Last Lecture…..

Proteins

Carbohydrates

Enzymes

Study Guide

Use study guide to determine what you need to know.

95% of test will be from study guide. Do I need to know that glucose +

glucose =maltose? Study guide says

recognize structures list functions of carbohydrates give characteristics and where found in cell

Do selected study questions only. If it was mentioned in lab/lecture and is in

the study questions then it has a higher probability of being on a test.

Carbohydrate - Monosaccharide

3. Is this a protein?

lipid?

nucleic acid?

carbohydrate?

OH OH

OH

OH

CH2OH

O

13. Understand protein structure and how it relates to function.

Explain how amylase structure relates to its function. Amylase is an enzyme that digests starch but not cellulose. Primary structure (amino acid sequence) determines the

secondary and tertiary structure. Secondary structure - sections of peptide chain coil or fold into

either alpha helices or beta sheets. Tertiary structure is extremely important to the functioning of

amylase. The tertiary structure is formed by the whole peptide chain (protein) folding and coiling around itself. This forms the active site (binding site) of the enzyme. The enzyme is held in a specific configuration (tertiary structure) by H-bonding, sulfide bridges, and non-polar/non-polar interactions. In order for amylase to break down starch it must bind the starch. It can only bind starch because its tertiary structure results in the formation of a binding site.

Quaternary structure would be more than one peptide chain associated with each other to form a functioning protein, but amylase is just one peptide chain.

14. Characteristics of Enzymes

Biological catalysts Proteins (usually) Names end in –ase Can be classified according to job they do Interactions with substrates can be described

using four terms Specificity – binding site designed for one type of

ligand When two or more ligands compete for the same site

one may have a higher affinity than the other. The ligand with the highest affinity will bind to the protein stronger.

If the protein is 50% saturated then half of the binding sites are filled. When an enzyme is 100% saturated the rate of reaction is at maximum.

Saturation (FOX fig 4.6)

This is at a fixed amount of enzyme

Functions of Carbohydrates

FuelSignaling MoleculeRibose is component of:

DNA RNAATPNAD/FADH

Digestive RegulationFibers normalize transit timeFibers decreases cholesterol, TAG and LDL

Chapters 4 and 5

Metabolism

Metabolism

• All the chemical reactions in the body • Specifically those that involve energy

transformations

• First Law of Thermodynamics• energy can not be created or destroyed

• Second Law of Thermodynamics• without the input of energy, disorder increases

Metabolism

• catabolism• reactions that break things down• exergonic• releases energy

• anabolism• reactions build things up• endergonic• takes energy

Oxidized electron

Carriers (NAD+, FAD)

ElectronTransport

andOxidative

Phosphorylation

LipidsPolysaccharidesNucleic Acids

Monosaccharides

Glucose

Amino Acids Nucleotides Glycerol Fatty Acids

Proteins

Glyceraldehyde-3-phosphate

Pyruvate

Acetyl-CoA

KrebsCycle

Glycolysis

Reduced Electron CarriersNADH, FADH2

ATP

ADP O2

H2O

CO2

e- e-

NH3

Energy Transformations (FOX 4.13)

ATP

ATP = adenosine triphosphate

• spending money (paper money) • universal energy carrier

Pi Pi Pi

Ribose

Base

adenosine triphosphate (ATP)

Pi Pi

Ribose

Pi +

ADP

Base

Energy

inorganicphosphate

This is a reversible reaction.

ATP

Cell respiration

• glycolysis• krebs cycle (citric acid cycle)• electron transport chain (ETC)• oxidative phosphorylation

Glycolysis• Substrates:

glucose (C6H12O6) + 2ADP + 2Pi + 2 NAD

• Products:2 pyruvate + 2ATP + 2 NADH

• Glycolysis occurs in the cytoplasm

• First step of glycolysis:• takes energy• traps glucose in the cell• example of substrate level phosphorylation

First steps take energy (FOX fig 5.1)

Substrate level phosphorylation

• Phosphate group transferred from ATP to another molecule.

• Catalyzed by kinase• Kinases add phosphate group to a molecule.

• Reverse reaction catalyzed by phosphatase

Pi Pi Pi

Ribose

Base

ATP

Pi Pi

Ribose

Pi

ADP

Base

Other Molecule Other Molecule

Substrate Level Phosphorylation

Glycolysis

FOX fig 5.6

Krebs Cycle (FOX fig 5.8)

Krebs Cycle

Krebs Cycle• Substrates:

acetyl CoA (two carbon molecule attached to coenzyme)

• Products:

CO2 + NADH + FADH2 + ATP

• Krebs cycle occurs in the mitochondrial matrix

FADH made from riboflavin (FOX fig 4.17)

NAD made from Niacin (FOX fig 4.17)

Electron Transport and Oxidative Phosphorylation

ETC and Oxidative Phosphorylation

• Located in the inner mitochondrial membrane.

• Energy stored in NADH and FADH2 used to create a concentration gradient.

• Proton concentration higher in intermembrane space.

• Protons flow through ATP synthase and ATP is made.

• ATP made this way is called oxidative phosporylation (vs substrate level phosphorylation)

• What if protein pores let H+ through?

What if no oxygen?

• Oxygen not available to accept electrons.• Electron carriers all fill up (saturated).• ETC stops.• So no way to oxidize (regenerate) FADH

and NAD so Krebs stops.• There is a reaction that will regenerate NAD

(next slide)• This is called anaerobic respiration

Credit card use. (FOX fig 5.3)

Anaerobic Respiration

• Good news • glycolysis continues

• Bad news • two ATP per glucose• lactic acid build up (pain, fatigue – chpt 12)• oxygen debt must be repaid – cori cycle

Cori Cycle (FOX fig 5.5)

Burning other fuel sources

• Carbohydrates• Proteins• Lipids

Oxidized electron

Carriers (NAD+, FAD)

ElectronTransport

andOxidative

Phosphorylation

LipidsPolysaccharidesNucleic Acids

Monosaccharides

Glucose

Amino Acids Nucleotides Glycerol Fatty Acids

Proteins

Glyceraldehyde-3-phosphate

Pyruvate

Acetyl-CoA

KrebsCycle

Glycolysis

Reduced Electron CarriersNADH, FADH2

ATP

ADP O2

H2O

CO2

e- e-

NH3

Burning other fuel sources

• Carbohydrates• glucose C6

• glycolysis – 2 pyruvates and 2 ATP and 2 NADH• complete cell respiration – 30 ATP• 5 ATP per carbon

• Lipids• fatty acids – C16

• beta oxidation – NADH and 8 Acetyl CoA• complete cell respiration – 108 ATP• 6.75 ATP per carbon

Fuels sources of select Organs

• Fox Table 5.3