Unit 4: Gene Expression Review

In which organelle does protein synthesis occur?

• mitochondria

• nucleus

• ribosome

• lysosome

The process of DNA Replication is said to be semi-conservative. Which statement BEST explains what that means?

• DNA is a single stranded molecule conserving nucleotides for the new strand.

• DNA is a two stranded molecule that remains intact at all times.

• DNA is a two stranded molecule consisting of one original strand and one new strand.

• DNA is a two stranded molecule consisting of either both original strands or both of the new strands.

Where does REPLICATION take place in a eukaryotic cell?

• cytoplasm

• nucleus

• ribosome

• vacuole

Which statement most accurately describes the DNA molecule?

• A single string composed of nucleotide bases, and a backbone of deoxyribose sugar and phosphate.

• A single string composed of nucleotide bases, and a backbone of ribose sugar and phosphate.

• A double-helix composed of nucleotide bases, and a backbone of deoxyribose sugar and phosphate.

• A double-helix composed of nucleotide bases, and a backbone of ribose sugar and phosphate.

All of the following are examples of mutagens EXCEPT

• vitamin C

• X-rays

• UV rays

• chemicals

Original DNA: GTG ATA CGC

Mutated DNA: GTG AAC GC

Which of the following mutations is illustrated in this example?

• Missense: one amino acid changes but reading frame stays the same

• Frameshift: the reading frame shifts and many codons change

• Silent: base change but same amino acid

• Nonsense: early stop codon created immediately

A mutation changes GTG ATA CGC to GTG ATT ACG C.

What category of mutation is this and what is the most likely effect on the polypeptide?

• Insertion; causes a frameshift altering downstream amino acids

• Substitution; usually changes only one amino acid

• Deletion; always creates an early stop codon

• Insertion; always has no effect on the protein

In eukaryotes, DNA is found in the

• cytoplasm

• vacuole

• ribosome

• nucleus

In the diagram pictured, which letter represents the "phosphate"?

• A

• B

• C

Which statement most accurately describes the RNA molecule?

• A single string composed of nucleotide bases, and a backbone of deoxyribose sugar and phosphate.

• A single string composed of nucleotide bases, and a backbone of ribose sugar and phosphate

• A double-helix composed of nucleotide bases, and a backbone of deoxyribose sugar and phosphate.

• A double-helix composed of nucleotide bases, and a backbone of ribose sugar and phosphate.