Biology Chapter 4

Front 1

energy

Back 1

Physicists define it as the ability to do work that is, to move matter. this is fundamental to biology

Front 2

Life depends on what?

Back 2

Rearranging atoms and tracking substances across the membranes in precise ways. these movements represent work and require energy

Front 3

What does a plant cell do?

Back 3

assembles glucose molecules into long cellulose fibers, moves ions across its membranes, and performs thousands of other task simultaneously

Front 4

gazelle gazes

Back 4

on plant tissues to acquire energy that will enable it to do its own cellular work. a crocodile eats the gazelle for the same reason

Front 5

potential energy

Back 5

Is stored energy available to do work.

Front 6

examples of potential energy

Back 6

EX: a bike at the top of the hill illustrates potential energy, unburned gasoline, and a chemical gradient

Front 7

kinetic energy

Back 7

is energy being used to do work; any moving object possesses kinetic energy

Front 8

examples of kinetic energy

Back 8

a bike going down a hill, moving pistons, a rolling bus, contracting mussels, light and sound, inside the cell each molecule.

Front 9

potential and kinetic energy

Back 9

potential energy in the chemical bonds of food is converted to kinetic energy as the muscles push the cyclist to the top of the hill. The potential energy provides a free ride by conversion to kinetic energy on the other side

Front 10

calorie

Back 10

calories are units used to mesure energy. one calorie is the amount of energy required to raise the temperature of 1 gram of water from 14.5 C to 15.5 C

Front 11

kilocalories

Back 11

The most common unit for measuring the energy content in food, which equals 1000 calories.

Front 12

in nutriton one food calorie with a capital C is actually?

Back 12

a kilocalorie

Front 13

a energy bar

Back 13

contains 240 kilocalpries of potential energy store in the chemical bonds of its ingredients : mostly carbohydrates, proteins, and fats

Front 14

Thermodynamics

Back 14

is a study of energy transformations

Front 15

first law of thermodynamics

Back 15

is the law of energy conservation. it states that energy can be converted to other forms. this means that the total amount of energy in the universe is constant

Front 16

photosynthesis and cellular respiration

Back 16

The most important energy transformations.

Front 17

photosynthesis

Back 17

plant and some microorganisms use carbon dioxide, water, and the kinetic energy in sunlight to assemble glucose molecules. these carbohydrates contain potential energy in their chemical bonds

Front 18

energy can take many forms

Back 18

in photosynthesis, plants transform the kinetic energy in sunlight into the potential energy contained in the chemical bonds of glucose

Front 19

cellular respiration

Back 19

the energy rich glucose molecules change back to carbon dioxide and water, liberating the energy necessary to power life

Front 20

cells

Back 20

translate the potential energy in glucose into the kinetic energy to do work

Front 21

the second law of thermodynamics

Back 21

states that all energy transformations are inefficient because every reaction loses some energy to the surroundings as heat

Front 22

entropy

Back 22

is a measure of this randomness, in general, the more disordered a system is, the higher its entropy

Front 23

metabolism

Back 23

encompasses all of these chemical reactions in cells, including those that build new molecules and those that brake down existing ones

Front 24

endergonic reaction

Back 24

requires an input of energy to proceed (the prefix endo means "put into") that is the products contain more energy than the reactants

Front 25

example of endergonic reaction

Back 25

is photosynthesis, glucose (CHO) the product of photosynthesis, contains more potential energy than do carbon dioxide (CO) and water (H2O) the reactants. sunlight

Front 26

exergonic reaction

Back 26

releases energy. the products contain less energy than the reactants. Such reactions break large, complex molecules into their smaller, simpler components

Front 27

cellular respiration

Back 27

the breakdown of glucose to carbon dioxide and water, contain less energy than glucose

Front 28

chemical equilibrium

Back 28

The reaction goes in both directions at the same rate. Equilibrium does not necessarily mean that the amounts of products and reactants are equal, rather than rates of formation are equal

Front 29

equilibrium

Back 29

does not necessarily mean that the amounts of products and reactants are equal; rather, their rates of formation are equal

