Biochem: Molecular Bio Flashcards
T/F: Amino acids are produced by the hydrolysis of nucleic acids.
False
What are the three major groups that make up DNA?
Sugar (-ose), phosphate, and amine base
Which base pair will have three hydrogen bonds?
G and C will always have THREE
A-T/U has two hydrogen bonds
T/F: A bond between guanine and cytosine will have a higher melt temp than adenine and thymine.
True
More bonds = stronger bond = higher melt temp
Which nucleotides are purines?
Pure Silver (Ag)
Adenine and guanine are purines
Which nucleotides are pyrimidines?
CUT the Py
Cytosine, Thymine, and uracil are pyrimidines
What type of bond links the monomeric units of nucleic acids?
Phosphodiester bonds at third and fifth carbons
T/F: DNA with a higher G-C content will have a higher melt temp.
True
Which base pair is found in DNA but not RNA?
A-T
Replaced with A-U
Histones add strength and support to DNA. What are they made of?
Basic amino acids such as lysine and arginine
Which RNA type is the most prevalent?
rRNA
T/F: mRNA contains the anticodon for ribosomes to read.
False
mRNA carries codon out of nucleus to ribosomes
T/F: Purines contain two ring structures.
True
What type of bonds hold the histone complex together?
Ionic bonds
What are the four major enzymes in DNA replication and what are their functions?
- Helicase - unwinds
- Primase - starts
- DNA polymerase - forms new DNA in 5’->3’
- Ligase - joins Okazaki fragments to the lagging strand
New DNA is always formed in which direction?
5’->3’
What is the difference on the leading strand vs the lagging strand?
When DNA is split - the end with 3’ is leading strand and the end with 5’ is lagging strand
DNA polymerase can run from 3’->5’ (leading strand) continuously
Since lagging strand runs from 5’->3’, DNA polymerase makes Ozaki fragments
T/F: Introns are removed from RNA in splicing.
True
Which enzyme catalyzes formation of uric acid from purines?
Xanthine oxidase
T/F: mRNA activates and selects the specific amino acids for protein synthesis.
False
tRNA does this with anticodon
HIV and Hep B utilize which enzyme to copy RNA into cDNA?
Reverse transcriptase
How does UV light damage DNA?
Dimerization adding bonds between thymine groups
T/F: Enzymes always read in 3’->5’ and build in 5’->3’.
True
What are the three codons that are nonsense and do not code for an amino acid (termination)?
UAA, UAG, UGA
What is the start codon?
AUG - Methionine
Replacement of guanine with an adenosine would be a ________ mutation.
transition
transverse is when pyrimidine is replaced with purine or vice versa
What is a missense mutation?
Causes new amino acid
What is the action of exonuclease?
Removes nucleotides to repair DNA
T/F: DNA replication, translation, and protein synthesis all occur in the M phase of the cell cycle.
False
Which phase involves DNA replication?
S phase
Which various blotting techniques identify which structures?
Sunny Day, No Rain, Warm Picnic
Southern: DNA
Northern: RNA
Western: Protein
T/F: Western blots use cDNA as a probe.
False
Antibodies
All others use cDNA
What will molecules do once they reach the their isoelectric pH in gel electrophoresis?
Stop moving
Which way will a molecule move a the pH is below the isoelectric point?
Toward the anode (negative pole)
