The Basis of Life Flashcards
metabolism
the sum of all chemical reactions that occur in the body
catabolic vs. anabolic
catabolic reactions
break down large chemicals; release energy
anabolic reactions
build up large chemicals; require energy
ingestion
acquisition of food and other raw materials
digestion
process of converting food into a useable soluble form; allows for passing through membranes in the digestive tract
absorption
passage of nutrient molecules through the lining of the digestive tract
diffusion vs. active transport
transport
the circulation of essential compounds required to nourish and remove wastes from the tissues
assimilation
building up of new tissues
respiration
the consumption of oxygen by the body
excretion
removal of waste products produced during metabolic processes
synthesis
the creation of complex molecules from simple ones
regulation
control of physiological activities
homeostasis
body’s metabolism functions to maintain its internal environment in a changing external environment
growth
an increase in size caused by synthesis of new materials
reproduction
generation of additional individuals of a species
enzymes are: (3)
- proteins
- organic catalyst that do NOT alter the equilibrium constant, are NOT consumed in the reaction
- selective (pH and temperature sensitive)
2 models for enzyme-substrate binding
Lock & key theory
Induced fit theory
lock & key theory
spatial structure of an enzyme’s active site is exactly complementary to the spatial structure of its substrate
receptor (lock) & drug substance (key)
induced fit theory
active site has flexibility
when appropriate substrate comes in contact with the active site, the conformation of the active site changes to fit the substrate
what affects the reaction rate?
concentration of substrate & enzymes
temperature
pH
Vmax
the maximum rate of a reaction under certain conditions; reflects how fast an enzyme can catalyze a reaction
increasing the substrate concentration will increase the rxn rate until all the active sites are occupied
competitive inhibition (2)
- when a similar molecule with comparable concentration to the substrate competes with the substrate for the binding site and interferes with enzyme activity
- enzyme is inhibited by the inactive competitor
noncompetitive inhibition (3)
- irreversible
- an inhibitor that is covalently bound to an enzyme that can not be displaced by the addition of excess substrate
- allosteric inhibition: inhibition takes place at a site other than the active site-> changes enzyme structure & active site
the _____ is the fundamental unit of all living things
cell
cell theory (5)
- all living things are composed of cells
- the cell is the basic functional unit of life
- chemical rxns take place inside the cell
- cells arise ONLY from pre-existing cells
- cells carry genetic information in the form of DNA
cell membrane
- encloses the cell and exhibits selective permeability
- regulates the passage of materials into & out of the cell
fluid mosaic model (4)
- describes the plasma membrane of each cell
- plasma membrane is made-up of a phospholipid bilayer (outward hydrophilic heads & inward hydrophobic tails)= FLUID at body temperature
- each cell resided in extracellular fluid, but the inside is also composed of cytoplasm
- proteins & other substances are embedded throughout the membrane and can move freely throughout within the membrane=MOSAIC
Lipid bilayer is permeable to: (2)
- small nonpolar hydrophobic molecules
ex. oxygen - small polar molecules
ex. water
Lipid bilayer is not permeable to: (2)
- charged ions
- larger charged molecules
nucleus (3)
- controls the activities of the cell
- contains the DNA
- contains the nucleolus: ribosomal synthesis occurs
ribosome
site of protein production
endoplasmic reticulum (ER)
network of membrane-enclosed spaces involved in the transport of material throughout the cell
Golgi apparatus
received vesicles from smooth ER, modifies them, repackages them into vesicles, distributes them to the cell surface
mitochondria
powerhouse
site of aerobic respiration within the cell & hence the supplier of energy
cytoplasm
where cell metabolic activity occurs
vacuoles/vesicles
membrane-bound sacs involved in the transport & storage of materials that are ingested, secreted, processed, or digested by the cell
centrioles (2)
- involved in spindle organization during cell division
- a pair of them can be found in an area known as the centrosome of animal cell
lysosomes (2)
- break down material ingested by the cell
- membrane bound vesicles that contain hydrolytic enzymes involved in digestion
cytoskeleton functions (3)
- supports the cell
- maintains its shape
- functions in cell motility
components of the cytoskeleton (3)
- microtubules
- microfilaments
- intermediate filaments
microtubules (2)
- hollow rods made up of tubulin
- radiated throughout the cell and used for support
ex. centrioles, cilia, flagella (made up of microtubules)
microfilaments (3)
- solid rods of actin
- important in cell movement as well as support
- move materials across the plasma membrane
ex. muscle contraction based on interaction of actin & myosin
passive transport (2); examples
- without energy
- with the concentration gradient
ex. simple diffusion & facilitated diffusion
active transport (2)
- require energy
- against the concentration gradient
simple diffusion
passive transport
movement of particles down their concentration gradient from high->low
osmosis
simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration
hypertonic vs hypotonic vs isotonic
- hypotonic: greater concentration of solutes within the cell, so water molecules enter the cell (CELL LYSIS)
- hypertonic: greater concentration of solutes outside the cell, so water molecules travel from the cell (CELL SHRIVEL)
- isotonic: equal concentration of solute outside & inside the cell
facilitated diffusion
passive transport
movement of particles down their concentration gradient through special channels or carrier proteins
endocytosis
cell membrane invaginates, forming a vesicle that contains extracellular material
exocytosis
vesicle within the cell fuses with the cell membrane and releases its content to the outside
