Bio Exam 2

the enhancement effect states that the rate of photosynthesis is fastest when both photosystems are activated. Which wavelength(s) of light would be most appropriate to demonstrate the enhancement effect?

700nm 680nm

which of the following is associated with the reaction center of PS 2?

P680

in 1981, Thomas Cech, et al. reported that certain reactions in the cell are catalyzed bu the nucleic acid _______

RNA

select the true statements about endergonic reactions

endergonic reactions are not spontaneous the products have a higher free energy than the reactants endergonic reactions have a positive change in free energy

during feedback inhibition, the final ______ of a metabolic pathway inhibits the _______ enzyme in the sequence, as shown in the image

endoproduct first

select all of the following that contribute to the formation of a proton gradient during the electron transport chain

energetic electrons cause a change in the shape of protein complexes pump proteins transport proteins form the matrix to the intermembrane space

select all of the following that contribute to the formation of a protein gradient during the electron transport chain

energetic electrons cause a change in the shape of protein complexes pump proteins transport protons from the matrix to the intermembrane space

all living things require which of the following, in order to carry out chemical reactions and thereby survive

energy

in chemical reactions, the ________ stored in the chemical bonds of a molecule can be used to make new bonds in a different molecule

energy

in the light-harvesting complex of the chloroplast, it is excitation _________, not the electrons themselves, that pass from one pigment molecule to the next

energy

the burning of wood in a fireplace and the aerobic catabolism of carbohydrates in cells both yield the products water, carbon dioxide, and

energy

the process of cellular respiration is how living cells obtain _______ from organic molecules

energy

work in the cell or in the physical world can only be done with expenditure of _________; it is defined as the capacity to do work

energy

first law of thermodynamics

energy can change forms but cannot be destroyed the total amount of energy in the universe remains constant

second law of thermodynamics

entropy increases, as potential energy is transformed into heat disorder is more likely than order

when a reactant binds to the active site of an enzyme, a _______-_______ complex forms

enzyme-susbtrate

_______ are proteins or RNA molecules that act as catalysts to speed up reactions in living organisms

enzymes

what do most enzymes function maximally in a narrow range of temperature

enzymes are not flexible enough at low temperatures, while higher temperatures can denature the enzyme

select the true statements about how enzymes function

enzymes may be used more than once in a cell enzymes have unique shapes that fit particular substrates enzymes stress chemical bonds of a substrate

in eukaryotes, glycolysis occurs in the cytoplasm, while the extraction of the remaining energy from pyruvate takes place in the

mitochondria

in eukaryots, the electron transport chain occurs in the inner membranes of

mitochondria

location of pyruvate oxidation in eukaryotes

mitochondria

where does the krebs cycle occur in eukaryotic cells

mitochondrial matrix

in the process of aerobic respiration, glucose is ________ to CO2 but unlike combustion, electrons are first transferred to electron carriers before they are donated to the final electron acceptor oxygen

oxidized

most organisms synthesize the majority of their ATP by harvesting energetic electrons from glucose, passing the electrons to the electron transport chain, and donating the electrons to ________ the final electron acceptor in aerobic respiration

oxygen

oxidative respiration is made possible by its final electron acceptor which is which of the following?

oxygen

aerobic respiration

oxygen is the final electron acceptor

select the factors that can influence enzyme activity

pH regulatory molecules temperature

select the roles of the krebs cycle

transfer electron and protons to form NADH and FADH2 regenerate the starting material harvest electrons from oxidation reactions

what organic molecules can accept electrons from the active site of one enzyme and then transfer them to another enzyme where the electrons are released to a substrate in a different reaction?

coenzymes

_________ are small chemical components, usually inorganic ions, that act at the active site of an enzyme to promote a chemical reaction

cofactors

many _______ are metal ions that participate in the reaction inside the active sites

cofactors

what are the small chemicals, usually inorganic ions, that temporarily attach to the surface of an enzyme and promote a chemical reaction?

cofactors

what are competitive inhibitors?

