B2.2 Organelles and compartmentalisation

Question 1

what are organelles

Answer 1

discrete subunits of cells that are adapted to perform specific functions

Question 2

not organelles

Answer 2

cell wall - outside cell
cytoskeleton - not discrete
cytoplasm - semifluid and no specialised function

Question 3

organelles

Answer 3

nuclei
vesicles
ribosomes
plasma membrane

Question 4

no membrane

Answer 4

ribosomes
centrioles
nucleolus

Question 5

single membrane bound

Answer 5

vesicles
vacuoles
ser
rer
Golgi apparatus
lysosomes

Question 6

double membrane structure

Answer 6

nucleus
mitochondria
chloroplasts

Question 7

why is compartmentalisation of the cell is advantageous

Answer 7

allows -
- Enzymes and substrates to be localised and therefore available at higher concentrations
- Damaging substances to be kept separated
- Optimal conditions to be maintained for certain processes e.g. optimal pH for digestive enzymes
- The numbers and location of organelles to be altered depending on requirements of the cell

Question 8

Organelle Adaptations

Answer 8

• complex cells organelles can become specialised for specific functions
• These specialised organelles have specific adaptations to help them carry out their functions

Question 9

centrifuge

Answer 9

machine that separates materials by spinning

Question 10

differential centrifugation

Answer 10

cells put in tubes in a homogeniser and spun at a very high speed

causes heavy organelles to settle at the bottom and the light ones float

can continue happening until all of it is separated

Question 11

why does the nucleus have to be separated from cytoplasm

Answer 11

Keeping them separate ensures no unwanted interactions occur during protein synthesis.

Question 12

why does the cytoplasm have to be kept separate

Answer 12

separation of incompatible biochemical processes

Question 13

lysosomes kept separate

Answer 13

they contain digestive enzymes
so that they don’t digest vital parts of the cell, in turn killing it