Chapter 25 Flashcards
Metabolism
All the chemical reactions in the body
2 phases of metabolism
Catabolic, anabolic
Catabolism
Reactions that break down complex molecules into simpler ones; decomposition
Anabolism
Reactions that combine simple molecules to make complex ones; synthesis
Type of metabolic reaction that uses ATP
Redox reactions
Type of metabolic reaction that generates ATP
Phosphorylation
Where energy is transferred from fuel molecule to
Intermediate molecule (reduced coenzyme)
Oxidation reduction reactions
Coupled reactions that use coenzyme to transfer energy, aka redox reactions
Oxidation
Addition of O2, loss of H+/removal of e- ; results in decrease in potential energy of substance that is oxidized
Reduction
Adding H+ or removing O2/e- ; results in incr. in potential energy of substance that is reduced
2 important coenzymes incolved in the reactions discussed
NAD and FAD (nicotinamide adenine dinucleotide and flavin adenine dinucleotide)
What carbohydrate metabolism is mostly
Glucose metabolism
Body’s needs for glucose
- ATP production
- Amino acid synthesis
- Glycogen synthesis
- Triglyceride synthesis
4 enzymatic pathways involved in carbohydrate metabolism
Glycolysis, acetyl-CoA formation, Krebs cycle, ETC
Where each pathway of catabolism of glucose occurs in the cell
- Glycolysis: cytosol
- Acetyl-CoA formation: mitochondria
- Krebs cycle: mitochondria
- ETC: inner membrane of mitochondria
Anaerobic or aerobic: 4 pathways of catabolism of glucose
- Glycolysis: anaerobic
- Acetyl-CoA formation: aerobic
- Krebs: aerobic
- ETC: aerobic
Products of glycolysis for one molecule of glucose
2 NADH, 2 ATP net gain, 2 pyruvic acid
Products of acetyl-CoA formation
2 NADH, 2 CO2, 2 acetyl-CoA
Decarboxylation
Loss of CO2
Products of krebs cycle from one glucose
6 NADH, 2 FADH, 4CO2, 2 ATP
What each carrier in ETC does
Picks up electrons/passes them to other carriers (releases energy from reduced coenzymes)
What the energy released from reduced coenzymes in ETC is used for
To build up H+ ion gradient b/w inner and outer membranes
Chemiosmosis
Mechanism that links chemical reactions w/ the pumping of H+ ions
Glycogenesis
Storing glucogen; occurs in liver and muscle cells
Glycogenolysis
Breakdown of stored glycogen; occurs in hepatocytes and the myocytes
Gluconeogenesis
Synthesis of new glucose from noncarbohydrate precursors; occurs in liver and kidneys
Hormones involved in other carbohydrate pathways
- Glycogenesis: insulin
- Glycogenolysis: glucagon and epinephrine
- Gluconeogenesis: glucagon, growth hormone, epinephrine, and cortisol
Why lipids need transport molecules to help move them across blood stream
They are nonpolar/hydrophilic
Lipoproteins
Lipid/protein molecules that transport lipids across blood plasma
Amphipathic lipid
Lipid with both hydrophilic and hydrophobic ends (polar/nonpolar)
Four classes of lipoproteins
- Chylomicrons
- Very low density lipoproteins
- Low density lipoproteins
- High density lipoproteins
Source of most cholesterol in our bodies
LDL’s/hepatocytes
Function of lipids in our bodies
Oxidized to produce ATP
Lypolysis
Splitting triglycerides into fatty acids/glycerol; lipid catabolism
Produced in lipolysis
Fatty acids/glycerol
Lipogenesis
Synthesis of fatty acids from glucose/amino acids; lipid anabolism
Functions of four classes of lipoproteins
- Chylomicrons: transport dietary lipids to adipose tissues
- Very low density lipoproteins: transport triglycerides from hepatocytes to adipocytes
- Low density lipoproteins: carry about 75% of the total cholesterol in blood and deliver it to cells
- High density lipoproteins: remove excess
cholesterol from body cells and the blood and transport it to the liver for elimination
Class of lipoproteins that having a high level of is good
HDL’s
Hormones involved in lipid metabolism
Epinephrine, norepinephrine, cortisol, etc.
Beta oxidation
Series of reactions that form coenzyme A
Happens when beta oxidation is excessive
2-C fatty acids get turned into acidic ketone bodies
Ketosis
Overproduction of ketone bodies
Ketoacidosis
Excess production of blood acids
Some functions that proteins provide
- Synthesizing proteins
- Enzymes
- Involved in transportation
- Antibodies
- Blood clotting
Produced when proteins are digested
Amino acids, fatty acids, ketone bodies, glucose
How amino acids are used in the body
Generate ATP via krebs
Chemical reaction that must occur in an amino acid before it’s used
Oxidative deamination
Where protein anabolism occurs in a cell
Ribosomes
3 key molecules at metabolic crossroads
- Glucose-6-phosphate
- Pyruvic acid
- Acetyl-CoA
Functions of glucose-6-phosphate
- Synthesis of glycogen
- Release of glucose into bloodstream
- Synthesis of nucleic acids
- Glycolysis
Functions of pyruvic acid
- Production of lactic acid
- Production of alanine
- Gluconeogenesis
Functions of Acetyl-CoA
- Helping 2-C acetyl groups enter Krebs
- Synthesis of lipids
Important factor in metabolic adaptations
Amount of time elapsed since last meal; determines if body is in absorptive or postabsorptive state
Absorptive state
- Last meal was recent
- Glucose is readily available for use by most cells in body to produce ATP by cellular respiration
- Glucose/other digestion products stored in variety of rxns in liver, muscles, and adipose tissue to produce storage compounds to be used later
Hormone that is important in absorptive state metabolism
Insulin
Postabsorptive state
- Last meal was not recent
- Stored foods must be broken down for energy
- Food has to be broken down to release energy for the production of ATP
- Greater variety of hormones involved
Basal metabolic rate
Overall rate at which metabolic rxns use energy
Main hormone that regulates metabolic rate
Thyroxin (thyroid hormone)
Factors that increase metabolic rate
- Increase in exercise
- Increase in thyroid hormones
- Sympathetic ANS stimulation
- Body temperature
- Food consumption
Thermostat of body
Hypothalamus
Two automatic physiological responses that help cool body if temperature rises above normal
Sweat glands stimulated and blood vessels dilate
Two automatic physiological responses that help to warm body if temperature drops below normal
Shivering and blood vessels constricting