competitive inhibitors bind to the active site of an enzyme and prevent substrates from binding

the first half of glycolysis does which of the following

converts a glucose molecule to 2 G3P molecules and requires ATP

which of the following is not part of chloroplasts

cristae

the synthesis of ATP during the light reactions in anoxygenic bacteria is achieved as the electron that was transferred out of the photosystem returns to the chlorophyll molecule in the reaction center; this is also known as _________ photophosphorylation

cyclic

photosystem 2 and photosystem 1 in the chloroplast are connected by a __________/b6-f complex

cytochrome

in the electron transport chain, electrons move from the bc, complex to the carrier cytochrome c, which then passes electrons the _______ ________ complex

cytochrome oxidase

select the names of the membrane protein complexes that are part of the electron transport chain

cytochrome oxidase complex NADH dehydrogenase bc, complex

glycolysis occurs in which of the following

cytoplasm

location of pyruvate oxidation in prokaryotes

cytoplasm

after proteins are broken down into amino acids, the removal of the nitrogen-containing side group is called

deamination

the first two steps of photosynthesis require light and are commonly known as the light- __________ reactions

dependent

the light- ________ reactions of photosynthesis occur on membranes

dependent

the role of the light-harvesting complex is to

directly absorb photons of light

the electron that is transferred out of the chlorophyll in the reaction center is restored by a nearby weak electron ________

donor

in energy-harvesting reactions, molecules such as NAD+ act as _______ and during each transfer of electrons _______ is released

electron acceptors; energy

electrons that are removed from the C-H bonds of glucose during glycolysis and the Krebs cycle are donated to

electron carriers

protons are pumped across the thylakoid membranes of the chloroplasts during the ________ _______ stage of the thylakoid (or light-dependent) reactions

electron transport

Electrons harvested by glycolysis and the Krebs cycle are passed to the ______ which uses the electrons to form an electrochemical gradient across in inner mitochondrial membrane

electron transport chain

during the reactions of energy metabolism, ______ from chemical bonds in food energy molecules are transferred to release energy and ultimately are donated to a final acceptor

electrons

in the reaction center which of the following excited subatomic particles are transferred to an acceptor?

electrons

oxidation is defined as the loss of one or more

electrons

during the breakdown of small organic molecules, oxidation occurs when

electrons are removed from an atom or molecule

when NAD+ is reduced, it accepts two ________ and one proton and becomes the molecule _________

electrons; NADH

a reaction that requires an input of energy is said to be a _______ reaction

endergonic

select the statements that describe the free energy (G) change of a spontaneous reaction

the free energy of the products is less than the reactants there is a negative free energy change

which of the following statements about oxidized molecules is true

the have less electrons and less energy than reduced molecules

select the processes that are used to strip electrons off of the C-H bonds of a glucose molecule

the krebs cycle glycolysis

select the true statement about enzymes

the lower the activation energy of a reaction by binding to the substrates

the excited chlorophyll in the reaction center transfers its electron to

the primary acceptor

Which of the following statements are correct about a reaction that is endergonic

the products contain more energy than the reactants the reaction required an input of energy

what is ultimately the main source of energy for almost all living cells on earth?

the sun

which of the following membranes contains pigments in a green plant?

the thylakoid membrane

the term ____________ describes energy changes, and two laws govern all energy changes in the universe

thermodynamics

which of the following described anoxygenic bacteria?

they cannot produce oxygen they cannot oxidize water

certain reactions in cells are endergonic. How do cells make those reactions proceed?

they couple them with ATP hydrolysis

in a chloroplast, chlorophyll molecules that captures light energy are found in the internal, or inner membrane, which is also called the ___________ membrane

thylakoid

the internal membrane of the chloroplasts is also known as the

thylakoid membrane

the light reactions of photosynthesis take place in the _______________ _______________ while the calvin cycle of photosynthesis occurs in the _________

thylakoid membrane stroma

free energy is the energy available

to do work in a system

during the reactions of glycolysis, one molecule of glucose is converted into how many molecules of pyruvate

two

how many ATP molecules are consumed during the priming reactions of glycolysis for one molecule of glucose?

two

how many different types of photosystems are found in chloroplasts?

two

in the electron transport chain, an electron carrier called __________ passes electrons from NADH dehydrogenase to the bc, complex

ubiquinone

select the structural components of the electron transport chain

ubiquinone protein complexes cytochrome c

which of the following wavelengths of light are preferentially absorbed by chlorophyll molecule?

