Harold Washington Bio 121 Test 3

Front 1

metabolism

Back 1

the totality of an organism’s chemical reactions; an emergent property of life that arises from orderly interactions between molecules

Front 2

metabolic pathway

Back 2

begins with a specific molecule and ends with a product; Each step is catalyzed by a specific enzyme

Front 3

catabolic pathway

Back 3

releases energy by breaking down complex molecules into simpler compounds; example: cellular respiration, the breakdown of glucose in the presence of oxygen

Front 4

anabolic pathway

Back 4

consumes energy to build complex molecules from simpler ones (synthesis); example: the synthesis of protein from amino acids

Front 5

kinetic energy

Back 5

energy associated with motion

Front 6

potential energy

Back 6

energy that matter possesses because of its location or structure

Front 7

heat (thermal energy)

Back 7

kinetic energy associated with random movement of atoms or molecules

Front 8

chemical energy

Back 8

potential energy available for release in a chemical reaction

Front 9

1st law of thermodynamics

Back 9

Energy cannot be created or destroyed but it can be transferred and transformed

Front 10

2nd law of thermodynamics

Back 10

Every energy transfer or transformation increases the entropy (disorder) of the universe

Front 11

spontaneous processes (reactions)

Back 11

occur without energy input; they can happen quickly or slowly; For a process to occur without energy input, it must increase the entropy of the universe

Front 12

∆G (Delta G)

Back 12

ΔG = G final state – G initial state

Front 13

exergonic reaction

Back 13

proceeds with a net release of free energy and is spontaneous (ΔG <0)

Front 14

endergonic reaction

Back 14

absorbs free energy from its surroundings and is nonspontaneous (ΔG>0)

Front 15

couple reactions (and how ATP relates)

Back 15

To do work, cells manage energy resources by energy coupling, the use of an exergonic process to drive an endergonic one.

Front 16

ATP-ADP cycle

Back 16

Front 17

catalyst

Back 17

is a chemical agent that speeds up a reaction without being consumed by the reaction

Front 18

enzymes

Back 18

a protein catalyst

Front 19

activation energy

Back 19

The initial energy needed to start a chemical reaction is called the free energy of activation; enzymes reduce the amount of initial energy needed to complete a chemical reaction

Front 20

substrate

Back 20

The reactant that an enzyme acts on

Front 21

enzyme-substrate complex

Back 21

when the enzyme binds to its substrate

Front 22

active site

Back 22

the region on the enzyme where the substrate binds; induced fit of a substrate brings chemical groups of the _____ into positions that enhance their ability to catalyze the reaction

Front 23

optimal condition

Back 23

Each enzyme has an optimal temperature in which it can function; each enzyme has an optimal pH in which it can function; optimal conditions favor the most active shape for the enzyme molecule

Front 24

cofactors

Back 24

nonprotein enzyme helpers; usually inorganic (such as a metal in ionic form) or organic

Front 25

coenzymes

Back 25

an organic cofactor

Front 26

Competitive inhibitors

Back 26

bind to the active site of an enzyme, competing with the substrate

Front 27

Noncompetitive inhibitors

Back 27

Allosteric inhibitors; bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

Front 28

allosteric activators and allosteric inhibitors

Back 28

Front 29

feedback inhibition

Back 29

the end product of a metabolic pathway shuts down the pathway; prevents a cell from wasting chemical resources by synthesizing more product than is needed

Front 30

Energy flow and chemical recycling in ecosystems

Back 30

Figure 9.2: Energy flows into an ecosystem as sunlight and ultimately leaves as heat, while the chemical elements essential to life are recycled

Front 31

fermentation

Back 31

The breakdown of organic molecules is exergonic; a partial degradation of sugars that occurs without O2

Front 32

aerobic respiration

Back 32

respiration that consumes organic molecules and O2 and yields ATP

Front 33

anaerobic respiration

Back 33

respiration performed by many bacteria do not use oxygen

Front 34

oxidation

Back 34

a substance loses electrons, or is oxidized

OIL RIG (oxidation is loss, reduction is gain)

