Biology 150 Exam 2

Front 1

Free energy (G)

Back 1

chemical energy available to do work

Front 2

Where is energy stored?

Back 2

-chemical bonds

-can be released and transformed by metabolic pathways

Front 3

Principles governing metabolic pathways

Back 3

- chemical transformations occur in a series of reactions

- each reaction is catalyzed by a specific enzyme

-most metabolic pathways are similar in all organisms

-in eukaryotes, many metabolic pathways occur inside specific organelles

- each metabolic pathway is controlled by enzymes that can be inhibited or activated

Front 4

energy-transforming reactions are often coupled

Back 4

2 coupling molecules are the coenzyems ATP and NADH

Front 5

exergenic

Back 5

-an energy-reaction

-cell respiration

-catabolism

Front 6

endergonic

Back 6

-an energy requiring reaction

-active transport

-cell movements

-anabolism

Front 7

Adenosine triphosphate (ATP)

Back 7

-energy currency in cells

-energy released by exergonic reactiosn is stored in the bonds

- when hydrolyzed free energy is released to drive endergonic reactions

Front 8

oxidization

Back 8

when a molecule loses a hydrogen atom

Front 9

reduction reaction

Back 9

gaining of electrons

Front 10

redox reaction

Back 10

energy is transfered

Front 11

more reduced molecule

Back 11

more energy is stored in its bonds

Front 12

oxidative phosphorylation

Back 12

transfers energy from NADH to ATP

Front 13

aerobic in 3 linked biochemical pathways

Back 13

-glycolysis

-pyruvate oxidation

-citric acid cycle

Front 14

glycolysis

Back 14

-10 reactions

-cytosol

Front 15

oxidation-reduction

Back 15

-exergonic

-glyceraldehyde 3-phosphate is oxidized and energy is trapped via reduction of NAD+ to NADH

Front 16

substrate-level phosphorylation

Back 16

-exergonic

-energy release transfers a phosphate from 1,3-bisphosphoglycerate to ADP, forming ATP

Front 17

pyruvate oxidation

Back 17

-mitochondria in eukaryotes

-products: co2 and acetate; acetate is then bound to coenzyme a (CoA) to form acetyl CoA

-NAD+ is reduced to NADH

Front 18

citric acid cycle (TCA cycle)

Back 18

-8 reactions

- mitochondria

-operates twice for every glucose molecule that enters gylcolysis

Front 19

oxidative phosphorylation

Back 19

-cells transfer from NADH and FADH2 to ATP by oxidative phosphorylation

-NADH oxidation is used to actively transport protons (H+) across the inner mitochondrial membrane, resulting in a proton gradient

-diffusion of protons back across the membrane then drives the synthesis of ATP

Front 20

respiratory chain

Back 20

-when NADH is reoxidized to NAD+, O2 is reduced to H2O

- NADH+H+1/2O2--> NAD++H2O

-occurs in a series of redox electron carriers, called respiratory chain, embedded in the inner membrane of the mitochondrion

Front 21

electron transport

Back 21

-electrons from the oxidation of NADH and FADH2 pass from one carrier to the next in the chain

-the oxidation reactions are exergonic, energy released is used to actively transport H+ ions across the membrane

Front 22

ATP synthesis

Back 22

uses the H+ gradient to drive synthesis of ATP by chemiosmosis

Front 23

chemiosmosis

Back 23

movement of ions across a semipermeable barrier from a region of higher concentration to a region of lower concentration

Front 24

ATP synthase

Back 24

converts the potential energy of the proton gradient into chemical energy in ATP

Front 25

role of O2

Back 25

most of the ATP is formed by oxidative phosphorylation, which is die to the reoxidation of NADH

Front 26

fermentation

Back 26

operate to regenerate NAD+

Front 27

ATP made in glycolysis

Back 27

overall yield of ATP is 2

Front 28

Lactic Acid Fermentation

Back 28

-end product is lactic acid (lactate)

-NADH is used to redice pyruvate to lactate acid, regenerating NAD+

-occurs in many microorganisms and complex organisms

Front 29

alcoholic fermentation

Back 29

-end product is ethyl alcohol (ethanol)

- pyruvate is converted to acetaldehyde, and CO2 is released

_NADH is used to reduce acetaldehyde is ethanol,regenerating NAD+

Front 30

catabolic and anabolic pathways are integrated

Back 30

-metabolic pathways are linked

-molecules with carbon skeletons can enter catabolic or anabolic pathways

-these relationships comprise a metabolic system

Front 31

catabolism

Back 31

-polysaccharides are hydrolyzed to glucose, which enters glycolysis

-lipids break down to fatty acids and glycerol. fatty acids can be converted to acetyl CoA

-proteins are hydrolyzed to amino acids that can feed into glycolysis or the citric acid cycle

Front 32

anabolism

Back 32

-many catabolic pathways can operate in reverse

acetyl CoA can be used to form fatty acids

-some citric acid cycles intermediates can form nucleic acids

Front 33

gluconeogenesis

Back 33

citric acid cycle and glycolysis intermediates can be reduced to form glucose

Front 34

enzymes

Back 34

can also be regulated by altering the transcription of genes that encode the enzymes

-slower than feedback inhibition

Front 35

cellular respiration and photosyntheis

Back 35

linked by their reactants and products and by the energy "currency" of ATP and reduce coenzymes

Front 36

ATP&reduced coenzymes link catabolism, anabolism, and photosynthesis

Back 36

-

Front 37

cellular respiration

Back 37

glucose is oxidized

Front 38

photosynthesis

Back 38

light energy is converted to chemic energy

Front 39

anabolic involves 2 pathways

Back 39

light reactions and carbon-fixation reactions

Front 40

light reactions

Back 40

convert light energy into chemical energy (in ATP and the reduced electron carrier NADPH)

Front 41

carbon-fixation reactions

Back 41

use the ATP and NADPH to produce carbohydrates

Front 42

photons

Back 42

-light is a form of electromagnetic radiation; it is propagated as a wave but also behaves as particles

-can be absorbed by specific receptor molecules, which are raised to an excited state (higher energy)

Front 43

wavelength

Back 43

the amount of energy in the radiation is inversely proportional to its wavelength

Front 44

pigments

Back 44

molecules that absorb wavelengths in the visible spectrum

Front 45

chlorophyll

Back 45

absorbs blue and red light; the remaining light is mostly green

Front 46

absorption spectrum

Back 46

plot of light energy absorbed against wavelength

Front 47

action spectrum

Back 47

plot of the biological activity of an organism against wavelength

Front 48

2 chlorophylls absorb light energy

Back 48

chlorophyll a and chlorophyll b

Front 49

accessory pigments

Back 49

absorb wavelengths between red and blue and transfer some of that energy to the chlorophylls

Front 50

chlorophyll

Back 50

consists of a complex ring structure with a magnesium ion at its center, plus a hydrocarbon "tail"

Front 51

photosystem

Back 51

-spans the thylakoid membrane in the chloroplast--> it consists of multiple antenna systems surrounding a reaction center

Front 52

autotrophs

Back 52

-photosynthetic organisms

-use most of this energy to support their own growth and reproduction

Front 53

heterotrophs

Back 53

cannot photosynthesize and depend on autotrophs for chemical energy