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44 Cards in this Set
- Front
- Back
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What are the substates for metabolism?
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Carbohydrates
Proteins Fats |
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What is "bioenergetics"?
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How each cell contains pathways that convert substartes (carbs, fat, protein) into usable energy
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What is ATP?
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The energy that we derive from food is stored as ATP and serves as an immediate source of energy for movement
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How are carbohydrates stored?
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Dietary carbs-->converted to glucose-->taken up by muscles and liver and converted to glycogen-->stored in the cytoplasm of muscle cells OR in liver, where it can be converted back into glucose when needed to produce ATP for the muscles
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How is fat stored?
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Stored as triglycerides and must be converted to free fatty acids (FFAs) to be utilized, so it is less readily available than carbs, but provides much more energy
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At rest, the body derives energy from ______________________________.
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the breakdown of carbohydrates and fats, equally.
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Under resting conditions, ingested carbs are stored in the _______________ as ___________________.
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in the muscles and liver
as glycogen (a complex sugar molecule) |
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What is the process by which protein is converted to glucose for energy in extreme cases?
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Protein in converted into fatty acids through lipogenesis
Gluconeogenesis converts FFAs to glucose |
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What is the process of converting protein into FFAs (free fatty acids)?
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Lipogenesis
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Protein can supply __________% of energy during prolonged exercise
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5-10%
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What is the role of enzymes in the catabolism (breakdown) of substrates?
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They use the lock and key mechanism to breakdown carbs, fat, or protein into smaller molecules and therefore control free energy release.
Their names end in -ase |
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What is the process by which a phosphate group is added to the ADP compund to generate ATP?
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Phosphorylation
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What are the three basic energy systems that generate ATP?
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1. ATP-PCr system
2. The glycolytic system (Glycolysis) 3. The oxidative system (oxidative phosphorylation) |
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What is PCr (phosphocreatine)?
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Cells contain this high-energy molecule that stores energy. When broken down, it regenerates ATP to maintain a relatively constant supply.
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How is energy released from PCr?
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The enzyme, creatine kinase, splits PCr into CREATINE and Pi moecules, which releases energy. This energy is used to add the Pi molecule to an ADP moecule, creating ATP!
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What are the limitations of the ATP-PCr system?
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It is substrate level matabolism and does not require oxygen, but is used up very quickly during intense exercise
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What is glycolysis?
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The breakdown of glucose (or glycogen) through a pathway that involveds a sequence of glycolytic enzymes.
Products are ATP and pyruvic acid, which turns into lactic acid if there is a lack of oxygen The result is +2 (if glucose was used) or +3 (if glycogen was used) ATP |
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What is glycogenolysis?
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When glycogen is stored in the liver or muscle, it is then broken down into glucose-1-phosphate, which enters the glycolysis pathway.
The first thing that has to happen to glucose in the glycolysis pathway is its conversion to glucose-6-phosphate using 1 mol ATP! |
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What are the limitations of the glycolytic system?
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Only 3 moles of ATP are produced for each mole of glycogen broken down...thats not very much
It is anaerobic (doesn't require oxygen), but if not enough oxygen is present this process causes lactic acid build up, which impairs the glycolytic enzymes and prevents further glycolysis (also, the acid decreases the muscle's Ca binding capacity and thus may impede muscle contraction) Between the ATP-PCr and glycolytic systems, there is only enough energy for 2 min of all-out activity |
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Where does the process of (anerobic) glycolysis take place? How many reactions are there?
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10-12 enzymatic reactions...in the cytoplasm of a cell
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Describe the oxidative system
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It is slow to turn on and therefore used primarily during endurance events.
Occurs in the cell's mitochondria Aerobic (requires oxygen) and produces much more energy than anaerobic |
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What three processes are involved in the oxidative system?
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Aerobic Glycolysis
Kreb's Cycle Electron Transport Chain |
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How is glycolysis different when oxygen is present?
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This is called aerobic glycolysis and when oxygen is present, the pyruvic acid that s produced turns into acetyl coenzyme (acetyl CoA) instead of lactic acid
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Describe the Kreb's cycle's role in the oxidative system
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Aerobic gycolysis produces acetyl CoA, which then enters a coplex series of chemical reactions (the Kreb's Cycle) that completely oxidize it and formed two additional moles of ATP, leaving the original substrate broken down into CO2 and H+.
