Urgent Weaknesses (AS)

Question 1

Contrast the structures of ATP and a nucleotide found in DNA to give two
differences.

Answer 1

ATP:
3 Phosphates
Adenine
Ribose Sugar

DNA Nucleotide:
Deoxyribose sugar
ATCG Pairs not just adenine
1 Phosphate

Question 2

Explain the advantages of lipid droplet and micelle formation

Answer 2

1. Droplets increase surface areas (for lipase /
   enzyme action);
2. (So) faster hydrolysis / digestion (of
   triglycerides / lipids);
3. Micelles carry fatty acids and glycerol /
   monoglycerides to / through membrane / to
   (intestinal epithelial) cell;

Question 3

Explain how Golgi Apparatus is involved in the absorption of
lipids.

Answer 3

Golgi (apparatus);
2. Modifies / processes triglycerides;
3. Combines triglycerides with proteins;
4. Packaged for release / exocytosis
OR
Forms vesicles;

Question 4

Explain why tissue fluid is moved out of the capillaries

Answer 4

VENTRICLE contractions cause high hydrostatic pressure forcing water into surrounding tissues

Question 5

Explain how the chromosome number is halved during meiosis.

Answer 5

Homologous chromosomes (pair). one of each moves to opposite poles

Question 6

Describe the process of crossing over and explain how it increases genetic
diversity

Answer 6

. Homologous pairs of chromosomes associate
/ form a bivalent;
2. Chiasma(ta) form;
3. (Equal) lengths of (non-sister) chromatids /
alleles are exchanged;
4. Producing new combinations of alleles;

Question 7

Describe the functions of SER RER and Golgi Apparatus

Question 8

Difference between mRNA and tRNA

Answer 8

mRNA is linear
tRNA is clover leaf shaped
tRNA has amino acid binding site and anticodon.
mRNA has codon.

Question 9

Describe Binary Fission