What defect is present in osteogenesis imperfecta?
bulky side chains replace glycine in collagen to triple-helical conformation (tropocollagen) cannot form
What is another name for osteogenesis imperfecta? What is the main symtom of OI?
brittle bone syndrome, bones bend and fracture
What is another name for sickle cell disease?
hemoglobin S disease
What defect is present in sickle cell anemia?
val replaces glu at position 6 of the beta-globulins in hemoglobin creating an unstable quarternary structure
What will low oxygen trigger in an individual with sickle cell ds?
the subunits of hemoglobin will become linear, the RBCs will distend and thier lifespan will decrease to less than 20 days
What race and age of people are most commonly affected by sickle cell ds?
What is alpha-antitrypsin?
a protease inhibitor that protects the lungs and liver
What are the two main symptoms of an alpha-antitrypsin (AAT) deficiency?
emphysema and cirrhosis
What is sanger's method?
an AA sequencing method of removing the N-terminal of the peptide as a dinitrophenyl (DNP) by adding 1-fluoro-2,4-dinitrobenzene
What enzyme will remove the C-terminal of a peptide?
What enzyme will cut at lys and arg?
What two enzymes cut at the aromatics (phe, trp, tyr)?
chymotrypsin and pepsin
What side of the AA do trypsin, chymotrypsin and pepsin cut from?
What do enzymes do? What do enzymes not do?
They increase the rate of a reaction by lowering the activation energy. They do not affect the equilibrium of the reaction.
What do lyases do?
they add or remove atoms from a double bond
What do ligases do?
combine molecules using ATP
What is the active site of an enzyme?
The site where substrate binds to the enzyme
Where does a competitve inhibitor bind? Will adding more substrate reverse its effects?
Active site, yes
Where does a noncompetitive inhibitor bind? Will adding more substrate reverse its effects?
A site separate from the binding site, no
What are the two types of cofactors?
metal and organic
Which type of cofactor are coenzymes and what do they do?
they are organic, they provide a functional group
What does FAD stand for? *Board Q
Flavin adenine dinucleotide
What does NAD stand for? *Board Q
Nicotinamide adenine dinucleotide
What coenzyme is formed from B2? *Board Q
What is the name of B2? *Board Q
What chemical group is transferred by FAD? *Board Q
What coenzyme comes from B3? *Board Q
What is the name of B3? *Board Q
What chemical group is transferred by NAD? *Board Q
What coenzyme comes from B5? *Board Q
What is the name of B5? *Board Q
What chemical group is transferred by coenzyme A? *Board Q
What coenzyme comes form B6? *Board Q
What is the name of B6? *Board Q
What chemical group is transferred by pyridoxal phosphate? *Board Q
What conezyme comes for B1? *Board Q
What is the name of B1? *Board Q
What chemical group is transferred by thiamin pyrophosphate (TPP)? *Board Q
What coenzyme is formed from B7? *Board Q
What is the name of B7? *Board Q
What coenzyme is the same as the vitamin it comes from? *Board Q
What chemical group is transferred by Biotin? *Board Q
What conezyme is formed from B9? *Board Q
What is the name of B9? *Board Q
Waht chemical group is transferred by THF? *Board Q
one carbon (methyl) group
What is the activation energy?
The energy required to reach the transition state
How does an enzyme decrease the activation energy of a reaction?
When substrate and enzyme bind a conformational change occurs in the substrate so that the activation energy is lowered
What is the rate limiting step?
the step with the highest activation energy (slowest)
Would an enzyme with a high affinity for its substrate have a high or low Km?
When Vo is (1/2)Vmax, what does Km = ?
What does the slope of the lineweaver-burke plot equal?
What is the y-intercept of the lineweaver-burke plot?
What is the x-intercept of the lineweaver-burke plot?
What do irreversible inhibitors do?
bind permanently, prevent the reaction from occuring
How do reversible competitive inhibitors affect Km and Vmax?
increase, no effect
How do reversible noncompetitive inhibitors affect Km and Vmax?
no effect, decrease
What are the three types of enzyme regulation?
Allosteric (reversible binding of an activator or inhibitor), covalent modification (ex. phosphorylation by kinase or removal of phosphate by phosphatase), activation by proteolytic cleavage of a zymogen (inactive precursor - short peptide blocks active site)
What is the zymogen of pepsin? What is it secreted by?
What are the three zymogens secreted by the pancrease and what are their active forms?
What are fatty acids? Are they polar or non-polar?
long hydrocarbon chains with a carboxylic acid on the end, they are amphipathic (have both polar and nonpolar parts)
What does saturated mean (when referring to fatty acids)?
there are no double bonds (saturated with hydrogen)
What type of double bonds (cis or trans) are found in naturally occuring unsaturated fatty acids?
What are three differences between saturated and unsaturated fatty acids?
Saturated fatty acids pack closer together, they have a higher melting temp., they are less fluid
How are fatty acids described (what numbers are used, how are they written)?
# of carbons:# of double bonds(delta)position of double bonds
What is the omega end? How is it used to name fatty acids?
The omega carbon is the carbon furtherest from the carboxyl end. Fatty acids can be named by the position of the double bond closests to the omega carbon (ex. an omega 1 fatty acid would have a double bond between the omega carbon and the carbon adjacent to it)
What are the three essential fatty acids?
Arachidonic acid, linoleic acid and alpha-linolenic acid
Which two omega 6 fatty acids are essential? How many carbons and double bonds do they have?
linoleic acid, 18:3, arachidonic acid 20:4
Which omega 3 is essential? How many carbons and double bonds does it have?
