Biochem C785 Module 1 Exam

Biochem C785 Module 1 Exam

You are designing a piece of DNA for a project and must select the appropriate nitrogenous bases. Which

combination of nitrogenous bases would you find most suitable for your work?

Select one:

a. Adenine, Guanine, Thymine, Cytosine Correct! These nitrogenous bases, in combination

with deoxyribose sugar and phosphate, form the nucleotides that are bonded together to form a long

polymer of DNA - the carrier of genetic information.

b. Adenine Guanine, Uracil and Thymine

c. Thymine, Uracil, Adenine, Cytosine

d. Adenine, Thymine, Cytosine, Uracil

The DNA sequence 3’-ATGATCCTT-5’ is part of the template strand during DNA replication. Which of

the following would be the correct sequence for the newly made DNA?

Select one:

a. 5’-ATGATCCTT-3’

b. 5’-GCAGCTTCC-3’

c. 5’-TACTAGGAA-3’

d. 5’-UACUAGGAA-3’ Incorrect. In this option U has been used instead of T. Although this is

how an mRNA molecule would be created from the DNA, it is not the appropriate complementary base

when replicating the DNA. Recall that during replication, the bases on the newly made daughter strand

are complementary to the bases on the template strand using the following base pairing rules: A with T

and G with C.

Which of the following statements is TRUE about RNA?

Select one:

a. There are several types of RNA in the cell, including mRNA, rRNA, and tRNA.

b. RNA nucleotides include the bases A, U, C, and G.

c. RNA is single stranded and contains a ribose sugar in the sugar-phosphate backbone.

d. All of these Correct! All of these statements about RNA are true. The cell contains mRNA,

rRNA, and tRNA molecules, RNA is single stranded, RNA contains a ribose sugar in the sugar-phosphate

backbone, and RNA nucleotides include the bases A, U, C, and G.

What is the complementary DNA strand for the DNA sequence 5'-ATT CGG GCT CCC -3'?

Select one:

a. 5' - CCC TCG GGC TTA -3

b. 5'- UAA GCC CGA GGG -3'

c. 5'- ATT CGG GCT CCC -3'

d. 5'- GGG AGC CCG AAT -3 Correct! The DNA complementary strand would be 5'- GGG

AGC CCG AAT -3', when written in the conventional way starting with the 5' end of the strand.

A research scientist is trying to create a new strain of bacteria that can produce a protein needed for her

research. Which of the following molecules will act as a template in creating the protein?

Select one:

a. Ribozyme Incorrect. Ribozymes are certain RNA molecules which are able to catalyze certain

reactions. They do not provide the template sequence for the creation of the Protein. DNA carries the

genetic information in the form of specific DNA sequences. The stretches of DNA which contain

information for specific proteins are referred to as genes. In order to make a protein, the gene must first

be transcribed into messenger RNA (mRNA) which contains the complementary sequence to one of the

DNA strands of that specific gene. This message within the mRNA is then translated by the ribosome to

produce a protein.

b. transfer RNA (tRNA)

c. messenger RNA (mRNA)

d. Ribosomal RNA(rRNA)

What is one direct effect of inhibiting translation?

Select one:

a. The level of proteins would remain the same.

b. Transcription would cease. Incorrect. Transcription is the copying of DNA into mRNA, and it

happends before translation. While mRNA is used during translation, inhibiting translation would not stop

transcription because the RNA polymerase that makes the mRNA would still be functional. Translation is

the production of proteins, so inhibiting (stopping) translation would stop protein production.

c. DNA would no longer be replicated.

d. Production of proteins would stop.

How many amino acids, and which ones, would be encoded by the following mRNA sequence: 5’-

AUGACUCCCGGG-3’? (The codon table below can assist you.)

Select one:

a. Three amino acids - Met, Ile, and Arg

b. Three amino acids - Met, Thr, and Pro

c. Four amino acids - Met, Thr, Pro and Gly Correct! Amino acids are coded by 3-letter

codons, and the sequence contains 12 nucleotides, which means is codes for four amino acids. The first is

AUG for Met, the second is ACU for Thr, the third is CCC for Pro, and the fourth is GGG for Gly.

d. Four amino acids - Met, Leu, Pro, Val