Miscellaneous Category

Question 1

During embryogenesis, oocytes are halted in what phase?

Answer 1

Prophase of meiosis I before puberty.

Question 2

In what stage does the secondary oocyte halt in meiosis?

Answer 2

Metaphase II.

Question 3

In what meiotic state does a secondary oocyte remain until fertilization?

Answer 3

Metaphase II

Question 4

What do homeobox genes encode for?

Answer 4

DNA binding transcription factors that alter the genes expressed in morphogenesis.

Question 5

What is morphogenesis?

Answer 5

The proper formation and placement of tissues, organs and structural elements of the body

Question 6

What does ‘degenerate’ mean in terms of the genetic code?

Answer 6

More codons than amino acids

Question 7

What is the monospot test?

Answer 7

Used to test for mononucleosis- A positive test involves agglutination of sheep erythrocytes.

Question 8

What is detected by a southwestern blot?

Answer 8

DNA binding protein

Question 9

What is used to detect DNA binding proteins in western blots?

Answer 9

Double stranded DNA probes.

Question 10

What are c-Jun and c-fos?

Answer 10

DNA binding proteins that bind DNA via a leucine zipper motif.

Question 11

What types of proteins are detected by Southwestern blots?

Answer 11

Transcription factors, nucleases, histones.

Question 12

What is the 16S rRNA and where is it found?

Answer 12

Found in the 30S subunit of prokaryotes. It contains a sequence complementary to Shine Delgarno sequence on mRNA; their binding initiates protein translation.

Question 13

How is the polyA tail transcribed?

Answer 13

Added as a posttranscriptional modification downstream of a consensus sequence; it is not transcribed from DNA

Question 14

What is the poly A tail consensus sequence?

Answer 14

AAUAAA

Question 15

What are the stop codons and what factors recognize and release them to terminate protein synthesis?

Answer 15

Releasing factors 1 and 3; they are UAA, UAG, UGA

Question 16

Name two properties of drugs with high intrinsic hepatic clearance?

Answer 16

High lipophillicity and high volume of distribution.

Question 17

What is the primary role of the liver vs the kidney in excretion?

Answer 17

Kidney- primary site of elimination; Liver- biotransformation to prepare for elimination.

Question 18

Describe the difference in location between enhancers/repressors and promoters in eukaryotic transcribed genes.

Answer 18

Promoters are located 25-70 bps upstream of their associated genes; enhancers/repressors can be located anywhere.

Question 19

What types of viruses are capable of genetic shifts through reassortment?

Answer 19

Viruses with segmented genomes (orthomyxoviruses, rotaviruses, etc.)

Question 20

What is the difference between genetic drift and genetic drift in terms of genome information alterations?

Answer 20

In genetic drifts, there is a single point mutation; in shifts, there is transfer of an entire segment of genome.

Question 21

What is expression cloning?

Answer 21

A type of DNA cloning where the signals necessary for transcription and translation are included in the cloned DNA; it allows bacteria to produce large amounts of a protein of interest.

Question 22

Name six types of proteins that can bind DNA and thus can be detected by DNA binding probes.

Answer 22

Transcription factors, steroids, thyroid proteins, vitamin D receptors, retinoic acid receptors, DNA transcription and replication proteins.

Question 23

In Downs syndrome, maternal nondisjunction occurs most commonly in what phase?

Answer 23

Meiosis I.

Question 24

What is phenotypic mixing?

Answer 24

Co-infection of a host cell by two viral strains, resulting in progeny virons that contain nucleotide capsid proteins from one strain and the genome of another strain. There is no change in genome so the next generation reverts to their original phenotypes.

Question 25

What is viral interference?

Answer 25

Inhibition by one virus of the replication and/or release of a second virus that is infecting the same cell.

Question 26

When is b-hCG detectable in maternal serum after ovulation?

Answer 26

Only after the blastocyst successfully implants. Implantation generally occurs on day 6 after ovulation thus b-hCG is usually detectable about 8 days after ovulation but it may take up to 11 days.

Question 27

What types of polymerases are used to by DNA to begin synthesis of daughter strands?

Answer 27

DNA dependent RNA polymerases.

Question 28

What enzyme removes RNA primers in bacterial DNA synthesis?

Answer 28

DNA polymerase I

Question 29

What is special about bacterial DNA polymerase I?

Answer 29

It is the only bacterial DNA polymerase with 5’-3’ exonuclease activity.

Question 30

Which histone proteins are not part of the nucleosome and are used to facilitate and package nucleosomes into compact structures?

Answer 30

H1 histones

Question 31

What is the function of H1 histones?

Answer 31

To bind the segment of DNA that lies between nucleosomes and facilitate the packaging of nucleosomes into more compact structures.

Question 32

In patients treated for allergic rhinitis, what type of receptor block causes facial flushing and pupillary dilation?

Answer 32

Muscarinic receptor blocking

Question 33

Name five classes of medications that have prominent antimuscarinic effects.

Answer 33

Atropine, TCAs, H1 receptor antagonists (ex. diphenhydramine), neuroleptics, antiparkinson drugs.