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49 Cards in this Set
- Front
- Back
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Major functions of lipids.
Phospholipids |
Structural component of membranes.
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Major functions of lipids.
Triacylglycerols |
Store metabolic energy
Provide thermal insulation Padding |
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Major functions of lipids.
Steroids |
Regulate metabolic activities
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Number of aas?
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20
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Number of essential aas?
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10
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Amino acids in solution..
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carry one or more charges.
depends on the pH of the solution. |
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Primary Structure
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Number and sequence of the aas.
joined by polypeptide bonds |
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Secondary Structure
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Contributes to conformation of the protien.
a-helixs and B-pleated sheets. Reinforced by H bonds between carbonyl O and H on the amino group. |
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Tertiary Structure
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In larger, globular proteins.
3d shape. |
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5 forces that create the tertiary structure =
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1. covalent disulfide bonds (cysteines)
2. Ionic interactions between acidic and basic side chains. 3. H bonds 4. van der Waals forces 5. hydrophobic side chains pushed away from water. |
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Quaternary Structure
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2 or more polypeptide chains bonded together.
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5 forces that cause quaternary structure=
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same five that cause tertiary structure.
1. Covalent disulfide bonds 2. ionic interactions between acidic and basic side chains. 3. H bonds 4. van der Waals forces 5. hydrophobic side chains pushed away from water. |
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Two types of proteins =
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1. globular (more types of glob than structural)
2. structural |
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Globular proteins function as
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1. enzymes
2. hormones 3. membrane pumps 4. channels 5. membrane receptors 6. inter/intracellular transport and storage 7. osmotic regulators 8. immune response |
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Structural proteins function to
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maintain and add strength to the cellular and matrix structure.
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Glucose uptake in the body
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Epithelial cells in digestive tract and proximal tubule - absorb glucose against the concentration gradient via secondary active transport down the conc gradient of sodium.
All other cells absorb glu via facilitated diffusion. (increased by insulin) Absence of insulin? only neural and hepatic cells are capable of absorbing. |
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Starch
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Formed from glucose in plants.
Two forms: Amylose and Amylopectin |
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Cellulose
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Formed from glucose in plants.
Beta linkages can't be digested by humans. |
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Amylose
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Form of starch.
Isomer of cellulose branched or unbranched alpha linkages - same as glycogen. |
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Amylopectin
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Resembles glycogen.
Alpha linkages. |
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Nucleotides - 3 components
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1. Five carbon sugar (pentose)
2. Nitrogenous base 3. Phosphate group |
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Nucleotides
- form... to create... - joined by... - written... |
- form polymers to create the nucleic acids (DNA and RNA)
- joined by phosphodiester bonds - written 5' to 3' |
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In DNA
- top strand is... - bottom strand is... |
- top is 5' to 3'
- bottom is 3' to 5' |
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Other important nucleotides =
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ATP
cyclic AMP (impt in 2nd mess systems) NADH FADH2 (coenzymes in the Krebs) |
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Enzymes do not alter..
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Equilibrium of a reaction
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Ezymes exhibit saturation kinetics.. =
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as the conc of substrate increases, the rate of the rxn also increases until Vmax (max rate). Vmax is proportional to enzyme concentration.
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Turnover number
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number of substrate molecules one enzyme active site can convert to product in a given unit of time when enzyme is saturated.
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Optimal temp for enzymes in the human body?
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37 degrees C
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Cofactor
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Enzymes sometimes require cofactors to reach their optimal activity level. (nonprotein components)
can be coenzymes or metal ions |
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Coenzymes
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Usually vitamins or their derivatives.
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Graph of
Reaction rate vs pH |
upside down V
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Graph of
Reaction rate vs Temp |
Upside down V with top part lopsided to the right.
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Graph of
Reaction rate vs substrate conc. |
wave to the right.
increases then levels off at Vmax. |
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Irreversible inhibitors
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bind covalently to enzymes and disrupt fxn.
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Competitive inhibitors
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compete with the substrate to bind reversibly (noncovalent bonds) to the active site.
Can overcome competitive inhibitors by increasing substrate concentration. |
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Noncompetitive inhibitors
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bind noncovalently to a regulatory site.
Commonly act on more than one enzyme. |
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Zymogen
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Enzymes are released into their environment in an inactive form called a zymogen.
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Proenzyme
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Enzymes are released into their environment in an inactive form called a proenzyme.
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Allosteric interactions
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the modification of the enzyme configuration resulting from the binding of an activator or inhibitor at a regulatory site on the enzyme.
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Negative feedback
Feedback inhibition |
When one of the products downstream comes back and inhibits the enzymatic activity in an earlier reaction
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Positive feedback
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when the product returns and activates the enzyme.
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Positive cooperativity
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When small increases in substrate conc increase the enzyme efficiency as well as rxn rate. The first changes the shape of the enzyme allowing other substrates to bind more easily.
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Negative cooperativity
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When the first substrate changes the shape of the enzyme and makes it more difficult for following substrate molecules to bind (hemoglobin)
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Chemical is an enzyme? What else..
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It contains nitrogen, and is subject to denaturation.
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Metabolism
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All cellular chemical reactions.
(catabolism + anabolism) |
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Respiration
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Energy acquiring stages of metabolism.
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Anaerobic respiration
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Glycolysis
- breaks 6C glucose into 2 3C pyruvate molecules. - produces 2 ATP and 2 NADH - Occurs in the cytosol |
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Substrate level phosphorylation
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Formation of ATP from ADP and inorganic phosphate using the enrgy released from the decay of high energy phosphorylated compounds.
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Fermentation
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Anaerobic respiration.
Glycolysis, reduction of pyruvate to ethanol or lactic acid, oxidation of NADH back to NAD+. |
