Biochem Exam 4 Flashcards
What are the purine bases?
adenosine and guanine
What are the pyrimidine bases
cytosine ,thymine, uracill
ribonucleotides
structural units of RNA
antiparallel
3 prime to five prime phosphodiester bonds run in opposite directions
parallel
3 prime to five prime phosphodiester bonds run in the same direction
phosphodiester linkage
covalent bond that joins successive nucleotides between DNA and RNA
What is the spectrometry finding of nucleotide bases
all bases absorb UV light. peak at 260nm
B form DNA
most stable for DNA molecules under physiological conditions Watson crick structure
Z form DNA
left handed helix more slender and elongated in shape 12bp/turn
A Form DNA
right handed helix . favored in the absence of water 11bp/turn. wider helix more tilted plane
palindrome
region of DNA that is identical when read forwards or backwards. applied to regions of DNA with inverted repeats
mirrored repeat
sequence when inverted repeat appears on the same strand
Contigs
long, contiguous sequences that are assembled from overlaps
Deamination
spontaneous loss of exocyclic amino groups
Hypochromic effect
the observed decrease in the absorption of UV light when complementary strands are paired
Hyperchromic effect
the observed increase in the absorption of UV light when a double-stranded nucleic acid is denatured
Monocistronic
codes for one polypeptide mostly in eukaryotes
Polycistronic
codes for 2+ different polypeptides bacteria and archaea
Malate dehydrogenase
reduces oxaloacetate to malate
Malic enzyme
oxidizes malate to pyruvate
Citrate transporter
transports citrate through the inner mitochondrial membrane
Citrate synthase
catalyzes the formation of citrate from acetyl-CoA and oxaloacetate
Citrate lyase
= catalyzes cleavage of citrate to regenerate acetyl-CoA and oxaloacetate
Statins
drug class used to treat patients with elevated serum cholesterol
Low-density lipoprotein (LDL
Rich in cholesterol and cholesteryl esters
Carries cholesterol to extrahepatic tissues and macrophages
HDL
lipoproteins that originate in the liver and small intestine as small, protein-rich particles
Mediates cholesterol scavenging and transport back to the liver to flush out
Biliary cholesterol
cholesterol contained in bile
What does bile do?
Bile removes excess cholesterol from the intestine and facilitates excretion
Bile acids
the principal components of bile, a fluid stored in the gallbladder
HMG-CoA reductase =
an integral membrane protein of the smooth ER that catalyzes the reduction of HMG-CoA to mevalonate
Carnitine
compound that transports fatty acyl-CoAs destined for mitochondrial oxidation across the inner mitochondrial membrane
Nucleotide-binding fold
single protein domain that binds adenosine
The double helix is stabilized by:
Metal cations that shield the negative charges of backbone phosphates
Base stacking interactions between successive base pairs
G and C content
Does hydrogen bond contribute to DNA stability
NO
N glycosol bond
covalently joins the 1′ carbon of the pentose to the base (at N-1 of pyrimidines and N-9 of purines
mRNA
portion of cellular RNA carrying the genetic information from DNA to the ribosome
Transcription
process by which mRNAs are formed on a DNA template
Carnitine shuttle =
transports long-chain fatty acids (containing 14+ carbons) through the mitochondrial membrane
Requires activation to a fatty acyl-CoA and attachment to carnitine
Fatty acyl-CoA
contains a thioester linkage between the fatty acid carboxyl group and the thiol group of coenzyme A
high energy hydrolysis of 2 ATP bonds
Carnitine acyl-transferase 1, CAT1 (carnitine palmitoyltransferase 1, CPT1
catalyzes a transesterification reaction to transiently attach a fatty acyl-CoA to the hydroxyl group of carnitine to form fatty acyl-carnitine
Acyl-carnitine/carnitine cotransporter =
allows the passive transport of the fatty acyl-carnitine ester
Carnitine acyltransferase 2 (CAT2, CPT2
transfers the fatty acyl group from carnitine back to coenzyme A to regenerate fatty acyl-CoA and free carnitine
Coenzyme A in the cytosol is used in
biosynthesis of fatty acids
Coenzyme A in the mitochondrial matrix is largely used in
oxidative degradation of pyruvate, fatty acids, and some amino acids
Probiotics are
foods or supplements that contain live microorganisms intended to maintain or improve the “good” bacteria (normal microflora) in the body
Prebiotics
foods (typically high-fiber foods) that act as food for human microflora.
