Homeostasis and Bioenergetics Flashcards
what is bioenergetics
when cell’s chemical pathways convert foodstuffs into a biologically usable form of energy
define homeostasis
maintenance of a constant and normal internal environement
what is considered a steady state
- physiological variable is unchanging, but not necessarily normal
- balance between demands placed on body and the body’s responses to those demeands
what are some examples of homeostasis in the body
body temperature regulation and arterial blood pressure
what are the intracellular control systems
- protein breakdown and synthesis
- energy production
- maintenance of stored nutrients
examples of organ systems that are part of the control system within the body
pulmonary and circulatory systems
define a biological control system
series of interconnected components that maintain a physical or chemical parameter at a near constant value
what are some components of the biological control system
- Sensor or Receptor: detects changes in variable
- control center: assesses input and initiates response
- effector: changes internal environment back to normal
negative feedback
response reverses the initial disturbance in homeostasis
positive feedback
response increases the original stimulus
what is “gain of a control system”
degree to which control system maintains homeostasis
-system with large gain is more capable of maintaining homeostasis than system with low gain (pulmonary and cardiovascular systems have LARGE gain)
what does the failure of the biological control system result in
disease, such as type 1 diabetes
exercise with regards to homeostasis
exercise actually disrupts homeostasis by causing changes in:
- pH
- oxygen and CO2 levels
- temperature
control systems are capable of maintaining steady state during submaximal exercise in a cool environemtn
Adaptation
Acclimatization
Cell Signaling
Adaptation: change in structure or function of cell or organ system, results in improved ability to maintain homeostasis
Acclimatization: adaptation to environmental stresses
Cell Signaling: communication between cells using chemical messengers, important for maintaining homeostasis
what areas of the brain maintains and regulates respiration
pons and medulla
at what levels are you considered to be hypoglycemic
below 70 mg/dL
what what levels are you considered to be hyperglycemic
above 99 mg/dL
list the 5 cell signaling mechanisms
- intracrine signaling: chemical messenger inside cell triggers response
- Juxtacrine signaling: chemical messenger passed between 2 connected cells
- autocrine signaling: chemical messenger acts on that same cell
- paracrine signaling: chemical messengers act on nearby cells
- endocrine signaling: chemical messengers released into blood, only affect cells with specific receptror
what do cells create when the body is under stress such as high temp or abnormal pH
cells synthesize stress proteins when homeostasis is disrupted
what are the 3 forms of biologic work
- mechanical work of muscle contraction
- chemical work for synthesizing cellular molecules
- transport work that concentrates diverse substances in body fluids
oxidation
a substance loses electrons
reduction
a substance gains electrons
what do redox reactions power
the body’s energy transfer processes
what is the main energy “currency”
ATP
what is a high energy phosphate compound
phosphocreatine
-releases large amounts of energy when bonds between creatine and phosphate are broken
how much more phosphocreatine does the body store than ATP
4-6 times as much PCr
what is phosphorylation
refers to the energy transfer through phosphate bonds
most of the energy for ATP phosphorylation comes from oxidation of carbs, lipids, and proteins
oxidative phosphorylation synthesizes ATP by transferring electrons from NADH and FADH2 to oxygen
what are 4 sources for ATP formation
- glucose derived from liver glycogen
- triglyceride and glycogen molecules stored within muscle cells
- FFA derived from triglyceride that enter the bloodstream for delivery active muscle
- intramuscular and liver derived carbon skeletons of amino acids
Characteristics of the ATP-PC system
anaerobic
very rapid
chemical fuel is PC
very limited ATP production and muscle stores are limited
used with sprinters or any short duration high power activity
characteristics of the lactic acid system
anaerobic
rapid
food fuel: glycogen
limited ATP production
by product is lactic acid that causes muscular fatigue
used with activities of 1-2 minutes long
characteristics of the oxygen sytem
aerobic
slow
food fuel: glycogen, fats and protein
unlimited ATP production, no by products
used with long duration activities
what are the 2 stages of glucose degradation
- anaerobic: glucose breaks down relatively rapidly to 2 molecules of pyruvate and lactic acid
- aerobic: pyruvate degrades further to carbon dioxide and water
what is glycolysis
glycogen catabolism
glycogenolysis
glycogen to glucose
glucogenesis
glucose to glycgoen
gluconeogenesis
more ATP from non carbs
citric acid cycle
second stage of carb breakdown
-degrade acetyl-CoA substrate to CO2 and hydrogen atoms within the mitochondria
what does NAD stand for and what vitamin is it
nicotinamide adenine dinucleotide (niacin)
what does FAD stand for and what vitamin is it
flavin adenine dinucleotide
what are the proteins in the ETC
cytochromes
name of a plasma protein
albumin
what is a coupled reaction
this is a reaction that has 2 parts, one has to happen with the other, they cant just individually exist. an example would be oxidation-reduction reactions
what 2 molecules play an important role in the transfer of hydrogens and electrons
NAD and FAD
what is the oxidized form of nicotinamide adenine dinucleotide
NAD
what is the reduced form of nicotinamide adenine dinucleotide
NADH
what is the enzyme that breaks down triglycerides into fatty acids and glycerol
lipase
what is a type of natural steroid in the body
cholesterol
what amino acid can be converted to glucose in the liver
alanine
what enzyme catalyzes the reaction
PC+ADP—–> ATP+C
creatine kinase
what is the net gain of ATP from glycolysis
2
where does glycolysis occur
in the sarcoplasm of the muscle cell
what are the inputs and outputs of glycolysis
Inputs: Outputs
- 1 glucose 2 pyruvate or 2 lactate
- 2 ADP 2ATP
- 2 NAD 2 NADH
what is LDH
LDH= lactate deydrogenase
this enzyme catalyzes the reaction of pyruvic acid accepting a hydrogen atoms to form lactic acid and the reformation of NAD
where does aerobic production of ATP occur
in the mitochondria
what are the hydrogen (energy) carriers to complete the oxidation of carbohydrates, lipids, and proteins
NAD and FAD
term for aerobic production of ATP
oxidative phosphorylation
how are fatty acids oxidized into acetyl-CoA
beta oxidation
what enzyme is responsible for carb metabolism (breakdown from glycogen to glucose)
phosphorylase
name the enzyme that breaks down fat (adipose) into free fatty acids and glycerol
hormone sensitive lipase
what substance can be synthesized from all three energy yielding nutrients
acetyl CoA
what is the net ATP gained from each NADH that passes through the electron transport chain
3
what is the net ATP gained from each FADH that passes through the electron transport chain
2
what is the enzyme required to transport fat from the muscle to the cristae of the mitochondria
carnitine transferase
name of the plasma protein which transports free fatty acids in the blood
albumin
what does the acetyl portion of acetyl-CoA join with to form the citric acid
oxaloacetate
during lipid metabolism:
what hormones help mobilization
- glucagon
- growth hormone
- testosterone
- epinephrin
during lipid metabolism, where are the uptake receptors
on the sarcolemma
what plays a role as an energy substrate during endurance activities and heavy training
protein
define deamination
nitrogen is removed from the amino acid molecule
define transamination
when an amino acid is passed to another compound
what are the remaining carbon skeletons do once proteins have been deaminated and transaminated
they enter metabolic pathways to produce ATP
what does protein catabolism facilitate
water loss
