MidTerm Exam

1
Mid-Term Exam

• Trace the transfer of energy from a Big Mac,
  french fries and a milkshake to muscle
  contraction during a long jump, 100 meter dash,
  and a marathon. Describe the effects of aerobic
  exercise training and strength training (where
  applicable) on each step of this process.

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How is the energy from food transferred from the
environment through the body to produce chemical,
mechanical and heat energy?
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Exercise and Body Composition

• What is exercise?
• What is training?
• What is the human body composed of?

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Atoms
Cells
Molecules
Tissue
Organs
Systems
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Objective 1 Be able to name the major
components of body composition at the atomic,
molecular, cellular, tissue, organ system level
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What is the Human Body Composed of?

• 96 made up of 4 key elements
• All 4 make up proteins
• Other 3 make CHO fat
• Can you name them?

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Components of Body Composition at the Atomic Level

• Oxygen
• Carbon
• Hydrogen
• Nitrogen
• Sodium
• Potassium

• Chloride
• Phosporous
• Calcium
• Magnesium
• Sulfur

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Components of Body Composition at the Molecular
Level

• Water
• Fat
• Protein
• Mineral (soft tissue bone)
• Glycogen

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Components of Body Composition at the Cellular
Level

• Cell mass
• Extracellular fluid (one-third)
• Interstitial fluid
• Plasma
• Intracellular fluid (two-thirds)
• Extracellular solids

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Components of Body Composition at the Tissue Level

• Adipose tissue
• Skeletal muscle
• Bone (skeleton)
• Blood
• Other tissue

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Quiz 1 Name at least 4 major components of the
body at the atomic, molecular, cellular, tissue,
organ, system levels
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Objective 2a Be able to describe the difference
between energy transformations and energy
transferObjective 2b Describe the efficiency
of energy transfer in the human body
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How does diet exercise alter BC?

• Energy transformations
• Original energy source for 100 meter dash?
• Transport energy
• Chemical energy
• Mechanical energy

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Energy Transfer
Plants (chemical) CHO, Fats Proteins
Sun (solar energy)
Animals (chemical) CHO, Fats Proteins
Humans (chemical) CHO, Fats Proteins ATP-PC
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Sun
6 CO2 6 H2O
C6H12O6
673 kcal/mole
6 CO2 6 H2O ATP
Glucose 6 O2
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Cellular Respiration (reverse of photosynthesis)
Transport Work
ATP
Glucose
Chemical Work
Mechanical Work
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Muscle Action
Digestion
Nerve transmission
ATP
Glandular secretion
Circulation
Tissue synthesis
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Catabolism
CHO, Fats Proteins
CO2 H2O NH3
Heat energy (60)
Chemical energy (40)
ATP
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Energy Transfer and Energy Transformation

• Movement from one source to another
• Change from one type to another
• What is energy?
• How is it transferred transformed?
• How does it relate to body composition?

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Energy Transfer, Training Body Composition
Relationships

• How do you change body composition?
• Can it be done by regular exercise (training)?
• The answer depends on
• The size of the contracting muscle mass
• The intensity of the exercise
• The duration of the exercise
• The frequency of the exercise

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Quiz 2a Name describe the steps in energy
transformation in which energy is transformed
from the environment to the human body
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Quiz 2b Name describe the steps for energy
transfer in which energy is transferred from the
environment to the human body
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What is the efficiency rating of energy transfer?

• 90
• 10
• 60
• 40
• 50

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Energy Transfer Obeys the Laws of thermodynamics
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Laws of Thermodynamics

• The science of energy transformations
• 1st law
• Total energy of a system remains constant
• It can be transferred or transformed
• 2nd law - total entropy increases
• Disorder or randomness increases
• E.g., Random motion from heat cant be completely
  converted to ordered motion
• Potential energy moves from high to low

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Objective 3 Be able to name the sequence of
body compartments and describe the process in
which energy passes through the human body prior
to storage
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Energy Content of a Big Mac, French Fries Milk
Shake