Front 35

reduction

Back 35

a substance gains electrons, or is reduced (the amount of positive charge is reduced)

Front 36

redox reaction

Back 36

Chemical reactions that transfer electrons between reactants

Front 37

reducing agents

Back 37

the electron donor in a redox reaction

Front 38

oxidizing agents

Back 38

the electron receptor in a redox reaction

Front 39

NAD is an electron carrier

Back 39

In cellular respiration, glucose and other organic molecules are broken down in a series of steps; Electrons from organic compounds are usually first transferred to NAD+, a coenzyme

Front 40

NADH

Back 40

the reduced form of NAD+; represents stored energy that is tapped to synthesize ATP

Front 41

NAD+

Back 41

As an electron acceptor, this functions as an oxidizing agent during cellular respiration

Front 42

electron transport chain (and how it involves ATP)

Back 42

NADH passes the electrons to the _____; Unlike an uncontrolled reaction, the _____ passes electrons in a series of steps instead of one explosive reaction; O2 pulls electrons down the chain in an energy-yielding tumble; The energy yielded is used to regenerate ATP

Front 43

Glycolosis (and where does it occur)

Back 43

Harvesting of energy from glucose has three stages; Stage 1 breaks down glucose into two molecules of pyruvate; occurs in the cytosol

Front 44

Citric acid cycle (and where does it occur)

Back 44

Harvesting of energy from glucose has three stages; Stage 2 completes the breakdown of glucose; occurs in the mitochondria

Front 45

Oxidative phosphorilation (and where does it occur)

Back 45

Harvesting of energy from glucose has three stages; Stage 3 accounts for most of the ATP synthesis; occurs in the mitochondria

Front 46

Respiration chart and what the phases of glycolosis produces

Back 46

Front 47

acetyl Coenzyme A (acetyl CoA)

Back 47

Before the citric acid cycle can begin, pyruvate must be converted to ___, which links glycolysis to the citric acid cycle; this step is carried out by a multienzyme complex that catalyses the reactions

Front 48

Citric Acid Cycle (chart)

Back 48

Front 49

Oxaloacetate -> citrate

Back 49

The citric acid cycle has eight steps, each catalyzed by a specific enzymeThe acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrateThe next seven steps decompose the citrate back to oxaloacetate, making the process a cycleThe NADH and FADH2 produced by the cycle relay electrons extracted from food to the electron transport chain

Front 50

ATP synthase

Back 50

H+ then moves back across the membrane, passing through this protein complex; uses the exergonic flow of H+ to drive phosphorylation of ATP

Front 51

Electron carrier #4 and why oxygen is relevant to it

Back 51

Most cellular respiration requires O2 to produce ATP; Without O2, the electron transport chain will cease to operate; In that case, glycolysis couples with anaerobic respiration or fermentation to produce ATP

Front 52

Alcoholic fermentation

Back 52

pyruvate is converted to ethanol in two steps; The first step releases CO2; The second step produces ethanol; yeast is used in brewing, winemaking, and baking

Front 53

Lactic acid fermentation

Back 53

pyruvate is reduced by NADH, forming lactate as an end product, with no release of CO2; ___ by some fungi and bacteria is used to make cheese and yogurt; Human muscle cells use this to generate ATP when O2 is scarce

Front 54

obligate anaerobes

Back 54

carry out fermentation or anaerobic respiration and cannot survive in the presence of O2

Front 55

facultative anaerobes

Back 55

Yeast and many bacteria are ___, meaning that they can survive using either fermentation or cellular respiration; in a ___, pyruvate is a fork in the metabolic road that leads to two alternative catabolic routes

Front 56

How are other food sources processed

Back 56

Front 57

Feedback inhibition

Back 57

Feedback inhibition is the most common mechanism for metabolic control; If ATP concentration begins to drop, respiration speeds up; when there is plenty of ATP, respiration slows down; Control of catabolism is based mainly on regulating the activity of enzymes at strategic points in the catabolic pathway

