Chapter 3 - Cell Membranes And Transport

Question 1

Phospholipid bilayer

Answer 1

Hydrophilic heads
Hydrophobic tails
Double membrane so enclosed

Question 2

How thick is the phospholipid bilayer

Answer 2

7-8nm

Question 3

Extrinsic protiens

Answer 3

Outer surface of plasma membrane and are hydrophilic

Question 4

Intrinsic protiens

Answer 4

Hydrophobic (channel/carrier proteins) and held in the plasma membrane

Question 5

Movement of molecules

Answer 5

The higher the temperature the more kinetic energy so the faster they move

Question 6

Diffusion

Answer 6

Movement of molecules from and area of high to low concentration down the concentration gradient

Question 7

Facilitated diffusion

Answer 7

The rapid passive movement of molecules across membranes down a concentration gradient aided by carrier and channel protiens
For hydrophilic molecules

Question 8

Active transport

Answer 8

Movement of molecules across membranes against the concentration gradient from low to high concentration requiring ATP therefore oxygen

Question 9

Channel protiens

Answer 9

Temporary hydrophilic pore that spans a membranes width which small ions and water soluble molecules can cross via facillitated diffusion

Question 10

Carrier protein

Answer 10

Carries molecules via active transport ATP is required

Question 11

Glycoproteins

Answer 11

Carbohydrates linked to a protein and used for cell to cell recognition

Question 12

Glycolipid

Answer 12

Lipid with a carbohydrates and used in cell to cell recognition

Question 13

Cholesterol

Answer 13

Steroid component making it more rigid and stable

Question 14

Osmosis

Answer 14

Form of diffusion high to low water potential down a water potential gradient down a water potential gradient through a selectively permeable membrane WATER ONLY

Question 15

Water potential

Answer 15

Water potential of the cell = solute potential + water potential and has the symbol (psi)

Question 16

What liquid has the highest water potential and what is it

Answer 16

Distilled water 0 kph

Question 17

Solute potential

Answer 17

Presence of solute molecules and always has a negative value as they lower water potential of the cell

Question 18

Pressure potential

Answer 18

Pressure produced by the cell wall pushing back against the cell surface membrane in plants

Question 19

Hyper tonic

Answer 19

Lower water potential and higher solute potential then the cell NET OSMOSIS OUT OF THE CELL

Question 20

Hypotonic

Answer 20

Higher water potential and lower solute potential then the cells NET OSMOSIS IS INTO THE CELL

Question 21

Isotonic

Answer 21

The same water potential as the cytoplasms of the cell

Question 22

Plasmolysis

Answer 22

When water moves out of the cell via osmosis causing the cytoplasms to shrink and the cell membrane to pull away from the cell wall

Question 23

Flaccid

Answer 23

Cell becomes limp after plasmolysis

Question 24

Incipient plasmolysis

Answer 24

50% plant cells are plasmolysis OR the cell membrane has just began to move away from the cell wall

Question 25

Turgid

Answer 25

When the cell membrane pushes against the cell wall

Question 26

Endocytosis

Answer 26

Bulk transport of substances into the cell and uses ATP to move the membrane and break to form a vesicle around the substance two types pinocytosis and phagocytosis

Question 27

Lysis

Answer 27

Animal cell bursts

Question 28

Exocytosis

Answer 28

Bulk transport of substances out of the cell requires ATP

Question 29

Phagocytosis

Answer 29

Bulk transport of solid materials

Question 30

Pinocytosis

Answer 30

Bulk transport of liquids into the cell

Question 31

Name some water soluble molecules

Answer 31

Glucose polar molecules and ions

Question 32

Name some lipid soluble molecules

Answer 32

Vitamin A oxygen and co2

Question 33

Why is it called the fluid mosaic model

Answer 33

Phospholipid molecules can move like a fluid and the protiens are imbedded

Question 34

How do carrier proteins work

Answer 34

Molecules or ion binds, | ATP transforms a phosphate group then it changes shape then the phosphate ions realest and binds with ADP to form ATP

Question 35

Why does facillitated diffusion’s graph of uptake reach a plateau

Answer 35

Carrier proteins become limiting factor

Question 36

Factors that effect diffusion

Answer 36

``` Concentration gradient Thickness exchange surface Surface area of membrane Size of molecule Whether it’s non polar (faster) Temperature ```

Question 37

How to spot incipient plasmolysis on a graph

Answer 37

The point the line crosses 0

Question 38

What happens to plasmolysis cells

Answer 38

Becomes flaccid and can’t provide support so the plant wilts

Question 39

What is the pressure potential at incipient plasmolysis

Answer 39

0 kpa

Question 40

In a hypotonic solution what happens to the cells water potential

Answer 40

Goes to 0 because no more water can enter

Question 41

Why is turgidity important to plants especially young seedlings

Answer 41

Provides support and helps to remain its shape

Question 42

Crenated

Answer 42

The red blood cells shrink

Question 43

What’s the process of red blood cells bursting

Answer 43

Haemolysis

Question 44

Are the vesicles for pinocytosis or phagocytosis bigger

Answer 44

Phagocytosis

Question 45

Control variable sin the onion osmosis experiment

Answer 45

Temperature Time of incubation of sucrose How much the potato is blotted is rhe same before and after

Question 46

Why are the onion pieces held with forceps

Answer 46

Avoid transmitting anything that will affect osmosis