Biochemistry Flashcards
(31 cards)
What are the major identifying characteristics of lipids?
1) It is a biomolecule
2) It is hydrophobic
What do fatty acids look like?
What do triacylglycerols look like?
What do phospholipids look like?
What do glycolipids look like?
What are the differences between saturated and unsaturated fats?
Saturated fatty acids have all possible hydrogens and no double or triple bonds. When double bonds are present they can create kinks in the chain that interfere with stacking and therefore lower the melting point. This makes conceptual sense because the fat on your steak is solid at room temperature (saturated fat), whereas olive oil (unsaturated fat) is a liquid at room temperature. Saturated fats can build up in your arteries, but unsaturated fats are already liquid at room temperature so they would be well above their melting point at 98.6°F.
What are ampipathic compounds. Give examples of ampipathic lipids.
Ampipathic compounds have both a polar and a non-polar region. Fatty acids are amphipathic and have a charged carboxylic acid functional group plus a long non-polar tail. Triglycerides are completely hydrophobic. Phospholipids are definitely amphipathic and this fact is the primary explanation for their role in biological membranes. Glycolipids are also amphipathic with the sugar portion being hydrophilic and the lipid portion being hydrophobic
What are some common nucleotides?
Besides DNA and RNA, other common nucleotides include cAMP, NADH, FADH2, FMN, Coenzyme A, ATP, GTP, UTP, etc.
What are the two types of vitamins and examples? How do their functions differ?
Fat-soluble (A,D,E,K)
-act as antioxidants
Water-soluble (B,C)
-act as co-enzymes/co-factors
What are the key differences between vitamins and minerals?
Vitamins and minerals are both essential for proper metabolic function. Vitamins are biological compounds that most often serve as coenzymes and cofactors. It is usually the water-soluble vitamins that play this role, while the fat-soluble vitamins act as antioxidants (Vitamin E), play a role in blood clotting (Vitamin K), aide in eyesight (Vitamin A) and maintain blood calcium levels (Vitamin D). Minerals are inorganic elements or compounds necessary for bone formation (calcium and phosphate), ion gradients (sodium and potassium), oxygen transport (iron- containing heme), muscle contraction (calcium), etc.—just to name a few.
What is the difference between a catalyst and an enzyme?
Catalysts are molecules that speed up a reaction without being altered or consumed themselves–and enzymes are organic protein catalysts.
Enzymes will _____ reaction rate
increase
Enzymes will _____ activation energy
Lower
Enzymes will __ equilibrium
Not effect
Enzymes will ___ yield /%yield
What is the substrate?
“Substrate” is the term used to refer to the reactant or reactants in a reaction that is enzyme catalyzed. Specifically, the substrate is the molecule that binds to the enzyme at its active site. So, if we were looking at protein hydrolysis, for example, we would call the protein and water the “reactants.” However, when examining enzyme catalyzed protein hydrolysis we would call the protein the “substrate” because it is the molecule that binds at the active site of the enzyme
What is the active site?
The active site is the portion of the enzyme to which the substrate binds. This is usually a pocket formation that more closely resembles the transition state for that reaction than it does the substrate itself.
What is the enzyme-substrate complex?
The enzyme-substrate complex is the name given to the enzyme and the substrate once they are bound together
What are two theories of enzyme specificity and which is more accurate?
. Induced Fit and Lock & Key are the two theories of enzyme specificity. The lock and key theory would indicate that the active site matches the shape of the substrate and would therefore tend to stabilize it in that form. This does not match well with an examination of the energy transitions involved in the reaction. If the binding of the substrate to the active site results in the substrate being stabilized “as is,” this would lower the energy of the substrate with respect to the transition state and thereby increase the energy of activation. By contrast, if—as the induced fit model suggests–the active site more closely resembles the transition state and stabilized the substrate only as it approaches that conformation/shape, this same process would lower the energy of the transition state. On an energy coordinate diagram it is easy to see that lowering the energy of the transition state would lower the energy of activation. For these reasons, the induced fit model is favored over the lock & key theory.
What are coenzymes?
non-protein species not permanently attached to the enzyme but required by the enzyme to function
What are prosthetic groups?
non-protein species that are permanently attached to the enzyme and are required by the enzyme to function
What are cofactors?
a general term for any species required by an enzyme to function; includes coenzymes and prosthetic groups
Describe competitive inhibition
Inhibitor binds at the active site. (resembles the same shape as the substrate).
Describe non-competitive inhibition
Inhibitor binds away from the active site and changes the shape of the enzyme.