• Carbohydrates 161 gms, 644 kcals, 47
• Fats 62 gms, 558 kcals, 41
• Proteins 43 gms, 172 kcals, 13
• Total calories 1,374

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Processes for Energy Transfer from Food

• Digestion
• Absorption
• Transport
• Uptake
• Storage
• Mobilization
• Utilization (oxidation)

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Sites for Food Processing Energy Transfer

• Mouth
• Stomach
• Intestines (microvilli or brush borders)
• Portal vein or lymphatics
• Liver or heart
• Extrahepatic tissue (muscle, adipose tissue, etc)

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Movement of Food through Intestines

• Peristalsis
• Longitudinal smooth muscle contractions
• Strongest in esophagus stomach
• Produces waves that moves food forward
• Segmentation
• Circular smooth muscle contractions
• Initiated from intestines
• Slows intestinal motility

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Movement of Food Through the Intestines (contd)

• Migrating motility complex
• Replaces segmentation during fasting
• Ceases when new meal arrives
• Peristaltic-type waves
• Travels short distances
• Stimulated by hormones such as motolin

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Factors Affecting Gastrointestinal Transit

• Fluid temperature
• Fluid osmolality (free glucose vs polymers)
• Exercise intensity
• Exercise training (aerobic vs strength training)

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Quiz 3a Name each step that must take place
before energy in the form of carbohydrates, fats
proteins can be stored in the form of glycogen,
adipose tissue specific proteins, respectively
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Quiz 3b Describe the actions that allow
movement of food from the mouth to storage sites
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Quiz 3c Which of the following is most likely to
occur during fasting?

• Segmentation
• Peristalsis
• Migrating motility complex
• Glycogenesis in the liver

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Objective 4 Name define the components of
carbohydrates found in food
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Main Functions of Carbohydrates

• Major energy source
• Gives structure to cell membranes
• Metabolic intermediates
• Large component of DNA RNA
• Important part of immune system

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Trace the path of Carbohydrates found in the
Hamburger, Fries Shake

• What carbohydrates?
• Starch
• Lactose
• Sucrose
• Maltose
• How are they broken down?
• How is energy obtained?

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Classification of Carbohydrates

• Monosaccharides
• Disaccharides
• Oligosaccharides
• Polysaccharides

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Monosaccharides

• Glucose
• Fructose
• Galactose

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Disaccharides

• Sucrose glucose fructose
• Lactose glucose galactose
• Maltose glucose glucose

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Polysaccharides

• Starch glucose molecules connected to form
  specific linkages
• Glycogen glucose molecules with more branching
  than starch
• Cellulose glucose molecules with bonds
• Fiber ?

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Quiz 4 Name define the major components of
carbohydrates found in a hamburger, fries milk
shake
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Objective 5 Be able to name describe 5
methods by which enzymes regulate metabolic
pathways for energy transfer
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Carbohydrate Digestion in the Mouth

• Salivary amylase brakes starch down to maltose
• What determines this?
• No action on lactose and sucrose
• What happens in the stomach?

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How do enzymes allow metabolic pathways to work?

• Lower activation energy
• Enzyme substrate interactions
• Active and allosteric sites
• Covalent modification
• Enzyme induction and repression

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Lower Activation Energy
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Enzyme Substrate Interactions
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Active and Allosteric Sites
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Covalent Modification
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Covalent Modification
Kinase reaction (adds phosphate)
Activates Phosphorylase
Phosphatase reaction (removes phosphate)
Activates Synthase
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Enzyme Induction Repression
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Enzyme Induction
E S
Nothing happens
ES P ES P ES P
E S S S S S S S S S S S
New enzymes are synthesized
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Enzyme Repression
P P P P P ES P P P P P
No new enzyme synthesized
End Product Inhibition
A B C D EEEE
EEEE
EEEE
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Enzyme Induction Repression

• Long term regulation (hrs to days)
• Stimulated by hormones, substrates or products
• Changes enzyme synthesis
• Regulates supply and demand
• Example lactose intolerance

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Quiz 5a Name the 5 methods for enzyme
regulation of metabolic pathways identify each
as being short term or long term regulation
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Quiz 5b Which of the following is not a
characteristic of the way enzymes allow metabolic
pathways to work?

