2.4 Movement in and out of cells

Question 1

WHy is differences in intracellular vs extracellular environments important

Answer 1

Ensures the cell contains the necesserary substances of the right concentration for survival. Therefore it needs to be different from the external environment. If these was no control, the cell would die

Question 2

Is there a greater sodium concentrataion on in intracellular concentration of muscle cells or the extracelluar concentration

Answer 2

Extracellular - 5-15 vs 145

Question 3

Is there greater concentration of potassium ions on the intracellular concentration or extracellular concentraiton of a muscle cell

Answer 3

Intracellular - 140 vs 5

Question 4

How is oxygen used in autotrophs vs heterotrophs

Answer 4

Used in autotrophs for aerobic respiration when rate of respiration exceeds rate of photosynthesis.

USed for aerobic respiration in heterotrophs

Question 5

Compare use of carbon dioxide in autrophs vs heteretrophs

Answer 5

Used in autotrophs in photosynthesis when the rate of photosynthesis exceeds rate of respiration.

Not required in hetertrophs

Question 6

How are nitrates used in autotrophs vs heterotrophs

Answer 6

Used as source of nitrogen for amino acid synthesis in both

Question 7

How are phosphates used in heterotrophs vs hetertrophs

Answer 7

Source of phosphorous for nucleotide synthesis in both

Question 8

How is calcium used in heterotrophs vs autotrophs

Answer 8

Component of plant cell walls in autotrophs, enzyme cofactor in heterotrophs

Question 9

Compare how other inorganic nutrients are used in heterotrophs ve autrotrophs

Answer 9

required for synthesis reactions in both

Question 10

compare how organic compunds are needed as inputs for heterotrophs vs autotrophs

Answer 10

Not required in autotrophs as manufactured by cell.

osme required in heterotrophs (e.g. gucose, some AA, lipids, as can not be manufactured by cell

Question 11

Compare oxygen as an output in hetero vs autotrophs

Answer 11

Released from autotrophs from photosynthesis when rate of photosynthesis exceeds rate of respiration.

not output in heterotrophs

Question 12

Compare carbon dioxide as an output in auto vs heterotrophs

Answer 12

Output from autotrophs from respiration and fermentation when the rat exceeds rate of photosynthesis.

Output in heterotrophs from aerobic respiraiton

Question 13

compare lactic acid as an output in auto vs heterotrophs.

Answer 13

Not normally produced in autotrophs.

Waste product of fermentation in heterotrophs

Question 14

compare output of ethanol in autotrophs vs heterotrophs

Answer 14

A product of fermentaiton in autotrophs

not normally produced in heterotrophs

Question 15

compare output of urea in auto vs heterotrophs

Answer 15

Not nomrally produced in autotrophs.

Nitrogenous waste product from breakdown of excess amino acids in heterotrophs

Question 16

define diffusion

Answer 16

movement of substances from a high concentration to low concentration until an equilibrium occurs

Question 17

is diffusion passive or active

Answer 17

passive as no energy is expended as particles move with concentration gradient

Question 18

Define
solute
solvent
solution

Answer 18

solute = particles that dissolve
solvent = liquid dong the dissolving
solution =resulting mixture

Question 19

What needs to happen when a substance is unable to pass through the phospholipid bilayer

Answer 19

Proteins within the cell membrane are able to select these substances and move them through

Question 20

Not only is the cell membrane semi-permeable, it is also…..

Answer 20

selectively permeable

Question 21

define facilitated diffusion

Answer 21

The use of a protein channel to speed up the diffusion process. These proteins are able to select molecules, bind with them and move them through. It is still considered passive as the molecules are moving with the concentration gradient

Question 22

define osmosis

Answer 22

The diffusion of water molecules from high-low concentration until an equilibrium occurs. across the cell membrane. The movement of water is dependant on the concentration of water molecules and solutes

Question 23

Define tonicity

Answer 23

Ability of an extracellular soluton to make water move in or out of a cell by osmosis

Question 24

Hypotonic =

Answer 24

Lower solute concentration than cell moving water into cell.

Effect: animal cells will lyse, plant cells will not lyse due to protection from the cell wall

Question 25

isotonic solution =

Answer 25

Same solute concentration as cell, no net movement of water across membrane

Effect: no change

Question 26

Hypertonic solution =

Answer 26

Has higher solute concentration than the cell, causing water to move out.

Effect: animal cell will shrivel, plant cell membrane will shrivel but overall shape is not affected due to cell wall

Question 27

Define active transport

Answer 27

Movement of substances against concentration gradient. This requires a protein carrier and requires ATP

Question 28

Name examples of active cell movement

Answer 28

Endocytosis (Phagocytosis and pinocytosis)
Exocytosis

Question 29

Define Endocytosis

Answer 29

Intake of large molecules by enclosing them in a vesicle. During this process the cell membrane invaginates around the particle forming a vesicle which then pinches off from the membrane and is taken into the cell

Question 30

What is phagocytosis

Answer 30

Intake of particles and sometimes called cell-eating. Once the food vacuole is within the cell, a lysosome contraining digestive enzymes attached to and breaks down the contents

Question 31

What is pinocytosis

Answer 31

Clel drinking, intake of liquids. It can be non-selective, such as the intake of extracellular luid, or selective such as the intake of fat droplets

Question 32

Define exocytosis

Answer 32

Secretion of materls produced by the cell. Substances are packaged by the golgi body into a vesicle. This vesicle then moves to the cell mebrane which it fuses to and then releases it’s contents

Question 33

Why is the cell membrane selectively permeable

Answer 33

Permeable to some materials but not other, whilst also being able to select substances to move

Question 34

What impacts the permeability of a substance

Answer 34

the permeability of a sybstance is dependant on it’s size and charge

Question 35

Provide and example of diffusion

Answer 35

Small hydrophobic molecules such as oxygen and carbon are able to pass through the lipid bilayer easily, without the need for energy

Question 36

Provide and exmaple of facilitated diffusion

Answer 36

Although water is a small molecule, it is hydrophilic, meaning it has trouble passing through the membrane. Hence there is a special channel protein called an aquaporin, allowing it to move rapidly across the membrane

Question 37

Provide an example of active transport

Answer 37

Glucose and amino acids are too large to pass through the membrane, hence they use a specific carrier protein, allowing it to pass through the membrane

Question 38

Give an exmapleof ions passing through the membrane

Answer 38

Atoms or molecules with a permanent charge are called ions. Because of their charge they are unabel tp pass through the membrane, hence they use a channel protein which opens in response to extracellular signals. This is facilitated diffusion

Question 39

As cells increase in size the SA:V

Answer 39

decreases

Question 40

Why do cells remain small in size

Answer 40

CReates a large SA:V, therfore increasing the efficiency of the intake of hutrients and removal of wastse

Question 41

Higher SA:V means

Answer 41

higher efficieny

Question 42

If the surface area to volume ration is too small…

Answer 42

the cell will have decreased rate of chemical exchange and could die