Cell Membranes II

Question 1

What does membrane functions rely on?

Answer 1

Depends on the structure.

Question 2

What are the functions of the membrane?

JETRAT

Answer 2

J unctions 
E nzymes
T ransport
R ecognition 
A nchorage
Transduction

Question 3

What does the cell membrane regulate?

Answer 3

Regulates the concentration of substances inside the cell.

Question 4

What molecules can move through the lipid bilayer?

Answer 4

Small and non - polar material.

Question 5

What are the two types of transport?

Answer 5

Active and Passive.

Question 6

Which solute carriers are used in active transport?

Answer 6

Uniport.
Antiport.
Symport.

Question 7

Which solute carriers are used in passive transport?

Answer 7

Uniport.

Simple Diffusion.

Question 8

Which two process are the reactive transport types that DO NOT involve membrane carriers?

Answer 8

Exocytosis.

Endocytosis.

Question 9

What is the definition of the concentration gradient?

Answer 9

Difference in concentration of a substance on two sides of a membrane.

Question 10

What are the main 3 types of passive transport?

Answer 10

Simple Diffusion
Osmosis
Facilitated Diffusion. (2 types)

Question 11

What are the 2 types of facilitated diffusion?

Answer 11

Channel Proteins

Carrier Proteins

Question 12

What is the difference between carrier mediated facilitated diffusion and simple diffusion?

Answer 12

Amount of solute that can be transported is HIGHER than the amount that can be transported without carrier simple diffusion.

Question 13

What is the definition of simple diffusion?

Answer 13

Movement of particles from HIGHER to LOWER concentration.

Question 14

What aids the diffusion of particles within the body?

Answer 14

Internal body temperature.

Question 15

Name some lipid soluble substances.

Answer 15

O2 / N2 / CO2 / Vit A / Vita D / Vit E

Question 16

What substance is of a higher concentration INSIDE the cell?

Answer 16

Carbon Dioxide

Question 17

What substance is of a higher concentration OUTSIDE the cell?

Answer 17

Oxygen

Question 18

What is the definition of osmosis?

Answer 18

Diffusion of water via a SEMI PERMEABLE membrane down the concentration gradient.

Question 19

What is an aquaporin and what is the purpose of it?

Answer 19

It’s a protein and allows water to pass through.

Question 20

Why can’t water pass through and instead needs to be transported via proteins?

Answer 20

Water is highly INSOLUBLE and therefore, selective permeability has to occur in order for water to pass through.

Question 21

What the 3 solution types?

Answer 21

Hypotonic Solution
Isotonic Solution
Hypertonic Solution

Question 22

What is a Hypotonic Solution?

Answer 22

Concentration of the solute is LOWER OUTSIDE than inside the cell.
Water moves INSIDE.
= Lysis occurs.

Question 23

What happens when water moves into the cell?

Answer 23

LYSIS occurs.

This is when the cell loses its shape and then, bursts.

Question 24

What is a Hypertonic Solution?

Answer 24

Concentration of the solute is HIGHER INSIDE than outside the cell.
Water moves OUTSIDE.
= Crenation occurs.

Question 25

What happens when water moves out of the cell?

Answer 25

CRENATION occurs. | This is when the cell loses its shape alongside its functions.

Question 26

What is an Isotonic Solution?

Answer 26

Balanced environment therefore, the cell can maintain its shape.

Question 27

What is facilitated diffusion?

Answer 27

Movement of substances through the membrane with the help of channel / carrier proteins.

Question 28

Which type of protein is less selective?

Answer 28

Channel proteins are LESS SELECTIVE than carrier proteins.

Question 29

What are channel proteins selective for transport of?

Answer 29

One or more specific ions / molecules.

Question 30

What is an example of facilitated diffusion : carrier mediated?

Answer 30

Glucose Transport.

Question 31

What are the key points regarding 'Glucose Transport'?

Answer 31

Conformational changes to the protein structure = Transport of glucose. Has bidirectional transport = Can move glucose in and out.

Question 32

How is the gradient maintained for glucose transport?

Answer 32

Maintained by phosphorylation.

Question 33

How can glucose uptake be increased?

Answer 33

Increase the number of the transporters.

Question 34

What is active transport?

Answer 34

Substances which move AGAINST the concentration gradient via protein channels. ENERGY NEEDED

Question 35

What is primary active transport?

Answer 35

Energy is derived from breakdown of ATP.

Question 36

What is an example of primary active transport?

Answer 36

Sodium - Potassium Pump

Question 37

Explain the procedure of a sodium - potassium pump.

Answer 37

1. Three binding sites for sodium ions on the portion of the protein that protrudes to the inside of the cell. 2. Two binding sites for potassium ions on the outside. 3. The inside portion of this protein near the sodium binding sites has adenosine triphosphatase (ATPase) activity.

Question 38

What is secondary active transport?

Answer 38

Energy derived secondarily from energy that has been stored in the form of ionic concentration differences or ionic substances between the two sides of a cell membrane, created originally by primary active transport.

Question 39

How does passive transport work in cellular sheets?

Answer 39

Passive transport through the membrane on the opposite side of the cell.

Question 40

How does active transport work in cellular sheets?

Answer 40

Active transport through the cell membrane on one side.

Question 41

How does endocytosis work?

Answer 41

External material is enveloped by cell membrane forming an intracellular vesicle.

Question 42

What is the aim of active transport?

Answer 42

To bring material into the cell that will be broken down or digested.

Question 43

What are the three types of endocytosis?

Answer 43

Pinocytosis / Phagocytosis / Receptor - Mediated Endocytsosis.

Question 44

What is autophagy?

Answer 44

Recycling organelles.