• Lower activation energy
• Accelerate the reaction
• Change their structure
• Bind to substrate
• Produce or inhibit new enzyme formation

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Objective 6 Be able to trace the steps involved
in the digestion absorption of carbohydrates
obtained from a Big Mac, fries milk shake
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Carbohydrate Digestion in the Mouth

• Salivary amylase brakes starch down to maltose
• What determines this?
• No action on lactose and sucrose
• What happens in the stomach?

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Carbohydrate Digestion in the Small Intestines

• Most broken down here by pancreatic amylase (PA)
• High carbohydrate diets can increase PA by 10
  fold
• Disaccharides broken down by brush border
  enzymes
• Maltose Maltase glucose glucose
• Sucrose Sucrase glucose fructose
• Lactose Lactase glucose galactose

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Carbohydrate Absorption

• Glucose galactose - active transport, Na
  dependent
• Fructose - facilitated diffusion

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Carbohydrate Transport to the Liver

• Mucosal cells
• Serosal cells
• Capillaries of villus
• Venules of villus
• Portal vein
• Liver sinusoidal capillaries
• Hepatocytes

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Quiz 6a Where does digestion of carbohydrates
(CHO) begin what are the final breakdown
products of ingested CHO from a Big Mac, fries
milk shake prior to absorption?
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Quiz 6b Which of the following is not a type of
carbohydrate ingested from the Big Mac, fries,
and shake

• Monosaccharides
• Dissaccharides
• Oligosaccharides
• Polysaccharides
• Glycogen

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Objective 7 Be able to name describe the
steps involved in glucose uptake storage in the
liver, skeletal muscle adipose tissue
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Insulin
Glucokinase
Pancreas
Glucose
G-6-P
Chyme GI Hormones (secretin, GIP etc.)
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Regulation of Glucose Uptake in the Liver

• Glucose and GI hormones stimulate insulin release
• Insulin increases the activity of glucokinase
• High glucokinase activity increases G-6-P
• Insulin also lowers glycogenolysis
  gluconeogenesis

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Maintenance of Blood Glucose Levels
Glucokinase
Glucose in portal blood
G-6-P
Glucose- 6-Phosphatase
Liver cell membrane
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Glycogen
2
Hexose Mono-P Shunt
1
3
Glucose from gut to portal vein
G-6-P
4
Pyruvate
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Sequential Steps for Hepatic Glucose Metabolism
After Feeding

• Glucose Glucokinase G-6-P
• G-6-P converted to glycogen
• Inactivation of glycogen phosphorylase
• Activation of glycogen synthase
• G-6-P NADPH through HMS
• G-6-P Pyruvate through glycolysis
• Inhibition of gluconeogenesis

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Hormonal Action

• Feeding
• insulin glucagon
• glucokinase G-6-P
• glycogen synthase glycogen
• Fasting prolonged exercise
• glucagon glycogenolysis
• gluconeogenesis
• How are blood glucose levels maintained?

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Quiz 7a Insulin release is first stimulated
from food entering the

• Stomach
• Gut
• Liver
• Pancrease
• Heart

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Quiz 7b Which of the following is not activated
in the liver shortly after feeding?

• Glucose-6-phosphatase
• Glucokinase
• Glycogen synthase
• Insulin

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Objective 8 Be able to answer the following
questions about glucose metabolism in the liver

• How is the CHO energy transferred from the
  ingested meal to the liver?
• What is the main signals that determine glucose
  entry exit from the liver?
• What are the initial end products of glucose
  metabolism in the liver?
• How are the effects of exercise training?

