The cell

Question 1

What is compartmentalisation?

Answer 1

Allows for regions of the cell to coexist with different composition and function.

Question 2

What are the key characteristics of separators?

Answer 2

MEMBRANES!!!
Are water insoluble.
Non rigid/flexible (accommodate expansion/contraction).
Make use of amphipathic molecules.
Cause different regions to have different molecular compositions and thus different chemical reactions.

Question 3

How do phospholipid characteristics affect membranes?

Answer 3

Fatty acids -> Fluidity/flexibility.
Polar groups -> Chemical properties of surface.
Both -> Protein binding.

Question 4

What does a combination of: Fatty acid + Glycerol + Phosphate make?

Answer 4

Phosphatidic acid.

Question 5

How do non-polar, small molecules get into the cell?

Answer 5

Simple diffusion through the lipid bilayer.

Question 6

How do polar molecules get into the cell?

Answer 6

require transport proteins:
Pump (low->high).
Carrier (High->low).
Channel (High->low).

Question 7

How do Large molecular assemblies get into the cell?

Answer 7

vesicle formation/ membrane fusion.
Clathrin.

Question 8

How are microtubules formed?

Answer 8

Polymerisation of alpha and beta tubulin.
Grow in one direction.
have a positive and negative end.
Negative end attached to microtubule organising centre (MTOC), contains gamma tubulin.

Question 9

How are vesicles transported?

Answer 9

Kinesins and dyneins.
ATP dependent motor proteins.
Drag cargo along microtubules:
Towards positive end = anterograde.
Towards negative end = retrograde.

Question 10

Functions of nucleolus?

Answer 10

Synthesis of rRNA by ribosomal polymerase1.
Process of initial rRNA into smaller fragments.
Pre-assembles and exports ribosomes.
Many (viral) proteins “piggyback” on nuclear export.