Ch. 6 Test Review

Different types of mutations can occur in DNA. The diagram represents a type of mutation.

Which statement describes the mutation in the diagram?

• A silent mutation results in the insertion of a different amino acid.

• A substitution occurs with the adenine base.

• A deletion of a cytosine base occurs.

• A base is inserted into one strand of the DNA.

In the early 1980s scientists were able to produce two biomolecules by splicing a human gene into the bacterium E. coli to make recombinant human insulin and growth hormone. Which statement best explains why this experiment was successful?

• Human cells are eukaryotic, and E. coli cells are prokaryotic.

• All living organisms share the same genome.

• The genes for all organisms are composed of the same building blocks.

• The human body contains many types of bacteria, including E. coli.

Students are given data from an investigation that identified some of the chemical elements present in four different samples.

Which sample was most likely DNA?

• Sample 1

• Sample 2

• Sample 3

• Sample 4

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 these 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.

The process represented in the diagram produces a molecule that is complementary to the template strand of DNA. What type of molecule is produced?

• New DNA

• Polypeptide

• Messenger RNA

• Carbohydrate

Which part of a DNA molecule is responsible for the direct coding of specific traits in an organism?

• The number of hydrogen bonds that hold the strands of DNA together.

• The number of carbons in the DNA molecule.

• The sequence of nucleotide bases in the DNA molecule.

• The sequences of phosphates along each DNA strand.

Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA.

The results provide evidence that —

• similar nucleotides are present in both fruit-fly and frog DNA

• fruit flies and frogs can be made to develop some of the same physical traits

• heat can cause mutations in the DNA sequences of organisms

• the replication of genetic material can occur at any temperature

Four different types of cells are shown below.

Which characteristic is shared by all four cells?

• A mechanism for transforming sunlight into energy

• Self-locomotion

• Membrane-bound organelles that transport substances

• Genetic material composed of DNA

A model of a DNA molecule is shown below.

The arrow indicates —

• the bond between adjacent phosphate and deoxyribose molecules

• the junction of introns and exons in the sense strand of DNA

• the hydrogen bond between complementary nucleotides

• the junction of a codon and a DNA triplet

Scientists use zebra fish to study human genetic diseases because zebra fish and humans share many of the same genetic diseases.

Which statement describes why zebra fish experience similar genetic diseases as humans?

• Zebra fish have an omnivorous diet similar to that of humans.

• Zebra fish have nucleotide sequences similar to those of humans.

• Zebra fish go through embryonic stages similar to those of humans.

• Zebra fish produce gametes through a process that is similar to that of humans.