Energy, Chemical Reactions, and Cellular Respiration

Energy

capacity to do work

how does energy differ from matter

it has no mass and does not take up space

two classes of energy

potential and kinetic

potential energy

energy of position or stored energy

kinetic energy

energy of motion

water behind a dam is an ex of ___ energy

potiential

potential energy must be converted to kinetic energy to __

be actively engaged in doing work

a form of potential energy

chemical energy

chemical energy

stored in bonds of molecules

three important high energy molecules within the body that function primarily in chemical energy

triglycerides, glucose, and ATP

kinetic energy ex

motion, sound, and light energy

triglycerides

store energy long term in fat tissue

glucose

stored as glycogen in liver and muscles

ATP

provides quick energy

electrical energy

involves charged particle movement, like electrons in wires

mechanical energy

results from motion, such as heartbeats

sound energy

arises from vibrating objects, like vocal cords

radiant energy

involves electromagnetic waves

heat is the kinetic energy resulting from the __

random motion of atoms, ions, or molecules

first law of thermodynamics

energy cannot be created or destroyed, only changed

second law of thermodynamics

some energy turns into heat during changes, so energy conversion is never 100% efficient

metabolism

collective term for all biochemical reactions in living organisms

what happens in a chemical reaction

reactants are transformed into products, represented in a chemical equation

reactants vs products?

reactants (left) are the substrates/substances, at the start of the chemical reaction. products (right) are whats formed from the reactants by the chemical reaction (ex. A+B ->C)

chemical reactions are classified by changes in __

structure, energy, and direction

decomposition

breaks down molecules

synthesis

builds molecules

exchange

swaps components

irreversible chemical reaction

proceed in one direction

reversible chemical reaction

can reach equilibrium

decomposition reaction

break big molecules into smaller parts - catabolism

synthesis reaction

combine smaller units into larger structures

exchange reaction

swapping parts between two chemical structures

oxidation reduction reactions involve __

moving electrons between molecules

when a molecule loses electrons its

oxidized

when a molecule gains an electron its

reduced

LEO

chemical structure that Loses Electrons is Oxidized

GER

chemical structure that Gains Electrons is Reduced

exergonic reactions

release energy as reactants with more energy become products with less

endergonic reactions

need energy to make products with more energy than reactants

ATP Cycling

when ATP, the cell's energy molecule, forms and breaks down

chemical reaction rate

how fast a reaction happens

activation energy

energy needed to start the reaction

catalysts

substances that accelerate or promote chemical reactions

enzymes

help chemical reactions in the body happen faster by lowering the energy needed to start them

key structural components of enzymes

special proteins with a unique shape, they have an active site where a substrate fits, allowing the enzyme to perform one specific reaction

what is the active site of an enzyme

a specific region with a unique shape that fits a substrate like a key fits into a lock

steps by which an enzyme catalyzes a chemical reaction

joining with substances and lowering energy needed

cofactors and their role in chemical reactions

cofactors assist enzymes, making reactions smoother

cofactors

nonprotein structure, either inorganic or organic substance associated with a particular enzyme or enzymatic reaction

inorganic cofactor

like zinc, attach to enzymes

organic cofactor

like vitamins, help without attaching

six major classes of enzymes

1. oxidoreductase moves electrons

2. transferase moves groups

3. hydrolase splits water

4. isomerase changes shape

5. ligase joins with ATP

6. lyase splits without water

how enzymes are generally named

by adding "-ase" to the name of their substrate or the reaction they help with, like lactase for lactose

how enzyme and substrate concentration affect reaction rates

enzymes speed up reactions. more enzymes or substrates make reactions faster

effects of temp on pH on enzyme structure and reaction rates

temp and pH affect enzyme shape, changing how well they work

how competitive inhibitors control enzyme reaction

block enzymes active site, stopping the reaction

how noncompetitive inhibitors control enzyme action

change the enzymes shape, preventing the reaction from happening

metabolic pathway

uses multiple enzymes in sequence to change a substrate into a product

multienzyme complex

group of enzymes attached through noncovalent bonds to form complex

cellular respiration

breaks down glucose to release energy, making ATP, the cells energy source

four stages of cellular respiration

glycolysis, does not require oxygen.

intermediate stage, citric acid cycle, and electron transport system, require oxygen

glycolysis

metabolic process that occurs in the cytosol without req. oxygen

mitochondrion

double membrane cellular organelle, composed of outer membrane and inner membrane

citric acid cycle

metabolic process that occurs in the mitochondria and requires oxygen