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Regulation of Glucose Metabolism in the Liver
Important Concepts

• Glucose availability
• Hormonal action (insulin/glucagon)
• Enzyme induction repression
• Allosteric regulation
• Covalent modification
• Oxidation/reduction

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Maintenance of Blood Glucose Levels
Glucokinase
Glucose in portal blood
G-6-P
Glucose- 6-Phosphatase
Liver cell membrane
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Regulation of Glucose Release from Liver

• Low CHO in GI tract low insulin high glucagon
  epinephrine levels
• Increased glycogenolysis by increased cyclic AMP
  activity
• High glucagon inhibits glycolysis
• Low glucokinase, G-6-P glycogen synthase
  activity

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Glycogen
2
Hexose Mono-P Shunt
1
3
Glucose from gut to portal vein
G-6-P
4
Pyruvate
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Exercise vs Training Effects on Hepatic Glucose
Metabolism

• Exercise effects
• Glucagon glycogenolysis
• Gluconeogenesis with duration
• Glucose release from liver
• Training effects
• Glucagon glycogenolysis
• Gluconeogenesis precursers
• Disruption of glucose homeostasis

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Quiz 8a Describe how the CHO energy is
transferred from a meal to storage in the liver
as glycogen
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Quiz 8b Which of the following is activated
during feeding inactivated during fasting?

• A. Glucose -6-phosphatase
• B. Glycogen phosphorylase
• C. Glycogen synthetase
• D. Glucokinase
• E. Both C D

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Quiz 8c Which of the following is not an effect
of exercise on liver glucose metabolism?

• A. Increase in glucagon
• B. Decrease in gluconeogenesis
• C. Increase in glucose release from liver
• D. Increase in glycogenolysis
• E. None of the above

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Obj 9a Be able to name describe the
following

• Two methods required for glucose uptake in muscle
• Effects of ATP AMP on glycolysis
• Two processes of energy transfer from glycolysis
  Krebs cycle to ATP production

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Obj 9b Determine whether each pathway functions
primarily in the liver, muscle or equally in both

• Glycolysis
• Gluconeogenesis
• Glycogenesis
• Uses glucokinase to make G-6-P
• Hexose monophosphate shunt
• Uses G-6-Phosphatase to release glucose

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Glucose Transport from Liver to Systemic
Circulation

• Rt and left hepatic veins
• Inferior vena cava
• Heart Lung circulation
• Systemic circulation

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Insulin
1
Insulin Receptor
Glucose
3
2
4
5
Glucose transporter
Glucose
6
Glucose
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Glucose Uptake by Skeletal Muscle

• Insulin binds to receptors
• This signals glucose transporters to cell
  membrane
• Glucose binds to glucose transporters
• Glucose is transported across membrane
• Glucose is released from glucose transporters
• Glucose transporter moves to original location
• Insulin dissociates from receptor

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Effects of Exercise on Glucose Uptake

• Muscular contraction
• May be mediated by calcium release
• Both isometric isotonic equally effective
• Increases the number of GLUT 4 transporters

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Effects of Training on Glucose Uptake

• Glucose insulin response to OGTT
• Aerobic vs Strength training
• Glucose response to OGTT
• Insulin response to OGTT
• Results from clamp studies

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ATP used
ATP used
Glucose or Glycogen
3
2
G-6-P
ATP gained
7a
6a
4
5
ATP gained
6b
7b
8a
ATP gained
10b
Pyruvate
9b
8b
ATP gained
10a
Pyruvate
9a
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Role of Glycolysis in Skeletal Muscle

• Converts glucose (6 C) into 2, 3 C phosphates
• Then converts them into 2 pyruvates (2 C acids)
• Releases energy to phosphorylate ADP to ATP
• Produces a net gain of 2 ATPs per glucose molec
• Releases energy to reduce NAD to NADH (aerobic)
• Oxidizes NADH to NAD to produce lactate

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NAD
NADH H
Pyruvate
Lactate
LDH
NAD
NADH
Acetyl CoA
Krebs Cycle
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Anaerobic Glycolysis

• NADH accumulates when O2 is low
• Unless electrons are donated to Pyruvate
  (lactate)
• When this happens NAD is generated
• And glycolysis can continue
• Net gain of 2 ATPs per glucose molecule

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Aerobic Glycolysis

• More ATP can be generated when oxygen is
  available
• Pyruvate is transported across the mitochondria
• NAD availability allows pyruvate to be converted
  to acetyl CoA
• Acetyl CoA enters Krebs cycle

