Biology Chapter 5 Lecture Notes
Characteristics of enzyme
- 3D structure - substrate specific - has an active site - fully biodegrable - tools of nature - body's own set of tools - stable and work in mild conditions - arrangement of amino acids determines the enzyme's function - break down food - mostly protein but some RNA - consist of long strips of amino acids - has a specific function - not permanently changed i the process
law of conversion of energy
- first law of thermodynamics - energy cannot be created or destroyed, is only transformed from one form to another, however it could be transferred between systems
activities affecting enzymes
1. environmental conditions= extreme temperature are the most dangerous, pH, and ionic concentration 2. cofactors and conenzyme 3. enzyme inhibitors
organisms can maintain osmotic balance in different ways:
1. some cells use extrusion in which water is ejected through contractile vacuoles 2. isosmotic regulation; involves keeping cells isotonic with their environment 3. Plant cells use turgor pressure to push the cell wall and keep the cell rigid
Where will cells store energy?
Cells will store energy in chemical bonds using endergonic reactions and release energy using exergonic reactions that break the bonds
induced fit
a change in the shape of an enzyme's active site; induced by the substrate; a change in the configuration of an enzyme's active site (H+ and ionic bonds are involved)
concentration gradient
a differences between the concentration on one side of the membrane and that one the other side
active site
a restricted region of an enzyme molecule which binds to the substrate
Bulk transport
accomplished through endocytosis and exocytosis
competitive inhibitors
chemical resemble an enzymes it for the active site
osmotic concentration
determine by the concentration of all solutes in solution
mechanisms of passive transport
diffusion and osmosis
noncompetitive inhibitors
do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn alters the active site
kinetic energy
energy of motion
potential energy
energy of position (stored energy)
second law of thermodynamics
energy spreads out spontaneously
cofactor
enzyme helpers; will not function properly without being assisted by metal ions or small organic molecules. some metals ions that act as cofactors stabilize enzyme structure without which the enzyme denatures; inorganic substances (zinc and iron) vitamins (respectively) are sometimes need for proper enzymatic activity
common enzymes
enzyme: amylase substrate: starch product: glucose enzyme:catalase substrate; hydrogen peroxide products; water and oxygen
hypertonic
have a higher relative solute conentration
hypotonic
have a lower relative solute concentration
isotonic
have equal relative solute concentration
energy
its' cell's capacity (amount of free energy available) to do work needed to sustain life, grow, move, acquire, nutrients, reproduce, eat, etc.
enzymes
macromolecular biological catalyst., that accelerate, or catalyze, chemical reactions of substrates and not changed in the process
entropy
measures amount of energy in a system dispersed
activation energy
minimum amount of energy needed to start a chemical reaction. Both endergonic, and ecergonic reactions require activation energy
membrane transport mechanisms
motion of substances in and out of the cell; cell membranes are selectively permeable; there's two types of transport mechanisms= passive and active transport
exocytosis
movement of materials out of the cell; occurs when material is discharged from the cell; vesicles in the cytoplasm fuse with cell membrane and release contents to exterior of cell; used in plants to export cell wall materials; used in animals to secrete hormones, neurotransmitters, digestive enzymes
passive transport
movement of molecules through the membrane in which no energy is required from the cell; molecules move in response to a concentration gradient; mechanisms only movement substance along the concentration gradient; substances move from an area of high concentration to an area of low concentration
diffusion
movement of solute molecules from high solute concentration to low solute concentration
osmosis
movement of solvent water from high solvent concentration to low solvent concentration; movement of water from an area of high to low concentration of water; movement of water toward an area of high solute concentration; in osmosis, only water is able to pass through the membrane, moves water through aquaporins
endocytosis
movement of substance into the cell; occurs when the plasma membrane envelops food particles and liquids
coenzyme
organic; carry chemical groups, atoms, or electrons from one reaction to another, often into and out of organelles. They can be modified which they take part in a reaction
producers use:
photosynthesis
exergonic
process involves energy release (ex. respiration); if reactants have more free energy then the reactions ends up with net energy released
endergonic
process requires inputs of energy (ex. photosynthesis); if reactants have less energy than the products, reaction will not proceed
active transport
requires energy ATP is used directly or indirectly to fuel active transport; able to move substances against the concentration gradient- from low to high concentration; allows cells to store concentrated substances; requires the use of carrier proteins
consumer use:
respiration
facilitated diffusion
substances must pass through transported proteins to get through the cell membrane; the cell membrane is selectively permeable; carriers proteins bind to the molecule that they transport across the membrane; movement of a molecule from high to low concentration with the help of a carrier protein ( is specific, is passive, saturates when all carriers are occupied)
simple diffusion
substances pass directly through the cell membrane; the cell membrane has limited permeability to small polar molecules water and ions; the motion of water across the membrane is known as osmosis; the rate (molecules/s) of simple diffusion depends on the degree of concentration gradient ; at the gradient reaches equilibrium diffusion slows; at equilibrium substances pass in and out of the membrane at equal rates
phagocytosis
the cell take in particulate matter
phinocytosis
the cell takes in only fluid
enzyme- substrate complex
the substance (reactant) an enzyme acts on is the substrate
receptor- mediated endocytosis
when specific molecules are taken in after they bind to a receptor