Diffusion

Question 1

The studenr concluded that molecules W is taken up by diffusion through a graph

Answer 1

Uptake slows down because of smaller concentration gradient

Question 2

Student left Red blood cells in distilled water
After 2 minutes the red blood cells had a larger volume and had burst
Why

Answer 2

Water has moved into the cell by osmosis from a high water potential to a low water potential
Cell membrane ruptures

Question 3

What does bacteria contain

Answer 3

Cytoplasm and nucleic acids

Question 4

What dies virus contains

Answer 4

Protein capsid

Nucleic acid

Question 5

Using the fluid mosaic model of cell membranes, explain how macrophages carry out phagocytosis of bacteria

Answer 5

Membrnae recpetos interact with bacteria
Macrophage surround bacteria
Membrane of something pinch off
Tot from a vacuous that contains bacteria
Change in shape of membrane is due to fluidity of membrane
Caused by the mocment of phospholipids

Question 6

What is the effect of ethanol on permeability of beetroot cell membranes

Answer 6

Ethanol causes the membrane to be disrupted
This is due to phospholipids dissolving in the ethanol
Membrane proteins dissolve in ethanol
Pigment escapes fro cell membrane when the membrane is disrupted

Question 7

Why might two different experiments focusing on permeability of cell membrane in beetroot might be different

Answer 7

Beetroot cells damaged when cutting
Beetroot not rinsed before being placed in ethanol
Colorimeter not calibrated properly
Different parts of Beetroot may have different conc of pigment

Question 8

The permeability of oxygen is the same for a phospholipid bilayer and a cell sufrcae membrane

Answer 8

Oxygen is non polar and small
So diffuse through phospholipid bilayer
Cell surface membrane has a phospholipid bilayer

Question 9

The permeability of chloride ion sis different I the two membranes

Answer 9

Chporide ions are charged
Caroline jibs not able to diffuse through he membrane
Chloride ions need carrier proteins to move across membrane
Via facilitated diffusion

Question 10

How does temperature affect permeability of cell mebrane

Answer 10

As tmepurtaure increases, permeability of cell membrane increases
Phospholipids move
Increased movement of molecules due to increase kinetic energy
Membrane proteins denatured
Mor edenturation at higher temperatures
Pigment escape form cell when the membrane is disrupted

Question 11

How validity and reliability for cell permaivilty in beetroots

Answer 11

Same species of beetroot
Same size of beetroot
Wash beetroot
Maintain temp of water baths
Repeats

Question 12

Three dimensional structure of glycoprotein

Cabrohydrtae

Answer 12

Proteins consist of amino acids joined together hu peptide bonds
H I d between r groups involved in holding 3d structure
Carbohydrates consist of monosaccardie
Glucoside bonds between adjacent glucose molecules

Question 13

Some anti viral drugs prevent HIV from entering the host cell
Suggest how these anti viral drugs could prevent HIV entering the host cell

Answer 13

Drug could bind to glycoprotein
Drug binding to receptors kn membrane
Called CD4 antigen
Preventing virus attaching to T helper cells

Question 14

How are the enzymes within the glycoprotein involved in HIV infection
RNA retrovirus

Answer 14

Production of reverse transcriptase
Formation of viral DNA
Fro viral RNA

Question 15

Suggest why people’s results when doing cell permeability in beetroot tests is reliabke

Answer 15

Repeats

Colorimeter is more precise and objective

Question 16

In the first students experiment at 5 degrees, the fluid was pale pink but the fluid in the second experiment is colourless

Answer 16

Pink colour due to Pigment
Pigment release when cells or vacuous damaged
And not been washed off

Question 17

Source of error when conducting an experiment based on diffusion and fruit

Answer 17

Some fruit reabsorbed during washing

Therfore loss of mass not as high as it should have been