The table shows the base sequence of one strand of a DNA molecule. What is the sequence of the strand that pairs with it?

Which pair of nitrogen bases in DNA is held together by three hydrogen bonds?

DNA replication is described as semiconservative. What does each of the two resulting DNA molecules contain?

A sample of double-stranded DNA is analyzed and 30% of its bases are adenine. What percentage of the bases in the sample is cytosine?

What are the two alternating units that make up the backbone of each DNA strand?

During replication the double helix is unzipped and each exposed strand is used as a template. Which enzyme adds the matching nucleotides along that template?

Because the two strands of a DNA molecule are complementary, either strand holds enough information to rebuild the other.

Use the codon chart. The mRNA strand AUG UCU CAC is translated at a ribosome. Which amino acids does it code for, in order?

Use the codon chart. A gene's template DNA strand reads TAC GAA CGT. Which amino acid sequence is produced when this gene is transcribed and then translated?

Use the codon chart. A ribosome begins at the first codon of the mRNA strand AUG UAU UGG UAA CCU. How many amino acids long is the polypeptide that is made?

In a eukaryotic cell, at which structure does translation take place?

Which molecule carries an amino acid to the ribosome and matches its anticodon to a codon on the mRNA?

A student compares a strand of mRNA with the DNA it was copied from. Which base appears in the mRNA wherever thymine would appear in DNA?

A length of mRNA has 300 bases of coding sequence, not counting its stop codon. How many amino acids will the finished polypeptide contain?

What does RNA polymerase do during protein synthesis?

The table gives the coding portion of an mRNA before and after a mutation. What kind of mutation happened?

A substitution changes one base in a gene, but the protein made from that gene has exactly the same amino acid sequence as before. What best explains this result?

One extra base is inserted near the beginning of a gene's coding sequence. What happens to the amino acids specified after that point?

A substitution in the middle of a gene changes a codon that specified an amino acid into a stop codon. What is the most likely effect on the protein?

Ultraviolet light causes a mutation in the DNA of a skin cell on a woman's arm. Why will this mutation not appear in her children?

Every mutation that occurs in an organism's DNA is harmful to that organism.

The table gives the number of chromosomes in a body cell of three organisms. How many chromosomes are in a single fruit fly gamete?

During prophase I of meiosis, homologous chromosomes pair up and exchange matching segments. What does this crossing over produce?

How does the independent assortment of chromosomes in metaphase I add to genetic variation?

One diploid cell completes meiosis. What is produced?

In one cell, a pair of homologous chromosomes fails to separate during anaphase I. What is the most likely result in the gametes formed from that cell?

Meiosis is not the only step that makes siblings genetically different from each other. Which additional event contributes to that variation?

In pea plants, round seed shape (R) is dominant to wrinkled (r). The square shows a cross between two round-seeded plants that each carry one allele for wrinkled seeds. What fraction of the offspring is predicted to have wrinkled seeds?

In rabbits, black fur (B) is dominant to brown fur (b). The square shows a black rabbit that carries one brown allele crossed with a brown rabbit. What ratio of black to brown offspring does the cross predict?

Snapdragons show incomplete dominance: two red alleles (R) give red, two white alleles (W) give white, and one of each gives pink. The square shows two pink plants crossed. What fraction of the offspring is predicted to be pink?

Red-green colorblindness is carried on the X chromosome and is recessive. A woman with normal vision who carries one allele for colorblindness has children with a man who has normal vision. Which children can be colorblind?

The pedigree shows one family, and a shaded symbol marks a person who has the trait. What does the chart show about the allele for the trait?

A bull with red hair is crossed with a cow with white hair, and the calves have coats showing both red hairs and white hairs together. Which pattern of inheritance does this cross show?

Human ABO blood type is controlled by three alleles. A father has type AB blood and a mother has type O blood. Which blood types are possible in their children?

In tomatoes, tall stems (T) are dominant to short (t) and round fruit (R) is dominant to oval (r). Two plants that are heterozygous for both traits are crossed. What phenotype ratio does this dihybrid cross predict?

A student says a dominant allele is the one most people in a population have. Why is this wrong?

In gel electrophoresis, DNA fragments travel away from the wells and toward the positive electrode. Why do they move in that direction?

What does a restriction enzyme do to a DNA molecule?

A forensic scientist has a very small amount of DNA from a crime scene and needs far more of one particular region before it can be analyzed. Which technique does this job?

The human gene for insulin is inserted into a bacterial plasmid, and the bacteria then produce human insulin. Why can bacterial cells make a human protein?