IB Biology 4

Question 1

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Answer

Transfer RNA (tRNA) carries specific amino acids and uses its anticodon to match complementary codons on the mRNA during translation.

Question 2

What observation led Charles Darwin to propose that species change over time?

Accepted Answer

Similarity between Galapagos finch beaks and their food sources on different islands

Answer

Darwin noticed that finches on different Galapagos islands had beaks adapted to the specific food sources available, suggesting descent with modification from a common ancestor.

Question 3

What happens to membrane fluidity when cholesterol is added to a phospholipid bilayer at body temperature?

Accepted Answer

Fluidity decreases because cholesterol stabilizes phospholipid packing

Answer

At physiological temperature, cholesterol intercalates between phospholipid tails, restraining their movement and reducing membrane fluidity.

Question 4

Which molecule acts as the final electron acceptor in aerobic cellular respiration?

Accepted Answer

Oxygen

Answer

Oxygen accepts electrons at the end of the electron transport chain and combines with hydrogen ions to form water.

Question 5

In a food web, what percentage of energy is typically transferred from one trophic level to the next?

Accepted Answer

10%

Answer

The ten percent rule states that only about 10% of energy stored in one trophic level is available to the next, with the rest lost as heat through metabolism.

IB - International Baccalaureate Practice Test

IB - International Baccalaureate Practice Test

IB Biology 4