Exam 1 Study Guide Flashcards
Understand the concept of oxidation-reduction reactions
oxidation-reduction reactions- describes the transfer of electrons between an electron donor (that becomes oxidized) and electron acceptor (that is reduced)
1.oxidation- removal of electrons from a substance, usually hydrogen atoms (H+ plus one electron)
oxidation reactions release energy (ex: glucose oxidation; glucose and 6 O2—> 6 H2O and energy (ATP, NADH)
2. Reduction- addition of electrons to a substance through addition of hydrogens (loss of O2 atoms); requires an input of energy
Know the 4 roles of carbohydrates
4 roles of carbohydrates:
- Energy source
- energy is derived from breakdown of blood-borne glucose
- Muscly glycogen powers various forms of biologic work including muscle contraction - Protein sparer
- Adequate carbohydrate intake helps preserve tissue protein - Metabolic primer
- the depletion of glycogen causes fat mobilization to exceed fat oxidation
- can lead to ketosis - Fuel for the Central Nervous system
- The brain almost exclusively uses blood glucose as its fuel source
- hypoglycemia is the reduction of blood glucose to <45 mg/dL.
Know the difference between lipolysis, lipogenesis, Gluconeogenesis and glycolysis
Lipolysis - process of breaking down TAGs through hydrolysis into glycerol and 3 fatty acids
Lipogenesis- formation of fat when glucose or protein is Not used to sustain energy metabolism (occurs in cytoplasm of liver cells)
Gluconeogenesis (LIVER, KIDNEYS)- process of synthesizing glucose from non-carbohydrate sources (lactate, glycerol, amino acids)
-describes when lactate from muscles is transferred to liver during hypoxic conditions (no O2). In liver, lactate will be converted into glucose.
(lactate–> pyruvate; which eventually converts to glucose)
Glycolysis- (CYTOSOL)- 10 step reaction pathway that converts one glucose molecule into two molecules of pyruvate
pyruvate (3 carbon compound)
Glycolysis- glucose—> pyruvate; 2 ATP and 2 NADH are produced.
Know the different types of lipids and their roles in the body
3 types of lipids:
1. Simple lipids:* consist primarily of triacylglycerols (TAG)
-major storage form of fat in adipocytes
-contain one glycerol and three fatty acids (longer the fatty acid, less water-soluble the molecule)
2. Compound lipids: are composed of phospholipids, glycoplipids and lipoproteins
-Phospholipids functions:
-to interact with water and lipid to modulate fluid movement across cell membrane,
-maintain structural integrity of cell
-important role in blood clotting
-provide structural integrity to insulating sheet that surrounds nerve fibers
Lipoproteins:
-Chylomicrons- transport Vitamins A, D, E and K
-High density lipoprotein (HDL)- good cholesterol
-very low-density lipoprotein (VLDL)- transport TAGS to muscle and adipose
-Low-density lipoprotein (VLDL)- Bad cholesterol
3. Derived lipids: like cholesterol, exist only in Animal tissue and diets high in cholesterol can cause increased risk of coronary heart disease and athersclerosis
Know the role of proteins in the body
Proteins are important for repair and building of tissues, allows for metabolic reactions to occur and many other functions (enzymes, hormones).
proteins can also be catabolized (broken down) to produce ATP if necessary when carbohydrate and lipid stores are depleted.
Amino acids (derived from proteins) can be degraded for energy, and lead to acetyl coa, pyruvate or TCA cycle intermediates
-major sources of body protein- blood plasma, visceral tissue, muscle tissue (NOT neural and connective tissue)
-protein makes up 12-15% of body mass
-body does NOT store protein reserves for fuel
stress, disease, and injury increase protein requirements.
Understand the concept of hyponatremia
Hyponatremia- describes water intoxication that occurs when the amount of sodium in blood is extremely low.
