3.2.3 Transport Across Cells

Question 1

Do plants have cell membrains

Answer 1

Yes

Question 2

Do bacteria have cell membrains

Answer 2

Yes

Question 3

Name four substances needed for a cell and what there function is

Answer 3

Water - metabolic reactions
Amino acids - protein synthesis
Glucose - respiration
O2 - aerobic respiration
Lipids - cholesterol

Question 4

Why does soup dissolve the membranes easily

Answer 4

Dissolves the nuclear membrane and plama membrane , as it is made up of pipes and fats

Question 5

What are the two main components of a cell membrane

Answer 5

Phospholipids and proteins

Question 6

What sort of partials do phospholipids allow to pass between themselves

Answer 6

Small
No charge
Lipid soluable

Question 7

What is the role of cholesterol

Answer 7

To reduce the fluidity of the cell membrane
Can be effected by heat

Question 8

What is a tonoplast

Answer 8

The membrane that surrounds the vacuole

Question 9

What are the 6 main functions of the cell membrane

Answer 9

1. Defines the boundary of the cell
2. Controls which substances pass through
3. Provides a receptor site for hormones
4. Plays a role in cell recognition (immune system)
5. Allows it to change shape
6. Helps cells to stick together

Question 10

What are the three main functions of the internal membrane

Answer 10

1. Compartmentalisation (isolating organelles )
2. A site of biological reactions
3. Controls which substances go in and out of

Question 11

What is another name for the cell membrane

Answer 11

Plasma membrane

Question 12

Which part of the phospholipid bi layer is
Hydrophobic
And
Hydrophilic

Answer 12

Fatty acids are - hydrophobic

Phosphate group is hydrophilic

Question 13

What are the three functions of phospholipids

Answer 13

1. Allow lipid soluble substances to pass through
2. Prevent water soluable substances to go through
3. Make the membrane flexible and self sealing

Question 14

There are two types of proteins embedded on a cell membrane what are those two protein types and give a small description

Answer 14

Intrinsic - they pass through the phospholipid bilayer either fully or partially

Extrinsic - only sit / lay on the phospholipid bilayer

Question 15

What are the function of extrinsic proteins ?

Answer 15

Act as a receptors for molecules ( mostly hormones)
Provide a mechanical support adhesion

Question 16

What is the function of intrinsic proteins

Answer 16

Protein channels- allows water soluble molecules to pass through

Carrier/ channel proteins that aid in transport

Question 17

What type of molecules use intrinsic proteins

Answer 17

Water
Na+
Cl-

Question 18

Cholesterol is a _______ and is found in the phospholipid bilayer . They add ______ to the membrane . Cholesterol are very _______ and therefore play an important role in _______. ______

Answer 18

Lipid

Strength

Hydrophobic

Limiting movement

Question 19

What are three functions of cholesterol

Answer 19

1. Reduce lateral movement of the membrane
2. Make the membrane less fluid at higher temperatures
3. Prevents leakage of water and ions

Question 20

What is the function of glycolipids

Answer 20

Recognition site
Helps maintain membrane stabablilty
Helps cells attach to each other

Question 21

What is the function of glycoproteins

Answer 21

Recognition site
Helps attach to cells to form tissue
Used in cell recognition

Question 22

What does the model name fluid mosaic mean

Answer 22

Fluid - because the individual phospholipids can move laterally and change places with each other

Mosaic - when seen under above looks line a mosaic of phospholipids

Question 23

Name some organelles that have an internal membrane

Answer 23

Mitochondria , chloroplast , vacuole , nucleus

Question 24

What are the five ways that’s substances can move across a membrane and say if there passive or active

Answer 24

Passive - does not require atp
Simple diffusion
Facilitated
Osmosis

Active - require atp
Active transport
Co-transport

Question 25

What is the definition of diffusion

Answer 25

The movement of particles from a region of high concentration to a region of low concentration

Question 26

What are the six factors that effect diffusion

Answer 26

Temperature - more kenetic energy Concentration gradient - increases rate of diffusion Stirring - increases kenetic energy Surface area - more chance of molecules moving through Diffusion distance Size of molecule - smaller molecules diffuse more quickly

Question 27

Why can O2 and CO2 pass through cell membrane

Answer 27

As they are lipid soluable

Question 28

What is the definition of osmosis

Answer 28

Osmosis is the passage of water molecules from a solution of high water potential to a lower water potential through a selective permeably membrane

Question 29

What are the similarities and differences of osmosis and diffusion

Answer 29

Sim Go through selective permeable membrane Passive no energy Differences High to low water potential Only involves water

Question 30

What does hypertonic mean in osmosis

Answer 30

Lots of solute , therefore low water potential

Question 31

What does hypotonic mean in osmosis

Answer 31

Little solute therefore high water potential

Question 32

What does isotonic

Answer 32

At an equalibriam

Question 33

Is something has a high water potential it’s water molecules are

Answer 33

Free

Question 34

What does free water molecules mean

Answer 34

The amount of non bound water molecules that have the potential to move across a semi permeable membrane .

Question 35

Pure water has a Kpa of

Answer 35

-0

Question 36

What is a protoplast

Answer 36

Refers to the entire cell , excluding the cell wall , is not in a animal cell as it does not have a cell wall

Question 37

In animal cell Water potential out side: hypotonic Net movement of water is ? State of cell

Answer 37

Net move : into the cell State of cell: burst

Question 38

In animal cell Water potential out side: isotonic Net movement of water is ? State of cell

Answer 38

Net move: none / equilibrium State of cell : normal

Question 39

In animal cell Water potential out side: hypertonic Net movement of water is ? State of cell

Answer 39

Net move : out of cell State of cell : shrunk / shrivelled

Question 40

In plant cell/ bacteria Water potential out side: hypotonic Net movement of water is ? State of cell Protoplast

Answer 40

Net movement: into the cell (turgid ) State of cell: turgid Protoplast : touching cell wall

Question 41

In plant cell/ bacteria Water potential out side: isotonic Net movement of water is ? State of cell Protoplast

Answer 41

Net movement : equilibrium State of cell : flaccid Protoplast : barely touching the cell wall

Question 42

In plant cell/ bacteria Water potential out side: hypertonic Net movement of water is ? State of cell Protoplast

Answer 42

Net move : out of cell State : plasmolysed Protoplast not touching cell wall vacoul shrunk

Question 43

What does incipient plasmolysis mean

Answer 43

Around 50% of the plan cells are plasmolyed

Question 44

Describe the net movement of water in Flaccid Turgid Plasmollyed Plant cells

Answer 44

Flaccid - no net movement Turgid - water is moving into cell Plasmolyed - water is moving out of cell

Question 45

Describe a channel protein

Answer 45

They transport SMALL polar and charged molecules They are gated so that can be shut off

Question 46

Describe a carrier protein

Answer 46

Allows larger polar molecules such as sugars and amino acids to pass through Has a specific binding site and changes shape when it binds

Question 47

What type of diffusion is channel and carrier proteins And do they require atp ?

Answer 47

Facilitated No they do not require atp

Question 48

Describe a protein pump

Answer 48

They are specific pumps that work against the concentration gradient and require atp

Question 49

Draw out co-transport

Answer 49

Check with internet