violet-blue, red

select the cofactors that are called coenzymes

vitamin B6 and B12

At the end of the electron transport chain, oxygen is the final electron acceptor and combines with hydrogen to form which compound

water

having two different linker photosystems in chloroplasts overcome the limitations of anoxygenic photosynthesis by allowing the oxidation of

water

the oxidation potential of PS 2 is high enough that it can oxidize

water

when carbohydrates are catabolized in a cell what are the products of this reaction

water carbon dioxide energy (heat and ATP)

earths first organisms

were anaerobic

what type of organism conducts the fermentation for the production of wine and beer

yeast

in chemical reactions, _________ refers to the process when one or more electrons are added to a molecule or atom

reduction

a leaf that appears to be green to the human eye contains pigment molecules that are

reflecting green light

which of the following are phases of the calvin cycle

regeneration of ribulose biphosphate carbon fixation reduction and carbohydrate production

select the reasons why fats are utilized for storing excess energy in many types of animals

respiration of fats yields 20% more ATP than the respiration of glucose if a molecule of carbohydrate and a molecule of fat produce the same amount of ATP, the molecule of fat weighs less

what uses the energy contained in NADH and FADH2 to create a proton gradient for ATP synthesis

the electron transport chain

select the main changes that occur during glycosis

-ADP is converted to ATP via substrate level phosphorylation -glucose is converted to 2 molecules of pyruvate -NAD+ is reduced to NADH

select the true statements about the regulation of enzyme activity in cells

-cells can increase efficiency by using substances that bind to an enzyme and change its shape -cells use inhibitors and activators to control changes during development -cells can regulate the activity of enzymes bu inhibiting or activating them

the select the true statements about the first half of glycolysis (priming and cleavage reactions)

-a 6-carbon molecule is split to form 2 3-carbon molecules -ATP is used

which of the following statements about chemical reactions are true?

-a reaction that is exergonic in the forward direction will be endergonic in the reverse direction -chemical reactions are reversible

select all of the following that exhibit potential energy only

-a stretched rubber band -bow ready to fire an arrow -a boulder sitting at the top of a hill -water at the top a dam

select the true statements about effects on enzymes activity

-any environmental factor that alters an enzyme's shape can influence its activity -the activity of enzymes can be affected by the presence of inhibitor chemicals

which of the following are the three stages of photosynthesis in plants

-capturing energy from the sunlight -using ATP and NADPH to produce organic compounds from CO2 -making ATP and NADPH

select all of the following that can be electron carriers

-carriers that move within the membrane -membrane-bound carriers that form a redox chain -soluble carriers

what factors determine the direction and rate of a chemical reaction?

-change in free energy will determine the direction of the reaction -thermodynamics governs the direction of a reaction but not the rate of reaction -catalysts influence the rate of a reaction

place the events of the formation of ATP by ATP synthase in the order that they occur, beginning with the first event at the top

1. protons move across the membrane down their concentrations gradient 2. the rotor and stalk structures rotate 3. mechanical energy changes the conformation of ATP synthase 4. ATP formation is catalyzed

select all of the following that are forms of energy

-mechanical energy -heat -sound -light -electric current

select the true statements about the last five reactions of glycolysis

-more ATP is produced than during the priming reactions -NADH is produced -Substrate-level phosphorylation occurs -pyruvate is produced

select the statements that accurately describe multi-enzyme complexes

-multienzyme complexes improve catalytic efficiency -enzymes in mutlienzymes complexes catalyze a sequence of reaction -within the mutlienzymes complex, products of one reaction can be delivered to the next reaction

select the true statements about ribosomes

-ribosomes are essentially large ribozymes -ribosomal RNA functions as a catalysts

select the reasons why changes in the pH of the fluid in which an enzyme is dissolved affects the enzyme's ability to function

-the balance between positively and negatively charged amino acids in the enzyme is affect by hydrogen ion concentration -most enzymes cannot maintain their 3-d shape at values about the optimum pH

select the true statements about allosteric sites on enzymes

-the binding of a substance to the allosteric site can switch an enzyme between its active and --inactive configurations this is where a non-competitive inhibitor would bind

How has H+ electrochemical gradient established and maintained in photosynthesis?

-the formation of NADPH -the splitting of water -the movement of electrons from PS2 to PS1

order the steps in enzyme catalysis starting at the top

1, substrate binds to enzyme 2. amino acids from enzyme interact with substrate 3. bonds in substrate(s) are broken and/or created; products form 4. products dissociate from the enzyme

place the membrane complexes and electron carriers in the order that electrons encounter them in the electron transport chain beginning with the first protein to receive the electrons

1. NADH dehydrogenase 2. ubiquinone 3. bc, complex 4. cytochrome c 5. cytochrome oxidase complex

place the four stages of the thylakoid reactions in the correct order starting with the first stage at the top

1. Primary photoevent 2. Charge seperation 3. Electron transport 4. Chemiosmosis

order the steps in the conversion of light energy into chemical energy in the reaction center (RC) as they occur.

