Title: BIOCHEMISTRY FOR MEDICAL STUDENTS
1BIOCHEMISTY
- IMEC Inc.
- Quick Learning
- Technique
2 THE CELL STRUCTURE
3 NUCLEUS
- The nucleus houses the DNA (deoxyribonucleic
acid) which stores genetic information for a
cell. The DNA contains instructions for the
production of the cell's proteins and for
reproduction. - To construct proteins, 1) The DNA is copied to
messenger RNA (ribonucleic acid) in the process
called transcription. 2) The mRNA goes to the
ribosomes, 3) Either in the nucleus or in the
endoplasmic reticulum, where the actual
construction of the proteins takes place.
Structurally, the nucleus is composed of three
main parts, the nucleolus, the nuclear envelope,
and the chromatin.
4 Nucleus of Cell
5Cromatin Structure
- Heterochomatin-Condensed/inactive
- Euchomatin-
- Loosely packed/ highly active
6Rough Endoplasmic Reticulum
- This is the site of Protein Synthesis
7Smooth Endoplasmic Reticulum
- This is the site of Steroidal Synthesis
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9Amino Acid Basics
- Proteins are built up from amino acids which are
linked by peptide bonds to form a polypeptide of
defined sequence. Many proteins are folded into
well defined globular shapes because the
hydrophobic effect forces hydrophobic side chains
along the polypeptide sequence to cluster
together in a hydrophobic core. The folded
protein is stabilized by a large number of weak
interactions. There are 4 levels of organization,
or structure, to a protein, going from the
primary (1) structure (the amino acid sequence),
via secondary (2) structure, tertiary (3, 3D)
structure, to quaternary (4) structure in the
case of multi-chain proteins. The amino acid side
chains have a variety of chemical groups that
make them particularly suitable for carrying out
the numerous tasks they perform in the cells.
10 Protein Structure/Function
- To a large extent, proteins are built up by
ordered structures the secondary structure
elements a-helices and b-pleated sheet. These
arise when the same phi/psi angles are repeated
over a number of residues and are stabilized by
hydrogen bonds involving the main chain carbonyl
oxygen and peptide nitrogen. - Secondary structural elements are joined by loops
or turns, and are often combined in particular
ways called motifs that in turn are combined to
generate functional protein domains.
11 2nd Function of Proteins
- Oxygen is transported in mammals by hemoglobin
and stored in muscles by myoglobin. Hemoglobin
has allosteric properties which makes it suitable
for picking up oxygen when the oxygen pressure is
high (in the lungs) and release it when the
oxygen pressure is low (in the muscles).
12 Carbohydrates
- Carbohydrates are the most abundant biomolecules.
Certain carbohydrates are staple of the human and
animal diet, and the oxidation of carbohydrates
is the central energy-yielding pathway.There are
three major classes of carbohydrates - 1) Monosaccharides, or simple sugars, consist
of a single polyhydroxy aldehyd or ketone unit. - 2) Oligosaccharides consist of short chains of
monosaccharide units joined together with
glycositic linkages. - 3) Polysaccharides consist of long chains. Some
polysaccharides, such as e.g. cellulose, have
linear chains of monosaccharides , whereas
others, glycogen for example, have branched
chains.
13 Fatty Acids
- Fatty acids have major physiologic roles, such as
being building blocks of phospholipids and
glycolipids (components of cell membranes),
precursors of hormones and intracellular
messengers, fuel molecules, etc. Because fatty
acids are highly reduced, yielding 9 kcal/g after
complete oxidation (twice as much as
carbohydrates and proteins). Fatty acids can
originate either in the diet or from de novo
synthesis in the cytosol of cells. Fatty acid
synthesis requires C atoms (as acetyl CoA) and
reducing power as NADPH. Acetyl groups are
translocated from mitochondria to the cytosol as
citrate (though in ruminants acetate from the
rumen is the main precursor of cytosolic acetyl
CoA).
14Energy Yield
15 Carbohydrates
- 4 Kcal/g carbohydrate
- Monosacchideglucose fructose
- DisaccharidesLactose, maltose, sucrose
- Currently 46 of dietshould increase to 55 of
diet
16 Fats
- 9 Kcal/g
- Saturated 10
- Coconut and palm oil
- Monosaturated 10
- Olive and canola oil
- Polysaturated 10
- Soybean and Corn
17 Protein
- 4 Kcal/g
- 20 amino acids
- Proteins from wheat, corn, rice, and beans have
lower biological value than meat proteins - NITROGEN BALANCE IS KEY
- Exwheat-lacks lysine
- Kidney beans lysine rich
18Carbohydrates
19Biochemistry
- Now we are biochemists
- The chemistry in living systems
20Carbohydrates
- Aldehydes or ketones
- Polyhydroxy compounds
- Important energy source in the body
- 4 cal/g
- Most important is glucose
21Classification
- Carbohydrates are classified according to size
- Monosaccharide a single polyhydroxy aldehyde or
ketone unit. - Disaccharide composed of two monosaccharide
units - Polysaccharide very long chains of linked
monosaccharide units. - Oligosaccharide- has between 3 10 units
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23Classification
24Monosaccharide Classification
- Classified by whether the monosaccharide is an
aldehyde (aldose) or ketone (ketose). - Classified by the number of carbon atoms in the
monosaccharide.
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28Physical Properties
- Most are called sugars because they taste sweet.
- Because of the many OH groups, they form
hydrogen bonds with water molecules and are
extremely water soluble. - Most are solids at room temperature because of
H-bonding between them
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30- All monosaccharides with at least five carbon
atoms exist predominantly as cyclic hemiacetals
and hemiketals. - A Haworth structure can be used to depict the ?
and ? anomers of a monosaccharide. - Anomers are stereoisomers that differ in the 3-D
arrangement of groups at the anomeric carbon of
an acetal, ketal, hemiacetal, or hemiketal group.
31- Six-membered pyranose ring system
-
32Five-membered furanose ring system
33- Monosaccharide Reactions, cont.
- A reducing sugar can be easily oxidized.
