Enzymes and Proteins
ABC ATPase: ATP Binding Casette: superfamily of ATPase proteins which play a role in
active molecular transport. Noted defects are CFTR and ATP Binding Cassette I in
Adaptins: Proteins which link clathrin to membrane
7 methylguanylate (m7G) (cap): methylated guanine that is placed as a cap on 5 end of
synthesised nascent RNA
AAUAAA: termination signal for RNA transcription defines a poly(A) site
Activators: transcription factors which help to activate mRNA s
Camptothecin: Inactivates Topo I, anti-cancer
m-AMSA: Inhibits Topo II, anti-cancer
Acyclovir: potent inhibitor of DNA polymerase by herpes simplex viruses
Zidovudine (AZT): potent inhibitor of reverse transcriptase encoded by HIV. Limited by
Genetics Lecture 1 Mendelian Inheritance and Non-Mendelian Inheritance Part I
- only one copy of mutant allele needed
- heterozygote has chance to pass on mutant allele, therefore have affected offspring
- no gender bias
- unaffected in
What are the two precursors of insulin? Preproinsulin and proinsulin.
What kind of bond holds the two peptide chains of collagen to one another? Disulfide bonds and non-covalent interactions.
What are the two modified amino acids present in collagen? Hydr
What is the preferred metabolic fuel for skeletal muscle at rest? Fatty acids.
What is the preferred metabolic fuel for skeletal muscle at work? Glucose.
What is the preferred metabolic fuel for the heart? Fatty acids.
What is the preferred metabolic f
What prosthetic group do myoglobin and hemoglobin have in common? Both proteins contain a heme prosthetic group.
What is the difference between a prosthetic group and a coenzyme? A prosthetic group is firmly attached to a protein and usually cannot be rem
What kind of bond links the amino acid residues of a protein to one another? Peptide bond.
What is a polypeptide? A polypeptide is a chain of amino acids linked together by peptide bonds.
What is meant by primary, secondary, tertiary, and quaternary struc
What subunits make up a eukaryotic ribosome? 60S and 40S.
What is the sedimentation coefficient of eukaryotic ribosomes? 80S.
Where are ribosomes usually found in the cell? In the cytoplasm or attached to the endoplasmic reticulum.
What is the fate of pro
Cells in the brain and cells in the liver contain the same DNA. How is it that these cells are different cell types? Each cell type has a distinct pattern of gene expression.
What is a housekeeping protein and in which cell type is it found? These are pro
List three differences between RNA and DNA. 1. The pentose sugar in RNA is ribose rather than deoxyribose, 2. RNA has Uracil (U) instead of Thymine (T), and 3. DNA normally exists as a double helix whereas RNA exists as a single strand.
True or False. mRN
What is the function of restriction endonucleases? They are bacterial enzymes that recognize and destroy foreign DNA.
How do bacterial enzymes differentiate endogenous DNA from foreign DNA? Bacterial DNA is methylated by endogenous enzymes, whereas foreig
Which type of diabetes results from a loss of beta-cells in the pancreas, leading to a defect in the production of insulin? Type I diabetes (also called insulin-dependent diabetes).
Which type of diabetes results from a defect in the response to insulin?
Which cofactor is required for the conversion of tyrosine to dopamine? Tetrahydrobiopterin.
Which enzyme catalyzes the conversion of 3,4-dihydroxyphenylalanine (Dopa) to dopamine? Dopa decarboxylase.
How is thyroxine synthesized? It is made from the iodin
The first step in pyrimidine synthesis is the synthesis of carbamoyl phosphate in the cytoplasm. What is the enzyme that catalyzes this step? Carbamoyl phosphate synthetase II (CPSII); not to be confused with CPS I which is in the mitochondria and involve
The nitrogen atoms in purines come from which amino acids? Glycine, glutamine and aspartate.
In which organ does the de novo synthesis of purines primarily occur? Liver.
PRPP, or 5-phosphoribosyl-1-pyrophosphate, is an important intermediate in the biosyn
More than 95% of the amino acids in plasma are replaced every _ minutes. 10.
Increased levels of which of the following compound(s) reflects an increase in protein intake: urea, ammonia, uric acid, and/or creatinine? Urea.
Name two physiological examples
Which amino acids are solely ketogenic? Leucine and lysine.
Which amino acids are both ketogenic and glycogenic? Isoleucine, phenylalanine, threonine, tryptophan, and tyrosine.
At which points can the carbon skeleton of glycogenic amino acids enter carboh
What kind of bond is most critical for DNA recognition by proteins? Hydrogen bonding.
On which part of the DNA helix do proteins typically make contact with DNA bases? In the major groove of DNA.
Many proteins contain _ (structural motif) that can fit in
What are the two most significant sources of nitrogen in our body? Approximately 3/4 of nitrogen comes from the breakdown of the body's own proteins, and the remaining 1/4 comes from the breakdown of dietary proteins.
In which organ is the breakdown of di
What is the function of cholesterol with regards to cell membranes? It intercalates itself between phospholipids to reduce the fluidity of the membrane.
Which pancreatic enzyme hydrolyzes dietary cholesterol esters into cholesterol and free fatty acids?
What is the structural difference between phospholipids and glycolipids? Phospholipids have a charged phosphate group attached to their backbone whereas glycolipids contain an O-linked sugar.
Which molecule(s) make up the backbone of phospholipids? Eithe
Cells in the intestine use 2-monoacylglycerol (2-MAG) as a backbone to synthesize fatty acids. What do hepatocytes use as a backbone for fatty acid synthesis? Activated glycerol.
Nascent lipoproteins in the liver are associated with which lipoprotein? Ap
In which cellular compartment does fatty acid synthesis occur? Cytoplasm.
What molecule is the major source of carbons for fatty acid chain synthesis? Acetyl-CoA (from mitochondria).
In order to direct acetyl-CoA into fatty acid synthesis, the TCA cycle
Carbons in fatty acids are numbered from the _ (functional group) carbon towards the terminal _ (functional group) carbon. Carboxyl, methyl.
Where is the beta carbon positioned on a fatty acid chain? The beta carbon is the 3rd carbon from the carboxyl end
Describe the structure of glycogen. Glycogen is composed of glucose molecules linked linearly with alpha(1->4) bonds, with branching chains linked alpha(1->6) to the main glucose chain at intervals of approximately eight residues.
In which tissue(s) is gl
Describe the structure of porphin rings. All porphin rings are a tetrapyrrole connected with methene bridges.
What is the most abundant porphyrin in mammals? Protoporphyrin.
In which tissue is most of the heme in mammals synthesized? Pre-erythroid cells
Name three enzymes that donate electrons to the electron transport chain from their flavin (FAD) prosthetic group. Succinate dehydrogenase, acyl-CoA dehydrogenase and glycerol phosphate dehydrogenase.
How many moles of ATP can be produced per mole of NADH
What are the chemical parts of a nucleotide? A nucleoside? Nucleotides contain a base, a sugar and a phosphate(s). Nucleosides contain only a base and a sugar.
What is the chemical difference between the second carbons of RNA and DNA? RNA has a 2' OH grou
What is the purpose of gluconeogenesis? To maintain blood glucose levels after glycogen stores have been depleted.
In what organ(s) does gluconeogenesis occur? 90% in the liver and 10% in the kidneys.
What are the three main substrates for gluconeogenes