This can occur during exercise in hot weather (increasing body’s water requirement ) and leading to excessive sweating combined with large volumes of plain water –> water intoxication
factors that lead to Hyponatremia- INCREASE in Total body water and DECREASE in plasma sodium concentration
Know the processes of glycolysis, anaerobic respiration, aerobic respiration (pyruvate cycle, Electron transport, and ATP synthesis)
- Glycolysis- converting 1 glucose molecule into 2 pyruvate molecules; generating 2 ATP and 2 NADH; exergonic process occurs in cytosol
- anaerobic respiration (occurs when NO O2 is present)
-Pyruvate is reduced by accepting electrons (protons) that must be removed from NADH. pyruvate reduction forms lactate, ethanol and CO2
most organisms are able to extract limited energy from glucose (via glycolysis)
-Fermentation- electrons removed during glucose oxidation are returned to organic molecule later in same pathway.
Lactic acid fermentation- biological process where sugars (glucose) are converted into cellular energy and byproduct lactate
2 Pyruvate is converted to 2 lactate (form 2 NAD+, 2 lactate) and generated by lactate DH.
lactate fermentation- anaerobic glucose catabolism seen in animals and bacteria
Alcohol fermentation- using glucose to convert to ethanol; seen in plant cells and yeast.
in fermentation (no external electron acceptor is involved, and no net oxidation occurs) - Aerobic respiration (O2 is present)
-pyruvate cycle- convert pyruvate into acetyl coa, using Pyruvate Dehydrogenase (DH), also CO2 and NADH (oxidation) is formed (after decarboxylation)
-Citric acid cycle- acetyl coa enters the TCA cycle and it reacts with Oxaloacetate and other TCA intermediates to be completely oxidized to CO2
-Electron Transport - describes the transfer of electrons from reduced coenzymes (NADH and FADH2) to oxygen that is coupled with active transport of protons across the membrane.
ATP Synthesis - describes the process of generating electrochemical proton gradient across inner mitochondrial membrane and having a proton motive force (pms) of that gradient is harnessed to make ATP.
ATP made by ATP synthase ( Fo/F1 complex: Fo- channel for exergonic flow of protons across membrane; intermebrane space
F1- carries out ATP synthesis (driven by energy of proton gradient in mito matrix)
Electron transport and ATP synthesis are not independent processes (they are functionally linked to each other)
Understand the basics of fatty acid catabolism (source of fatty acids, hydrolysis beta of fatty acids)
Fat catabolism- describes the complete oxidation of a triacylglycerol molecule which yields about 460 ATP molecules
-TAGs are stored directly within the muscle fiber in close proximity to mitochondira
-circulating TAGs in lipoprotein
-Circulating free fatty acids mobilized from TAGs in adipose tissue
process of fat catabolism:
1. breakdown of TAG to free fatty acids
2. Transport of free fatty acids in the blood
3. uptake of free fatty acids from blood to muscle
4. preparation of fatty acids for catabolism
5. Entry of activated fatty acids into muscle mitochondria
6. Breakdown of fatty acid to acetyl-CoA via Beta-oxidation and the production of NADH and FADH
7. Coupled oxidation in citric acid cycle and electron transport chain
Know how pyruvate is formed and its fate
pyruvate is formed during glycolysis- where one glucose molecule undergoes 10 step path to form two pyruvate molecules (also produces ATP and NADH)
pyruvate- three carbon compound
fates of pyruvate:
1. aerobically: in the presence of oxygen, pyruvate is further oxidized to form acetyl coenzyme A (acetyl-CoA; which generates 30 ATP)
2. Anaerobically (no O2) , pyruvate is REDUCED by accepting electrons (and protons) that must be removed from NADH
-pyruvate can lead to formation of products lactate, ethanol (yeast), and CO2.
conversion of pyruvate is decarboxylation because one carbon liberated as CO2.
it can also be oxidation since two electrons (one proton) are transferred to NAD+ to form NADH
Understand how ATP is stored, processes that produce ATP, respiratory control, ATP as an energy molecule
ATP forms from adenosine linked to 3 phosphates.
the body stores only (80 to 100 g) a small amount of ATP at any time (during normal resting conditions)
ATP is stored by extracting energy (Potential energy) from food macronutrients and conserve it within the bonds of ATP.
Then when you extract and transfer the chemical energy in ATP to power biological work.
ATP is stored within high energy phosphates.
ATP is stored in NADH and FADH2
Processes that produce ATP:
Glycolysis: makes 2 ATP
TCA cycle: makes 2 ATP
Oxidative phosphorylation/ETC- makes 34 ATP (by transferring electrons from NADH and FADH2 to oxygen)
Respiratory Control: describes when availability of ADP regulates the rate of oxidative phosphorylation and thus of electron transport.
