Unit 6 Review

Match the following enzymes to their roles in DNA replication.

• Synthesizes the new strands of DNA

• Primase

• Unwinds the parent DNA strands

• Helicase

• Fills in the gaps in the new DNA strands

• DNA polymerase

• Adds a small RNA "primer"

• Ligase

Tags

IST-1

Label the stages of protein synthesis.

a

b

c

Transcription

mRNA processing

Gene regulation

Translation

Tags

IST-1

Match the following genetic regions to their roles:

• Regulatory gene

• Makes a repressor protein

• Promotor

• The on/off switch where the repressor protein binds

• Operator

• Codes for the main protein / enzymes

• Genes of Operon

• Place where transcription begins

Tags

IST-2

The operon model was discovered in E. Coli and is almost exclusively found in ​ (a)   .

• prokaryotes
• eukaryotes

Tags

IST-2

Reorder the following stages of protein synthesis in eukaryotes:

• Activators bind to the enhancer

• RNA polymerase transcribes the DNA beginning at the promotor

• Introns are removed from the mRNA; a poly-A tail is added

• A DNA bending protein folds the enhancer toward the promotor

• mRNA leaves the nucleus to find a ribosome for translation

Tags

IST-2

Match the following processes to their associated phrase.

• The addition of chemical groups to certain bases of DNA which regulates gene expression.

• Transposon

• A mobile segment of DNA that can travel from one location on a chromosome to another.

• Transcription

• The synthesis of mRNA from a DNA template.

• DNA methylation

• The synthesis of polypeptides from the genetic information coded in mRNA

• Translation

Tags

IST-2

When does DNA replication take place?

• Whenever new genes are needed

• During the S phase of the cell cycle

• In the middle of mitosis or meiosis

• Immediately before cytokinesis begins

Answer explanation

The DNA must be replicated before cell division takes place so that the daughter cells each receive all the necessary information

Tags

IST-1

DNA replication involves many different enzymes. Helicase unwinds the DNA so that the parent strands can be seperated. DNA polymerase adds the nucleotides to synthesize the daughter strands. What is the role of primase?

• It adds a small RNA "primer" to allow DNA polymerase to begin

• It sorts the prime numbers of RNA into even piles

• It removes incorrecly matched nucleotides to avoid mutations

• It connects the gaps between nucleotide segments

Tags

IST-1

Which of the following would lead to an increase in the rate of transcription?

• methylation of DNA, particularly the cytosine bases

• acetylation of histone proteins

• binding of the operator in an operon

• negative feedback from accumulating product

Tags

IST-2

The trp operon in E. Coli is responsible for making 5 polypeptides involved in the tryptophan synthesis pathway. When tryptophan is present, it combines with the repressor protein to block the operator. What type of operon is trp?

• Repressible

• Inducible

Tags

IST-2