Bioenergetics Flashcards
Physical activity
any movement produced by muscle contractions, which result in an elevated energy expenditure above the basal metabolic rate ex: work, sports, leisure activities, daily activities
Exercise
Structured physical activity executed on a regular basis with the objective to improve fitness and/ or performance
Bioenergetics
the science that involves studies of energetic events in the biological world is called bioenergetics
Thermodynamics
The physical science dealing with energy exchange is called thermodynamics
Laws of thermodynamics
- Energy can neither be created nor destroyed 2. Whenever the energy is exchanged, the efficiency of the exchange will be imperfect and some energy will escape, usually in the form of heat
6 primary forms of energy
- thermal
- chemical
- mechanical
- electrical
- radiant
- atomic
3 ways energy is provided
Immediate (anaerobic galactic)
Non oxidative (anaerobic lactic)
Oxidative (aerobic)
General equation of bioenergetics
Echm (food)= Emch (work)+Ethrm (heat)
Metabolism oxidative equation
Food + O2–heat +co2+H2O
What is the upper limit of mechanical efficiency
25-30%
Mass
the amount of matter in a body measured in kg
Weight
is the force that results from the action of gravitation field on mass (N)
Unit for energy
Joule (J)
Unit for power
Watt (W)
What is 1 calorie in J
4.2 J
What is 1 kilocalorie in J
4.2 kJ
MET- metabolic equivalent
3.5 ml O2.kg-1.min-1
What is the energy equivalent of oxygen
the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius
Direct Calorimetry
Measurement of energy expenditure from body’s heat production
Indirect Calorimetry
Measurement of energy expenditure from the ratio between VO2 and VCO2
Numerical value of the energy equivalent of oxygen
1 litre of O2= 5kcal
What is a MET
the ratio of the rate of energy expended during an activity to the rate of energy expended at rest.
1 met is equal to 3.5ml.kg-1.min-1
ECR (energy cost of running)
1kcal.kg-1.km-1
Monosaccharides
one sugar
Disaccharides
two sugars
Polysaccharides
multiple sugars
Lipids
contain C,H, O but less than carbohydrates, and sometimes contain P (phosphorus)
Main types of lipids
-Triglycerides or neutral fats
-phospholipids
-steroids
Eicosanoids
Triglycerides or neutral fats
- called fats when solid and old when liquids
- large molecules
- composed of three fatty acids bonded to glycerol molecule
Proteins
- compromise 10-30% of cell mass
- have most varied functions of any molecules
Amino acids
building blocks for protein
Enzymes
globular proteins that act as biological catalysts
What is ATP
chemical energy released when glucose is broken down is captured in ATP
What does ATP do?
directly powers chemical reactions in cells, offers immediate, table energy needed by body cells
Without ATP what happens?
Without ATP, molecules cannot be made or degraded, cells cannot shorten to tug on other structures, and life processes cease
What is ATP also known as
the common chemical intermediate
Respiration
conversion of the chemical energy in foodstuffs into useful chemical form
Cell work
Conversion of that useful form to other forms of energy
Metabolism
the su of processes occurring in a living organism
Metabolic rate
the rate of hear production, all cellular events result in heat
Anabolism
synthesis of large molecules from small ones (example: synthesis of proteins from amino acids)
Catabolism
Hydrolysis of complex structures to simpler ones (example: breakdown of proteins into amino acids)
what is it called when a substance loses electrons
oxidization
what is it called when a substance gains electrons
reduction
Complete glucose catabolism requires three pathways
- Glycolysis
- Krebs cycle
- Electron transport chain and oxidative phosphorylation
Glycolysis
- also called glycolytic pathway
- involves 10-step pathway
- occurs in cytosol
Three major phases of glycolysis
Phase1. Sugar activation
Phase2. Sugar cleavage
Phase3. Sugar oxidation and ATP formation
Phase 1 sugar activation
phosphorylation activates glucose. Glucose is converted to fructose-1, 6- diphosphate
Phase 2 sugar cleavage
fructose -1 6-biphosphate is cleaved into two carbon fragments
Phase 3 Sugar oxidation and ATP formation
a. each 3-carbon fragment is oxidized by removal of a pair of H, which is picked up by NAD+
b. inorganic phosphate groups (Pi) are then attached to each oxidized fragment and 4 ATP molecules are formed
Citric acid cycle
occurs in mitochondria matrix and is fueled by pyruvic acid from glucose breakdown and fatty acids from fat breakdown
Main functions of the Krebs cycle
- Carbon dioxide production 2. NADH and FADH production 3. produce some ATP (2 will be formed)
Electron transport chain phase 1
Phase 1 creates a proton (H+) gradient across mitochondrial membrane using high energy electrons removed from H from food fuels
Electron transport chain phase 2
Phase 2: chemiosmosis uses energy of the proton gradient to synthesize ATP
Redox
reduction oxidation reactions; represented by NADH/NAD
Glycogenesis
glycogen can be formed with excess glucose; catalyzed by glycogen synthase
glycogenolysis
breakdown of glycogen via glycogen phosphorylase
Lipogenesis
triglyceride synthesis that occurs when cellular ATP and glucose levels are high
Lipolysis
breakdown of stored fats into glycerol and fatty acids; reverse of lipogenesis
Nitrogen balance
homeostatic state where ratte of protein synthesis equals
