Exam 1 9/6 Dr. Howard Flashcards
Globular proteins function
- regulatory, maintenance and catalytic roles
- dissolve or form colloidal suspensions in water
- sensitive to temperature and pH change
What are fatty acids?
long chain hydrocarbons represented by the chemical formula R-COOH
Enzyme regulation is accomplished by:
amount of enzyme, modification of enzyme activity
Examples of fibrous proteins
collagens and elastins, keratins, fibrin
Triglycerides are hydrolyzed by:
lipases
Which amino acids are acidic?
glutamic acid, aspartic acid
How to overcome competitive inhibitor
increase substrate concentration
Which amino are aliphatic?
glycine, alanine, valine, leucine, isoleucine
uncompetitive inhibitors
bind to ES complex, cannot be overcome by more S
lineweaver burk plot x axis intercept
-1/kM
True or false: sucrose is a reducing sugar
False - no free anomeric carbon
Two categories of proteins
Fibrous proteins and globular proteins
True or false: alpha carbon in amino acid is chiral
True - it is asymmetrical so is a chiral center, except for glycine
HbA1C
Measure of long term glucose control
Examples of molecules where carbohydrates are attached to noncarbohydrates
-purine and pyrimidine bases
-aromatic rings (ie steroids)
-proteins (glycoproteins, proteoglycans)
-lipids
keratins are major components of
skin and hair
When a hemiacetal is formed, what is created?
Anomeric carbon at carbon 1 (asymmetric)
Fructose anomeric carbon
Carbon 2
Catabolism
Releases energy to break down polymers into monomers
Most abundant lipid
triglycerides
Glycogen structure
Heavily branched linked chains of glucose (alpha 1,4 and 1,6 linkages)
Characteristics of fibrous proteins (3)
- fiber-like structures
- insoluble in water
- unaffected by changed in temperature and pH
Velocity ___ with substrate concentration
increases (eventually reaches vmax when all active sites are saturated)
Polar amino acids
S T N Q D E H K R C Y
HbA1C measured by:
amount of glycosylated hemoglobin. Normal people <6%, diabetic >10%
__ is chiral for glyceraldehyde
C2
Hydroxyl group can react with aldehyde or ketone to form:
Hemiacetal (ring structure)
Proline causes:
bends in proteins
aldohexose has _ chiral centers
4
Carbonic anhydrase catalyzes:
forward and backwards reaction of bicarbonate buffer system between CO2 + H2O <-> H2CO3
Protein that forms when blood clots
Fibrin
Acylglycerols
neutral fat, glycerides
Enzyme kinetics Km:
substrate concentration where velocity is at half of max
lineweaver burk plot slope
km/vmax
competitive inhibitor effect on km and vmax:
increases kM, vmax stays the same
Which amino acids have negative charges at pH 7?
aspartic acid, glutamic acid
True or false: there are only trace amounts of free fatty acids in the body
True
AGE
advanced glycosylation end products; AGE = glucose + products
smallest carbohydrates are:
aldose and ketose (3 carbons)
Which amino acids are neutral?
serine, threonine, asparagine, glutamine
which residue is hydroxylated in collagen?
proline and lysine
Anabolism
Monomers are used to create polymers with energy input (build molecules)
Aromatic amino acids unique property
Absorb uv light ~280 nm
Sucrose
glucose + fructose
The arrangement of sugars into D and L configurations is based upon their resemblance to D and L?
Glyceraldehyde
Product of starch digestion
beta-maltose
Naturally occurring form of carbohydrates in humans is mostly ___
D enantiomer
aldohexose has _ stereoisomers
2^4 = 16 (8 D sugars, ex glucose, mannose, fructose)
How is enzyme activity modified
- allosteric control (changes in substrate, activators, inhibitors)
- isozymes of multiple forms of enzyme
- covalent modifications
True or false: cellulose is digestible
False - we do not have the enzymes to break it down
Difference in structure of galactose and glucose
orientation of the hydroxyl group (OH) at carbon 4
Principle fat storage is via what molecule?
triglycerides
How are -uronic acids formed?
