Homeostasis, metabolism, and bioenergetics 1 Flashcards
define homeostasis
ability of an organism to maintain a relatively stable internal environment in response to changing internal and/or external conditions
define steady state
tendency of a control system to achieve a balance between an environment demand and the response of a physiological system to meet that demands to allow the body to function over time
ex. exercise
define biological control systems
series of interconnected components that maintain a physiological variable at or within the homeostatic range for the variable
two types: local and reflex control systems
features of local control systems
cells in the vicinity initiate the response
local change and local response
ex. vasodilation and vasoconstriction
features of reflex control systems
cells at a distant site control the response
long-distance signaling
reflex response loops
nervous (quicker) and endocrine systems (sustained)
4 steps to a biological control system
stimulus
sensor (receptor)
control center (integrating center)
effectors
features of negative feedback
variable fluctuates within a normal range around a set point
ex. temp regulation and blood pressure
features of positive feedback
stimulus is reinforced to continue moving variable in the same direction of stimulus
ex. labor
definition of energy
capacity to do work
two types of energy
kinetic and potential
definition of potential energy
energy of position or stored energy
definition of kinetic energy
energy of motion
SI unit for energy
joules (J)
2 main storage sites for potential energy
chemical gradient and in chemical bonds
definition of free energy
the potential energy stored in the concentration gradient and/or chemical bonds of a molecule
what is potential energy converted into in order to do work
kinetic energy; some energy is lost in the process
sodium moves down its concentration gradient into the cell; what type of energy is this an example of?
kinetic
what type of energy is chemical energy
a type of potential energy
features of chemical energy
stored in a molecule’s chemical bonds
released when the bond is broken
used for movement; making of molecules; and establishing a concentration gradient
what are 4 molecules that store chemical energy
triglycerides
glucose
protein
ATP
electrical energy
movement of charged particles
type of kinetic energy
mechanical energy
exhibited by objects in motion due to applied force
type of kinetic energy
sound energy
molecule compression caused by vibrating object
type of kinetic energy
radiant energy
energy of electromagnetic waves
type of kinetic energy
definition of heat as a form of energy
kinetic energy from movement of atoms, ions, and molecules
measured as temp
usually can’t do work
equation for work
force (N) x distance (m) = work (J)
thermodynamics
study of energy transformations
1st law of thermodynamics
energy can’t be created or destroyed, it can only change from one form to another
2nd law of thermodynamics
some energy is lost to heat once transformed
never 100% conversion of one form to another
chemical reaction
occurs when chemical bonds in an existing molecular structure are broken and new ones are formed to produce a different structure
what are the reactants in a chemical equation
before the arrow
what are the products in a chemical equation
after the arrow; formed by the reaction
metabolism
total sum of all cellular reactions in living organisms
divided into anabolism and catabolism
anabolism
making of large things from small things
uses energy in the bonds
catabolism
breakdown of large molecules into smaller ones
releases energy
exergonic reactions
exothermic - energy releasing
more energy in reactants than in products
net decrease in potential energy
endergonic reactions
endothermic - energy absorbing
reactants have less energy than products
net increase in potential energy
coupled reactions
exergonic and endergonic reactions that are happening at the same time and place
helps the cell acquire activation energy
reaction rate
measure of how quickly a chemical reaction takes place
determines about of product formed per unit of time
activation energy
energy required to initiate a reaction
energy needed to break bonds to allow the chemical reaction to proceed
determines reaction rate
chemical reaction occurs when there is more energy than the activation energy
enzymes
globular proteins that catalyze chemical reactions by lowering activation energy of reaction
increase amount of product formation
bind to reaction substrates to bring them into the best position for reacting with each other
active site
portion of enzyme that is specific
cofactor
molecules required to ensure that a reactions occur
inorganic cofactor
molecule that is attached to the enzyme and helps to ensure the reaction occurs
organic factors or coenzymes
not attached to the enzyme and have specific functions in assisting enzymes
oxidoreductases
transfers electrons from one substance to another
transferases
transfer atoms or molecules between chemical structures
ex. kinase transfers phosphate from ATP to a different substance
hydrolases
split chemical bonds using water
ex. phosphatase removes phosphate
isomerases
convert one isomer to another
ligases
bond to molecules together
ex. synthetase bonds two molecules using ATP
lyases
split bonds without using water
what accelerates the rate of a chemical reaction
more enzymes and more substrates
optimum temperature and pH
saturation
so much substrate is present that all enzyme molecules are engaged in reaction
competitive inhibitor
enters the active site and blocks it
noncompetitive inhibitor
binds to an allosteric site to induce a conformational change in the enzyme with an accompanying change in its active site
