Biology Quiz DNA, Transcription and Translation

Differences in traits such as hair texture are determined by differences in -

• the location of sugar groups in DNA

• the sequence of nucleotides in DNA

• the number of nitrogenous bases in DNA

• the molecules attached to the phosphate in DNA

The initial steps in gene expression are modeled in the two diagrams on the left. Double-stranded DNA first unwinds into two strands. Which process and product are represented in Diagram 2?

• Process: transcription; product: mRNA

• Process: translation; product: protein

• Process: replication; product: tRNA

• Process: recombination; product: polymerase

Different types of mutations can occur in DNA. The diagram represents a type of mutation. Which statement(s) describes the mutation in the diagram? Choose all that apply.

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

• A nucleotide, with adenine, is inserted into one strand of the DNA.

• A deletion of a cytosine base occurs.

• A substitution occurs between the thymine and cytosine.

Chromosomes are composed of two types of biomolecules. One of the biomolecules in chromosomes is called DNA, which functions as the genetic code. The other biomolecules in chromosomes are called histones, which bind the DNA tightly for cell division. Genes in DNA have the code for making histones. Based on the information above, which types of biomolecules are in chromosomes?

• Carbohydrates and lipids

• Proteins and nucleic acids

• Proteins and carbohydrates

• Nucleic acids and carbohydrates

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.

The following are some steps that take place when protein synthesis occurs in the cell. Messenger RNA attaches to the ribosome. Amino acids bond together to form a polypeptide chain. A specific anti-codon on transfer RNA bonds to a specific codon on messenger RNA. Messenger RNA is produced using DNA as a template. First Last

The table shows a DNA sequence and three types of mutations that can change the DNA sequence. Which mutation will cause translation to stop?

• Mutations 1 and 3 only

• Mutation 1 only

• Mutation 2 only

• Mutations 1, 2, and 3

What is the function of the nucleic acid tRNA?

• Carries genetic information from the DNA to ribosomes

• Carries amino acids to protein-building ribosomes

• Facilitates chemical reactions that form ribosomes

• Serves as the site of protein synthesis

In 1952 Rosalind Franklin took the x-ray photograph shown here, which gave the world its first look at DNA. By studying this photograph, scientists gained knowledge about the —

• role of DNA in protein synthesis

• mutation of nucleotide sequences in DNA

• sequence of DNA that makes up the human genome

• double-helix structure of DNA

Part of an important cellular process involving a DNA strand is modeled below. What is the purpose of this cellular process?

• Preserving genetic information for future generations

• Deleting the information in the sequence produced from the DNA template

• Transcribing information in the DNA sequence for use by the cell

• Producing more nucleotides for the DNA sequence