1.3 Transport In Cells

Question 1

diffusion

Answer 1

The net movement of particles or molecules from an area of high concentration to an area of low concentration

Question 2

Particles

Answer 2

Units of matter

Question 3

Concentration

Answer 3

A measure of how much solute, for example, is in a given volume of solvent

Question 4

Solute

Answer 4

A substance that dissolves in a solvent

Question 5

Solvent

Answer 5

Something that a solvent can be dissolved in

Question 6

Temperature

Answer 6

How hot/cold something is

Question 7

Osmosis

Answer 7

Movement of water particles from high concentration to a low concentration
Through a partially permeable membrane

Question 8

Membrane

Answer 8

Organelle that controls what enters and exits a cell

Question 9

Active transport

Answer 9

Movement of particles from low to high concentration, requiring energy

Question 10

What three things affect the rate of diffusion?

Answer 10

• temperature
• difference in concentration
• surface area to volume ratio

Question 11

Concept of concentration gradient

Answer 11

Particles will diffuse down a concentration gradient, from areas of higher concentration to areas of lower concentration, until they are evenly spaced
‘[from p. 8] The bigger the difference in concentration (i.e the steeper the concentration gradient) the quicker diffusion will occur.’

Question 12

The bigger the DIFFERENCE IN CONCENTRATION (i.e. the steeper the concentration gradient)…

Answer 12

The quicker diffusion will occur

Question 13

Explain why a bacterium can rely on diffusion for gas exchange but animals need a transport system

Answer 13

• bacterium is smaller
• has larger SA:V ratio
• therefore diffusion can occur quickly enough

Question 14

How does temperature affect rate of diffusion

Answer 14

As temperature increases particles gain more kinetic energy causing the particles to move more quickly, therefore diffusion happens more quickly.

Question 15

Diffusion adaptations in LUNGS IN MAMMALS

Answer 15

Good blood supply - concentration grad
Millions of alveoli in each lung - sa:v
Alveolus wall only one cell thick - diff pathway
Ventilation of the lungs - concentration grad

Question 16

Diffusion adaptations in SMALL INTESTINE IN HUMANS

Answer 16

Surface is folded to form villi and microvilli - sa:v ratio
Villi walls are one cell thick - diff pathway
Good blood supply - concentration grad

Question 17

Diffusion adaptations in GILLS IN FISHHHHHh

Answer 17

Many gill filaments - sa:v
Filaments very thin - diff pathway
Good blood supply - concentration grad
Water pumped over gills - concentration grad

Question 18

Diffusion adaptations in ROOTS AND LEAVES IN PLANTS

Answer 18

Many roots - sa:v
Root har cells are long - sa:v (because they’re long and thin)
Root hair cells are thin - short diff pathway
Leaves are flat and thin - diff pathway

Question 19

OSMOSISSISISISISISISISSISISISIISSSS

Answer 19

Is the movement of water molecules across a partially permeable membrane from a high water potential to a low water potential

Question 20

OSMOSIS MODLE ANSWER

Answer 20

Water will move VIA OSMOSIS from the __1__and into the __2__. This because the water potential of the solution of the __1__ is HIGHER (n.b. Remember to use comparative wording) than in the __2__.

Question 21

OSMOSIS model answer for no movement

Answer 21

No net movement of water particles as the water potential inside the _______ and the ______ is the same.

Question 22

Hypotonic solution

Answer 22

Solution outside has higher water potential

E.g. red blood cels will swell and burst :o
Plant cells like hypertonic solutions because the cell wall can withstand the pressure and it keeps the leaves stretched out flat and the stems upright

Question 23

Isotonic solution

Answer 23

Both sides have same water potential

E.g. red blood cells are normal :)
Plant cells not great but bearable

Question 24

Hypertonic solution

Answer 24

Solution inside has higher water potential than outside

E.g red blood cells shrivel and it affects o2 transport :(
Plant cells shrivel and WILTTTTT

Question 25

Active transport

Answer 25

A method by which particles can cross membrane against a concentration gradient, but this process requires energy