1. a chlorophyll molecule in the RC absorbs a photon of light 2. an electron in the chlorophyll molecule is excited to a higher energy level 3. a high energy electron is transferred to a primary electron acceptor 4. the oxidized chlorophyll molecule restores its electron by oxidizing a donor molecule

sequence the phases of the calvin cycle from first to last

1. carbon fixation 2. reduction and carbohydrate production 3. regeneration of ribulose biphosphate

Put the steps of glycolysis in the order that they occur, beginning with the first step at the top

1. glucose is converted to a 6-carbon diphosphate sugar, requiring 2 ATP molecules 2. a 6-carbon sugar is split to yield 2 molecules of G3P 3. G3P is oxidized and phosphorylated, forming NADH and BPG 4. Phosphates are transferred from BPG to ATP, and pyruvate are produces

put the events of the oxidation of glucose during glycolysis and the krebs cycle in the correct order, beginning with the earliest event at the top

1. pyruvate is produced during glycolysis 2. pyruvate is oxidized and a CO2 is cleaved off 3. an acetyl group is attached to coenzyme A 4. Acetyl-CoA is fed into the krebs cycle

when you take inot account the net equation of the calvin cycle, how many ATP molecules are needed to synthesize 2 G3P molecules?

18

what is the net gain of the calvin cycle

2 molecules of G3P

select all of the following that are produced with 1 turn of the krebs cycle

3 NADH 1 FADH2 1 ATP

in eukaryotes, the predicted yield is _____ ATP molecules per glucose molecule during cellular respiration while for prokaryotes the predicted yield is _____

30 32

if a 6-carbon fatty acid undergoes two rounds of beta oxidation, and then the three molecules of acetyl-CoA produced enter the krebs cycle, what is the total energy yield for the catabolism of a 6-carbon fatty acid?

36 ATP

select all of the following that are true statements describing one round of the krebs cycle

4 pairs of electrons are produced 1 molecule of ATP is produced A 2-carbon group from acetyl-CoA enters the cycle

the human eye can detect light wavelengths between _______ and _______ nm, which represents the visible light range of the electromagnetic spectrum

400; 740

how many molecules of NADPH would be needed to make one molecule of G3P in the Calvin cycle?

6

during oxidative phosphorylation, the enzyme channel uses energy stored in a proton gradient to phosphorylate ______ and make _____

ADP ATP

ADP is phosphorylated to form

ATP

all cells use a molecule called ______ to carry and release energy cyclically

ATP

during the priming stage of glycosis, 2 reactions involve the transfer of phosphates to prime glucose, and thus two molecules of which of the following are required to supply the phosphates?

ATP

for each acetyl-CoA molecule produced from a fatty acid during beta oxidation, one molecule of ____ is used

ATP

in cellular respiration, electrons are harvested from the bonds of organic molecules containing chemical potential energy and ultimately used to drive the production of the end product ________, which the cell can use to power its activities

ATP

removal of a phosphate from phosphophenolpyruvate (PEP) creates pyruvate and _______

ATP

what molecule is considered to be the energy currency of the cell and is used to do work

ATP

which of the following are used to synthesize carbohydrates in photosynthesis

ATP CO2 NADPH

select the molecules that are allosteric inhibitors of the enzyme phosphofructokinase in glycolysis

ATP citrate

the key product of aerobic respiration, ______, shuts down the biochemical pathways of aerobic respiration when its levels are high, an example of ________ inhibition

ATP feedback

select molecules that are produced during the second half (last 5 steps) of glycolysis

ATP pyruvate

select all of the following that are true about the products of glycolysis

ATP, NADH, and pyruvate can all be used to provide energy for the cell NADH produced by glycolysis can be used to generate ATP by oxidative phosphorylation The ATPs produced during glycolysis of one mole of glucose can provide the cell with 14.6 kcal of energy when hyrdolyzed

the electron transport chain directly associated with photosystem 2 is used to generate _______, while the electron transport chain directly associated with photosystem 1 is used to generate ________