-electron transport and ATP generation is favored when ADP concentration is high, and inhabited when ADP [ } is low.
ATP- INTERMEDIATE energy molecule because:
1. intermediate level is key in ability to be phosphate donor to many molecules and donate phosphate to lower energy molecules
2. ATP can also uitilize many molecules for phosphorylation.
Understand the continual synthesis of ATP during aerobic respiration
Cells contain a SMALL quantity of ATP- so hence we must continually resynthesizes it at its rate of use
ATP is necessary to power all cellular processes, so it is constantly being used by cells and hence must constantly being produced.
by maintaining small amounts of ATP, its relative concentration changes rapidly in response to minimal ATP decrease
The small amount of ATP In muscles is only enough for fuel for seconds of exercise, so ATP must be resynthesized to fuel movement and for survival.
Understand the concept of “metabolic mill:
Metabolic Mill: Citric Acid Cycle- the link between macronutrient energy (food) and chemical energy (ATP)
-describes the mill that energy falls into
foods that contain fats, carbs and proteins are converted into fatty acids, glucose/glycogen, and amino acids which further undergo many metabolic processes that lead to citric acid cycle
know how BMR relates to age, gender, FFM (free fat mass), and body mass
BMR (basal metabolic rate): the minimum level of energy to sustain vital functions in the waking stage (reflects body’s total heat production)
BMR Decreases with age.
As FFM (free fat mass) decreases, BMR decreases
Also as body fat increases, there is a decrease in BMR.
The Larger the body mass, the HIGHER the BMR
Females have lower (5-10% less) BMR than males since women possess less fat free mass (FFM)
males have higher BMR, since they have higher proportion of lean body mass
-with higher FFM, you have higher BMR.
Know how oxygen consumption (VO2) relates to body mass and heart rate
Heart Rate and Oxygen consumption relate LINEARLY over a large range of exercise intensities.
So exercise HR provides an estimate of Oxygen consumption and thus energy expenditure during aerobic exercise
As you increase body mass, the you increase O2 consumption (VO2 max)
-trained individuals have higher O2 consumption more quickly than untrained due to their training adaptations
HR lower for trained individuals.
Understand the widely believed misconceptions about the effects of lactate
Widely believed misconceptions:
Lactic acid is cause of
1. fatigue
lactate does not equal fatigue because:
-muscle fatigue occurs while lactic acid [] in muscle is LOW
-you often see NO fatigue when lactic acid [ } concentration in muscle is HIGH
-At end of 100 km raceL fatigue is high, but blood lactate [ ] is not much higher than at rest
-Mcardle’s disease- incapable of producing and accumulating lactic acid; but many people are prone to suffering from muscle fatigue (so muscle fatigue accompanied by very low or NO lactic acid at all)
seen in exhaustive isometric exercise (immediately after exercise fatigue high; after exercise low)
2. Cramps
muscle cramps not caused by lactic acid:
-all runners in 400 m finish with blood lactate { } that is 20-25x higher than resting level, but cramps are RARE
-people suffer from CRAMPS while sleeping, when bl lactate { } is LOW
-Usually cramps occur during strenuous efforts of long duration (where lactate [ ] is higher than at rest, but far below max levels of intense, brief efforts
cramps are due to electrolyte disturbances (K+ and Ca^2+) (interstitial fluid is lost through sweat leading to loss of ions, and cells swells causing Sarco ER CA shorts and Calcium bound to troponin
-Mcardle’s disease- occurs when there is a lack of muscle glycogen phosphorylase (still suffer from cramps), not able to break down glycogen into glucose for immediate energy; prone to muscle fatigue even though lactate levels low
- soreness
lactic acid has NOTHING to do with muscle soreness
-instead soreness after exercise is due to DOMS (Delayed onset muscle soreness) the pain that appears 1-2 days after an unfamiliar intense effort
-occurs with eccentric muscle contractions (muscle that contract while lengthening themselves) study proved that flat run(higher lactate concentration) and did not generate soreness; compared to downhill running causing lower lactate [ } and severe soreness. proving lactic acid not correlated with muscle soreness.
