KA 5

Question 1

The cytoskeleton gives?

Answer 1

Mechanical support and shape to cells

Question 2

The cytoskeleton consists of different? Including?

Answer 2

Protein structures including microtubules, which are found in all eukaryotic cells

Question 3

Microtubules are? They radiate from the…

Answer 3

Hollow cylinders composed of the protein tubulin. They radiate from the microtubule organising centre (MTOC) or centrosome.

Question 4

Microtubules control the movement of?

Answer 4

Membrane-bound organelles and chromosomes

Question 5

Cell division requires remodelling of the?

Answer 5

Cytoskeleton

Question 6

Formation and breakdown of microtubules involves?

Answer 6

Polymerisation and depolymerisation of tubulin

Question 7

Microtubules form the?

Answer 7

Spindle fibres that are active during cell division

Question 8

The cell cycle consists of?

Answer 8

Interphase and mitotic (M) phase

Question 9

Interphase involves?

Answer 9

Growth and DNA synthesis including G1, a growth phase; S phase, during which the DNA is replicated; and G2, a further growth phase.

Question 10

Microtubules form the?

Answer 10

Spindle fibres that are active during cell division

Question 11

The cell cycle consists of?

Answer 11

Interphase and mitotic (M) phase

Question 12

Interphase involves?

Answer 12

Growth and DNA synthesis including G1, a growth phase; S phase, during which the DNA is replicated; and G2, a further growth phase.

Question 13

Mitotic phase involves?

Answer 13

Mitosis and cytokinesis

Question 14

In mitosis the chromosomal material is separated by?

Answer 14

The spindle microtubules.

Question 15

Mitosis is followed by? What occurs in this phase?

Answer 15

Cytokinesis, in which the cytoplasm is separated into two daughter cells.

Question 16

Mitosis consists of?

Answer 16

Prophase, metaphase, anaphase and telophase

Question 17

What occurs in Prophase?

Answer 17

DNA condenses into chromosomes each consisting of two sister chromatids. Nuclear membrane breaks down; spindle microtubules extend from the MTOC by polymerisation and attach to chromosomes via their kinetochores in the centromere region.

Question 18

What occurs in Metaphase?

Answer 18

Chromosomes are aligned at the metaphase plate (equator of the spindle).

Question 19

What occurs in Anaphase?

Answer 19

As spindle microtubules shorten by depolymerisation, sister chromatids are separated, and the chromosomes are pulled to opposite poles.

Question 20

What occurs in Telophase?

Answer 20

The chromosomes decondense and nuclear membranes are formed around them.

Question 21

Progression through the cell cycle is controlled by?

Answer 21

Checkpoints

Question 22

Checkpoints are?

Answer 22

Mechanisms within the cell that assess the condition of the cell during the cell cycle and halt progression to the next phase until certain requirements are met.

Question 23

Cyclin proteins that…

Answer 23

Accumulate during cell growth are involved in regulating the cell cycle

Question 24

Cyclins combine with and activate?

Answer 24

Cyclin dependent kinases (CDKs).

Question 25

Active cyclin CDK complexes phosphorylate proteins that regulate?

Answer 25

Progression through the cycle.

Question 26

If sufficient phosphorylation is reached?

Answer 26

Progression occurs.

Question 27

At the G1 checkpoint, retinoblastoma protein (Rb) acts as a? By doing what?

Answer 27

Tumour suppressor by inhibiting the transcription of genes that code for proteins needed for DNA replication

Question 28

Phosphorylation by G1 cyclin-CDK inhibits? What does this allow?

Answer 28

The retinoblastoma protein (Rb) This allows transcription of the genes that code for proteins needed for DNA replication

Question 29

Cells progress from G1 to?

Answer 29

S phase.

Question 30

At the G2 checkpoint what is assessed?

Answer 30

The success of DNA replication and any damage to DNA is assessed DNA damage triggers the activation of several proteins including p53

Question 31

What can p53 do?

Answer 31

Stimulate DNA repair, arrest the cell cycle or cause cell death

Question 32

A metaphase checkpoint controls?

Answer 32

Progression from metaphase to anaphase

Question 33

At the metaphase checkpoint, progression is? Until?

Answer 33

Halted until the chromosomes are aligned correctly on the metaphase plate and attached to the spindle microtubules.

Question 34

An uncontrolled reduction in the rate of the cell cycle may result in?

Answer 34

Degenerative disease

Question 35

An uncontrolled increase in the rate of the cell cycle may result in?

Answer 35

Tumour formation

Question 36

A proto-oncogene is a?

Answer 36

Normal gene, usually involved in the control of cell growth or division, which can mutate to form a tumour promoting oncogene.

Question 37

Apoptosis is triggered by?

Answer 37

Cell death signals that can be external or internal

Question 38

The production of death signal molecules from lymphocytes is an example of?

Answer 38

An external death signal.

Question 39

DNA damage is an example of an?

Answer 39

Internal death signal.

Question 40

External death signal molecules bind to a? And trigger?

Answer 40

Surface receptor protein and trigger a protein cascade within the cytoplasm

Question 41

An internal death signal resulting from DNA damage causes?

Answer 41

Activation of p53 tumour suppressor protein

Question 42

Both types of death signal result in the?

Answer 42

Activation of caspases (types of protease enzyme) that cause the destruction of the cell

Question 43

Apoptosis is essential during? To do what?

Answer 43

Development of an organism to remove cells no longer required as development progresses or during metamorphosis.