- All monosaccharides are reducing sugars.
- Benedicts reagent tests for the presence of
reducing sugars - Reducing sugar Cu2 ? oxidized compound
Blue Cu2O orange-red
precipitate
34- Monosaccharide Reactions, cont.
- The OH groups of monosaccharides can behave as
alcohols and react with acids (especially
phosphoric acid) to form esters.
35- Important Monosaccharides
- Ribose and Deoxyribose Used in the synthesis of
DNA and RNA. - Glucose Most nutritionally important
monosaccharide Sometimes called dextrose or
blood sugar - Galactose A component of lactose (milk sugar)
- Fructose The sweetest monosaccharide Sometimes
called levulose or fruit sugar
36- Disaccharides
- Two monosaccharide units linked together by
acetal or ketal glycosidic linkages. -
37- Important Disaccharides
- Maltose Two glucose units linked ?(1?4) Formed
during the digestion of starch to glucose - Reducing sugar
- Lactose Galactose and glucose units linked
?(1?4) Found in milk - Reducing sugar
- Sucrose Fructose and glucose units Found in
many plants (especially sugar cane, sugar
beets) Not a reducing sugar
38Maltose in solution
39- Polysaccharides
- StarchA polymer consisting of glucose units Has
two forms - Unbranched amylose
- Branched amylopectin
- Complexes with iodine to form a dark blue color
40Polysaccharide Structure
41The Structure of Amylose
42Amylopectin Structure
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44- Polysaccharides, cont.
- Glycogen (animal starch) a polymer of glucose
units.Used to store glucose, especially in the
liver and muscles.Structurally similar to
amylopectin with ?(1?4) and ?(1?6) linkages, but
glycogen is more highly branched.
45- Polysaccharides, cont.
- Cellulose A polymer of glucose units The most
important structural polysaccharide Found in
plant cell walls Linear polymer like amylose,
but has ? (1?4) glycosidic linkages. Not easily
digested, a constituent of dietary fiber.
46Cellulose Structure
47Polysaccharide linkages
48Lipid Metabolism
49Lipids
- Important source of energy
- 9 cal/g
- Used to store energy in the body
- 30-40 day supply
50Blood Lipids
- Lipids are non-polar and therefore do not like
the aqueous blood environment - Complex themselves with proteins to form
lipoprotein aggregates called chylomicrons - Chylomicrons are further processed by the liver
to form lipoproteins we are familiar with
51Lipoproteins
- Classed based on density
- Lipids are less dense than proteins
- So, lipoproteins with a higher proportion of
lipids are less dense
52Chylomicron
53Lipoproteins
54Lipid Digestion
- Triglycerides are hydrolyzed to glycerol, fatty
acids, and monoglycerides - Phosphoglycerides are hydrolyzed to their
individual components - These smaller molecules are absorbed in the
intestines - Blood lipids follow similar pattern to blood
sugar levels and are highest after a meal
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57Fat Mobilization
- When energy is required messengers are sent out
to interact with adipose tissue - Epinephrine stimulates triglyceride hydrolysis in
the process of fat mobilization - Fatty acids are then transported to the tissues
that need the energy
58Fat cells
59Fat Mobilization, contd
- Some cells cannot use fats for energy, brain
cells and red blood cells - Other cells preferentially use lipids for energy
to conserve the supply for the other cells,
muscles and liver - They break fatty acids down for energy
60Glycerol Metabolism
- Glycerol is converted into dihydroxyacetone
phosphate in two reactions
61Fatty Acid Oxidation
- Fatty acid must be activated before it can be
metabolized - Passes through mitochondrial membrane
- Requires energy in the form of ATP
- Fatty acid then enters the fatty acid spiral and
undergoes b-oxidation
62Lipids contd
- Fig. 14.6
- Fatty acids are transported across the inner
mitochondrial membrane in the form of acyl
carnitine.
63Fatty acyl refers
64b-Oxidation
The b-carbon is oxidized to a ketone in a series
of four reactions in the mitochondrion
65Fatty Acid Oxidation
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67b-Oxidation, contd
- The final step breaks the chain between the a and
b carbon atoms by reaction with coenzyme A - A new fatty acyl CoA is formed that is two carbon
atoms shorter then original - Fatty acid spiral continues until all carbons are
used - Fatty acids are broken down two carbons at a time
68Energy Produced
- Every two carbon unit produces one acetyl CoA
- Every two carbon unit except the last has to go
through the fatty acid spiral to produce the
acetyl CoA - Every spin through the fatty acid spiral produces
1 FADH2 and 1 NADH
69Energy Production, contd
- Each acetyl CoA has the potential to enter the
citric acid cycle and produce 1ATP, 3NADH, and
1FADH2 - The NADH and FADH2 then go to the electron
transport - NADH ? 2.5ATP
- FADH2 ?1.5ATP
70Energy produced
71Question for You
- How many molecules of ATP are produced by the
complete oxidation of palmitic acid, (16C) to
carbon dioxide and water?
72Answer
- 16 carbon atoms ? 8 acetyl CoA
- 7 fatty acid spirals ? 7NADH 7FADH2
- Activation step ? -2ATP
- Acetyl CoA ? 10ATP
- Overall (8 x 10) (7 x 2.5) (7 x 1.5) -2
- 106ATP
73Ketone Bodies
- Under certain conditions (e.g. fasting and
diabetes) an imbalance between carbohydrate and
fatty acid metabolism occurs and more acetyl CoA
is produced by fatty acid oxidation than can be
processed by the citric acid cycle. - Glycolysis is essentially shut down and
oxaloacetate is used in gluconeogenesis - The citric acid cycle slows down and acetyl CoA
builds up in the body - The body synthesizes ketone bodies to rid itself
of excess acetyl CoA
74Ketone Bodies
75Ketone Bodies
76Ketone Bodies
- Are oxidized to meet energy needs
- Excess amounts causes a change in blood pH as two
are acids, ketoacidosis - Diabetes can cause this as a lack of insulin
means cells do not take glucose in and thus fatty
acid oxidation is used as the energy source and
causes the build-up of ketone bodies
77Fatty Acid Synthesis
- Excess nutrients are stored rather than excreted
- Excess is converted first to fatty acids and then
to body fat - Most body fat production is in the liver, adipose
tissue and mammary glands - Biosynthesis of fatty acids is not the exact
opposite of degradation
78Fatty Acid Synthesis, contd
- Occurs in the cytoplasm
- Acetyl CoA is moved from the mitochondrion to the
cytoplasm - Fatty acid synthetase system makes the fatty
acids two carbons at a time - Requires large amounts of energy which is then
stored in the synthesized fatty acid
79Lipids contd
- Fig. 14.10
- The citrate-malate-pyruvate shuttle system for
transferring acetyl CoA from a mitochondrion to
the cytosol.
