Learning Objectives

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Learning Objectives - Exam 3

Carbohydrates:

Know the basic formula

Know the difference between Mono- vs. Oligo- vs. Polysaccharides

Understand that there are aldehydes and ketones

Be able to recognize the well known sugars (aldoses = ribose, glucose, mannose, galactose and ketoses

= fructose)

Recognize epimers

Realize that there are  and  anomers at carbon1

Be able to identify and define the anomeric carbon

Understand how a glycosidic bond forms

Be able to identify the reducing vs. nonreducing end of oligo- and polysaccharides

Know the components of well-known disaccharides (lactose, sucrose)

Know the basics of the well-known polysaccharides

Storage = starch, glycogen

Starch/glycogen made of amylose (  1  4) and amylopectin (  1  4 and  1  6)

Structure = cellulose, chitin

 1  4 linkages

Why structural so rigid and storage are not? Related to  1  4 links vs.  1  4 links

Why can’t humans live on grass (cellulose)?

Metabolism:

Six principles – name them and describe something about them (an example, etc.)

Glycolysis - know ALL the details for the QUIZ, including net reaction, ATP/NAD used and made

Know importance of phosphorylated intermediates

What are the three nonequilibrium steps? How are each regulated?

Hexokinase

Phosphofructokinase-1

Pyruvate kinase

Understand enzyme mechanisms

Aldolase

Glyceraldehyde 3-phosphate dehydrogenase

Regulation of glycolysis

What is flux? What limits it?

What is homeostasis? What maintains homeostasis?

By cellular energy charge

By hormones

By coordination with other pathways

Citric acid cycle

What is it? What does it do? Where does it occur?

Know how pyruvate dehydrogenase complex works (cofactors involved, mechanism, regulation)

Know net reaction

Know where ATP, CO

2

, FADH

2

and NADH are made

Know ultimate # ATP formed

Stereospecificity of aconitase, fumarase

Know how  -ketoglutarate dehydrogenase complex works

What is only membrane-bound enzyme?

Regulation of citric acid cycle

Oxidative phosphorylation

What is it? Where does it occur?

Chemiosmotic hypothesis – what is it? experimental support for it

What are electron carriers? What proteins are they associated with?

Inhibitors of oxidative phosphorylation

Movement of electrons in Complexes I, II, III, IV

ATP synthase

Control & regulation

Gluconeogenesis

What three steps are different between glycolysis and gluconeogenesis?

Understand mechanisms of important enzymes:

Pyruvate carboxylase

Phosphoenolpyruvate carboxykinase

Fructose 1,6-bisphosphatase

Glucose 6-phosphatase (only in liver and kidney cells)

Futile cycles

Reciprocal regulation of glycolysis and gluconeogenesis (F26BP, AMP, citrate, glucagon, insulin)

Glycogen metabolism

Breakdown

Breakdown glycogen to produce glc because mobilized fast

Understand mechanism and control of Glycogen phosphorylase (muscle vs. liver)

Debranching enzyme

Glucose 1-phosphate

Synthesis

Synthesize glycogen mostly in muscle and liver

UDP-glucose pyrophosphorylase (used to make activated form of glc - UDP-glucose)

Glycogen synthase

Glycogenin

Branching enzyme

Understand Reciprocal control of breakdown & synthesis

(glucagon, epinephrine, insulin)

Know the Phosphorylation/dephosphorylation of key enzymes

Lipid metabolism

Breakdown

Know how fats metabolized by lipases (regulated step)

Understand that hormones trigger mobilization of stored triacylglycerols

Understand importance of "priming" fatty acid with CoA to make fatty acyl-CoA

Transport fatty acid into mitochondria using carnitine acyltransferase (regulated step)

 -oxidation of fatty acids (breakdown) even # carbons - get acetyl CoA and FADH odd # carbons - get acetyl CoA and FADH

2

and NADH + succinyl CoA double bonds - extra enzyme step to isomerize double bond

Know how the process is regulated by:

2

and NADH

Acyltransferase as rate-limiting step

Malonyl CoA (synthesis molecule)

NADH

Acetyl CoA

Ketone bodies

Why/when do these form?

Acetone, acetoacetate,  -hydroxybutyrate

Lipid biosynthesis

Know the classes of lipoproteins and the lipids they carry

Know the committed step of synthesis - acetyl CoA carboxylase to make malonyl CoA

Fatty acid synthase

All enzyme activities on one enzyme

Addition of malonyl CoA each time

Uses NADPH

Understand regulation of lipid metabolism by

Committed steps

Hormones

Cholesterol synthesis

Important enzyme = HMG CoA reductase (how regulated?)

High cholesterol and heart disease

Use of lovastatin

Other metabolic pathways

Pentose phosphate pathway

Produces NADPH and ribose 5-phosphate - what are these used for?

Amino acid metabolism

Breakdown to get amino groups (nitrogen)

Breakdown with HCl and proteases in stomach and intestines

Urea cycle - way to excrete NH

4

out of body

Understand how the urea cycle is regulated

Know what it means to be an essential vs. nonessential amino acids

Know the enzyme cofactors used in AA metabolism tetrahydrofolate, S-Adenosylmethionine

Know what it means to be a glucogenic vs. a ketogenic AA

Genetic defects affecting AA metabolism- phenylketonuria

Other roles of AAs

Integration & Hormone regulation

Use this note packet as a study/review tool

Understand the organ specialization during metabolism

Know the branchpoints in metabolism

Understand all the ways that hormone control affects metabolism

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