

Question 33

Where does meiosis occur?

Answer 33

It occurs in the testes and ovaries

Question 34

How is variation achieved in meiosis?

Answer 34

Crossing over, random assortment and random fusion

Question 35

What happens during fertilisation and what does it ensure?

Answer 35

When two haploid gametes fuse the diploid chromosome number is restored. This ensures that in sexual reproduction fusion of haploid gametes restore the original chromosome number (diploid) and that chromosome numbers are kept constant

Question 36

What are the stages of meiosis?

Answer 36

Meiosis 1, meiosis 2, crossing over, prophase 1, independent assortment, metaphase 1, anaphase 1, telophase 1, prophase 2, metaphase 2, anaphase 2 and telophase 2

Question 37

Give 3 examples of differences between mitosis and meiosis

Answer 37

Mitosis has one nuclear division, meiosis has 2 nuclear divisions Mitosis is used for growth and repair and meiosis for the production of gametes Meiosis has crossing over and independent segregation which occurs in meiosis 1 and mitosis has no crossing over or independent segregation