ATP; NADPH

select the events that occur in the reaction that produces acetyl-CoA

An acetyl group is attached to coenzyme A (CoA) NAD+ is reduced CO2 is removed from pyruvate

products yielded by the passage of glucose through glycolysis and the krebs cycle

Atp NADH CO2

in the presence of oxygen, pyruvate is first oxidized to yield a molecule of ____ and a two-carbon molecule with the electrons transferred to _____

CO2 NAD+

after glucose is primed and becomes a 6-carbon diphosphate sugar, the cleavage reactions of glycolysis split the 6-carbon sugar to from two molecule of which

G3P

which of the following is the primary output of the calvin cycle

G3P

select the examples of cellular activities that use energy from ATP

Movement of chromosomes during cell division movement of organelles muscle contraction

which of the following statements describes the reduction reaction involving nicotinamide adenine dinucleotide

NAD+ accepts a pair of electrons and a proton to form NADH

fermentation uses organic molecules to accept electrons from the ____ molecules that are produced during glycolysis

NADH

the krebs cycle produces substantial amounts of which of the following? it can carry electrons to the the electron transport chain to drive ATP sythesis

NADH

which of the following molecules is generated during the oxidation phase of glycolysis

NADH

select the molecules produced by the oxidation of pyruvate

NADH Carbon dioxide Acetyl-CoA

select the true statements about NADH

NADH is an electron carrier NADH can donate electrons to fatty acid precursors NADH can donate electrons to drive the synthesis of ATP

which of the following is the source of electrons used to ultimately reduce the C-O bond of PGA?

NADPH

which of the following are necessary for carbon fixation in the calvin cycle?

NADPH ATP

in broad terms, energy can exist in two states: ______ energy and _____ energy

kinetic and potential

the _________ diagram describes the energy transitions of electrons as they move through the ________ reactions

Z; light

select all of the following that are examples of the second law of thermodynamics

a column of bricks tumbles over soda fizzes a room becomes disordered

which of the following are parts of a chlorophyll molecule?

a hydrocarbon tail a porphyrin ring

a photon of light has properties of both

a particle and a wave

a particle of light that acts as a discrete bundle of energy is called

a photon

what occurs during the primary photoevent?

a photon is captured by a pigment in the photosystem

the energy associated with the motion of swinging a bat is a type of

kinetic energy

T

absolute temperature in K

pigments are molecules that

absorb light in the visible range

when a carbon dioxide is removed from pyruvate, the product is a _______ group, which then attaches to coenzyme A

acetyl

oxidation pathways of food molecules are interrelated. Which of these is an intermediate that links the breakdown of food molecules from different starting points

acetyl CoA

almost all molecules that are catabolized for energy are first converted into which of the following

acetyl-CoA

what molecule enters the krebs cycle and combines with oxaloacetate to form citrate

acetyl-CoA

select the molecules that are key intermediates in food oxidation pathways, intermediates that allow the interconversion of different molecules

acetyl-CoA succinyl-CoA pyruvate

_________ energy is the energy required to destabilize existing chemical bonds and initiate a chemical reaction

activation

the ________ ________ for an exergonic reaction is lower in the presence of a catalyst for the reaction

activation energy

in which process can NAD+ be recycled because oxygen accepts electrons taken from pyruvates?

aerobic respiration

select the ways that NADH can be recycled to NAD+ so that glycolysis can continue

aerobic respiration fermentation

_______ enzymes are enzymes that can exist in either an active or inactive conformation

allosteric

a molecule that bins to a site on the enzyme other than the active site and inhibits the enzyme's activity is called a ________ inhibitor

allosteric

proteins are broken down into ______ acids, which are then deaminated to enter as constituents of glycolysis and the krebs cycle

amino

which of the following are the two components of a photosystem

an antenna complex a reaction center

anaerobic respiration

an inorganic molecule other than oxygen is the final electron acceptor

fermentation

an organic molecule is the final electron acceptor

which of the following are chloroplast membranes

an out membranes an inner membranes the thylakoid membrane

what is the function of anabolic reactions?

anabolic reactions are involved in the synthesis of larger molecules from smaller precursor molecules

which are the two main forms of photosynthesis

anoxygenic oxygenic

which of the following organisms have only on photosystem?

anoxygenic bacteria

first step of the krebs cycle involves which of the following

attachment of an acetyl group to oxaloacetate

in terms of obtaining energy, plants are ________ and animals are ________

autotrophs; heterotrophs

if the light reactions produce roughly equal amounts of ATP and NADPH, how can plant cells ensure that there is enough ATP for the Calvin cycle?

