Bio 442 - Test 1 Review

The synthesis of purine and pyrimidine nucleotides differ in that:

• ATP is required in the synthesis of purines but not in the synthesis of pyrimidines.

• purine formation requires a THF derivative, whereas pyrimidine formation does not.

• purine biosynthesis starts with the formation of PRPP, whereas pyrimidines incorporate the PRPP near the end of the pathway.

• pyrimidine biosynthesis is tightly regulated in the cell, whereas purine biosynthesis is not.

Which one of the following statements is true of the biosynthetic pathway for purine nucleotides?

• Inosinate is the purine nucleotide that is the precursor of both adenylate and guanylate.

• CO2 does not participate in any of the steps in this pathway.

• Deoxyribonucleotides are formed from 5-phosphodeoxyribosyl 1-pyrophosphate.

• Orotic acid is an essential precursor for purine nucleotides.

Which of the following is not true of the reaction catalyzed by ribonucleotide reductase?

• Glutathione is part of the path of electron transfer.

• It acts on nucleoside diphosphates.

• Its mechanism involves formation of a free radical.

• There is a separate enzyme for each nucleotide (ADP, CDP, GDP, UDP).

Which of the following occupies the smallest relative proportion of DNA in the human genome?

• exons

• introns

• retrovirus-like sequence

• short interspersed elements

Restriction Enzymes . . . 

• cut DNA at precise locations
• help bacteria to pick up DNA
• move DNA through a gel
• copy DNA

Some restriction enzymes produce "sticky ends". Sticky ends are . . .

• single-stranded DNA "overhangs" that can bind to complementary DNA

• double stranded DNA aligned with each other

• single-stranded DNA aligned with host DNA

• ends of a double stranded DNA strand

What is transformation?

• Procedure though which a piece of protein incorporated into bacterium

• Procedure though which a piece of lipid incorporated into bacterium

• Procedure though which a piece of DNA incorporated into bacterium

• Procedure though which a piece of carbohydrate incorporated into bacterium

T6- What type of macromolecule are restriction enzymes?

• nucleic acid
• carbohydrate
• protein
• lipid

_________ DNA is created by using the ______ from a bacteria and splicing a section of DNA into it.

• recombinant, plasmid
• Cloning, ribosome
• transcription, translation
• cumulus, mitochondria

Uric acid is an example of a _________.

• a.nucleotide
• b.ribonucleoside
• c.pyrimidine
• d.purine
• e.tyrosine derivative