PTA Science Fundamentals 3

Question 1

Which of the following describes an isotonic muscle contraction?

Accepted Answer

Muscle tension stays the same while length changes

Answer

Isotonic contractions occur when muscle tension remains constant while the muscle changes length, as seen in lifting a fixed weight.

Question 2

Which body system is primarily responsible for regulating blood pH?

Accepted Answer

Renal and respiratory systems

Answer

The kidneys regulate bicarbonate excretion and the lungs control CO₂ levels, together maintaining blood pH near 7.4.

Question 3

In a lever system, the mechanical advantage increases when:

Accepted Answer

The effort arm is longer than the resistance arm

Answer

Mechanical advantage = effort arm length ÷ resistance arm length; a longer effort arm relative to the resistance arm produces greater mechanical advantage.

Question 4

Covalent bonds are formed by:

Accepted Answer

Sharing of electron pairs between atoms

Answer

Covalent bonds form when two atoms share one or more pairs of electrons, as in water (H₂O) or glucose.

Question 5

Which organelle synthesizes proteins based on mRNA instructions?

Accepted Answer

Ribosome

Answer

Ribosomes translate mRNA sequences into polypeptide chains, which then fold into functional proteins.

(PTA) Practice Tests Academy Practice Test

(PTA) Practice Tests Academy Practice Test

PTA Science Fundamentals 3