80- Liver is most involved in fatty acid synthesis
- Can modify fatty acids by adding/ removing carbon
atoms - Can also reduce or oxidize
- Glucose ? fatty acids
- Fatty acids cannot ? glucose (lack the enzyme for
acetyl CoA ? pyruvate)
81Lipids contd
- Fig. 14.13
- Overview of the biosynthetic pathway for
cholesterol synthesis.
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83Proteins
84Proteins
- Made up of amino acids
- Have amino group, C-N
- Have acid group, COOH
- 20 amino acids
- All but one are chiral
- All L-amino acids
85Functions
- Catalysts
- Structural component
- Storage
- Protection
- Regulation
- Movement
- Transport
- Nerve impulse transmission
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87Amino Acids
- Called a-amino acids as amino group is on alpha
carbon atom - All except glycine are chiral
- Classified according to type of R group
- Non-polar/ Polar
- Acidic/ Basic
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90Abbreviations and Codes
- Leucine L, Leu
- Lysine K, Lys
- Methionine M, Met
- Phenylalanine F, Phe
- Proline P, Pro
- Serine S, Ser
- Threonine T, Thr
- Tryptophan W, Trp
- Tyrosine Y, Tyr
- Valine V, Val
Alanine A, Ala Arginine R, Arg Asparagine N,
Asn Aspartic acid D, Asp Cysteine C,
Cys Glutamine Q, Gln Glutamic Acid E,
Glu Glycine G, Gly Histidine H, His Isoleucine I,
Ile
91Essential Amino Acids
- Lysine
- Leucine
- Isoleucine
- Histidine
- Methionine
- Phenylalanine
- Threonine
- Valine
- Tryptophan
- Arginine, only in children
92Peptides
- Connected by amide bond
- Now called a peptide bond
- Always put free N-group on left and free acid
group on right
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97Proteins
- May be simple or complex
- Complex proteins have an extra non-protein bit
- Non-protein bit is called prosthetic group
- Protein is inactive without prosthetic group
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99Protein Shapes
- Fibrous proteins long rod-shaped or stringlike
molecules that intertwine to form fibers
(collagen, elastin, keratin). - Globular proteinssphericalshaped proteins that
form stable suspensions in water, or is water
soluble (hemoglobin, enzymes). - Based on water solubility
100Some Common Fibrous and Globular Proteins
101Myoglobin
- Fig. 20.4
- The primary structure of human myoglobin.
102Biochemically Important Small Peptides
- Small peptide hormones, oxytocin and vasopressin
- Both are nonapeptides
- Amino acids at spots 3 and 8 are different
- Oxytocin regulates uterine contractions and
lactation - Vasopressin regulates water excretion by kidneys
and blood pressure
103Cont
- Enkephalins are pentapeptide neurotransmitters
produced by the brain - They bind to receptor sites to reduce pain
- Also play a role in the natural high runners
get at the end of a long run - Morphine and codeine bind to the same receptor
sites as enkephalins
104And theres more
- Small peptide antioxidants
- Glutathione, Glu-Cys-Gly
- Protects cells from oxidizing agents
105Protein Structure, 50 a/a
- Four levels of structure
- Primary Amino acid sequence
- Secondary a-helix or b-sheet
- Tertiary How one chain folds up
- Quaternary How more than one chain folds up
106Protein Structure
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108Protein Structure Primary
- Amino acid sequence
- Held together by peptide bond
- Also determines the secondary structure of the
protein - Not affected by denaturation
- Very stable covalent bond holds it together
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110Protein Structure Secondary
- a-helix
- b-sheet
- Hydrogen bonding holds it together
- Depends on amino acid residues present
111a-helix
112b-Sheet
113Secondary Structure
114Protein Structure Tertiary
- A single chain folds up
- Hydrogen bonding
- Disulfide bonding
- Salt bridges
- Hydrophobic interactions
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116Tertiary Interactions
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119Disulfide Bond Formation
120Myoglobin, tertiary structure
121Insulin
- Fig. 9.11
- Human insulin, a small two-chain protein, has
both intrachain and interchain disulfide linkages
as part of its tertiary structure.
