Notes/Add. Pointers for Lab Flashcards
Functions of amino acids:
- to serve as building blocks for proteins
- constituents of proteins
- act as the monomer unit in protein synthesis
T/F - Your body needs 20 different amino acids to function correctly.
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Functions of Proteins:
Structural – for support (ex. collagen, elastin)
Catalytic – for hastening biochemical reactions (ex. amylase)
Storage – for storage of amino acids (ex. casein, ovalbumin)
Transport – for transport of other substances (ex. hemoglobin)
Regulation – for regulation of bodily activities (ex. insulin, glucagon)
Receptor – for response of cell to external stimuli (ex. neuron receptors)
Contractile – for movement (ex. myosin, actin)
Defensive – for protection against disease (ex.antibodies)
T/F - Millon’s test is an analytical test used for the detection of the amino acid tyrosine, which is the only amino acid containing the phenol group.
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Test that detects tripeptides
Biuret test (at least two peptide bonds)
T/F - Xanthoproteic test is used to detect amino acids containing an aromatic nucleus (tyrosine, tryptophan and phenylalanine) in a protein solution which gives yellow color nitro derivatives on heating with conc. HNO3.
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factors that denature proteins
Heat, acid, high salt concentrations, alcohol, and mechanical agitation
the biuret reagent is made up of (salts)
hydrated copper sulfate
sodium hydroxide
Rochelle salt (sodium-potassium tartrate)
how do heavy metals denature proteins?
Heavy metal salts, Ag+, Hg+ and Pb+ denature proteins by reacting with the sulfhydryl groups to form stable, metal-sulfur bonds. This prevents formation of needed disulfide bonds.
what test uses HNO3?
Xanthoproteic test (involves heating of protein with conc. HNO3 which produces yellow colour)
Function of proenzymes
group of proteins that display no catalytic activity but can be transformed into active enzymes within an organism.
Products of urea cycle:
1 molecule of urea
2 molecules of ADP
1 molecule each of AMP
fumaric acid
Overview of Urea Cycle
The urea cycle or ornithine cycle converts excess ammonia into urea in the mitochondria of liver cells. The urea forms, then enters the blood stream, is filtered by the kidneys and is ultimately excreted in the urine.
the urea cycle consumes _______ by combining it with the basic ammonia, helping to maintain a neutral pH.
acidic waste carbon dioxide
One of the nitrogen atoms in the urea cycle is obtained from the ___
transamination of oxaloacetate to aspartate
(The fumarate that is produced in step three is also an intermediate in the citric acid cycle and is returned to that cycle)
urea cycle takes place in what organ?
The liver (only site where urea is synthesized and ultimately excreted by the kidneys)
not present in the urea cycle
Asparagine
fate of amino group in citrulline-aspartate condensation
A condensation reaction occurs between the amino group of aspartate and the carbonyl group of citrulline to form argininosuccinate.
The eleven non-essential amino acids are:
alanine
arginine
asparagine
aspartic acid
cysteine
glutamic acid
glutamine
glycine
proline
serine
tyrosine
nine essential amino acids:
histidine
isoleucine
leucin
lysine
methionine
phenylalanine
threonine
tryptophan
valine
a biologically important process by which living cells reversibly transfer the amino group from an amine or α-amino acid to an α-keto carboxylic acid
Transamination
Role of chymotrypsin
a digestive enzyme synthesized in the pancreas that plays an essential role in proteolysis, or the breakdown of proteins and polypeptides
aids in the digestion of proteins in the duodenum by preferentially cleaving peptide amide bonds.
chymotrypsin
a serine protease produced by the pancreas that catalyzes cleavage of carboxyl groups present on small hydrophobic amino acids, such as glycine, alanine, and valine.
Elastase
the breakdown of elastin, a protein that imparts elasticity to connective tissue.
elastase
breaks down proteins as a component of the digestive process.
trypsin
acts on proteoses and peptones and converts them into polypeptides.
trypsin
secreted by the pancreas as trypsinogen, is activated by enterokinase in the duodenum, and hydrolyzes protein molecules to peptides and amino acids.
trypsin
involved in the degradation of proteins in the digestive tract
Digestive carboxypeptidases A and B
a zinc-containing metalloprotease that removes the amino acid residue from the C-terminal of a peptide chain
Carboxypeptidase A
acts upon basic amino acids, such as arginine and lysine (releases C-terminal lysine and arginine from substrates)
Carboxypeptidase B
a method to purify DNA by using physical and/or chemical methods from a sample separating DNA from cell membranes, proteins, and other cellular components.
DNA extraction
causes local pH changes and denatures proteins
HCl
Lab technicians can add ethanol or isopropyl alcohol (rubbing alcohol) so that the DNA clumps and form a visible white precipitate. t’s important to use cold alcohol because?
it allows a larger amount of DNA to be extracted. If the alcohol is too warm, it may cause the DNA to denature [bold], or break down.
What is the complementary base pairing rule for DNA?
in a double strand of DNA, adenine will always pair with its complement thymine and cytosine will always pair with its complement guanine.
