Question 1

Which experiment provided the first strong evidence for the 'one gene-one enzyme' hypothesis?

Accepted Answer

The use of X-rays to induce mutations in Neurospora and analysis of their growth on minimal media

Question 2

Alkaptonuria is an example of an 'inborn error of metabolism.' What is the underlying cause of this disorder?

Accepted Answer

A mutation that prevents the synthesis of a specific enzyme in a metabolic pathway

Question 3

In the arginine biosynthetic pathway, a Class II mutant of Neurospora can grow on minimal medium supplemented with citrulline or arginine, but not with ornithine. Which enzyme is defective in this mutant?

Accepted Answer

Enzyme B (converts ornithine to citrulline)

Question 4

Which of the following best describes the process of transcription?

Accepted Answer

The synthesis of an RNA molecule from a DNA template

Question 5

A DNA template strand has the sequence 3’ - TAC TTC ACC CGT - 5’. What is the corresponding mRNA sequence?

Accepted Answer

$$5' - AUG AAG UGG GCA - 3'$$

Question 6

Using the genetic code, what amino acid sequence is produced from the mRNA strand $$5' - AUG AAG UGG GCA - 3'$$?

Accepted Answer

Met-Lys-Trp-Ala

Question 7

Which modification occurs at the 5’ end of a eukaryotic mRNA during RNA processing?

Accepted Answer

Addition of a modified guanine nucleotide (5’ cap)

Question 8

What is the primary function of the spliceosome during RNA processing?

Accepted Answer

To remove introns and join exons together

Question 9

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is nearly universal among all organisms

Question 10

A mutation changes a codon from $$CCG to$$ $$CCA in $$the mRNA. What type of mutation is this, and what is its effect?

Accepted Answer

Silent mutation; no change in the amino acid

Question 11

Which of the following best explains why bacteria can produce human insulin?

Accepted Answer

The genetic code is universal, allowing human genes to be expressed in bacteria

Question 12

What is the main difference between gene expression in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes modify RNA before translation, while prokaryotes do not

Question 13

Which of the following mutations is most likely to result in a nonfunctional protein?

Accepted Answer

Nonsense mutation

Question 14

A frameshift mutation occurs when:

Accepted Answer

A nucleotide is added or deleted, shifting the reading frame

Question 15

During translation, which site on the ribosome does the incoming aminoacyl-tRNA bind to?

Accepted Answer

A site

Question 16

Which of the following is a real-world example of the universality of the genetic code?

Accepted Answer

Jellyfish genes can be expressed in zebrafish to produce fluorescent proteins

Question 17

Which step in gene expression involves the conversion of nucleotide sequence information into amino acid sequence?

Accepted Answer

Translation

Question 18

If a mutation occurs in gene C of the arginine biosynthetic pathway, which supplement is required for growth?

Accepted Answer

Arginine

Question 19

Which of the following best describes alternative splicing?

Accepted Answer

The joining of different combinations of exons to produce multiple polypeptides from one gene

Gene Expression: From Gene to Protein (Chapter 17) – Mini-Textbook Study Notes

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