Unit 3 Gene Expression Test Review

Humans have thousands of genes that combine in different ways to help create unique individuals. Where is the genetic code primarily located?

• Ribose sugar in RNA

• Phosphates in DNA

• Nucleotides in DNA

• Exons in RNA

A diagram of the steps in the production of a protein is shown. Which description identifies the purpose of Step A in this process?

• To copy the DNA sequence onto a strand of mRNA

• To copy an exact copy of DNA

• To correct mutations in the DNA sequence

• To translate the DNA into the folding of a protein

The Himalayan rabbit's habitat has cold, snowy winters and mild summers. The body is typically covered in white fur except for the nose, feet, tail, and ears, which are covered in black fur. A scientist shaved an area of white fur on the back of a Himalayan rabbit and placed an ice pack over the shaved area. The shaved area grew black fur. Which of this best explains why the hair that grew back where the ice pack was placed was black and not white?

• The genes for black hair were activated by specific temperatures.

• The white hair mutated to black hair as the rabbit's body temperature decreased.

• The coat color changed from white to black with the age of the rabbit.

• White hair only grows during certain times of the year.

Which of these is the direct result of an error in the transcription of a DNA nucleotide?

• The nuclear membrane is ruptured.

• Amino acids do not bond to tRNA.

• A codon sequence is incorrect.

• Transportation of mRNA does not occur.

A mutation is least likely to affect a cell when that mutation . . .

• reverses the order of the nitrogen bases in the DNA strand.

• reduces the total number of nitrogen bases in the DNA sequence.

• replaces a nitrogen base with its complementary nitrogen base.

• still codes for the same amino acid as the original codon.

Albumin is a protein that is secreted by the liver cells and transported to the bloodstream. What factor most directly determines the amino acids that are combined to create albumin?

• The sequence of nucleotides in DNA

• The number of chromosomes in a cell

• The amount of energy that is available in the cell

• The temperature of the cell when translation is taking place

What is the complementary base of adenine in RNA?

• cytosine

• thymine

• guanine

• uracil

Human bone, muscle, and nerve cells all contain the same number of chromosomes with the same complement of genes. What enables these cells to perform specialized activities?

• The ability of some cells to remove unnecessary DNA sequences

• The regulation of gene expression within each cell type

• The mutation of genes within each cell type

• The use of different methods of cell division

A base sequence of the DNA from a gene is shown. ATC GGC TA Due to a mutation, the base sequence was changed as: ATT GGC TA Which type of mutation has occurred in the gene?

• Deletion

• Substitution

• Insertion

• Translocation

Select the correct statement that gives two differences between the structure of DNA and RNA.

• DNA is double-stranded and contains thymine, while RNA is single-stranded and contains uracil.

• DNA is single-stranded and contains uracil, while RNA is double-stranded and contains thymine.

• Both DNA and RNA are double-stranded and contain uracil.

• DNA and RNA have the same structure and both contain thymine.