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Describe the Electron Transport Chain's role in the oxidative system
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Glycolysis and the Krebs Cycle both produce H+, which need sto be removed or the cell would become too acidic. SO, the H+ combines with two coenzymes (NAD and FAD) and is carried to the elctron transport chain, which splits them into protons and electrons
At the end of the chain, the H+ is combined with oxygen to form water, preventing acidification. Yay! Bonus: the leftover electrons are used for phosphorylation of ADP, thus forming ATP. |
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For the ATP-PCr system, what is the...
1. Rate-limiting enzyme 2. Stimulators 3. Inhibitors |
1. Creatine kinase
2. ADP 3. ATP |
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For the process of glycolysis, what is the...
1. Rate-limiting enzyme 2. Stimulators 3. Inhibitors |
1.Phosphofructokinase
2. ADP, high pH 3. ATP, low pH |
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For the process of the Kreb's Cycle, what is the...
1. Rate-limiting enzyme 2. Stimulators 3. Inhibitors |
1. Isocitrate dehydrogenase
2. ADP, Ca, NAD 3. ATP, NADH, |
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For the process of the electron transport chain, what is the...
1. Rate-limiting enzyme 2. Stimulators 3. Inhibitors |
1. Cytochrome oxidase
2. ADP, Pi 3. ATP |
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What are the products of the Krebs cycle?
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Acetyl CoA forms 2 mol ATP, carbon dioxide, and hydrogen
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Through the metabolic pathways, one mole of glycogen can produce up to ____________ molecules of ATP.
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37-39
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Describe the oxidation of fat. Why does it require more oxygen than glucose?
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Triglycerides get broken down into FFAs and glycerol via lipolysis.
Blood takes FFAs to the muscle fibers where enzymes the mitochondria break them down into acetic acid, which gets converted to acetyl CoA via beta-oxidation The Acetyl CoA then enters the Krebs cycle Fat oxidation requires more oxygen than glucose because FFAs have a ton more carbon-->more electrons--> a lot more energy |
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What is the oxidative capacity of muscle? (QO2) How is it measured?
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It is a measure of the muscles maximal capacity to use oxygen.
It is measured through the representative enzymes: -citrate synthase -succinate dehydrogenase |
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Why don't you burn (oxidize) fat during high-intensity exercise?
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During high-intensity exercise, the utilization of ATP outweighs the formation of ATP from fat oxidation
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What is protein's role in energy production?
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Protein does not contribute very much to energy production and it is complex because amino acids contain nitrogen, which cannot be oxidized
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What determines the oxidative capacity of a muscle?
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-oxidative enzyme levels
-muscle fiber type -oxygen availability |
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Why do Type I muscle fibers have a greater capacity for aerobic activity?
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Because Type I fibers are slow-twitch and they have more mitochondria and higher concentrations of oxidative enzymes
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What are steroid hormones? Where are the receptors for them? What glands/organs secrete them?
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Chemical structure similar to cholesterol, soluble in lipids and diffuse easily through membranes
Secreted by the adrenal cortex, ovaries, testes, placenta Ex. testosterone, aldosterone, cortisol, estrogen, progesterone Receptors for steroid hormones are in the cytoplasm or nucleus...the complex then binds to the cell's DNA and activates certain genes |
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What are nonsteroid hormones? What are the two kinds? Where are the receptors for them? Where are they secreted from?
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Not lipid soluble, so cannot easily cross cell membranes.
*Protein/peptide hormones OR amino acid-derived hormones From thyroid gland or adrenal medulla Ex. epinephrine or norepinephrine, thyroxine, triiodothyronine are amino acid hormones. All others are peptide/protein. Receptors for nonsteroid hormones are on the cell membrane |
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Describe "second messenger" hormone action
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a nonsteroid hormone binds to a receptor on the membrane-->triggers enzymatic actions-->an intracellular second messenger is formed-->causes cellular changes and hormonal effects
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How is hormone secretion regulated?
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Through negative feedback
Upregulation-increased # of receptors Downregulation- decreased # of receptors |
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What hormones work to increase plasa glucose concentrations (during exercise)?
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Glucagon
Epinephrine Norepinephrine Cortisol |
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How does insulin help during exercise?
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One blood glucose levels are incresed, insulin helps transport glucose through the cell membranes and into the muscle cells
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How do hormones regulate fat metabolism during exercise?
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Lipolysis (breaking down triglycerides to form FFAs) is increased by:
-DECREASED INSULIN ^epinephrine and norepinephrine ^cortisol ^growth hormone |
