Honors Biology - Module 5: Energy and Enzymes

Energy

ability to do work

Potential Energy

• energy of an object due to its position

• Ex) chemical energy stored in covalent bond of food

• concentration gradient

• energy level of electrons in atom

Kinetic Energy

• energy of motion

• light: sun

• sound: voice

• mechanical: movement of atoms and molecules

• thermal: heat produced by living and nonliving things

• electrical: impulses produced in neurons

First Law of Thermodynamics

• Law of Conservation of Energy

• energy cannot be created nor destroyed

Second Law of Thermodynamics

• entropy constantly increases

• nothing is 100% efficient

• energy is lost as heat

• a constant input of free energy is required to keep up organization of system

Entropy

-a measure of the disorder of a system

Decomposition Metabolism

catabolic

Decomposition Entropy

entropy increases

Decomposition Energy

exergonic; energy is released

Biosynthesis Metabolism

anabolic

Biosynthesis Entropy

entropy decreases

Biosynthesis Energy

energy is stored

Chemical Reactions May Require

• energy input (endergonic)

• energy release (exergonic)

RedOx

reduction/oxidation

Reduction

• molecule gains electrons

• charge gets more negative

• the molecule that gets reduced gains energy

• RIG (Reduced is gained electrons)

Oxidation

• molecule loses electrons

• charge gets more positive

• the molecule that gets oxidized loses energy

• OIL (Oil is loss of electrons)

ATP

• adenosine triphosphate

• temporarily "stores" and transfers energy in cells

ATP -> ADP + P

• hydrolysis of ATP

• energy FOR endergonic reactions is released

ADP + P -> ATP

• Uses energy FROM exergonic reactions

• phosphorylation of ADP

Phosphorylation

the addition of a phosphate group to a molecule

Enzyme

• type of protein

• biological catalyst

• lowers activation energy/increases reaction rate

• has ideal conditions

• can build or breakdown molecules

• can be specific in what they attach to

Activation Energy

minimum amount of energy required for reactant(s) to form product(s) in a chemical reaction

Enzyme Specificity

• names usually describe what they breakdown

• one enzyme breaks down only one type of molecule

Induced Fit

• enzyme-substrate binding

• changes shape to break it apart

• "grabs it"

Lock and Key Fit

• enzyme-substrate binding

• attachment point for molecules

• enzyme does not change shape

Increase Reaction Rate

AFFECTING FACTOR

• increase amount of enzyme

• increase amount of substrate

Decrease Reaction Rate

AFFECTING FACTOR

• altering environment conditions beyond ideal range (temp.

Enzyme Denaturation

• conditions affect the unfolding of the tertiary structure of a protein

• the shape of the enzyme can change

Noncompetitive Inhibitor

• allosteric

• the inhibitor is not on actual active site

Competitive Inhibitor

• orthosteric

• inhibitor on the active site

Negative Feedback

• the product of a reaction slows production of more of its own product

• ex. the regulating of blood sugar with insulin and glucagon; production of cholesterol

Positive Feedback

• product of a reaction stimulates production of more of its own product

• ex. oxytocin production during child birth

Selectively Permeable

a property of cell membranes that allows some substances to pass through

Gradient

A difference in concentration

Passive Transport

Requires NO energy

Simple Diffusion

Diffusion that doesn't involve a direct input of energy or assistance by carrier proteins.

Facilitated Diffusion

the transport of substances through a cell membrane along a concentration gradient with the aid of channel or carrier proteins

Osmosis

Diffusion of water through a selectively permeable membrane

Aquaporin

A membrane protein

Tonicity

The ability of a solution surrounding a cell to cause that cell to gain or lose water.

Hypertonic

Having a higher concentration of solute than another solution.

Hypotonic

Having a lower concentration of solute than another solution

Isotonic

Having the same solute concentration as another solution.

Lysis

Bursting of an animal cell after being placed in a hypotonic solution

Crenation

This happens when a cell is placed in a hypertonic solution shrinks and shrivels; can result in cell death if severe.

Turgor Pressure

The pressure that water molecules exert against the cell wall

Plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

Active Transport

The movement of materials across a cell membrane using energy (ATP)

Protein Pumps

Transport proteins that require energy to do work

Primary Active Transport

Active transport that relies directly on the hydrolysis of ATP.

Secondary Active Transport

Form of active transport which does not use ATP as an energy source; rather

Bulk Transport

The process by which large particles and macromolecules are transported through plasma membranes with a vesicle.

Uniporter

A carrier protein that transports a single molecule across the plasma membrane.

Cotransporter

A carrier that moves two types of molecules at one time

Na/K pump

Active transporter that moves three Na+ out of a cell and two K+ into the cell against their respective concentration gradients.

Symport

A membrane transport process that carries two substances in the same direction across the membrane. One of the substances moves down the concentration gradient

Antiport

A membrane transport process that carries one substance in one direction and another in the opposite direction. One of the substances moves down the concentration gradient

Exocytosis

A process by which the contents of a vesicle are released to the exterior through fusion of the vesicle membrane with the cell membrane.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells.

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Receptor Medicated Endocytosis

The main mechanism and a very selective mechanism for taking molecules inside the cell. Ex. insulin