Exam 1 Flashcards
which 3 systems provide ATP for muscle contraction?
immediate energy
non-oxidative/anaerobic
oxidative/aerobic
Immediate energy system
Phosphagen system/ Creatine Phosphate
Little bit of ATP around within cell
Short term/high intensity
How long can the immediate energy system last
~30 seconds
Anaerobic system
breakdown of glucose and glycogen
how long does the anaerobic system last
30 sec - 4 minutes
Aerobic/Oxidative system
Oxidation of carbs, fat, and protein
how long does the aerobic system last
hours
Exercise physiology
the study of the human as a machine
What percent O2 is the atmosphere
21%
“first machine”
Prokaryotes
Solar energy > carbs > ATP > Mechanical energy
input: CO2
output: O2
Anaerobic
“second machine”
Eukaryotes
Food > ATP > Mechanical work
Endosymbiosis
mitochondria was its own cell, now symbiotic relationship with other cells
Why is multicellular better than single celled eukaryotes?
More surface area = more space for reactions
What type of feedback loop regulates homeostasis
Negative feedback loop
steady state
seemingly constant conditions
During exercise, certain functions have attained consistency at a new level
ex. heart rate or core temp while walking on flat land
what are metabolic pathways?
sequences of enzymes catalyzed chemical reactions that begin with initial substrate, progress through intermediates, and end with a final product
Catabolic
break down
anabolic
build up
hydrolysis
break down of molecules to release ATP
Glycogen
animal polysaccharide made up of glucose
carb storage form for animals
Where is glycogen stored?
in the muscles and liver
Glycogen synthesis
making glycogen from glucose
Glycogenolysis
break down of glycogen into glucose
starts at beginning of exercise
Glycolysis
glucose broken down in pyruvate
in cytoplasm
Produces ATP, Pyruvate, NADH
Gluconeogenesis
creating glucose from non carb sources
ex. lactate
Where are lipids stored?
adipose tissue
intramuscular lipid droplets
What type of lipids are used to fuel exercise?
Free fatty acids
Saturated lipids
no double bonds between carbons
solid at room temp
animal products
Unsaturated lipids
at least one double bond “kink”
Liquids at room temp
plant oils
lipolysis
breakdown of triglycerides into FFAs and Glycerol
In adipose tissue and cell
Lipases
enzymes responsible for lipolysis
Lipid hydrolysis
lipolysis requires 3 molecules of water
condensation
formation of molecules
glycerol and FFAs join together and form 3 molecules of water
Protein functions
enzyme catalyst
transport/storage
mechanical support
immune function
Factors that affect rate of enzyme catalyzed reactions
External conditions (pH, temp)
Substrate concentration
Allosteric regulation (activators/inhibitors)
Covalent modification (turning enzymes on/off)
Enzyme concentration
Temp on enzyme action
high temp = faster reaction until ~ 45º
denaturation ~55º
pH on enzyme action
pH peak at 8
denatured at 5.5 and 10.5
substrate concentration on enzyme action
as substrate increases, enzyme activity increases until saturation is met
Km = substrate concentration at half saturation (Vmax)
Low Km =.more affinity
High Km = low affinity
Isozymes
enzymes catalyzing the same basic reaction with different kinetic properties
Allosteric regulation
binding a substance to a site other than the active site which activates or inhibits enzyme activity
Fine tune control
Covalent modification
turning enzymes on and off
Protein kinases
enzymes that control phosphorylation
Protein phosphatases
enzymes that control dephosphorylation
Glycogen phosphorylase
breaks down glycogen into glucose-1-phosphate
Increasing enzyme concentration
training increases enzyme concentration which speeds reaction rate
Thermodynamics (energetics)
physical science dealing with energy exchange
Bioenergetics
the science dealing with energetic events in the biological world
Why study bioenergetics?
the ability to do work dependson the ability to convert energy from one form (carb/fat) to another (ATP) and finally do work
True or false: energy is created.
False
It is converted from one form to another
Are energy conversions 100% efficient?