122Protein Structure Quaternary
- How two or more chains fold up together
- Hydrogen bonding
- Salt bridges
- Disulfide bonds
- Hydrophobic interactions
123Hemoglobin
124a-Keratin
125Collagen
126Collagen
- Most abundant protein in humans, 30
- Major structural material
- Tendons
- Ligaments
- Blood vessels
- Skin
- Bones and teeth
127Collagen Content
128Protein Denaturation
- Break 2o, 3o, and 4o structure only
- Does not affect 1o structure
- Protein is unfolded
- Native conformation is changed
- Protein is inactivated
- May sometimes be renatured
129Denaturation
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133Protein Hydrolysis
- Breaks peptide bond
- Peptide bond is very stable so need heat, and
acid/base, or the use of an enzyme
134 ALCOHOL
135Enzyme activity 1
136Energy Transition
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139Michaelis-Menton
140Biochemical Energy Production
141Metabolism
- Sum of all biochemical reactions that take place
in a living organism - In 40 years we consume 6 tons of solid food and
10,000 gallons of water - Catabolism break-down of larger molecules into
smaller ones - Anabolism Build-up, smaller molecules make
bigger ones
142Metabolism
143Cell Structure
- Prokaryotic cells have no nucleus, bacteria
- Eukaryotic cells have nucleus, organelles, and
are much bigger (1000X) than bacterial cells - Cell walls in eukaryotic (plant cells)
- We are eukaryotic
144Cell Structure and Metabolism
145Inside a cell
- Cytoplasm water based material of a eukaryotic
cell - Organelle minute structure that carries out a
specific cellular function - Cytosol Water based fluid part of the cytoplasm
146Organelles
- Lysosome Contains hydrolytic enzymes needed for
repair, rebuilding and degradation - Proteins ? amino acids
- Polysaccharides ? monsaccharides
- Destroy bacteria and viruses
147Organelles, Cont
- Mitochondrion Responsible for the generation of
energy - ATP synthase complexes on cristae of inner
membrane
148Mitochondrion
149Intermediate Compounds With Nucleosides
- Adenosine phosphates, ATP, ADP, AMP
150Contd
- Hydrolysis of the phosphate ester bonds in ATP
yields energy - Bonds are reactive and are called strained
bonds - ATP is our unit of currency for energy
151ATP Hydrolysis
152ATP
153Flavin Adenine Dinucleotide, FAD, FADH2
- Coenzyme required in many redox reactions
- Comes from flavin and ribitol, the vitamin
riboflavin - This is then attached to ADP
154Nicotinamide Adenine Dinleotide, NAD
- Coenzyme required in redox reactions
- Has nicotinamide, B vitamin as part of structure
- Also attached to ADP
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156FAD
157Types of Reactions for FAD
158NAD Reactions
159Reaction Types
160Coenzyme A
- Derived from a B vitamin, pantothenic acid
- Active part is the SH group and often abbreviated
CoA-SH - Get a thioester bond
161Coenzyme A
162Overview
163High Energy Phosphate Compounds
- Has a greater free energy of hydrolysis than that
of a typical compound - Easily broken bonds so the energy absorbed by
bond breaking is much less than that of bond
formation in the products - Greater than normal electron-electron repulsive
forces are the cause of the bond strain
164Overview of Biochemical Energy Production
- Energy needed to run the body is derived from
ingested food
165Contd
- Multi-step process involving several catabolic
pathways - There are four stages in energy production
- Digestion
- Acetyl group formation
- Citric acid cycle
- Electron transport chain and oxidative
phosphorylation
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167Stage I Digestion
168Stage IIAcetyl Group Formation
169Stage III Citric Acid Cycle
Hans Adolf Kreb
170Citric Acid Cycle
171Citric Acid Cycle
- Stage III in the oxidation of fuel molecules
- Key intermediate is citric acid
- Also called Krebs cycle
- Also called tricarboxylic acid cycle
- Principal process for generation of reduced
coenzymes, NADH and FADH2 - Occurs in the matrix of the mitochondrion
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173Citric Acid Cycle
- Starts and ends with the same four carbon
molecule, oxaloacetate - Addition of Acetyl CoA gives a six carbon
molecule, citric acid - Two molecules of CO2 are produced, thus returning
to the four carbon molecule - Water is required also
174Citric Acid Cycle, contd
- Acetyl CoA is the fuel
- Depends on adequate supply of NAD and FAD,
supplied form electron transport chain - Four oxidation-reduction reactions produce three
NADH, and one FADH2 - One GTP also produced
175Citric Acid Cycle
- Overall reaction
- Several redox reactions involving coenyzmes
- Hydration
- Condensation
176Regulation of the Citric Acid Cycle
177Citric Acid Cycle Regulation
- There are three main points of regulating citric
acid cycle activity - Citrate synthetase the first step of the cycle
is inhibited by ATP and NADH and activated by
ADP. - Isocitrate dehydrogenase the third step of the
cycle is inhibited by NADH and activated by ADP. - Alpha-ketoglutarate dehydrogenase the fourth
step of the cycle is inhibited by succinyl CoA,
NADH, and ATP.
178Electron Transport Chain
- Series of reactions in which protons and
electrons from the oxidation of foods are used to
reduce molecular oxygen to water. - NADH and FADH2 produced in citric acid cycle
supply hydrogen ions and electrons to combine
with oxygen to form water
179Electron Transport Chain
- Occurs in inner mitochondrial membrane
- Series of reactions
- Electrons from the reduced coenzymes are passed
assembly line fashion from one electron carrier
to the next - The electrons finally combine with oxygen to form
water
180ETC
- As the electrons pass along the carriers they
lose some energy with each transfer and this
energy is used to make ATP in oxidation
phosphorylation - Four protein complexes involved
181Electron Transport Chain
182Oxidative Phosphorylation
- Biochemical process where ATP is synthesized from
ADP as a result of the transfer of electrons and
hydrogen ions from NADH or FADH2 to oxygen
through the electron carriers in the electron
transport chain - Coupled reactions are pairs of biochemical
reactions that occur concurrently where energy
produced by one reaction is used in the other
reaction
183Chemiosmotic Hypothesis
- Theory that a proton flow across the inner
mitochondrial membrane during the electron
transport chain provides energy for the
production of ATP - This proton pump causes the formation of ATP by
F1 -ATPase.
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185Proton Pump
186Step 1 Proton gradient is built up as a result
of NADH (produced from oxidation reactions)
feeding electrons into electron transport
system.
187Electrons are transferred from electron carriers
to the Electron transport chain, involving many
enzyme complexes.
188Step 2 Protons (indicated by charge) enter
back into the mitochondrial matrix through
channels in ATP synthase enzyme complex. This
entry is coupled to ATP synthesis from ADP and
phosphate (Pi)
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190ATP Production
- NADH ? NAD gives 2.5 ATP from ADP
- FADH2 ? FAD gives 1.5 ATP from ADP
- Acetyl CoA ? 10 ATP
- 3NADH ? 7.5ATP
- 1FADH2 ? 1.5ATP
- 1GTP ? 1ATP
191Overview of CAC and ETC
192Pentose Pathway
193Non-Oxidative Stage of Pentose Pathway
194 195 Krebs Pneumonic
- Can
- Intelligent
- Karen
- Solve
- Some
- Foreign
- Mafia
- Operations
196Krebs Cycle or Sometimes called the TCA Cycle
Krebs cycle occurs in the matrix of the
mitochondria. This is a series of reactions
that occur in a cycle as the name indicates.
