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