because of cyclic photophosphorylation

why is the calvin cycle also known as C3 photosynthesis

because the first molecule in the cycle has 3 carbon atoms

in which of the following processes do enzymes remove 2-carbon acetyl groups from fatty acids and combine the, with Coa to form acetyl-CoA, which enters the krebs cycle?

beta oxidation

the metabolic reactions of a cell often occur in sequences called

biochemical pathways

which of the following are included in metabolism

both the synthesis and breakdown or organic molecules

how is the course of metabolism determined in cells

by the specificity of particular enzymes to only one or a few reactions

which of the following molecules in food can be used as energy sources by living organisms

carbohydrates fats proteins

in photosynthesis, glucose is produced via the reduction of which of the following?

carbon dioxide

the third stage of photosynthesis is also called

carbon fixation

the two most important classes of pigments in chloroplasts are chlorophylls and _________

carotenoids

metabolic reactions are broken down into two main categories. Of those two main categories, what type of reactions are involved in the harvest of energy by breaking down larger molecules into smaller molecules?

catabolic

select the statements that correctly describe differences between anabolic and catabolic reactions

catabolic reactions release energy, while anabolic reactions need energy input in catabolic reactions large molecule are broken down, while in anabolic reactions large molecules are made from smaller ones

cells harvest energy during ______ reactions and expend energy during ______ reactions

catabolic; anabolic

the process of influencing chemical bonds to lower the activation energy of a reaction is called

catalysis

select the ways that catalysis effect chemical reactions

catalysts reduce activation energy catalysts accelerate both the forward and reverse reactions by the same amount

delta H

change in bond energy

delta S

change in disorder of the system

delta G

change in free energy

during the light dependent reactions of photosynthesis, an excited electron is transferred from chlorophyll in the reaction center to an acceptor molecule; this stage in the thylakoid reactions is also known as _________ _________

charge seperation

during photosynthesis light energy is converted to __________ energy a form of potential energy that organisms can use

chemical

name the type of energy that is a form of potential energy stored in chemical bonds

chemical

during aerobic respiration, NADH and FADH2 contribute electrons that drive proton pumps in the electron transport chain. the resulting proton gradient provides the energy to drive the synthesis of ATP by which process?

chemiosmosis

during the process of _______, a force similar to osmosis (diffusion of protons form the high concentration in the intermembrane space to an area of lower concentration within the matrix of the mitochondria) powers of ATP and from ADP and Pi

chemiosmosis

in the light reactions, ATP is generated via:

chemiosmosis

during the 4ht stage of the thylakoid reactions, known as the ______________ stage, protons flow back ________ the photosynthetic membrane and in the process ATP is synthesized

chemiosmosis: across

similar to ATP synthesis in mitochondria, ATP synthesis in chloroplasts is achieved by a _________ mechanism called photophosphorylation

chemiosmotic

in chloroplasts, the light-harvesting is composed of a web of ________ molecules linked together and held tightly in the thylakoid membrane by a matrix of proteins

chlorophyll

which of the following are used by green plants to absorb light energy

chlorophyll a chlorophyll b

which of the following pairs is matched INCORRECTLY

chlorophyll b: main photosynthetic pigment in plants (this is chlorophyll a)

similar to mitochondrion, a ________ contains an outer and inner membrane, with an intermembrane space between the two. Unlike a mitochondrion, it also contains chlorophyll-containing membranes called ________ membranes

chloroplasts thylakoid

small organic molecules that assist enzymes in promoting a chemical reaction are called

coenzymes

select the products of lactic acid fermentation

lactate NAD+

during fermentation in yeast cells, pyruvate is decarboxylated to acetaldehyde, which accepts a pair of electrons from NADH to produce NAD+ and ______

ethanol

the ATP synthases of chloroplasts and mitochondria are

evolutionary related

what type of reaction or process releases free energy

exergonic

what types of reactions occur spontaneously

exergonic reactions with a negative change in free energy

other than glucose, what organic molecules are also major sources of energy

fats and proteins

when ATP levels are high, and the oxidative pathway is inhibited, acetyl-CoA can be channeled into the synthesis of _____ acids

fatty

in the process known as beta oxidation, acetyl groups are removed form the end of which molecules to be combined with coenzyme A to produce acetyl-CoA

