last lecture….. proteins carbohydrates enzymes. study guide use study guide to determine what you...
TRANSCRIPT
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