osmosis, diffusion, active transport

Question 1

What are the factors making rate of diffusion faster

Answer 1

Thinner surface of the exchange
Higher concentration gradient
Larger surface area
Higher temperature

Question 2

What are the passive types of movement of particles

Answer 2

Osmosis, diffusion and facilitated diffusion

Question 3

Definition of osmosis

Answer 3

Net movement of water particles from an area of low concentration to high concentration through a partially permeable membrane

Question 4

What are the active types of movement of molecules

Answer 4

Active transport, Bulk transport, Endocytosis, Exocytosis

Question 5

What is the value of the highest water potential

Answer 5

The water potential of pure/distilled water Is 0kpa kilopascales So solutions with a lower water potential have a negative value

Question 6

What is water potential and what is it used for

Answer 6

It is the tendency of water molecules in a system to diffuse, Used to determine the net movement of water by osmosis by the difference in water potential

Question 7

Equation of water potential

Answer 7

Pressure potential + solute potential

Question 8

What a solute potential

Answer 8

The most solute added, the value for solute potential becomes more negative causing water potential to decrease also

Question 9

Solute potential is 250 and pressure potential is 200 what is water potential

Answer 9

-50

Question 10

-50 -10 -300 Which is the most dilute solution

Answer 10

-10

Question 11

-50 -10 Which direction would water pass

Answer 11

high to low concentration so -10 to -50

Question 12

What happened if insoluble molecules are in the solution

Answer 12

Insoluble molecules do not affect osmosis concentration

Question 13

hypertonic hypotonic and isotonic

Answer 13

Hypertonic (higher water conc in the cell) - Water has moved out, cell becomes plasmolyzed (shrinks)
hypotonic (Higher water conc out of the cell) - Water has moved in to the vacuole, cell It becomes turgid and may burst
isotonic - Same concentration inside and out So the cell stays flaccid

Question 14

Why does dissolving more solute decrease water potential And why is there only negative values

Answer 14

The water potential of pure water is zero and the addition of solute decreases water potential so all resolutions have negative order potential

Question 15

Why is it important to keep solute concentrations at the correct level

Answer 15

To help prevent excess water loss and to help maintain correct fluid balance for reactions which are necessary for many body processes

Question 16

What is an example of diffusion

Answer 16

Gas exchange Across respiratory surfaces like lungs of mammals

Question 17

Fick’s law: Rate of diffusion is proportional to:

Answer 17

Surface area X concentration gradient % thickness of membrane

Question 18

due to a flood There is now seawater on top of a plant, How would the plant be affected

Answer 18

Seawater has high salt concentration So low water concentration. Water from the plant undergoes osmosis from high to low concentration out of the plant. Therefore the plant cell shrinks and is plasmalised

Question 19

What is the difference between simple and facilitated diffusion

Answer 19

In simple diffusion small non polar molecules eg co2 and lipid soluble substances easily pass through the bilayer
In facilitated diffusion polar and charged molecules such as carbohydrates amino acids nucleotides and ions pass through the membrane

Question 20

Explain how polar molecules pass through the bilayer through facilitated diffusion

Answer 20

Through carrier or channel proteins

Question 21

How do carrier proteins assist in moving large molecules in and out of the cell

Answer 21

A specific shaped molecule can bind to the carrier protein change its shape making the protein release the molecule onto the opposite side of the membrane

Question 22

how do channel proteins assist in moving Small ions and polar molecules in and out of the cell

Answer 22

They opened to allow ions like na+ or cl- to pass through the membrane in response to the binding of a chemical messenger eg Ligand

Question 23

State two changes to the structure of the cell membrane that would increase rate of diffusion of polar molecules

Answer 23

More channel and carrier proteins
Largest surface area and thinner membrane

Question 24

Movement requires energy but diffusion requires none why is this

Answer 24

Diffusion does not require external energy sources Diffusion relies on kinetic energy from the natural random movement of particles

Question 25

What is an example turgor pressure

Answer 25

When a plant cell has lots of water (Is in a turgid state) the cell membrane is pushed against the cell wall

Question 26

What is active transport

Answer 26

Movement of particles against a concentration gradient, requires energy in the form of ATP

Question 27

Examples of processes that needs active transport

Answer 27

Absorption of minerals by plant root hair cells
uptake of glucose and amino acids in the small intestine
excretion of hydrogen ions in urea by kidneys
Exchange of sodium and potassium ions in neurons and muscle cells

Question 28

what is bulk transport endocytosis

Answer 28

Transport of large substances into the cell
Can be split into three processes:
phagocytosis (solids) pinocytosis (liquids) and receptor mediated endocytosis

Question 29

When is bulk transport used

Answer 29

when extremely large substances need to move through a cell membrane

Question 30

what is bulk transport exocytosis

Answer 30

Transport of large substances out of the cell
Vesicles fuse with the plasma membrane and release their content

Question 31

What are the steps of bulk transport

Answer 31

Invagination of cell membrane
Membrane folds until vesicle forms
Vesicle pinches off and moves into cytoplasm for further processing EG by lysosomes

Question 32

Why is it important for plants to go through Active transport from the soil in an area of low concentration of minerals

Answer 32

Plants need mineral ions to survive as concentration is higher in the root hair cells they will diffuse out of root hair cells but energy is required to move mineral ions against the concentration gradient

Question 33

Droplets of ink are dropped in water and start to spread why does this happen

Answer 33

Then moving from high concentration (the original droplet of ink) to low concentration (the surrounding water)

Question 34

What happens when potato cells have a lower water potential than the solution

Answer 34

They gain water by osmosis causing vacuoles to swell and the cell content to be pushed against the cell wall making the cell turgid

Question 35

What happens when potato cells have a higher water potential than the solution

Answer 35

The cells become flaccid so they will lose water by osmosis and they may become Plasmolyzed

Question 36

What’s the difference between an animal cell and a plant cell in a hypotonic solution

Answer 36

Water moves into the cells by osmosis,
Animal cells could burst
plant cells vacuole and cytoplasm push against the cell wall but don’t burst

Question 37

Why does a rate of oxygen consumption increase as rate of active transport increases

Answer 37

Active transport needs energy oxygen is used in aerobic respiration in the mitochondria to produce atp. this atp is used as energy to go against the concentration gradient So the more oxygen the more atp released so the more active transport can take place