Cell Structure

Question 1

What is the function of the plasma membrane?

Answer 1

Separates the intracellular components from the extracellular environment
Controls the movement of molecules into and out of cells and is important for cell-cell signalling and adhesion

Question 2

What is role of the mitochondrion?

Answer 2

Makes ATP

Question 3

What is the role of lysosomes?

Answer 3

Digest excess/worn-out organelles, food particles and engulfed viruses/bacteria
pH 4.5

Question 4

What is the role of the nucleus?

Answer 4

Responsible for housing the cell’s genome and RNA synthesis

Question 5

What is the role of the endoplasmic reticulum?

Answer 5

Interconnected network of tubules and vesicles that is the site of lipid, membrane and secretory protein synthesis

Question 6

What does the smooth ER do?

Answer 6

Fatty acid and phospholipid biosynthesis, detoxification

Question 7

What does the rough ER do?

Answer 7

Protein synthesis, facilitates protein folding and transport of all secretory proteins

Question 8

What is the role of the Golgi complex?

Answer 8

Process and package macromolecules such as proteins and lipids that are synthesised by the cell

Question 9

What is the role of peroxisomes?

Answer 9

Contain catalase which helps to convert peroxide to water
Break down very long fatty acids to produce acetyl groups

Question 10

What is the role of the cytoskeleton?

Answer 10

Internal support for organelles
Plays roles in important in both intracellular transport and cellular division

Question 11

What proteins form the cytoskeleton?

Answer 11

Microfilaments - actin filaments
Intermediate filaments
Microtubules - tubulin filaments

Question 12

What is the biosynthetic pathway?

Answer 12

Outward direction of material transport
ER to Golgi to Plasma membrane

Question 13

What is the endocytic pathway used for?

Answer 13

Regulated transport of receptors/ligands and lipids from the cell surface inwards and for either the degradation, recycling or transcytosis of these biomolecules in a specific manner

Question 14

What drugs help for patients with heart disease or hypertension?

Answer 14

Beta blockers - acts on catecholamine receptors

Question 15

What drugs are used to treat pain and what receptors do they work on?

Answer 15

NSAIDS - non steroids anti inflammatories
Act on eicosanoid receptors

Question 16

What drugs help treat skin cancer and what receptors do they work on?

Answer 16

Herceptin/Trastuzumab
Epidermal growth factor receptors (Her-2/neu/EGF-R2) inhibiting growth signalling pathways

Question 17

Give a brief synopsis of Huntington’s Disease.

Answer 17

Progressive, late-onset, neurodegenerative disease affecting 1/10000 humans. It is characterised by dance-like movements and personality changes. After a long illness, individuals with HD die from complications such as infections and choking.

Question 18

What is the gene, chromosome and protein associated with Huntington’s?

Answer 18

Gene - Htt
Chromosome 4
Huntington protein

Question 19

How does the abnormal Huntington’s gene cause the disease?

Answer 19

Usually has ~10-28 Glutamines repeated in tandem but individuals who suffer from the disease have additional glutamines (between 40 and 100 extra) - HttQ128

Question 20

How do the additional glutamines affect the individual?

Answer 20

Abnormal Htt-Q128 aggregates and is defective in binding protein Hip1, leading to endocytic defects
Consequences = increased apoptosis, perturbations in endocytosis and transcription and in the turnover of the Huntington protein

Question 21

What cell type is particularly sensitive to abnormal Htt protein and why?

Answer 21

Neurons
Caused by post-mitotic and thus cannot tolerate increased cell death without consequences for the individual