Bio

Question 1

Identify component A of the chloroplast and its adaptation.

Answer 1

A = Grana
Contains photosynthetic pigments

Question 2

Identify component B of the chloroplast and its adaptation.

Answer 2

B = Stroma
contains enzymes for calvin cycle (RuBP)

Question 3

One similarity between chloroplasts and mitochondria.

Answer 3

Both have double membranes / ATP synthase.

Question 4

One difference between chloroplasts and mitochondria.

Answer 4

Chloroplasts have thylakoids/photosystems; mitochondria have cristae/matrix.

Question 5

Rf calculation for the most soluble pigment?

Answer 5

Distance travelled = 91 mm; Rf ≈ 0.83.

Question 6

How to increase intensity of TLC spots?

Answer 6

Let spot dry and re-spot; add more extract; evaporate solvent to concentrate.

Question 7

How to increase accuracy of Rf value?

Answer 7

Allow solvent to run further / mark solvent front immediately / measure centre of spot.

Question 8

Why Rf values didn’t match the data book?

Answer 8

Different solvent/plate/temperature or different plant extract.

Question 9

How to identify pigments without calculating Rf?

Answer 9

Run known pigments under same conditions and compare positions/colours.

Question 10

What type of reaction does PFK catalyse?

Answer 10

Phosphorylation.

Question 11

The intermediate compound PEP is a reversible non-competitive inhibitor of PFK.

Explain how PEP inhibits PFK.

Answer 11

Binds allosteric site → changes active site shape → substrate cannot bind → reversible.

Question 12

Why can’t ATP be a competitive inhibitor of PFK?

Answer 12

Not similar shape to substrate;
Can’t compete w itself for active site

Question 13

Name this type of inhibition in glycolysis.

Answer 13

End-product inhibition.

Question 14

How does PFK regulate glycolysis rate?

Answer 14

PFK activity is determined by ATP
When ATP inhibits PFK rate DECREASES

Question 15

Name for inhibitors forming strong covalent bonds.

Answer 15

Non-reversible inhibitors.

Question 16

Name the reaction producing CO₂ in respiration.

Answer 16

Oxidative decarboxylation.

Question 17

Two stages where CO₂ is produced.

Answer 17

Link reaction & Krebs cycle.

Question 18

How does oxidation occur in glycolysis?

Answer 18

Dehydrogenation from TP
H+ goes to NAD

Question 19

Null hypothesis for gibberellin experiment.

Answer 19

No significant difference in internode length between treated and control.

Question 20

Does the t-test support the conclusion?

Answer 20

t > critical → reject H₀ → significant increase; but sample small, large SDs, few controls, environmental factors uncontrolled.

Question 21

Why does inhibiting gibberellin increase yield in crowded soybeans?

Answer 21

Reduces GA → shorter stems → plants don’t fall over → less damage & more resources for yield.

Question 22

Two variables to keep constant in algal bead experiment.

Answer 22

Temperature, volume of indicator / bead number / wavelength of light.

Question 23

Relative light intensity & mean at 375 cm.

Answer 23

7.11 × 10⁻⁶; mean = 79.3 min.

Question 24

Improvement for more accurate photosynthesis rate.

Answer 24

Use colorimeter to measure absorbance change or pH probe for pH change.

Question 25

Why can't hydrogencarbonate indicator be used to test CO₂ concentration?

Answer 25

CO₂ changes indicator colour → indicator becomes dependent variable → confounding.

Question 26

How to measure rate at different CO₂ concentrations?

Answer 26

Measure oxygen production (gas syringe/O₂ sensor) or DCPIP decolourisation time.

Question 27

Evidence CO₂ is limiting factor.

Answer 27

Higher CO₂ gives higher rate at same light; rate plateaus meaning light no longer limiting.

Question 28

Why CO₂ affects rate more than temperature?

Answer 28

Doubling CO₂ ≈ doubles rate; Q₁₀ (30°C/20°C) < 2 → temperature effect smaller.

Question 29

Blood vessel transporting deoxygenated blood to lungs.

Answer 29

F (pulmonary artery).

Question 30

Site of gas/nutrient exchange.

Answer 30

H (capillary).

Question 31

Controls blood flow near skin surface.

Answer 31

G (arteriole).

Question 32

Why no valves in pulmonary veins?

Answer 32

Flow not against gravity; short distance; pressure not low.

Question 33

Identify J, K, L, M in heart diagram.

Answer 33

J = SAN; K = AVN; L = septum; M = Purkyne fibres.

Question 34

Describe how heart contraction is initiated & linked to ECG.

Answer 34

SAN initiates depolarisation → atria contract (P wave) → AVN delay → ventricles depolarise via His/Purkyne (QRS) → ventricles repolarise (T wave).

Question 35

Identify abnormality in ECG 1.

Answer 35

Bradycardia — heartbeat intervals longer.

Question 36

Identify abnormality in ECG 2.

Answer 36

Ectopic beat (early beat) OR atrial fibrillation (no P wave).

Question 37

Three adaptations of fish gills for gas exchange.

Answer 37

Large SA (lamellae), thin surfaces, countercurrent flow / extensive blood supply.

Question 38

Why can insects use open circulatory systems?

Answer 38

Tracheal system delivers O₂ directly; haemolymph not for O₂; distances small.

Question 39

Why can marine mammals grow bigger than fish?

Answer 39

Double circulation allows high pressure & fast transport; more efficient gas exchange.

Question 40

How haemoglobin structure helps oxygen transport.

Answer 40

4 haem groups bind O₂; cooperative binding; high affinity in lungs, low in tissues.