Enzymes strip off the CoA from acetyl CoA and
combine the acetyl...the two carbon fragment...
to a four carbon molecule in the cycle. Two
redox reactions produce two CO2, two NADH and one
ATP. Two more redox reactions produce one FADH2
and a an additional NADH Relating products of
Krebs cycle to one glucose moleculeEach turn of
the cycle utilizes one pyruvate or 1/2 of a
glucose molecule. This means we must consider the
cycle turning twice for each glucose.With two
turns of the cycle the following are produced per
glucose molecule. Two ATP Two FADH2 Six NADH
197PROTEIN SYNTHESIS
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199Sterol Biosynthesis
200Oxidative Phosporylation
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202Consider the Weak Acid s
203 pH
204 ACID BASE H20C02ltgtH2CO3ltgtHCO3H
205ANION GAP
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211 DNA Pol B
212DNA replication-synthesis
- G1, S, G2, (interphase)
- M, (mitosis)
- Muscles, nerves, stay in O
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216Transcription
- Develop mRNA
- Devoped as precursor (HETEROGENOUS NUCLEAR RNA)
- IN NUCLEUS---
- LOOK AT PREVIOUS SLIDE
217SAM
- SAM is the methyl donor man
- Methyl cap is at 5 end (LEFT)
- Poly-A-tail is at 3 end (right)
- INTRONS ALWAYS IN BETWEEN EXONS
- INTRONS STAY IN NUCLEUS
- Splicing cuts out introns and fuses EXONS to get
sequenced by - (SPLICASOMESNURPS)
- ALL HAPPENS IN NUCLEUS
218mRNA
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220Translation
- Need tRNA and rRNA
- In cytoplasm
221Nucleic Acid
- Composed of Nucleotides
- BASE
- SUGAR
- PHOSPHATE
- If Remove Phosphate it is a nucleoside
- Difference in bases are purine and pyrmidines
- Purines are BIG ( ADENINE and GUANINE)
- Pyrimidine are small(C, U, T, bases U in RNA
and T in DNA) - Changes T into U , by removing amine group by
deaminase - Cytosine is the most highly Methylated- Turns
genes off in that area of the chromosomesto turn
them on must demethylate
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223Linkage
- Nucleotides linked together by covalent
phosphodiaster bond - The one end is 5 and the other end is 3
- Always Read from 5 to 3left to right
- This happens in all except some virus like dsDNA
- CODON IS 3 nucleotides (AUG. UAA.)
- BASE PAIRING BY HYDROGEN BONDS
- A-?T
- C-?G
- THIS IS ALSO CALLED HYDRIDIZATION-anti-parallelmu
st run in opposite direction
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227Synthesis
- DNA or RNA polymerases, synthesize 5-3 by
- Copy template in 3-5
- This is complementary base pairing
- 3 EXONUCLEASES REMOVE FROM END
- This is really important in DNA synthesis
proof-reading, ONLY HAPPENS IN DNA polymerases
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232RNA PROTEIN SYNTHESIS
- Starts protein synthesis at AUG, nucleotides
added to 3 end, Shein-Delvarno-Sequence (just a
ribosomal binding site before AUG) - Left to right----downstream
- TATA -25 Promotor is start site and binding
for RNA polymerase----(1 START SITE) - STOP IS STEM LOOP STRUCTURE
- Operon is a set of genes being transcribed,
influenced by the promotor - RNA CODING STRAND ALWAYS 5-3 (POLY-A- TAIL)
- Protein is always made Amino to Carboxyl
- RNA stop protein synthesis
- UAA (you are alien)
- UGA (your going away)
- UAG (you are gone)
233PROKARYOTES Bacteria
- Transcription and translation both happen in
cytoplasm - Because no nucleus in Bacteria
234INSULIN
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236 Structure of Insulin
- Insulin is composed of 51 amino acid composed in
a polypeptide chains, designated A B. - Insulin is either Synthesized from Porcine
Insulin or Synthesized from recombinant DNA
237Insulin Receptor
238 Regulation of Insulin
- STIMULATION
- Glucose- The beta cells are the most important
glucose sensing cells in the body. The ingestion
of glucose or carbohydrate rich meals leads to a
rise in blood glucose which is a signal for
insulin release - Amino Acids- Ingestion of protein causes a
transient rise in plasma amino acids levels which
in turn induces an immediate secretion of insulin - Gastrointestinal Hormones-the intestinal peptide
secretin , gives an anticipatory rise to insulin
levels in the portal vein before there is an
actual rise in blood glucose - Glucagon-Glucose stimulates the secretion of
insulin and inhibits the release of glucagon.
Type I diabetes where B-cell destruction removes
the inhibitory influence of insulin on glucagon,
Many of the symptoms of the disease are due to
unrestrained activity of glucagon on target
tissue
239(No Transcript)
240Regulation of Insulin
- Inhibition
- Epinephrine-the catachol which is secreted by the
adrenal medulla in response to immediate stress,
trauma, or extreme exercise. It has direct effect
on energy metabolism, causing rapid mobilization
of energy yielding fuels of glucose from the
liver, fatty acids from adipose tissue. Thus,
epinephrine can override normal glucose
stimulated release of insulin. - Cortisol GH These hormones usually play a role
in long-term maintenance, rather than short term - Normally, cortisol levels rise during the
early morning hours and are highest in midmorning
(about 8 a.m.). They drop very low in the evening
and during the early phase of sleep.
