Download powerpoint 24 Aug

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?
CH2OH
O
OH
OH
OH
OH
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
 Fuel
 Signaling Molecule
 Ribose is component of:
 DNA RNA
 ATP
 NAD/FADH
 Digestive Regulation
 Fibers
normalize transit time
 Fibers 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
Proteins
Nucleic Acids
Polysaccharides
Amino Acids
Nucleotides
Monosaccharides
Lipids
Glycerol
Glycolysis
Glucose
Glyceraldehyde3-phosphate
Pyruvate
Acetyl-CoA
Krebs
Cycle
e-
CO2
eReduced
Electron Carriers
NADH, FADH2
NH3
ADP
ATP
O2
Electron
Transport
and
Oxidative
Phosphorylation
Oxidized electron
Carriers (NAD+, FAD)
H 2O
Fatty Acids
Energy Transformations
ATP
(FOX 4.13)
ATP = adenosine triphosphate
• spending money (paper money)
• universal energy carrier
Base
Pi
Pi
Base
Pi
Pi
Ribose
+
Pi
Pi
Ribose
Energy
adenosine triphosphate (ATP)
inorganic
phosphate
This is a reversible reaction.
ADP
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
Other Molecule
Other Molecule
Base
Pi
Pi
Base
Pi
Pi
Pi
Ribose
ATP
Substrate Level Phosphorylation
ADP
Ribose
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
Proteins
Nucleic Acids
Polysaccharides
Amino Acids
Nucleotides
Monosaccharides
Lipids
Glycerol
Glycolysis
Glucose
Glyceraldehyde3-phosphate
Pyruvate
Acetyl-CoA
Krebs
Cycle
e-
CO2
eReduced
Electron Carriers
NADH, FADH2
NH3
ADP
ATP
O2
Electron
Transport
and
Oxidative
Phosphorylation
Oxidized electron
Carriers (NAD+, FAD)
H 2O
Fatty Acids
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