Front 58

Feedback inhibition (chart)

Back 58

Front 59

Photosynthesis

Back 59

the process that converts solar energy into chemical energy

Front 60

producers/autotroph

Back 60

sustain themselves without eating anything derived from other organisms; the producers of the biosphere, producing organic molecules from CO2 and other inorganic molecules

Front 61

consumers/heterotrophs

Back 61

Heterotrophs obtain their organic material from other organisms; Heterotrophs are the consumers of the biosphere; Almost all heterotrophs, including humans, depend on photoautotrophs for food and O2

Front 62

Sites of photosynthesis

Back 62

Leaves are the major locations of photosynthesis; Chloroplasts are found mainly in cells of the mesophyll, the interior tissue of the leaf; Each mesophyll cell contains 30–40 chloroplasts; CO2 enters and O2 exits the leaf through microscopic pores called stomata

Front 63

Where is chlorophyll in plants (chart)

Back 63

Front 64

Structure of a chloroplast

Back 64

Front 65

stroma

Back 65

A chloroplast has this envelope of two membranes surrounding a dense fluid

Front 66

thylakoids

Back 66

connected sacs in the chloroplast which compose a third membrane system; may be stacked in columns called grana

Front 67

chlorophyll

Back 67

the pigment which gives leaves their green colour, resides in the thylakoid membranes

Front 68

2 stages of photosynthesis

Back 68

The light reactions take place on the thylakoid membrane; The Calvin cycle takes place in the stroma

Front 69

light reaction

Back 69

Split H2O - Release O2 - Reduce the electron acceptor NADP+ to NADPH - Generate ATP from ADP by photophosphorylation

Front 70

Calvin cycle

Back 70

in the stroma; forms sugar from CO2, using ATP and NADPH; begins with carbon fixation, incorporating CO2 into organic molecules

Front 71

Light Reaction and calvin cycle interactions and what each part produces

Back 71

Front 72

NADP+ and NADPH

Back 72

?

Front 73

visible light

Back 73

Visible light consists of wavelengths (including those that drive photosynthesis) that produce colors we can see

Front 74

chlorophyll a

Back 74

is the main photosynthetic pigment

Front 75

carotenoids

Back 75

Accessory pigments that absorb excessive light that would damage chlorophyll

Front 76

photosystems

Back 76

A photosystem consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes

Front 77

primary electron acceptor

Back 77

in the reaction center accepts excited electrons and is reduced as a result; Solar-powered transfer of an electron from a chlorophyll a molecule to this is the first step of the light reactions

Front 78

Chloroplast Photosystem II

Back 78

There are two types of photosystems in the thylakoid membrane; functions first

Front 79

Linear electron flow

Back 79

the primary pathway, involves both photosystems and produces ATP and NADPH using light energy

Front 80

10.17, 10.18, 10.19

Back 80

?

Front 81

rubisco

Back 81

an enzyme involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is converted by plants to energy-rich molecules such as glucose.

Front 82

Photorespiration

Back 82

In this, rubisco adds O2 instead of CO2 in the Calvin cycle, producing a two-carbon compound; consumes O2 and organic fuel and releases CO2 without producing ATP or sugar

Front 83

What is the main product of the Calvin Cycle?

Back 83

G3P

Front 84

C4 pathways

Back 84

C4 plants minimize the cost of photorespiration by incorporating CO2 into four-carbon compounds There are two distinct types of cells in the leaves of C4 plants:Bundle-sheath cells are arranged in tightly packed sheaths around the veins of the leaf; Mesophyll cells are loosely packed between the bundle sheath and the leaf surface

Front 85

CAM pathways

Back 85

Some plants, including succulents, use crassulacean acid metabolism (CAM) tofix carbon; open their stomata at night, incorporating CO2 into organic acidsStomata close during the day, and CO2 is released from organic acids and used in the Calvin cycle