241INSULIN RECEPTOR leads to many diseases
242Glucagon
- Glucagon binds to high-affinity receptors on the
cell membrane of the hepatocyte. - Glucagon binding results in activation of
adenylate cyclase in plasma membrane - This causes a rise in cAMP, a second messenger,
which in turn activates cAMP dependent protein
kinase and increases the phosphorylation. - This cascade is presented for the case glycogen
degradation.
243Lipoproteins
244Cholesterol Intermediates
- "A Hot Momma Is Good For Sex, Love, and
Cuddling."A-Acetyl CoAH-HMG CoAM-Mevalonic
acidI-Isopentenyl pyrophosphateG-Geranyl
pyrophosphateF-Farnesyl pyrophosphateS-Squalene
L-LanosterolC-Cholesterol
245 Chylomicrons-VLDL
- Intestinal Mucosa secrete TG-Rich chylomicrons
(produced primarily from dietary lipids) - Liver secretes TG rich very low density
lipoprotein particles
246(No Transcript)
247 TG-Breakdown
- Extra-cellular lipoprotien lipase, activated by
apo CII degrades TG in chylomicrons and VLDL - Chlyomicron remnant travels via the vasculature
and binds to specific receptors in liver where
they are endocytosed
248 IDL-LDL
- IDL-LDL binds to receptors on extra-hepatic
tissues (and on Liver), where they are endocytosed
249(No Transcript)
250Cellular uptake and degradation of LDL
- LDL receptors are negatively charged
glycoprotiens molecules that are clustered in
pits on cell membraneacts in Type II
hyperbetalipoproteinemia - After binding, the LDL are internalized as intact
particle by endocytosis - The vesicles containing LDL rapidly loose its
Clathrin Coat and fuse with similar vesicles
called ENDOSOMES - The pH of the endosomal falls(due to a proton
pump of endosomal ATPase, allowing separation of
LDL from receptors - The CURL is then form-Compartment for Uncoupling
of Receptor and Ligand
251 TYPE I
- Type I Familial Hyperchylomicronemia
- Massive fasting hyperchylomicronemia even after
following normal dietary fat intake - Deficiency of lipoprotien lipase or deficiency of
normal apoprotein CII rare - Type I is not associated with an increase in
coronary heart disease - Treatment low fat diet-No drug therapy
252Type IIA Familial Hyperbetaprotienemia
- Elevated LDL, with normal VLDLs level due to a
block in LDL degradation, therefore increase
serum cholesterol but normal triacylglyerol - Caused by a decrease number of LDL receptors
- Ischemic Heart disease is greatly accelerated
- TX Low cholesterol/ Low Fat diet
- Heterozygotes-Cholestyramine or Colestipol, and
Lovastatin or mevastatin - Homozygotes-As above, plus niacin
253Type II B Familial Combined (mixed)
Hyperlipidemia
- Similar to IIA, except VLDL is also increased,
resulting in elevated serum triacylglyerol as
well as cholesterol - Relatively common
- TxDietary restriction as above, low cholesterol,
fat and no alcohol - Similar to IIA, except heterozygotes also receive
Niacin
254Type III Familial Dysbetalipoproteinemia
- Serum Concentrations of IDL are increased
resulting in increasing triacyglyerol and
cholesterol - Cause is either overproduction or
underutilization of IDL, perhaps due to mutant
apoprotien - Xanthomas and accelerated coronary and
peripheral resistance develop by middle age - TX-Weight reduction, Dietary restriction of
cholesterol and alcohol - Drug therapy includes niacin, and clofibrate (or
gemfibrizol), or lovastatin (or mevastatin)
255- Type IV Familial
Hypertriglyceridemia - VLDL are increase, while LDL level as are normal
or decreased, resulting in normal to elevated
cholesterol, and greatly elevated circulation
triacylglycerol - Cause is either overproduction or decreased
removal of VLDL in serum - This is relatively common disease. It has few
clinical manifestations other than accelerated
ischemic heart disease - Weight reduction is of primary
importance-Dietary restriction of controlled
carbohydrate, modified fat, low alcohol
consumption - If necessary, drug therapy includes niacin and
or gemfibrizol (or Clofibrate), lovastatin or
mevastatin
256 Type V Familial Mixed
Hypertriglyceridemia
- Serum VLDL and Chylomicroms are elevated, LDL is
normal or decreased. This results in elevated
cholesterol and greatly elevated triacylglycerol - Cause is either increased production or decreased
clearance of VLDL and chylomicrons - TX Weight reduction is important. Diet should
include protein, low fat, controlled carbohydrate
and NO ALCOHOL. - Drug therapy include niacin, Clofibrate and/or
Gemfibrizol , or lovastatin (or mevastatin)
257 KETONES
- Ketones are substances the body produces when
it breaks down fats for energy (metabolism).
Normally, the body obtains energy from sugars
(carbohydrates), but if a person's diet does not
include enough sugars to supply the body with
energy, or if the body cannot use sugars
properly, it will break down stored fat and
produce ketenes (a process called ketogenesis). - If large amounts of ketones accumulate in the
blood, a condition called ketosis may occur.
Ketosis occurs most often in people who have
poorly controlled type 1 diabetes. In type 1
diabetes, the body lacks insulin to use sugars
properly. To obtain energy from sugars, people
with type 1 diabetes must inject insulin so their
bodies can obtain energy the normal way, from
sugars. If a person with diabetes does not take
enough insulin, his or her body will have to
break down fat for energy.