fatty acids

in ________ inhibition, the end product of a pathway affects the first enzyme in the series to shut down the pathway

feedback

in the absence of oxygen, __________ can regenerate NAD+ when an organic molecule acts as an electron acceptor

fermentation

the second half of glycolysis

generates ATP

a key difference between PS 2 and PS 1 is

how their pigments receive electrons how they transfer their electrons

a key difference between PS2 and PS1 is

how their pigments receive electrons how they transfer their electrons

changes in pH affect an enzyme because the interaction of charged amino acid residues in the enzyme are affected by

hydrogen ion concentrations

select the reactants of aerobic carbohydrate catabolism

glucose oxygen

in the absence of oxygen, what pathway do cells that are unable to conduct anaerobic respiration rely on to produce ATP?

glycolysis

nearly every organism that breaks down glucose for energy conducts ________, an ancient energy-yielding pathway that has later presumably been enhanced by the evolution of other pathways

glycolysis

the metabolic pathway, in which glucose is converted into 2 pyruvate molecules to yield two ATP molecules is called

glycolysis

which of the following are parts of the chloroplasts

grana stroma thylakoids inner membrane

in several stages, cells extract energy from complex organic molecules mainly by _______

harvesting energy from C-H bonds

as shown in the image, most human enzymes work best at a pH range of 6 to 8, but the enzyme pepsin ____________ because it works in the acidic environment of the stomach

has a lower optimum pH

select the true statements about the krebs cycle

in the krebs cycle, electron are accepted by FAD to produce FADH2 electron carriers receive electrons that cane be used to generate ATP two carbons are lost as 2 CO2 molecule

select the true statements about the effect of temperature on a uncatalyzed chemical reaction

increased temperature increases the rate of the reaction increased temp. increases random molecular movements which increases stress on bonds

select the main control points for the krebs cycle

inhibition of citrate synthetase by ATP inhibition of pyruvate dehydrogenase by NADH

a substance that binds to an enzyme and decreases its activity is called a

inhibitor

citrate

inhibits phosphofructokinase

ATP

inhibits phosphofructokinase, citrate synthetase, and pyruvate dehydrogenase

NADH

inhibits pyruvate dehydrogenase

two types of ribozymes include ribozymes that catalyze reactions on themselves, a process called _______ catalysis, and ribozymes that act on other molecules without being changed, a process called _______ catalysis

intramolecular; intermolecular

which of the following happens to the molecule formed by the addition of carbon dioxide to ribulose biphosphate

it is immediately split into two more stable three carbon molecules

which of the following describes the active site of an enzyme?

it is the part of the enzyme where the substrate fits

heat is a measure of the random motion of molecules, a form of _______ energy

kinetic

what causes the rate of some chemical reactions to be very slow

large activation energy

the light reactions convert ________ energy into ________ energy stored in covalent bonds

light chemical

living organisms can convert the potential energy stored in chemical bonds into what other forms of energy

light energy electrical energy (electricity) kinetic energy potential energy in the bonds of new molecules

similar to other pigments, carotenoids assist photosynthesis by capturing energy from ________, however, they absorb wavelengths that are not efficiently absorbed by _______. in addition, they scavenge _______ ________

light; chlorophylls; free radicals

the thick layer of cells in a leaf that are rich in chloroplasts is called the _________

mesophyll

_________ improve catalysis because substrates can proceed through several reactions without diffusing away or entering into other reactions

multi-enzyme complexes

2

net number of ATP produced directly by glycolysis number of ATP produced directly by the krebs cycle

the cofactor __________ plays a role in the catalysis of many redox reactions of energy metabolism

nicotinamide adenosine dinucleotide (NAD+)

a _______ inhibitor binds to an area outside of the active site of an enzyme and impairs proper functioning of the enzyme

noncompetitive

roughly equal amounts of NADPH and ATP are generated in

noncyclic photophosphorylation

18

number of ATP produced by the NADH and FAHD2 from the krebs cycle per molecule of glucose

5

number of ATP produced by the NADH from glycolysis number of ATP produced by the NADH from the oxidation of pyruvate to acetyl-CoA per molecule of glucose

1.5

number of ATP synthesized by ATP synthase per one molecule of FADH2

2.5

number of ATP synthesized by ATP synthase per one molecule of NADH

4

number of protons required by ATP synthase to produce 1 molecule of ATP

6

number of protons transported by one molecule of FADH2

10

number of protons transported by one molecule of NADH

which of the following colors are attributed to carotenoid pigments?

