Biology Test Practice Test: Video 1 Answers (25 Questions)

Question 1

Which cytoskeletal element is primarily responsible for maintaining cell shape in animal cells?

Accepted Answer

Microfilaments (actin)

Answer

Actin microfilaments form a network beneath the plasma membrane that supports cell shape and enables cell movement.

Question 2

During meiosis, homologous chromosomes exchange genetic material through which process?

Accepted Answer

Crossing over (recombination)

Answer

Crossing over occurs during prophase I when non-sister chromatids of homologous chromosomes exchange segments at points called chiasmata.

Question 3

What is a nucleosome?

Accepted Answer

DNA wrapped around a histone octamer

Answer

A nucleosome consists of approximately 147 base pairs of DNA wrapped around a core of eight histone proteins, forming the basic unit of chromatin.

Question 4

What is the primary role of cyclin-CDK complexes in the cell cycle?

Accepted Answer

Regulating progression through cell cycle checkpoints

Answer

Cyclin-dependent kinase (CDK) complexes phosphorylate target proteins to drive the cell through key transitions such as G1/S and G2/M checkpoints.

Question 5

Which process allows cells to engulf large particles or other cells by forming membrane vesicles?

Accepted Answer

Phagocytosis

Answer

Phagocytosis is a form of endocytosis in which the cell membrane engulfs large particles like bacteria, forming a phagosome.

Biology Practice Test