Cellular

Question 1

Site of protein synthesis

Answer 1

Ribosome

Question 2

Chloroplasts

Answer 2

Only found in plant cells contains chlorophyll.
Low light intensity = more chloroplasts
High light intensity = less chloroplasts

Question 3

plasma membrane / semi permeable

Answer 3

Is a phospholipid bi-layer

Question 4

Passive Transport (Doesn’t require energy)

Answer 4

Osmosis, facilitated diffusion, diffusion

Question 5

Active Diffusion (requires energy - against concentration gradient)

Answer 5

Cytosis ( Endo (pino and phago), exo)

Question 6

Diffusion (passive)

Answer 6

The random movement of particles in liquid(l) and gas(g) results in the net movement from an area of high [ ] to an area of low [ ].

Question 7

[ ] gradient

Answer 7

DIFFERENCE in [ ] between 2 solutions.
- higher [ ] gradient = faster rate of diffusion

Question 8

Factors affecting the rate of diffusion

Answer 8

• Size: small particles diffuse faster than big particles.
  -Temp: higher temp = faster diffusion of particles ( more kinetic energy)
  -State: (g) particles diffuse faster than (l).

SMALL molecules (O2, CO2, glucose) diffuse freely across the membrane, with the direction of movement depending on the [ ].

LARGE molecules (starch) prevented from diffusing.

Question 9

Facilitated diffusion (passive)

Answer 9

Special carrier /transport proteins embedded in the membrane -> provide channels for molecules to pass through.

carrier protein specific to a molecule (open at one end)
e.g glucose and O2
- High [ ] to low [ ] therefore passive.

Question 10

Osmosis

Answer 10

Movement of water across a semi-permeable membrane from an area of high water potential (low [solute]) to an area of low water potential (high [solute]).

Question 11

High water potential + Low [solute]

Answer 11

Fresh water

Question 12

Low water potential + High [solute]

Answer 12

seawater salt water (salt ions dissolved) therefore high [solute].

Question 13

Hypotonic solution
( low [solute] )

Answer 13

weak /diluted solution

Question 14

Hypertonic solution
( High [solute] )

Answer 14

strong /concentrated solution

Question 15

Isotonic

Answer 15

2 solutions with = [water+solute]

Question 16

Active transport

Answer 16

movement of particles from an area of [low] to [high]

Question 17

active where happens ?

Answer 17

Lots of active transport = cells with lots of mitochondria + uses lots of glucose + oxygen in respiration.

Question 18

Cytosis

Answer 18

Movement of large amounts of substances into + out of cells by the folding of membranes.

Question 19

Endocytosis

Answer 19

Taking of substances into the cell by infolding of the cell membrane.

Question 20

Pinocytosis

Answer 20

fluids are taken in via membrane pinching + forming vesicles.

Question 21

Phagocytosis

Answer 21

Large particles (food) taken in by the membrane flowing around the particle + closing off forming a food vacuole.

Question 22

Exocytosis

Answer 22

Removal of substances from cells essentially opp of endocytosis. energy is involved and therefore active.

Question 23

cell membrane impact of cytosis

Answer 23

Endocytosis removes part of the cell membrane.
Exocytosis adds to the cell membrane.

Question 24

Surface Area to Volume ratio

Answer 24

Cells need to be small due to their dependency on diffusion.
- When cells grow, their V ( cytoplasm, organelles) increases at a much faster rate than their S.A (Cell Membranes). Because v=cm3 and s.a= cm2

• As cells grow, the S.A: V ratio decreases, therefore less cell membrane for diffusion and more organelles require diffusion.

-Diffusion gets less efficient when cells exceed a certain size, diffused particles don’t reach the centre of the cell. So cell split into 2 new small cells which will have a high S.A : V ratio, therefore, higher rate of diffusion.