orange yellow

the reactions of energy metabolism in which energy is harvested from organic molecules are _________ reactions

oxidation

during the krebs cycle, citrate proceeds through several ______ reactions, yielding electrons to be donated to electron carriers, two molecules of ______ and _____ to begin the cycle again

oxidation CO2 oxaloacetate

redox reaction is a term used to describe an ______-________ reaction

oxidation reduction

the term ________ phosphorylation describes the synthesis of ATP using a proton gradient established by electrons moving down an electron transport chain and ultimately donated to the final electron acceptor which is oxygen in aerobic respiration

oxidative

When ATP is synthesized by the enzyme ATP synthase, which of the following is occurring

oxidative phosphorylation

Select the two mechanisms that eukaryotic cells and aerobic prokaryotic cells combine to synthesize the majority of their ATP

oxidative phosphorylation substrate-level phosphorylation

hydrolysis of which covalent bonds in ATP releases a considerable amount of energy?

phosphate-phosphate bond

pigment molecules within the photosynthesis capture packets of light energy that are called

photons

a fraction of the energy from the Sun is captured by plants, algae, and some bacteria through the process of

photosynthesis

in ___________, glucose is produced via the reduction of CO2

photosynthesis

the process by which plants capture light energy and use it to synthesize carbohydrates is called

photosynthesis

in all photosynthetic organisms studied to date, except one class of photosynthetic bacteria, light is captured by clusters of chlorophyll and accessory pigment molecules, which together are called

photosystems

ATP is synthesize as _________ flow down their concentration gradient through ATP synthase

protons

as a result of the electron transport chain, positively charged ______ are transported out of the mitochondrial matrix and into the intermembrane space

protons

the protein complexes of the electron transport chain _______ into the inter membrane space of the mitochondria

protons

the movement of _______ into the mitochondrial matrix through an enzyme called _____ power the synthesis of ATP is oxidative phosphorylation

protons; ATP synthase

the muscle cells of animals regenerate NAD+ in the absence of oxygen by transferring electrons from NADH to which compound

pyruvate

during fermentation in muscle cells, the organic molecule ______ is reduced to form a 3-carbon compound called ________

pyruvate lactate

the primary electron acceptor for the excited electron leaving photosystem 2 is a _______ molecule

quinone

what types of reactions occur spontaneously

reactions with a negative change in free energy exergonic

energy is extracted from food molecules using enzyme-catalyzed ________ reactions that convert the energy to ATP

redox

in energy metabolism, cells couple oxidation reactions with reduction reactions, called _______ reactions

redox

Molecules of RNA that act as catalysts are called

ribozymes

the range and efficiency of photons that a pigment molecule is capable of absorbing constitute its characteristic absorption __________

spectrum

the ATP produced during glycolysis is the result of ___________-level phosphorylation

substrate

during glycolysis, ATP is formed via

substrate-level phosphorylation

____________, or reactants, are molecules that bind to an enzyme at the active site and are converted to products in chemical reactions

substrates

during the 6th reaction of the krebs cycle, the high-energy bond between the 4-carbon succinyl group and CoA is cleaved to drive the formation of what products?

succinate, GTP, then ATP

after it is transported into the cytoplasm, the G3P made during photosynthesis is usually used to synthesize fructose 6-phosphate and glucose 1-phosphate, which can be used to form

sucrose

most plants combine glucose and fructose to produce __________ which is the major transport sugar

sucrose

with very few exceptions, all energy that enters biological systems ultimately come from the

sun

during photosynthesis, small inorganic molecules are combined into organic molecules using energy from

sunlight

unlike heterotrophs, many autotrophs can use energy from what source to synthesize organic compounds

sunlight

what do cells do when the products synthesized by a biochemical pathway are not needed?

temporarily shut down the pathway

the net yield from one glucose molecule going through glycolysis and the krebs cycle (including the oxidation of pyruvate to acetyl-CoA) is _____ molecule of NADH and ______ molecules of FADH2

ten two

select the true statements about allosteric activators

the binding of an allosteric activator keeps an enzyme in its active configuration binding of an allosteric activator increases enzyme activity

during the process of photosynthesis, the energy from sunlight becomes stored as potential energy in

the bonds between atoms in sugar molecules