BC: Exam II Questions

What is the general empirical formula for monosaccharides?

(CH₂O)ⁿ

What is the substrate of glycolysis?

1 Glucose

What is the second prime step and what enzyme is used?

10: Pyruvate kinase

What is the total ATP produced for 3 glucose molecules? Net ATP?

12, 6

One glyceraldhyde 3-phosphate yields how many ATP?

2

What is the final product of glycolysis?

2 pyruvate

How do you calculate how many stereoisomers a compound has.

2^ⁿ

What is the first substrate-level phosphorylation step and what enzyme is used?

7: Phosphoglycerate kinase

The energy released in glycolysis is preserved in the form of ______ and ______

ATP and NADH

Carbohydrates are classified as either ____________ or __________

Aldehyde or ketone

What is the function of alpha, beta, and gamma subunits in G-proteins?

Alpha subunit when activated by GTP serves to activate adenylyl cyclase. Beta and gamma are part of the inactive G complex that is attached to GDP

Cellulose has _________ linkage

Beta1-4

How does coupling work?

By taking a reaction that releases energy and putting it with a reaction that requires energy.

What is the order in which the body breakdown metabolic fuels?

Carbohydrates-->fats-->proteins

Hydrophobic intracellular messengers generally need a ______________

Carrier protein

What is deltaG?

Change in free energy

Where does glycolysis take place?

Cytosol

What is the role of phosphodiesterase?

Deactivate cAMP

Give an example of a ketose triose.Tetrose. Pentose. Hexose

Dihydroxyacetone, erythrulose, ribulose, fructose

Optically active isomers are known as __________

Enamtiomers

How do endergonic reactions in biological systems proceed?

Energy coupling

T or F - Glycolysis can not generate ATP in the absence of oxygen.

False

Cholera stimulates ___________ which activates _________ and activates/ inhibits _______ which increases/decreases ______,while pertussis stimulates ___________ which activates __________ and activates/inhibits ________ which increases/decreases _________.

G-alpha-s, activates adenylate cyclase increasing cAMP. G-alpha-i, inhibits adenylate cyclase decreasing cAMP

What are the three different kinds of membrane bound receptors and give examples of each?

G-protein coupled - muscarinic. Tyrosine kinase - insulin. Ion channel - nicatinic

What is GPCR?

G-protein coupled reaction

Nuclear receptors stimulate _____________.

Gene expression

Abnormally low levels of blood glucose causes secretion of glucagon and decreases blood insulin release by?

Glucagon

Acetyl-CoA is used to form ________

Glucose

What is the most important carbohydrate?

Glucose

__________ can make all other carbohydrates in our system.

Glucose

What are GLUTs?

Glucose transporter proteins

Give an example of an aldose triose.Tetrose. Pentose. Hexose.

Glycerose, erythrose, ribose, glucose

Liver, muscle , and adipose tissue take up glucose and convert it to ________ and __________ for storage.

Glycogen and fatty acid

The method in which tissues breakdown glycogen is called?

Glycogenolysis

Give two examples of glycosaminoglycans.

Hyaluronic acid, chondroitin sulfate

IP3 depletes _________ from their stores increasing/decreasing concentration in the cytosol leading to __________ dependent pathways.

IP3 depletes CALCIUM from their stores INCREASING concentration in the cytosol leading to CALCIUM dependent pathways.

What is the second law of thermodynamics?

If a process is to occur spontaneously it must increase entropy

What stimulates GLUTs?

Insulin

Name 3 different 1st messengers.

Insulin, epinephrine, norepinephrine,Acytl-CoA, and many others

Any enzyme that attaches a P is known as a __________.

Kinase

In humans all Isomers are D/L.

L

Cortisol is used to mediate the body's response to _______________.

Long term stress

Name the two general mechanisms of hormone action.

Membrane and nuclear

What kind of receptors use second messengers?

Membrane bound

Which create a faster response; membrane bound or nuclear receptors?

Membrane bound

What cofactors are needed to cause glycolysis to move forward?

Mg+ and Zn

What does epinephrine act on and what type of response does it mediate?

Muscle, lungs, heart for quick bursts of activity

What are the two kinds of Ach receptors, and what kind of response to they generate?

Nicatinic - excitatory Na⁺ channel. Muscarinic - inhibitory g-protein coupled

What does insulin activate?

Oxidation of glucose in liver, glycogen synthesis, fat synthesis

Where are insulin and glucagon produced?

Pancreas

What are the precursors to insulin?

Preproinsulin-->proinsulin-->insulin

What are selective PDE inhibitors?

Prevent the breakdown of cAMP and cGMP. Modulate mood and cognitive activity

What activates protein kinase?

Protein kinase a - cAMP

ATP hydrolysis ______________

Releases energy

What is a stereoisomer?

Same structural formula but differ in spatial arrangement

What is the general sequence of events from signal---->response?

Signal-->receptor--->transducer-->effector-->response

What is the substrate and product of adenylate cyclase?

Substrate - ATP. Product - cAMP

What makes something an amino sugar?

Sugar with an amine group

What is autophosphorylation?

The phosphorylation of a kinase by its open enzymatic activity

What is the first law of thermodynamics?

Total energy of a system must remain constant

Insulin receptor is a _____________

Tyrosine kinase

What kind of receptor is specific for insulin?

Tyrosine kinase Enzyme

What is down regulation of receptors?

When there is an increased amount of substrate leading to hyperactivity.The cell decreases the amount of membrane receptors

Linear polymers have only _______ linkage branched polymers also have ________ linkage at the branches.

• 1-4 • 1-6

What are the three rate limiting steps of glycolysis and what are the enzymes used for each?

• 1:Hexokinase • 3: Phospho-fructokinase 1 • 10: Pyruvate kinase

What are the three kinds of cell-to-cell communication and what kind of cells do they activate?

• Autocrine - similar cells locally. • Paracrine - different cells locally. • Exocrine - different cells long distance

Exergonic reactions are termed as ___________ and endergonic reactions are termed________

• Catabolic • Anabolic

Mannose is an _________ of glucose at _______ while galactose is an _______ at __________.

• Epimere at C2 • Epimere at C4

Animals store polysaccharides as _______ and plants store it as _______

• Glycogen • Starch

What is the difference between homopolysaccharides and heteropolysaccharides?

• Homo- same polysaccharide units • Hetero- different polysaccharide units

What hormones regulates blood glucose levels?

• Insulin • Glucagon

Insulin tells tissue blood glucose is too high/too low, glucagon tells tissues blood glucose is too high/too low.

• Insulin - too high • Glucagon - too low

What are the three possible destinations of pyruvate?

• Lactate • CO₂ and Water • Ethanol and CO₂

What is deltaG in an exergonic reaction, and what does that mean? Endergonic? Equilibrium?

• Negative spontaneous/heat is released. • Positive heat is released.

What are the three major sources of P?

• Oxidative phosphorylation • Glycolysis • Citric acid cycle

What are the two phases of glycolysis? What is their relationship to ATP?

• Priming -2 ATP • Payoff +4 ATP

What two hexose are used for Nucleic acid formation? Which is more stable?

• Ribose • Deoxyribose

Name some common second messengers.

• cAMP, • Ca²⁺ • cGMP • IP3

What is the formula for calculating ∆G in biochemical relations?

∆G = ∆E - T∆S