Biology Test Biology Cellular and Molecular 4

Question 1

Which organelle is the site of fatty acid oxidation (beta-oxidation) in eukaryotic cells?

Accepted Answer

Mitochondria

Answer

Beta-oxidation of fatty acids occurs in the mitochondrial matrix, where the acetyl-CoA produced enters the Krebs cycle.

Question 2

What is the significance of the reading frame in mRNA translation?

Accepted Answer

It specifies the correct sequence of codons from which amino acids are assembled

Answer

The reading frame defines the grouping of nucleotides into codons; a frameshift mutation shifts the reading frame and alters every downstream amino acid.

Question 3

Which type of cell junction allows direct communication of small molecules between adjacent animal cells?

Accepted Answer

Gap junction

Answer

Gap junctions form channels (connexons) that allow ions and small signaling molecules to pass directly between neighboring cells.

Question 4

What does the fluid mosaic model describe?

Accepted Answer

The structure of the plasma membrane with embedded proteins in a phospholipid bilayer

Answer

The fluid mosaic model depicts the plasma membrane as a flexible phospholipid bilayer with proteins that can move laterally within it.

Question 5

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.

Biology Practice Test

Biology Practice Test

Biology Test Biology Cellular and Molecular 4