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Glucose
ATP
G-6-P
-
PFK

AMP Citrate
Pyruvate
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Regulation of Glycolysis in Muscle

• Activity of hexokinase determines G-6-P levels
• G-6-P levels determines fate of glucose
• G-6-P hexokinase
• Energy needs control glycolysis through PFK
  regulation
• ATP
• AMP
• Citrate

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Regulation of Muscle Glycogenolysis
Muscle Contraction
Epinephrine
Nerve Impulse
Ca2
cAMP
ATP
Ca2 - Calmodulin
Protein kinase A
Phosphorylase Kinase
P
ADP
P
Glycogen Phosphorylase a
Glycogen Phosphorylase b
AMP
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Regulation of Glycogenolysis in Muscle

• Similar to liver except epinephrine more
  important than glucagon
• Calcium or cyclic AMP mediated (cascade reaction)

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NAD
Acetyl-CoA
NADH H
NAD
CO2
Krebs Cycle
NADH H
NAD
FAD
NADH H
FADH H
GDP
GTP
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Krebs Cycle

• Electrons are transferred to NADH FADH
  (electron carriers)
• 1 ATP is formed from phosphorylating ADP
• Each NADH can produce 2 ATPs 1.3 ATPs are
  produced from each FADH

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Outer Mitochondria Membrane
Inner Mit. Membrane
H
NADH FADH2
ADP Pi
H
H
ATPase
H
H
H
NAD FAD H2O
ATP
H
H
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Oxidative Phosphorylation

• Electrons passed to NAD FAD are then passed to
  oxygen
• Iron containing enzymes transfer electrons from
  NADH FADH
• After being transfered to oxygen, water is formed
• ADP is phosphorylated through proton (H)
  exchanges to form ATP

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Carbohydrates
O2
Oxidative Phosphorylation (Mitochondria)
Glycolysis (cytosol)
H2O
ATP
NADH H FADH H
Krebs Cycle (Mitochondria)
Pyruvate
CO2
Lactate
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Regulation of Glycogenesis in muscle

• High G-6-P high glycogen synthetase high
  glycogen
• High insulin high glycogen synthetase
• Low calcium cyclic AMP increased conversion
  to glycogen

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Glucose Metabolism in Muscle vs Liver

• Muscle - self serving
• ATP production only
• No gluconeogenesis
• Glucose entry dependent on insulin or muscle
  contraction

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Glucose Metabolism in Muscle vs Liver (contd)

• PFK 20 times more active in muscle
• More dependent on catecholamines for
  glycogenolysis
• Glucose phosphorylated by hexokinase

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What determines tissue metabolism of glucose?

• Energy needs of muscle
• High G-6-P inhibits glucose uptake by lowering
  hexokinase activity
• Excess glucose is converted to triglyceride in
  adipose tissue

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Quiz 9a Fill in the blanks

• Either ___________ or ___________ is required for
  glucose to be taken up by skeletal muscle.
• Electons are taken up from glycolysis and the
  Krebs cycle and transported to electron transport
  in the mitochondria by _______ and __________.
• High levels of ATP __________ glycolysis, whereas
  high levels of AMP __________ glycolysis.

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Quiz 9b Place an a, b, or c after each
term if it functions primarily in liver, muscle,
or both

• Glucokinase ____
• Glucose-6-phosphotase ____
• Four major pathways from G-6-P ____
• Glycogenolysis ____
• Gluconeogenesis ____
• Glycolysis _____

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Obj 10 Name describe the following processes

• A. Fat storage through excess glucose
• B. Fat digestion
• C. Fat absorption
• D. Fat storage through fat transport
• E. Fat breakdown
• F. Fat mobilization
• G. Fat utilization

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Lipogenesis in Adipose Tissue
Insulin
glycolysis
Glucose
Glycerol P
TG
LPL
TG
Fatty acids
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How is glucose converted to fat?

