Semester 2 Final Review

A substitution mutation occurs in a DNA sequence, as represented below. The table below shows the mRNA codons for some amino acids.

• The polypeptide will contain an additional amino acid.

• The polypeptide will have the same amino acids.

• The polypeptide will have fewer amino acids.

• The polypeptide will contain a different amino acid.

A small portion of an mRNA sequence is shown below.

AAUGACUGGCUC

Starting with the first base, how many codons does this portion of the sequence contain?

• 1

• 4

• 6

• 12

Because most nerve cells do not typically undergo mitosis, they are generally not capable of which of the following?

• transporting ions against a concentration gradient

• producing enzymes

• making more nerve cells

• performing cellular respiration

Chargaff observed that a sample of human DNA contained approximately 30% adenine and 20% guanine. Based on DNA structure, what are the expected percentages of the other nitrogenous bases in the sample?

• 10% thymine, 40% cytosine

• 20% thymine, 30% cytosine

• 30% thymine, 20% cytosine

• 40% thymine, 10% cytosine

Lipids, carbohydrates, and DNA all exist in human cells as long molecular chains. Which of the following describes how DNA differs from lipids and carbohydrates?

• Only DNA has carbon atoms.

• Only DNA is found in the cytoplasm.

• Only DNA is needed to create new cells.

• Only DNA contains genetic information.

Which of the following is a reason for DNA replication in skin cells?

• to produce identical daughter skin cells

• to enable the skin cells to make more proteins

• to allow the skin cells to adapt to a changing environment

• to ensure daughter skin cells will have higher genetic diversity

What is one advantage of sexual reproduction?

• The offspring inherit a wider variety of genetic information.

• The offspring are genetically identical to the parents.

• The offspring are born live, rather that from eggs.

• The offspring are resistant to viruses.

If a body cell in an animal has 8 chromosomes, the egg or sperm cell would contain:

• 4 chromosomes

• 8 chromsomes

• 16 chromosomes

• 32 chromosomes

The diagram below shows homologous chromosomes during prophase I of meiosis. Which of the following correctly describes the process being illustrated?

• mutation in which the DNA content of the gene is altered

• segregation of sister chromatids

• crossing-over in which genes are exchanged

• condensation and segregation of genes

One form of color blindness is an X-linked trait that is recessively inherited. If a man with normal color vision has a child with a woman who is a carrier for X-linked color blindness, what is the probability that they will have a child with color blindness?

• 0%

• 50%

• 75%

• 25%