258Storage Diseases
- Glycogen Storage
- Type I- Von Geirkes
- Type II- Pompes
- Type V- McCardles
- Mucopolysacchridosis
- Scheies Syndrome (MPS I S)
- Hurlers Syndrome (MPS I H)
- Hunters Syndrome (MPS II)
- Sanfillipos Syndrome (MPS III) Types A-DSlys
Syndrome (MPS VII) - Glycospingolipids (sphingolipidosis) gangliosides
- GM 1
- Tay-Sachs
- Metachromatic Leukodystophy
- Fabrys Disease
- Neiman Pick Disease
- Farbers Disease
259Glycogen Storage Diseases
- Type I Von-Gierkes
- Glucose-6-Phosphatase Deficiency
- Affects liver, kidney, and intestine
- Fatty liver, hepatomegaly
- Severe Fasting HYPOglycemia
- Normal Glycogen structure
- NOTE In Von Geirkes the only source of glucose
is food
260Glycogen Storage Diseases
- Type II-Pompes Disease
- (Lysosomal Alpha-Glucosidase Deficiency)
- Alpha 1-4 glucosidase (ACID MALTASE)
- Inborn lysosomal enzyme defect
- Generalized (LIVER, HEART, MUSCLE)
- EXCESSIVE GLYCOGEN CONCENTRATION-found in
cytosomal vacuoles - Normal blood sugar levels
- SEVERE CARDIOMEGALY
- Early death occurs
- Normal Glycogen Structure
261Glycogen Storage Diseases
- Type V- McArdles Syndrome
- (Glycogen Phosphorylase Deficiency)
- Temporary weakness and cramping after exercise
- No rise in blood lactate during exercise
- Myoglobinuria in later years
- Fair to good prognosis
- High level of glycogen in Muscle
- No ATP synthesis?no co A?no TCA cycle
262 Mucopolysacchridosis
- Scheies Syndrome (MPS I S)
- Alpha-L-Iduronidase Deficiency
- Corneal Clouding, stiff joints, aortic valve
disease, normal intelligence and life span - Degradation of dermatan sulfate and heparan
sulfate
263 Mucopolysacchridosis
- Hurlers Syndrome (gargoylism) (MPS I H)
- Alpha-L-Iduronidase Deficiency
- Corneal Clouding, Mental retardation, Dwarfing,
Coarse Facial Features - Degradation of Dermatan Sulfate and Heparan
Sulfate Affected - Deposition in coronary artery leads to ischemia
and early death
264 Mucopolysacchridosis
- Hunters Syndrome (MPS II)
- Iduronate sulfatase deficiency
- X-linked
- Wide Range of Severity-No corneal Clouding, but
physical deformity and mental retardation is mild
to severe - Degradation of dermatan sulfate and heparan
sulfate
265Mucopolysacchridosis
- Sanfilippos (MPS III) Type A-D
- Four enzyme steps are necessary for removal of
N-sulfated or N-acetylated glycoaminoglycan
residues from heparin sulfate - Type A-Heparan sulfamidase defiency
- Type B-N-Acetylglucosamidase deficiency
- Type C N-Acteyltranferase deficiency
- Type D N Acetylglucosamine deficiency
- SEVERE NERVOUS SYSTEM DISORDERS, MENTAL
RETARDATION
266Mucopolysacchridosis
- Slys Syndrome (MPS VII)
- B-Glucuronidase deficiency
- Hepatosplenomegaly
- Degradation of dermatan sulfate and heparan
sulfate affected
267 Sphingolipidosis
- TAY-SACHS-hexoamidase a
- Increased gangliosides
- Mental retardation
- Blindness
- Cherry Red Macula
- Muscle weakness
- Seizures
- Fatal
- AUTOSOMAL RECESSIVE
268 Sphingolipidosis
- GM-1 Gangliosidosis
- Mental Retardation
- Liver enlargement
- Skeletal deformities
- Accumulation of gangliosides and mps
- Fatal
- AUTOSOMAL RECESSIVE
269 Sphingolipidosis
- Sandhoffs Disease
- Same symptoms as Tay-Sachs but more progressive
- AUTOSOMAL RECESSIVE
270 Sphingolipidosis
- GAUCHERS- q11-22
- Increases Glucocerebrosides
- Liver and spleen enlargement
- Osteoporosis
- Mental Retardation
- Frequently Fatal
- AUTOSOMAL RECESSIVE
271 Sphingolipidosis
- Fabrys Disease (alpha galactosidase)
- Increased Globulosides
- Reddish-purple skin rash
- KIDNEY and Heart
- Pain in Lower extremities
- X-LINKED RECESSIVE
272 Sphingolipidosis
- Neimann-Pick Disease
- Increased Sphingomyelin
- Enlarged liver and spleen
- Mental Retardation
- Fatal Early in Life
- Autosomal Recessive
273 Sphingolipidosis
- Metachromic Leukodystrophy
- Increased sulfatides
- Mental Retardation
- Demyelination
- Progressive paralysis and dementia
- Nerves stain Yellow-Brown
- Fatal in First Decade
- Autosomal Recessive
274 Sphingolipidosis
- FARBERS DISEASE
- (ceraminidase)
- Painful and progressively deformed joints
- Sub Q nodules
- Tissue shows Granuloma
- Fatal early in life
- Autosomal Recessive
275 MCAD
- Medium chain Acyl CoA dehydrogenase deficiency.