• Glycolysis in adipose tissue
• In the presence of insulin glucose enters adipose
  tissue
• Glycolysis produces glycerol phosphate (P)
• Glycerol P combines with fatty acyl CoA to make
  triglyceride

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Quiz 10A Name the metabolic pathway responsible
for the storage of fat in adipose tissue from the
excess glucose not metabolized by other tissues.
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What are fats and lipids?

• Fats are esters of fatty acids with glycerol
• Lipids are esters of fatty acids with an alcohol
  group attached (includes glycerol)
• Alcohol groups are contained in oils, fats and
  waxes

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Classification of Lipids

• Simple lipids
• Fats (oils in liquid state)
• Waxes
• Compound lipids
• Phospholipid
• Glycolipids
• Other
• Derived lipids

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Classification of Dietary Lipids

• Triglycerides (triacylglycerols or neutral fats)
  - 3 fatty acids glycerol
• Phospholipids - 2 fatty acids, 1 phosphoric acid
  glycerol
• Steroids - interconnected carbon rings
  (cholesterol, sex hormones, etc)

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Digestion of Lipids in the Mouth

• No chemical action
• Lingual lipase is secreted in the dorsal surface
  of the tougue

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Digestion of Lipids in the Stomach

• Lingual lipase or gastric lipase can break down
  some lipids
• Primarily short medium chain lengths
• Not much digestion of fats occurs in stomach

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Bile
Large Lipid Droplet
Pancreatic Lipase
Emulsified Lipid Droplet
Micelles
TG
TG
Monoglycerides fatty acids
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Digestion of Triglycerides in the Small Intestines

• Food in the duodenum stimulates hormones to
  release bile
• Bile emulsifies lipids aids function of
  pancreatic lipase
• Small emulsified droplets called micelles are
  formed
• Triglycerides (TG) are broken down to FFA and
  monoglycerides then reesterified back to TG

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Quiz 10B True or False (If false, explain why)
Digestion of fats occur primarily in the
intestines and involves emulsification, micellar
formation, lipolysis lipogenesis.
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Lipid Absorption

• Triglycerides (TG) undergo lipolysis
  lipogenesis
• TG are then packaged into chylomicrons
• TG can then travel through the blood stream
• TG are then transported through lymphatic system

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Digestion of Cholesterol in the Small Intestines

• Dissolved in micelles (mixed micelles)
• Can be hydrolyzed by pancreatic cholesterol
  esterase
• Only unbound (free) cholesterol is absorbed

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Digestion of Phospholipids

• Some may be hydrolyzed (e.g., lecithin)
• Most remain undigested are used in the
  formation of chylomicrons
• Part of micelle formation

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Components of Chylomicrons

• Phospholipids
• Cholesterol
• Cholesterol esters
• Triglycerides
• Protein (apoprotein B, C E)

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Pathway of Chylomicron Absorption Transport

• Lacteals
• Lymphatic channels
• Left thoracic duct
• Superior vena cava
• Heart circulation
• Systemic circulation
• Liver

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Quiz 10C Describe the difference between the
way that carbohydrates are absorbed versus the
way long chain fats (fatty acids) are absorbed.
142
Lipoprotein Lipase
Dietary fat
E
C
Fatty acids Glycerol
TG
Chylomicrons
Gut
B-48
E
Chylomicron Reminant
Liver
B-48
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Fate of Chylomicrons

• Bind to lipoprotein lipase (LPL) in capillaries
  of extrahepatic tissue
• Hydrolysis of triglyceride releases fatty acids
  glycerol
• Fatty acids taken up by tissue (i.e., heart
  adipose tissue)
• Glycerol taken up by liver chylomicron remanant
  remains

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Chylomicron Reminant Consists of

• Cholesterol esters
• Phospholipids
• Some fatty acids
• Some triglyceride
• Apoproteins (B-48, E)

145
Cholesterol Fatty acids Glycerol
Chylomicron Remnant Receptor
TG
Liver
B-48
E
Chylomicron Remnant
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Chylomicron Remnants Bind to Liver

