AS paper 2 wrong

Question 1

Starch is a carbohydrate often stored in plant cells.
Describe and explain two features of starch that make it a good storage molecule.

Answer 1

• coiled for more efficient storage
• insoluable in water so doesnt affect water potentia

Question 2

Describe the advantages and disadvantages of SEM and TEM microscopes

Answer 2

• TEM has higher resolution than SEM
• TEM produces 2D images, SEM produces 3D images
  -TEM requires very thin specimin, SEM does not
• both must be done in a vaccum

Question 3

How does a TEM work?

Answer 3

Electrons pass through specimin

Question 4

how does a SEM work?

Answer 4

Electrons scattered over surface of specimin and detected

Question 5

Explain how changes in the shape of haemoglobin result in the S-shaped
(sigmoid) oxyhaemoglobin dissociation curve for HbA.

Answer 5

At lower % saturation o2 Hb has lower affinity and causes change in shape of the Hb. Adding second and third is easier. Last O2 is harder to bind. Co-operative binding

Question 6

Explain why chromasome mutation in a gamete is worse than a body cell?

Answer 6

• all cells derive through mitosis of the gamete
• so all cells will have chromasoem disfunction

Question 7

What happens if body tissue cell doesn’t receive enough oxygen?

Answer 7

Tissues and cells respire less so doesn’t grow and develop properly and could lead to organ failure

Question 8

Describe water cohesion tension theory of water transport in the xyllem

Answer 8

hydrogen bonding keeps water molecules attached to eachother
-forms a continuos collum
-transpiration causes lower hydrostatic pressure in the leaves causes suctiom of constant flow of water up
adhesion of water molecules to the wall of the xylem

Question 9

Describe how a peptide bond is formed between 2 amino acids to form a dipeptide

Answer 9

condensation reaction between amine and carboxyl

Question 10

The secondary structure of a polypeptide is produced by bonds between amino acids. Describe how.

Answer 10

between NH and CO hydrogen bonding/ disulfide bridges
forming B pleated sheets or alpha helix

Question 11

Two proteins have same number and type of amino acids but different tertiary structures. Explain why.

Answer 11

May be in a different order
so form H bonding at different points

Question 12

Explain the uptake of monasacharides (transport of cell membranes)

Answer 12

proportional at first
movement through carrier proteins
all carrier proteins become saturated

Question 13

Why would you press down firmly on a cover slip?

Answer 13

single thin layer of cells so light can pass through

Question 14

What is digestion

Answer 14

Break down of large insoluable molecules into smaller soluable molecules

Question 15

What are the similarities between eukaryotic DNA and prokaryotic DNA

Answer 15

-nucleotide structure
-nucleotides join via phosphodiester bonds
- DNA in mitrocondra and chloroplast similar

Question 16

How could the primary structure of haemoglobin change?

Answer 16

• base mutation causing changes to amino acids
  -mutations build up over time

Question 17

What type of bond forms between monassacharides

Answer 17

Glycosidic

Question 18

describe amylose

Answer 18

lineur straight chained a-glucose

Question 19

describe amylopectine

Answer 19

branched a-glucose

Question 20

Describe the structure of glycogen

Answer 20

alpha glucose polysacharide joined by glycosidic bonds

Question 21

Describe structure of tryglycerides

Answer 21

They have three fatty-acid tails that are ester-bonded via a condensation reaction to a glycerol

Question 22

Whats a glycolipid and its role?

Answer 22

A carbohydrate attached to a phospholipid used in cell recognition

Question 23

Describe the Biuret test for proteins.

Answer 23

Sodium hydroxide solution is added
A few drops of copper(II) sulphate solution are added. Changes from blue to purple if peptide bonds are present.

Question 24

Function of the golgi

Answer 24

transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations

Question 25

2 uses of phosphates

Answer 25

make ATP
make phospholipids for membranes

Question 26

Name the type of reaction used to break down phospholipids

Answer 26

hydrolysis

Question 27

What does a reduction in the volume of oxygen do

Answer 27

reduce aerobic respiration
reduce the volume of oxygen entering the lungs
reduce carbon dioxide removal

Question 28

HIV attaches to a specific protein receptor on helper T cells. A low percentage
of people have a mutation of the CCR5 gene which codes for this protein
receptor. This mutation results in a non-functional protein receptor.
Explain how this mutation can result in the production of a non-functional protein
receptor.

Answer 28

Change to the base sequence
change to the amino acid sequence
alters the position of the h, disulfide and ionic bonds
changes the tertiary structure

Question 29

Define tertiary structure

Answer 29

3D shape of a protein determining its function

Question 30

how is glycogen different from amylopectin

Answer 30

glycogen is soluble and amylopectin is insoluble in water