What are triacylglycerols made of?
glycerol and 3 fatty acids
Where do oils come from? Are they saturated or unsaturated? What is the exception?
plants, all unsaturated except cocunut oil which is saturated
Where do fats come from? Saturated or unsaturated?
What is olestra? What vitamins does it deplete in the body?
fat substitute which is not absorbed by the body, depletes A,D,E,K
What does lipase do?
Break down triglycerides in the adipocytes and the intestines
What is saponification?
Making soap by adding triglycerides, NaOH and heat
How do phosphoacylglycerols (phospholipids, phosphoglycerides) differ from triacylglycerides?
An ester replaces one fatty acid
Where is phospholipase A2 found? What does it do? *Board Q
snakes, hydrolyzes the second fatty acid in triacylglycerides --> dissolves membranes of RBCs
What is a sphinolipid?
sphingosine + 1 fatty acid + O-X
What accumulates in Tay-Sachs? What 3 places does it accumulate? What deficiency causes this? What is the result of Tay-Sachs?
gangliosides (oligosaccharides) accumulate in nerve cells, brain and spleen causing death, defeciency in hexosaminidase A
Niemann-Pick is a deficiency in what? What are the symptoms?
sphingomyelinase (phosphocholine) which makes up myelin, mental retardation and death
What is Gaucher ds a deficiency in? What accumulates? What are the 3 symptoms?
glucocerebrosidase deficient, glucocerebrosides (sugar) accumulates causing an enlarged liver and spleen, bone pain, anemia
A transport protein in the membrane that only transports one molecule
What is a symporter?
A transport protein in the membrane that transports two molecules in the same direction
What is an antiporter?
A transport protein in the membrane that transports two molecules in opposite directions
What is facilitated diffusion?
Transport of molecules by membrane proteins without the use of energy (from high to low concentration)
What is active transport? What is the difference between primary and secondary?
Transport from low to high concentration (requires energy), in primary the energy comes from ATP, in secondary the energy comes from simultaneously transporting another molecule from high to low concentration
What is an example of primary active transport?
Na-K pump (3Na out, 2K in)
What is an example of secondary active transport?
Na-glucose pump (glucose moves high to low while Na moves low to high)
What is the general formula for carbohydrates?
What type of sugar is glyceraldehyde?
What type of sugar is dihydroxyacetone?
What type of sugar is ribose?
What type of sugar is glucose?
What type of sugar is galactose?
What type of sugar is fructose?
What 3 ketones exhaled by diabetics?
Acetone, acetoacetate, beta-hydroxybutyrate
What does "ul" in the name of a sugar indicate?
It is a ketose
What monosaccharide does not have at least one chiral center?
What is the number of chiral centers in an aldose?
# of C's - 2
What is the # of stereoisomers of a monosaccharide?
2# of chiral centers
What chiral carbon is the D or L of a sugar based on?
the one furthest from the carbonyl
What are epimers?
Sugars that differ around only 1 chiral carbon
What is an example of an epimer?
Glucose and Galactose
What type of ring do aldoses form?
What are two common monosaccharides tha form pyranose rings?
What type of ring do most ketoses form?
What are two common furanoses?
What is the anomeric carbon of a monosaccharide ring? What does it form?
Carbon that was part of the carbonyl group, forms the reducing end of the sugar
What is the structure of maltose? Is it reducing?
glucose and glucose form a (1,4)-o-glycosidic bond, reducing
What is the structure of trehalose? Is it reducing?
glucose and glucose form a (1,1)-o-glycosidic bond, non-reducing
What is the structure of lactose? Is it reducing?
glucose and galactose form a (1,4) bond, reducing
What is the structure of sucrose? Is it reducing?
fructose and glucose form a (1,2) bond, non-reducing
What are 3 common examples of homopolysaccharides?
Starch, glycogen and cellulose
Is amylose branched? What type of O-glycosidic bonds does it have?
No, alpha1-4 only
Is amylopectin branched? What type of O-glycosidic bonds does it have?
highly branched, alpha1-4 and alpha1-6
Is glycogen branched? What type of O-glycosidic bonds does it have?
Even more branched than amylopectin, alpha1-4 and 1-6
What are the two types of starch and where do they come from?
amylose and amylopectin, from plants
Where is glycogen found?
What type of O-glycosidic bonds does cellulose have? Where is it found? Can we digest it?
beta1-4, plant (structural), no
Where are peptidoglycans found?
Bacterial cell walls
Where are glycoproteins found?
plasma membranes, hormones, antibodies
What is the difference between an enantiomer and an epimer?
An enantiomer is the mirror image (all of the chiral carbons have groups switched), an epimer has groups switched at only one carbon
What does UDP do to glucose? Where does this occur?
Cytoplasm, UDP activates it and marks it for polymerization (add to glycogen)
Glucose is converted to G6P by which enzymes and what coenzyme?
Hexokinase (all other tissues), Glucokinase (liver), ATP
Which has a higher Km hexokinase or glucokinase?
What enzyme converts G6P to G1P?
Where does UDP-glucose to begin a glycogen chain?
Tyr on glycogenin
What enzyme creates alpha1-4-O-glycosidic bonds?
What enzyme creates alpha1-6-O-glycosidic bonds?
glycogen branching enzyme
Where is glucagon made?
alpha-cells of pancreas
What does glucagon do?
decrease blood sugar by decreasing glycogen synthesis in the liver and increasing glycogen breakdown
Where is epinephrine made?
What does epinephrine do?
Mobilize energy by decreasing glycogen synthesis in muscle and increasing glycogen breakdown
Where is insulin made?
beta-cells of pancreas
What does insulin do?
decrease blood sugar by increase synthesis and decrease breakdown of glycogen