MTTC MTTC Biology 3

Question 1

Which phase of meiosis is responsible for genetic recombination through crossing over?

Accepted Answer

Prophase I

Answer

During Prophase I, homologous chromosomes synapse and exchange genetic material through crossing over at chiasmata.

Question 2

An enzyme's active site becomes permanently blocked by a molecule that resembles the substrate but cannot be released. This is:

Accepted Answer

Irreversible inhibition

Answer

Irreversible inhibitors form covalent bonds with the active site, permanently blocking enzyme activity.

Question 3

Which blood vessel type has walls only one cell layer thick, allowing gas and nutrient exchange?

Accepted Answer

Capillaries

Answer

Capillaries have walls composed of a single layer of endothelial cells, enabling efficient exchange of oxygen, CO2, nutrients, and wastes.

Question 4

In a dihybrid cross between two plants that are both RrYy (round yellow seeds), what fraction of offspring would be round and green?

Accepted Answer

3/16

Answer

The RrYy × RrYy cross yields a 9:3:3:1 ratio; 3/16 of offspring are round (R_) and green (yy).

Question 5

Which hormone triggers the 'fight-or-flight' response by increasing heart rate and blood glucose?

Accepted Answer

Epinephrine

Answer

Epinephrine (adrenaline), released by the adrenal medulla, rapidly prepares the body for emergency response by increasing heart rate, dilating airways, and raising blood glucose.

MTTC Test Practice Test

MTTC Test Practice Test

MTTC MTTC Biology 3