AOS 1; THE PLASMA MEMBRANE DOT POINTS 1-3

Question 1

Define solute

Answer 1

Solute refers to the particles that are bing dissolved into a solvent

Question 2

Define solvent

Answer 2

Solvent refers to the substance that does the dissolving. water is known as the universal solvent

Question 3

what is osmotic potential

Answer 3

the tendency for water to move across a semi permeable membrane based on solute concentrations

Question 4

Define osmosis

Answer 4

is the net movement of water from an area of low solute concentration to an area of high solute concentration across a semi permeable membrane

Question 5

Define plasmolysis

Answer 5

is the rupturing of a membrane in a plant cell because water leaves the cell when placed in strong hypertonic solutions

Question 6

What is turgid referring to?

Answer 6

Is when a plant cell

Question 7

What is the phospholipid bilayer ?

Answer 7

is the primary structure of the cell membrane. The phospholipid bilayer is made up of non-polars fatty acid tails which are hydrophobic and then on the other end there are polar hydrophilic phosphate head. these two components are held together by glycerol

Question 8

define non-polar molecules

Answer 8

non- polar molecules are molecules which share electrons evenly

Question 9

define polar molecules

Answer 9

molecules which share electrons with another molecule unevenly

Question 10

How is the bi-layer created?

Answer 10

The reason that there are two phospholipid layer is so that the fatty acid tails can get as far from the water and closer towards other non polar molecules

Question 11

what does the term amphipathic mean?

Answer 11

that the compound had hydrophobic snd hydrophilic regions

Question 12

How can the fluidity of the membrane be modified?

Answer 12

The amount of double bonded fatty acids( unsaturated fat) in the phospholipid the bilayer can alter the fluidity making it more fluid.

Question 13

Why do unsaturated fatty tails make the bilayer more fluid?

Answer 13

due to the double bonds of unsaturated fats the fatty oil tails do not stack neatly together therefor creating a more fluid texture

Question 14

What is the purpose of carrier proteins?

Answer 14

allow the transportation of specific molecules which are hydrophilic and uncharged in or out of a cell by facilitated diffusion

Question 15

What is the purpose of channel proteins in the membrane?

Answer 15

channel proteins create a hydrophilic pore for water soluble molecules to pass through the membrane. to allow ions to pass through facilitated diffusion

Question 16

List 2 examples of substances which use facilitated diffusion via carrier proteins

Answer 16

• glucose

- amino acids

Question 17

List 2 eagles of substances which require the use of facilitated diffusion via protein channels

Answer 17

• sodium ions

- potassium ions

Question 18

What is facilitated diffusion?

Answer 18

Is an example of protein mediated transport. it is another form of passive transport and moves substances down their concentration gradient.

Question 19

How does temperature effect the integrity of the membrane?

Answer 19

As the temperature surrounding the cells increases the cellular membranes becomes less permeable until it ruptures

Question 20

Define endocytosis

Answer 20

endocytosis is the bulk transportation of materials into a cell

Question 21

How does endocytosis work ?

Answer 21

It occurs when part of the pasta membrane forms around particles ( either Phago or Pino) and pinches off too form a vesicle inside of the cytosol of cell.

Question 22

What is phagocytosis?

Answer 22

phagocytosis is the endocytosis movement of solid food particles

Question 23

What is pinocytosis?

Answer 23

is the endocytosis of materials in solution

Question 24

What is exocytosis?

Answer 24

The bulk transport of material out of the cell

Question 25

How does exocytosis work?

Answer 25

Vesicles formed by the Golgi apparatus fuse with the plasma membrane to either be recreated by the cell or voided by the cell

Question 26

Define hypertonic

Answer 26

when solution has a higher solute concentration than cell contents

Question 27

Define hypotonic

Answer 27

Is when solution has a lower solute concentration than cell contents

Question 28

define isotonic

Answer 28

when the solution has an equal solute concentration than cell contents

Question 29

What happens when an animal cell when it is in a hypertonic solution?

Answer 29

The cell will shrink till it becomes ruptured

Question 30

What happens to a plant cell in hypertonic solution?

Answer 30

the cell membrane will shrink within the cell wall. In strong hypertonic solutions plasmolysis will occur

Question 31

What is plasmolysis?

Answer 31

the rupturing of a membrane due to water leaving cellular membrane in strong hypertonic solutions

Question 32

What happens to an animal cell in a hypotonic solution?

Answer 32

The animal cell will increase in size due to the uptake of water until the membrane bursts

Question 33

What happens to a plant cell in a hypotonic solution?

Answer 33

The cell will swell until it becomes rigidly swollen (turgid) but will not burst because of the thick cell wall

Question 34

what can go through the cell membrane via simple diffusion?

Answer 34

non- polar, small, lipophilic( can dissolve in fatty acids) molecules, e.g. Oxygen, carbon dioxide, ethanol, urea

Question 35

What is the width of the cellular membrane ?

Answer 35

8nm

Question 36

Define simple diffusion

Answer 36

movement of molecules along the concentration gradient, this means molecules will move from an area of high concentration to an area of low concentration. it is passive therefor requires no energy. this continues until equilibrium is reached

Question 37

What are integral proteins?

Answer 37

are fundamental components to the plasma membrane. they are embedded in the bilayer

Question 38

What are peripheral proteins?

Answer 38

are either anchored to exterior plasma membrane through bonding with lipids or directly associated due to interaction with integral proteins

Question 39

function of cholesterol in plasma membrane

Answer 39

They help maintain the structure and flexibility