Intro to BioChem - Exam 3

Inorganic nitrogen is initially assimilated into which of the following amino acids

Glutamine

The conversion Folate to THF requires the addition of electron from NADH.  Which of the below enzymes are inhibited by methotrexate to aid in treatment of acute leukemia?

dihydrofolate reductase

Most aminotransferaes utilize ________as the recipient alpha-keto acid.

alpha-Ketoglutarate

All of the following are purine bases except _____.

Thymine

Long strands of nucleotides are broken down into oligonucleotides during the first step of degradation to be re-utilized by which enzyme?

exonucleases

In the following diagram, which molecules are in their oxidized form?

2, 3, 6, 7

Which of the following molecules is the first intermediate made in adenosine catabolism to uric acid?

Inosine

All of the following statements concerning folic acid are true except:

Folic acid requires intrinsic factor for its absorption in the intestine.

Fixed nitrogen is assimilated into ________________________?

Glutamate

The intracellular portion of the G-Coupled Protein that exchanges GDP for GTP, dissociating from the other two and becomes active is called?

alpha

Which of the following does not contribute to the noncovalent interactions that stabilize the helical strands of DNA

Phosphodiester bonds

Used DNase enzyme to prove Fred Griffith correct.

Oswald Avery, Colin MacLeod and Maclyn McCarty

Found that the ratios of A:T and C:G are 1:1.

Erwin Chargaff

Used T2 bacteriophage and radioactive sulfur and phosphorus to confirm that DNA is the genetic material, not protein.

Hershey and Chase

Estimated the diameter and pitch of the helix from other X-Ray defractions.

Wilkins and Alex Stokes

Had their direct X-Ray defraction results used by Watson and Crick and only got recognition by the Nobel committee after they were deceased.

Rosalind Franklin

Had solved the structure of the alpha helix and was trying to apply this to DNA.

Linus Pauling

DNA transforms R pneumococci into the S form but had some protein contamination issues and therefore was not conclusive enough.

fred griffith

How many hydrogen bonds exist between this DNA strand and its complimentary strand?
TCCAAG

15

A scientist performs an experiment that uses a chemical inhibitor to inhibit a kinase enzyme in a signaling pathway and this results in a decrease in signaling. If the scientist wanted to be sure that this kinase was indeed responsible for the decrease in signaling, which of the following would be the best to use?

Use of siRNA to the kinase mRNA in question.

The following enzyme utilizes ATP to drive parental strand unwinding during DNA replication. 

Helicase

Reverse Transcriptase is in the lab to create which molecule that enables PCR to be done?

cDNA

In retroviruses, the replication of their RNA genomes uses which of the following DNA polymerases?

reverse transciptase

Eukaryotic initiation begins with the assembly of ________________.

Preinitiation complex

DNA Footprinting was used to show what about RNA polymerase in E. Coli?

Footprinting showed that RNA polymerase was bound to the -35 and -10 region

Which of the following is a role of the 7-methylguanosine cap?

It stabilizes the messenger RNA.

Which of the following is a useful outcome of alternative splicing?

Splice variants can be used to identify tissue samples.

In the following picture, which arrow is pointing to the acceptor stem of tRNA?

A

What will be the resulting polypeptide from the following coding DNA?

3' GCA TTG ACC 5'

Proline-Valine-Threonine

What is the role of Elongation Factor Tu (EF-Tu) during elongation of translation in Prokaryotes?

EF-Tu ensures proper tRNA anticodon to mRNA codon interactions occur at the A site of the ribosome.

When prokaryotic pre-proteins are secreted into the periplasmic space their leader sequences are cleaved off by a membrane protein.  Which of the following is the membrane protein that facilitates the cleavage of the leader sequence of a secreted prokaryotic pre-protein?

peptidase

Under which conditions are the lac structural genes expressed least efficiently?

No cAMP, no lactose

The following amino acids on histones are likely targets to be altered and lead to chromatin remodeling.

Lysine