• Apoproteins bind to receptor sites on liver cells
• Glycerol, fatty acids cholesterol are taken up
  by the liver
• Glycerol fatty acids are reesterified to
  triglyceride
• Cholesterol can be recirculated or excreted

147
Liver
B-100
LDL
B-100 Receptors
VLDL
Lipoprotein Lipase
IDL
VLDL
Extrahepatic Tissues
E
C
B-100
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LDL
Liver
Chol
Chol
Extrahepatic tissues
HDL
Chol
VLDL
Enterohepatic circulation
Intestines
Cholesterol excretion
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Lipid Transport Hepatic to Extrahepatic

• VLDL - TG, CHOL,PL
• VLDL to IDL to LDL - CHOL
• VLDL to HDL
• Enterohepatic circulation
• CHOL excretion
• CHOL reabsorption

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Cholesterol Transport to Liver

• Chylomicron reminant
• VLDL reminant (IDL)
• LDL
• Reverse cholesterol transport from HDL
• From intestines through enterohepatic circulation

151
How do you get rid of Cholesterol?

• Through biliary duct to intestines (ileum)
• Reabsorbed through enterohepatic circulation
• Excreted through feces

152
Cholesterol to and from Extrahepatic Tissue

• LDL binds to receptors and releases cholesterol
• HDL picks up cholesterol for transport back to
  liver

153
Quiz 10D1 Which of the following best describes
triglycerides and cholesterol transport from the
liver?

• VLDL is primarily a cholesterol transporter
• LDL is primarily a triglyceride transporter
• VLDL is primarily a triglyeride transporter
• HDL is primarily a triglyceride transporter
• None of the above are true

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Lipogenesis in Adipose Tissue
Insulin
glycolysis
Glucose
Glycerol P
TG
LPL
Fatty acids
VLDL
Chylomicrons
TG
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Triglyceride Synthesis in Adipose Tissue

• Feeding increases insulin which increases glucose
  entry
• Glucose entry increases glycolysis which produces
  glycerol
• Feeding increases LPL activity which increases
  fatty acid uptake from
• Chylomicrons
• VLDL
• Reesterification after breakdown (lipolysis)

156
Quiz 10D2 Name describe the 2 primary sources
of fat transport to adipose tissue.
157
Catecholamines glucagon
Fasting exercise
Adenylate Cyclase
Adipose Tissue
Cyclic AMP
Hormone sensitive TG lipase
Albumin
FFA
TG
Glycerol
Liver
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Lipolysis in Adipose Tissue

• Fasting exercise increase catecholamines
  glucagon
• A series of steps activate hormone sensitive LPL
• This hydrolizes bonds to release fatty acids
  glycerol
• Some fatty acids can be reesterified

159
Mobilization of Fat from Adipose Tissue

• Most fatty acids (FFA) bind to albumin
• Albumin transfers FFA to tissue sites for uptake
• Glycerol cannot be reesterified in adipose tissue
• Glycerol is taken up by tissue with glycerol
  kinase (e.g., liver)

160
Quiz 10E F Fill in the blank. The process of
fat breakdown is known as _________ and releases
_______ and _________ . The _____ binds to _____
for transport to tissues such as muscle that use
______ as an energy source.
161
FFA-FABP
FFA-Albumin
Fatty acyl CoA
Cytosol
carnitine transferase
Krebs cycle
Fatty acyl CoA
Acetyl CoA
Beta oxidation
Mitochondria
162
Fat Uptake in Muscle

• FFA released from albumin
• Facilitated diffusion from a fatty acid binding
  protein (FABP)
• Activation
• Translocation

163
Fat Utilization in Muscle

• Beta oxidation
• Utilization of acetyl CoA to produce NADH, FADH
  ATP
• ATP production through oxidative phosphorylation
  ET

164
Quiz 10G Which of the following is not involved
in fat use by muscle?

• A. FFA binds to FABP
• B. Fatty acids are transported across mit.
• C. Fatty acids then go through glycolysis
• D. Acetyl CoA is produced from beta oxid.
• E. Both B C are not involved

165
Obj 11 Describe the effects of exercise
training on the following aspects of fat
metabolism

• Lipolysis
• Fat mobilization
• Fat utilization
• Muscle triglycerides

166
Obj 12 Explain the biochemical basis of gaining
losing fat.
167
Exercise, Lipolysis, Fat Mobilization
Utilization

• Increase in lipolytic hormones
  (e.g.,catecholamines)
• Increase in lactic acid - inhibits lipolysis
• Increase in total, but depends on intensity

168
Training, Lipolysis, Fat Mobilization
Utilization

• Decrease in lipolytic hormones
• Decrease in fat mobilization
• Decrease in blood levels
• Increase in utilization
• Why?

