Unit 1

Question 1

Endoplasmic Reticulum

Answer 1

The endoplasmic reticulum forms a network of membrane tubules, continuous with the nuclear membrane.

Question 2

Golgi Apparatus

Answer 2

The Golgi apparatus is a series of flattened membrane discs.

Question 3

Lysosomes

Answer 3

Lysosomes are membrane bound organelles, that contain a variety of hydrolases that digest proteins, lipids, nucleic acids and carbohydrates.

Question 4

Vesicles

Answer 4

Vesicles transport materials between membrane compartments.

Question 5

Proteins

Answer 5

Proteins are polymers of amino acid monomers.

Question 6

Ligand

Answer 6

A ligand is a substance that can bind to a protein.

Question 7

Kinase

Answer 7

Kinase adds a phosphate onto the target protein. It catalyses the transfer of a phosphate group to other proteins.

Question 8

Phosphatase

Answer 8

Phosphatase encourages phosphates away from the protein. It catalyses the reverse reaction from kinase.

Question 9

ATPases

Answer 9

ATPases hydrolyse ATP

Question 10

Type 1 Diabetes

Answer 10

Failure to produce insulin

Question 11

Type 2 diabetes

Answer 11

Loss of insulin receptor function

Question 12

Resting Membrane Potential

Answer 12

Resting membrane potential is a state in which there is no net flow of ions ACROSS the membrane.

Question 13

Action Potential

Answer 13

Action potential is a wave of electrical excitation along a neuron’s plasma membrane.

Question 14

Retina

Answer 14

The retina is the area within the eye that detects light and contains 2 types of photoreceptor cells : rods and cones.

Question 15

Cytoskeleton

Answer 15

The cytoskeleton gives mechanical support and shape to cells.

Question 16

Microtubules

Answer 16

Hollow cylinders composed of the protein tubulin. They control the movement of membrane bound organelles and chromosomes. They form spindle fibres that are active during cell division.

Question 17

Degenerative disease

Answer 17

Caused by an uncontrolled reduction in the rate of the cell cycle.

Question 18

Tumour formation

Answer 18

Caused by an uncontrolled increase in the rate of the cell cycle.

Question 19

Proto-oncogene

Answer 19

A proto-oncogene is a normal gene, usually involved in the control of cell growth or division, but can mutate to form a tumour promoting oncogene.

Question 20

Prosthetic group

Answer 20

A prosthetic group is a non-protein unit, tightly bound to a protein and is necessary for the proteins function.

Question 21

Facilitated Diffusion

Answer 21

Facilitated diffusion is the passive transport of substances across the membrane through specific transmembrane proteins.

Question 22

Rods

Answer 22

Rods contain rhodopsin to detect low levels of light

Question 23

Cones

Answer 23

Different forms of opsin combine with retinal to give DIFFERENT photoreceptor proteins, each with a maximal sensitivity to specific wavelength : R G B UV

Question 24

External death signal

Answer 24

External death signal molecules bind to a surface receptor protein which triggers a protein cascade within the cytoplasm.

Question 25

Internal death signal

Answer 25

An internal death signal caused by DNA damage results in the activation of the p53 tumour suppressor protein.

Question 26

Caspases

Answer 26

Both types of cell death signals result in the activation of caspases that cause destruction of cells. Caspases digest and break down proteins.

Question 27

Prophase

Answer 27

Chromosomes condense and the nuclear membrane disintegrates

Question 28

Metaphase

Answer 28

Chromosomes move and line up along the metaphase plate on the equator

Question 29

Anaphase

Answer 29

Spindle fibres separate the sister chromatids

Question 30

Telophase

Answer 30

The separated chromosomes form daughter nuclei The chromosomes decondense 2 nuclear membranes form

Question 31

Cytokinesis

Answer 31

Division of the cytoplasm 2 daughter cells formed

Question 32

G1 checkpoint

Answer 32

Cell size is checked. Retinoblastoma protein acts as a tumour suppressor by inhibiting the transcription of genes that code for proteins needed in DNA replication. Phosphorylation by the G1 cyclin-CDK inhibits the Rb protein.

Question 33

G2 checkpoint

Answer 33

The success of DNA replication and any damage to DNA is assessed. DNA damage, triggers the activation of several proteins including p53 which can stimulate DNA repair, cell cycle arrest or cause cell death.

Question 34

Metaphase checkpoint

Answer 34

Controls progression from metaphase to anaphase

Question 35

Electrochemical gradient

Answer 35

The electrochemical gradient is a combination of the concentration gradient and the electrical gradient across the plasma membrane.