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USMLE 1 Review: Molecular Bio, Biochem, and Genetics
Review
48
Medical
Professional
06/15/2010

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Cards

Term
Which nucleotide bases are purines and which are pyrimidines?
Definition
PYrimidines = "CUT the PY" = Cytosine, Uracil, Thymine
PURines = PURe As Gold = Adenine and Guanine
Term
Which proteins make up the core of a nucleosome?
Definition
Histones = H2A, H2B, H3, H4
Term
Which proteins are associated with DNA between nucleosomes?
Definition
Histone H1
Term
Type of mutation that does not result in a change in the amino acid sequence?
Definition
silent
Term
Type of mutation that results in a change in the amino acid sequence?
Definition
Missense
Term
Type of mutation that results in a stop codon?
Definition
Nonsense "NO sense"
Term
Type of mutation that changes the reading frame?
Definition
frameshift
Term
Type of mutation in which a portion of DNA is lost?
Definition
Deletion
Term
Type of mutation in which a single base is exchanged?
Definition
point
Term
failure of chromosomes to disjoin properly during cell division?
Definition
nondisjunction
Term
What is the loss of a portion of a chromosome?
Definition
deletion
Term
Two internal chromosomal breaks with inverted reincorporation of a portion of the chromosome?
Definition
inversion
Term
Single breaks in two chromosomes resultnig in exchange of the two segments between the chromosomes without the loss of genetic material?
Definition
balanced reciprocal translocation
Term
Single breaks in 2 acrocentric chromosomes resulting in one large chromosome and one small one accompanied by the loss of some genetic material - hereditary form of down syndrome?
Definition
Robertsonian translocation
Term
Mitotic error in early development leading to the development of two karyotypically distinct populations of cells in an organism?
Definition
mosaicism
Term
What term is used to describe the AT rich sequences in the genome where DNA replication begins?
Definition
Origin of replication
Term
What is the start codon?
Definition
AUG
Term
In which direction are DNA and RNA made?
Definition
5' to 3'
Term
What are the three stop codons?
Definition
U Go Away = UGA (Univ of GA)
U Are Away = UAA
U Are Gone = UAG
Term
What term is used to describe the DNA strand made discontinuously away from the replication fork?
Definition
lagging strand
Term
What term is used to describe the DNA strand synthesized continuously toward the replication fork?
Definition
leading strand
Term
Which proteins are involved in removal of damaged bases from DNA?
Definition
apurinic or apyrimidinic endonuclease, exonuclease and DNA ligase
Term
Which proteins are used to repair UV damage to DNA?
Definition
UV specific endonuclease, exonuclease and DNA ligase
Term
Which proteins are used for proofreading newly made DNA strands?
Definition
DNA Pol III (3'-5' exo)
Term
Which proteins are used in DNA chain elongation in prokaryotes?
Definition
DNA Pol III
Term
Which proteins are used in the removal of RNA primers from DNA made discontinuously?
Definition
DNA Pol I (5' to 3' exo)
Term
Which proteins are used in the placement of RNA primers at the site where replication is initiated?
Definition
Primase and RNA Polymerase
Term
Which proteins are used in the prevenetion of supercoiling during replication?
Definition
DNA topoisomerases
Term
Which proteins are used in the unwinding of the DNA double helix?
Definition
DNA helicase
Term
Which proteins are used in the recognition of AT rich sequences and origin of replication and separation of DNA strands in bacteria?
Definition
DnaA protein
Term
Which protein is used to stabalize single-stranded DNA?
Definition
Single stranded DNA binding proteins
Term
What is the largest RNA molecule?
Definition
mRNA
Term
What is the most abundant type of RNA?
Definition
rRNA
Term
What is the smallest RNA molecule?
Definition
tRNA
Term
What is the portion of RNA transcript encoding information for protein synthesis?
Definition
exons (exons are expressed)
Term
Portion of the RNA transcript that is found between sequences of RNA encoding info for protein synthesis?
Definition
introns
Term
Type of RNA covalently bound to a single amino acid?
Definition
tRNA
Term
Region of genomic DNA where RNA polymerase and transcription factors bind to regulate transcription?
Definition
promotor
Term
Region of genomic DNA where transcription factor activators bind to enhance transcription?
Definition
Enhancer
Term
region of genomic DNA where repressors bind?
Definition
silencer
Term
Enzyme needed for synthesis of rRNA? mRNA? tRNA?
Definition
rRNA = RNA Pol I
mRNA = RNA Pol II
tRNA = RNA Pol III
Term
Name the three major regulatory mechanisms of transcription in eukaryotes?
Definition
1. regulation by transcription factors at the level of the promotor
2. regulation by histones binding to specific genomic regions
3. regulation of DNA structure - methylation, rearrangement, amplification
Term
What genetic structure regulates transcription in prokaryotes?
Definition
operon
Term
Which part of the operon is reponsible for:
1. region where proteins bind to enable transcription
2. molecule that binds at the promotor
3. sequence in DNA where regulatory proteins bind
4. molecule that binds the operator to regulate transcription
Definition
1. promotor region
2. activator or repressor
3. operator
4. repressor
Term
What are the three modifications made to an RNA transcript before it leaves the nucleus?
Definition
1. 5' capping
2. 3' polyadenylation
3. splicing of introns
Term
which small molecule provides the energy for charging a tRNA with its amino acid?
Definition
ATP
Term
Which small molecule provides the energy for binding a tRNA with its amino acid?
Definition
GTP
Term
Which molecules central to the discipline of molecular bio, recognize and cleave specific sequences of a DNA molecule?
Definition
restriction enzymes
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