OH group replaced by an -NH2 or acetylated -NH2
D-glucose preferred structure
Ring. more stable
Which 3 reactions of the 4 basic biological compounds require condensation reactions?
protein synthesis, DNA and RNA formation from nucleotides, starch/glycogen production from monosaccharides
Reducing sugar assay for measuring blood sugar levels
Benedicts/Fehlings solution is heated, reduces Cu2+ to Cu+, forms red colored precipitate
Isoelectric point
pH at which there is equal number of positive and negative ions so overall charge is zero
glucose, galactose, and six other sugars are all:
aldohexoses
____ _____ of glutamate in prothrombin - an essential blood clotting factor; requires ______
gamma carboxylation; requires vitamin k
aliphatic
having a straight or branched chain structure; opposite of aromatic
amphoteric
able to react both as a base and as an acid
Most abundant sterol in animal tissue
Cholesterol
example of ketohexose
fructose
noncompetitive inhibitor effect on km and vmax:
decrease vmax, kM unchanged
Collagens are found in
skin, bone, tendon, cartilage, teeth
Which amino acids can be phosphorylated?
tyrosine, serine, threonine
Which amino acids contain sulfur?
cysteine, methionine
Amylases like ptyalin in saliva digest ____ to form ____
starch; maltose
cellulose is linked by:
beta 1,4 linkages
Which amino acids do sugar linkages occur on?
S, T, N
Which amino acids are basic?
histidine, lysine, arginine
What is the exception to protein molecules as enzymes?
ribozymes
Allosteric enzymes show ___ curve
sigmoidal
Function of bicarbonate buffer system:
- maintain blood pH
- Used extensively to create acidic or alkaline environments
True or false: there is an anomeric carbon in sucrose
False
Nonpolar amino acids:
G A L V I M F W P
____ is found at every 3rd amino acid in collagen
glycine (G)
What does AGE do
alters normal protein function, detrimental (aging, arteriosclerosis, diabetes)
Polypeptide chain backbone has large potential for:
hydrogen bonding
Function of lipids
- energy storage
- structural components of membrane
- precursors for hormones, vitamins, bile salts
- cellular messengers
- lipid mediators
collagen is made up of
3 helical polypeptides
True or false: biomembranes require condensation reactions in order to form
False - spontaneously form due to nature of lipids
uncompetitive inhibitor effect on km and vmax:
decreases both
Globular proteins characteristics
nonpolar interior, polar charged on surface
Phosphoglycerides made from:
alcohol component esterified to phosphoric acid group to form phosphodiester
ketohexose # of D sugars
4
Which amino acids are aromatic?
tyrosine, phenylalanine, tryptophan
collagens and elastins are found in:
connective tissues, tendons, ligaments
Which isomer is found exclusively in proteins?
L isomer
competitive inhibitor competes for:
active site
Which amino acid is methylated in membrane receptors
Histidine
True or false: All monosaccharides are reducing sugars
True
Lactose bond
beta 1,4 linkage
True or false: noncompetitive inhibitor can be overcome by increasing S
false
Bicarbonate buffer system equation
CO2 + H2O <-> H2CO3 <-> H+ + HCO3-
True or false: maltose is a reducing sugar
True
noncompetitive inhibitor binds to:
site other than active site, can bind to enzyme or enzyme substrate complex
____ is the most abundant carbohydrate in mammalian cells
Glycogen
amphipathic
having both hydrophilic and hydrophobic parts
How many residues of glucose in cellulose?
> 3000
Starch made up of:
more than 200 molecules of glucose
Which amino acids can form disulfide bridges?
cysteine
lineweaver burk plot y axis intercept
1/vmax
___ proteins are not sensitive to changes in temperature and pH
fibrous proteins
In tissues, glucose is converted to:
glycogen (liver and muscles)
