Biology Paper One – 2025 – Practice Questions with Model Answers – Secondary School

BIOLOGY PAPER ONE.2025

, 1



"Describe how we breathe in.
[3 marks] - CORRECT ANSWER 1. Diaphragm (muscle) contracts pulling diaphragm
down;
2. External intercostal muscles contract
pulling/moving ribs upwards/outwards;
3. (Causes) volume increase and pressure
decrease in thoracic cavity;"

"Use your understanding of osmosis to explain why the air pressure in the
tube increased.
[3 marks] - CORRECT ANSWER 1. Molasses/solution has a lower water potential
2. Water moves in (across) partially/selectively permeable bladder;
3. Increased (molasses/solution) volume"

"Describe the appearance and behaviour of chromosomes during prophase and during
anaphase of mitosis.
[4 marks] - CORRECT ANSWER (In prophase)
1. Chromosomes/chromatids (continue to) condense;
2. Chromosomes attach to spindle (fibres)
(In anaphase)
3. Centromeres divide/split;
4. Chromosomes/chromatids moved/pulled to
opposite poles/sides/ends;"

"r = -0.98 (P < 0.05)
What can you conclude from this result?
[2 marks] - CORRECT ANSWER 1. Strong/significant negative (correlation);
2. (Because probability of) correlation occurring by
chance is less than / < 0.%
3. Reject null hypothesis;"

"Give three structural differences between an mRNA molecule and a tRNA molecule.
[3 marks] - CORRECT ANSWER mRNA
1. (Has) codon(s)
2. No hydrogen/H
bonds
3. Linear/straight/not
folded
4. Long/many
nucleotides/bases
tRNA
1. (Has) anticodon;
2. Has hydrogen/H
bonds
3. 'Clover (leaf' shape)/