No, significant energy lost as heat
1st law of thermodynamics
energy is transferred, not created or destroyed
2nd law of thermodynamics
energy transformations increase entropy (disorganization)
what kind of energy can be used to do work?
free energy (energy in an organized state)
The change in energy (enthalpy) in an exergonic reaction has two components…
Free energy (useful)
Entropy (useless)
Endergonic reactions
require input of energy
products contain more free energy than reactants
Exergonic reactions
release energy
products contain less free energy than reactants
Coupled reactions
cells require constant inputs of free energy from environment to buck entropy and remain highly organized (endergonic and exergonic reactions work together)
requirements to return to ATP
must be able to yield energy to reactions requiring energy input
must be able to receive energy from energy yielding reactions
It is an energy donor and receiver
Reduction
molecule gains an electron (hydrogen)
Oxidized
molecule loses an electron (hydrogen)
reducing agent
donates electrons
NADH
FADH
ELECTRON CARRIERS
oxidizing agent
accepts electrons
NAD+
FAD
3 components of immediate energy system
Stored ATP (split by hydrolysis)
Phosphagen system
Adenylate Kinase (enzyme turns ATP to 2ADP)
Creatine kinase
hydrolysis that makes ATP from Creatine phosphate
red muscles are used for…
aerobic exercise
red because more O2
ex. duck
White muscles are used for…
anaerobic exercise
Less O2
high levels of phosphagen
ex. chicken
Power
(Force x Distance) / Time
Work
Force x Distance
Glycogen Phosphorylase
enzyme that breaks down glycogen into glucose
regulated by covalent modification (on/off)
Pyruvate pathways
1: reduced to lactate (anaerobic glycolysis)
2: pyrucate enters krebs cycle as acetyl CoA and be further oxidized in mitochondria (aerobic glycolysis)
Lactate dehydrogenase
reduces pyruvate to lactate
NADH > NAD+
Products of krebs cycle
CO2
ATP
NADH
FADH
basic process of krebs cycle
Acetyl CoA is stripped of hydrogen atoms and electrons from those hydrogens are given to NAD or FAD
Result: 36-38 molecules of ATP
Electron transport chain
series of protein complexes (cytochromes) in mitochondrial inner membrane
Oxidative phosphorylation
Oxidative: passing protons and electrons from cytochrome to cytochrome to molecular oxygen
Phosphorylation: union of Pi and ADP to make ATP
What limits exercise performance if you are asked to run faster and faster on a treadmill? Which systems are used?
O2 Intake limits energy
Aerobic system works until no more O2 can be taken in, Aerobic system kicks in again but lactic acid builds up
Benefits as fat as fuel source
almost unlimited amount compared to carbs
high energy per weight (9kcal/gram)
Spares muscle glycogen
How fast are carb reserves depleted during exercise?
~ 3 hours for hard/moderate exercise
~ 8 hours for walking
Downsides to fat as fuel source
slower than carbs
only aerobic
more O2 is necessary
Mobilization
breakdown of adipose and intramuscular triglycerides
Circulation
transport of FFAs into muscles from the blood
Uptake
entry of FFAs in to muscles from the blood
Activation
raising the energy level of FFAs preparatory to catabolism
Translocation
Entry of activated FFAs into the mitochondria
Beta-oxidation
Catabolism of Acetyl CoA of activated fatty acids and the production of reducing equivalents inside mitochondrial matrix
Mitochondrial oxidation
krebs cycle and electron transport chain activity
Lipoprotein
surrounds FFA in blood b/c FFAs are hydrophobic
ergogenic aid
Performance enhancer
ex. caffeine
Why if caffeine a good ergogenic aid?
Cyclists use is during race to delay the full use of their glycogen stores because caffeine stimulates lipolysis
With increasing intensity, the relative contribution of lipid as a fuel substrate _____ and the relative contribution of carbohydrates ______.
decreases, increases
intensity
burn fat first, the carbs as intensity increases
duration
burn carbs first, the fat as duration increases
2 Steps to protein metabolism
Deamination and Urea Cycle
Deamination
removal of an amine group before amino acid is used as fuel (carbon skeleton is used in oxidative metabolic pathways)
Urea cycle
Processes amine gorup to urea in the lliver for removal by kidneys