Front 30

oxidation-reduction (redox) reactions

Back 30

most energy transformations in organisms occur, which transfers energized electrons from one molecule to another

Front 31

oxidation

Back 31

means the loss of electrons from a molecule, atom, or ion

Front 32

oxidation reactions

Back 32

such as the breakdown of glucose to carbon dioxide and water, are exergonic; they release energy as they degrade complex molecules into simpler products

Front 33

reduction

Back 33

means a gain of electrons (plus any energy contained in the electrons)

Front 34

reduction reactions

Back 34

are therefor endergonic;they require a net input of energy

Front 35

Oxidation and Reduction

Back 35

occur simultaneously because electrons removed from one molecule and reduce it. that is, if one molecule is reduced (gains electrons) , then another must be oxidized (loose electrons)

Front 36

electron transport change

Back 36

each protein accepts an electron from the molecule before it and passes it to the next. like a bucket brigade

Front 37

electron transport chain

Back 37

an electron donor transfers an electron to the first protein in the chain. this protein denotes the electron is transferred to a final electron acceptor. both photosynthesis and respiration use electron transport chains

Front 38

adenosine triphosphate

Back 38

the covalent bonds of a molecule more commonly known as ATP, temporarily store much of the released energy

Front 39

ATP

Back 39

holds energy released in exergonic reaction such as the digestion of an energy bar just long enough to power muscle contractions and all other endergonic reactions

Front 40

ATP Hydrogen Releases energy

Back 40

removing the endmost phosphate group of ATP yields ADP and a free phosphate group. The cell uses the related energy to do work

Front 41

coupled reactions

Back 41

are simultaneous reaction in which one provides the energy that drives the other

Front 42

phosphorylating

Back 42

a cell uses ATP as an energy source ( transferring its phosphate group to) another molecule

Front 43

one of the results of transferring of phosphorylating

Back 43

the presents of the phosphate may energize the target molecule, making it more likely to bond with other molecules. in this way ATP fuels endergonic reactions

Front 44

another result of transferring of phosphorylating

Back 44

is a change in shape of the target molecule. Ex: adding phosphate can force a protein to its original form.

Front 45

muscle contraction

Back 45

Is the large scale effect of millions of small molecules changing shape in a coordinated way. ATP provides the energy.

Front 46

energy "currency" sometimes refereed as ATP

Back 46

For the cell. All cells use ATP in many chemical reactions to do different kinds of work.

Front 47

ATP JOBS

Back 47

transporting substances across cell membranes, moving chromosomes during cell division, and synthesizing the large molecules that make up cells, also analogous to a full charged rechargeable battery

Front 48

organisms

Back 48

require a huge amount of ATP. recycle ATP at a furious pace, adding phosphate group to ADP to reconstitute ATP, using the ATP to drive reactions, and turning over the entire supply every minute of so, if you ran out of ATP you would die

Front 49

adult human

Back 49

uses the equivalent of 2 billion ATP molecules a minute just to stay alive.

Front 50

enzyme

Back 50

are among the most important of all biological molecules. it is an organic molecule that catalyzes (speeds up) a chemical reaction without being consumed. most are proteins some are made of RNA

Front 51

energy of activation

Back 51

enzyms speed reactions by lowering the amount of energy required to start a reaction

Front 52

exergonic reactions

Back 52

Which ultimately release energy, require an initial "kick" to get started.

Front 53

active site

Back 53

the region to which the substance bind

Front 54

feedback

Back 54

also called feedback inhibition in which the product of a reaction inhibits the enzyme that controls its formation.

Front 55

non completive inhibitions

Back 55

product molecules bind to the enzymes at a location other than the active site, in a way that alters the enzymes shape so that it can no longer bind substrate

Front 56

competitive inhibition

Back 56

the product of a reaction binds to the enzymes active site, preventing competes with the substrate to occupy the active site

Front 57

positive feedback

Back 57

in which a product activities the pathway leading its own production

Front 58

blood clotting

Back 58

begins when a biochemical pathway synthesizes fibrin, a threadlike protein.