- Child can get comatose, with brief generalized
seizures. Intravenous administration of Glucose
helps the situation. - NORTHERN EUROPEAN
- Autosomal Recessive
276 HNPCC
- Hereditary non-polyposis colerectal cancer is
Autosomal Dominant - Often happens before the age of 50 years
- 90 are a mismatch in repair of mutations during
G2 phase of cell cycle - Female relative are at risk for endometrial
carcinomas
277ESSENTIAL AMINO ACIDS
- This Lying Mr. Liu Pong Is Trying Very
Hard."This-
ThreonineLying- LysineMr-
MethionineLiu-
LeucinePong-
PhenylalanineIs-
IsoleucineTrying-
TryptophanVery-
ValineHard- Histidine in
infants
278CARBONIC ANHYDRASE LOCATIONS
- P PECKERS"P-PancreasP-Parietal cells (gastric
mucosa)E-ErythrocyteC-CNSK-Kidney
(PCT)E-EyesR-Respiratory (lungs)S-Saliva
279 IRON VALANCES
- Iron valenceFerroUS - Fe2 - just the 2 of US
- FerRic - Fe3 - Rich in positive charge
280BASIC AMINO ACIDS
- Basic amino acids - positively charged at pH
6.0"H-A-L's Base voice earned him much Argent
Arg, a Positive event."H-
HistidineA- ArginineL- Lysine
281 Negativily Charged
- Acidic amino acids - negatively charged at pH
6.0"G-A-gging on Acid is a Negative
experience."G-Glutamic acidA-Aspartic acid
282Embden-Meyerhoff Pathway
283Hexokinase Deficiency (HK)
- HK is a major determination of glucose
consumption and of the formation of a first
enzyme in the glycolytic pathway. - Shown most with reticulocytes since enzyme is
highly inactive after RBCs mature
284Phosphofructokinase Deficiency
(PFK)
- PFK is tetrameric enzyme that has effects in
- M(muscle)
- F (fibroblast, platelets)
- L (granulocytes)
285 Pyruvate Kinase (PK)Deficency
- The most common enzyme deficiency in
Embden-myerhoff
286Enzymes of HMP shunt
287 Glucose-6-Phosphate dehydrogenase G6-PD
- G6PD is an inborn error of erythrocyte metabolism
affecting most geographic areas around the world. - Affected by some race effects
- It involves the HMP shunt
- bandXq28
288Pyruvate Dehydrogenase
- This is found in Chronic alcoholics, present with
a lateral gaze and difficulty walking. - May be Weirnicke encephalopathy
- It is caused by Thiamine deficiency in which TPP
is needed for pyruvate dehydrogenase
289Vitamins
290 Non B complex
- Ascorbic Acid-
- Well documented as a coenzyme for hydrolylization
of lysyl and propl residues in collagen - Benefit as an antioxidant- except for a presence
of high Iron - Deficiency-SCURVY
291Fat Soluble Vitamins
- Vitamin A
- Vitamin D
- Vitamin K
- Vitamin E
292 Vitamin A (retinol)
- Vit A is a collective term for several
biologically related active molecules - Retinol-is a primary alcohol with an unsaturated
side chain-Found in animal tissue as long fatty
acids - Retinal-an aldehyde that can readily be converted
- B-Carotene-activity 1/6th of retinol
- Functions-visual cycle-growth-reproduction-differe
ntiation of cells - Toxicity is well noted especially in pregnant
women. - Transported as Chylomicrons
293Vitamin D (1, 25 Dihydoxycholeecalciferol)
- D2 and D3 are bioactive-employing cyto p450. It
is tightly regulated by plasma phosphate and
calcium ions. - Overall function is to increase uptake of calcium
by intestines - It stimulate calcium and phosphate from bone to
maintain plasma levels - Diseases-Rickets in adult
- Osteomalacia in adults
- Found in milk supplemented--sunlight
- NOTEVIT D is the MOST TOXIC OF ALL VITAMINS
294Vitamin K Menaquinone
- Vit K is required for Hepatic synthesis of
Clotting Factors II, VII, IX, X (1972) - Found in cabbage, cauliflower and spinach,
eggyolk, and liver - Deficiency leads to
- hypo-prothrombinism
- Newborns require one dose because inability to
synthesize
295Vitamin E alpha-tocopherol
- Found in liver and eggs and fish oil
- Infants may have deficiency to vitamin E,
therefore erthrocytes mat may have obscure cell
membrane - Vitamin E in supplements of 400 IU may reduced
heart disease by 40 by decreasing LDL
296Water Soluble Vitamins
297Thiamine(B-1) energy releasing
- Thiamine pyrophosphate is a bioactive coenzyme in
the oxidative-decarboxylation of
alpha-ketoacidstransketolase - This decrease the function of pyruvate
dehydrogenase - Clinically
- Beri-Beri-Infants-Tachycardia, vomiting, Adults
dryskin, irritability and progressive paralysis - Wernicke-Korsakoff Syndrome-ALCOHOLICS
298Riboflavin (B-2) energy releasing
- Flavins (FMN) and (FAD) are formed by the
transfer of ATP, they are in an
oxidation-reduction reaction - Found in Milk, eggs, liver and green vegetables
- The vitamin is destroyed by ultraviolet light
- Deficiency-cheliosis,glossitis
299 Niacin (B-3)
- Niacin or nicotinic acid is a pyridine derivative
- Serves as a coenzyme for (NAD and NADP)
- Found in Whole Grains and Milk
- Def Pellegra (dementia, diarrhea, dermititis)
- USED in Treatment of Hyperlipidemia-decreasing
triaclyglycerol synthesis and Decreasing LDL and
VLDL- - Specifically TYPE II b Hyperlipoprotienemia
300 Biotin
- Coenzyme in carboxylation reactions
- Very rare deficiency
- Some people with an addition to RAW EGGS, could
in fact have an effect because the glycoprotein
AVIDIN does bind to it tightly. - gt than 20 raw eggs a day
301Panthothenic Acid
- CoA-functions in the transfer of the Acyl Group
- Serves as a component of FATTY ACID SYNTHASE
- Eggs, Liver and yeast are common sources..FDA has
no established criteria
302FOLIC ACID-hematopoetic
- Most Common Vitamin Deficiency
- Bio active form is (THF) which is produced by a
two step reduction of folate by Dihydrofolate
reductase - Sulfonamides and Methotrexate used this chain in
their action - Found in Green Vegetables, lima beans and whole
grain cereals (or Bacteria) - DEPENDENCY-First week of Pregnancy
- DX-Megaloblastic Anemia
- Dx-Neural Tube Defects
303 Colbalmin (B-12)corrin ring hematopoietic
- When fatty acids accumulate into cell membranes
B12 deficiency may show neurological
manifestations - B12 deficiency also happens in total or partial
gastrectomy - PERNICIOUS ANEMIA-is probably due to an
Auto-immune destruction of Gastric Parietal Cells
and responsible for the synthesis of a
glycol-protein called Intrinsic Factor (IF) - Lack of (IF) prevents abscoption of B-12
therefore Pernicious Anemia
304 Pyridoxine
- B6 is an enzyme that functions in many reactions
- Transamination
- Deamination
- Decarboxylation
- Condensation
- Requirements increased by a large amountt of
proteins - Isoniazid, a TB drug can decrease B6