169
What is Necessary for Fat Loss?

• Lipolysis vs lipogenesis
• Mobilization utilization vs lipogenesis

170
Quiz 11 Exercise and training have the same
effects on which of the following?

• Lipolysis
• Fat mobilization
• Plasma FFA
• FFA uptake
• Beta oxidation
• Oxidative phosphorylation
• Use of intramuscular triglyceride

171
Write out an essay exam to show that you have
mastered objective 12
172
What are proteins?

• High molecular weight polypeptides
• Contains carbon, oxygen, hydrogen nitrogen
• Found in eggs, meat, milk, beans, fish poultry

173
Where Does Protein Digestion Occur?

• Mouth - none
• Stomach - some are broken down to polypeptides
• Small intestines - tripeptides, dipeptides
  amino acids

174
Stomach
1
Stomach distension
Proteins
2
Promotes swelling
8
6a
4
Pepsin
Gastrin
HCL
3a
Parietal cells
6b
7
3b
5
Chief cells
Pepsinogen
175
Protein Digestion in the Stomach

• Stomach distension proteins stimulate gastrin
  release
• Gastrin stimulates HCL pepsinogin
• HCL
• Swells proteins
• Activates pepsinogens
• Converts pepsinogin to pepsin by H release
• Pepsin hydrolyzes protein bonds to release
  polypeptides

176
Polypeptides enter duodenum
Enzyme
CCK, Secretin
Zymogens
Activated Zymogen
Polypeptides
Trypsin other activated zymogens
Tripeptides
Polypeptides
Dipeptides
Amino Acids
177
Trypsin and other activated zymogens
Polypeptides
Tripeptides, Dipeptides some Amino Acids
Dipeptidases and Aminopeptidases
178
Protein Digestion in Small Intestines

• Acid chyme stimulates the release of secretin
• Secretin CCK stimulate the release of inactive
  enzymes known as zymogens
• Zymogens are activated by CCK
• Activated zymogens convert polypeptides to
• Tripeptides
• Dipeptides
• Amino acids
• Brush border enzymes make final hydrolysis

179
Absorption of Amino Acids

• Similar to glucose
• Na dependent
• Active transport
• Same pathway as glucose to liver

180
Dietary Proteins
Tissue proteins
Plasma proteins
Heme
Ketone bodies
Amino Acids in Liver
Nucleotides
Urea
Blood glucose
Blood amino acids
Energy CO2
181
Amino Acid Metabolism

• Transamination
• Oxidative deamination
• Significance
• Energy metabolism

182
Transamination and Deamination

• Transamination - transfer of NH2
• From an amino acid
• To a keto acid or another amino acid
• Oxidative deamination
• Removes NH2 from an amino acid
• Results in urea a keto acid

183
Liver
Muscle Cell
Ketoacids
Leucine
Glucose
Urea
Krebs cycle
NH2
Pyruvate
NH2
Pyruvate
transamination
oxidative deamination
Alanine
Alanine
Alanine
Blood
184
Blood
Muscle
Protein
Triglycerides
Glycogen
Amino Acids
FFA
Glucose
Glucose FFA Amino Acids Oxygen
Krebs, ETC Oxidative Phosphorylation
CO2 H2O
ATP
185
Liver
Adipose Tissue
Muscle
Lungs
Glucose Free Fatty Acids Amino Acids
Oxygen
Acetyl CoA
Muscle Glycogen
ATP
Krebs ET OP
CO2 H2O