AP Biology - Unit 3 Test

Engelmann's experiment

- The man placed a strip of green alga under light reflected through a prism, creating a visible light spectrum - Then put oxygen-using bacteria into the mix and they congregated where photosynthesis was most active (violet/blue and red light)

excess carbohydrates

--Glucose is first stored in liver --Extra then goes to muscles --Then the glucose is converted into fat and stored in fat tissue

What is the Delta G of cell respiration?

-686 kcal/mol (exergonic) --coupled w/ the formation of CO2 & H2O

How much ATP does glycolysis use?

2 ATP

CO2 + RuBP

= 6 carbon molecule which splits into two 3-carbon molecules

Fermentation

A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product, such as ethanol alcohol or lactic acid.

Photorespiration

A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.

Substrate

A specific reactant acted upon by an enzyme

noncompetitive inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

Carotenoids

An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.

faculative anaerobes

An organism that makes ATP by aerobic respiration if oxygen is present, but that switches to fermentation under anaerobic conditions.

metabolic pathway

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.

first law of thermodynamics

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

Which of the following molecules is not needed for the Calvin Cycle?

H2O

ATP cycle

How a cell regenerates its ATP supply. ADP forms when ATP loses a phosphate group, then ATP forms as ADP gains a phosphate group.

How does entropy affect the spontaneity of a reaction?

If there's more space, the entropy increases. Therefore, the entropy increases in a spontaneous process.

competitive inhibition

Inhibition of an enzyme's ability to catalyze a chemical reaction via a non-reactant molecule that competes with the substrate(s) for access to the active site.

what life was the first to use ATP?

LUCA (Last Universal Common Ancestor)

ATP synthase

Large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

electron carriers (cell respiration)

NADH and FADH2

What must be available for pyruvate to enter the mitochondrion?

O2 (oxygen)

Autotroph

Organisms that make their own food

Which molecule isn't an energy carrier?

Oxygen

what carbohydrates does glycolysis accept?

Polysaccharides -- starch or glycogen that can be hydrolyzed to glucose monomers

anaerobic respiration

Respiration in the absence of oxygen. This produces lactic acid.

aerobic respiration

Respiration that requires oxygen

What is getting oxidized and reduced during cellular respiration?

The carbon atoms in glucose are oxidized, and oxygen is reduced.

lactic acid fermentation

The conversion of pyruvate to lactate with no release of carbon dioxide.

entropy

a measure of the disorder of a system

system

a part of the universe on which you focus your attention

oxidation-reduction reactions

a reaction that involves the transfer of electrons between reactants

active site

a region on an enzyme that binds to a protein or other substance during a reaction.

Total ATP made in cellular respiration

about 32 ATP

How do we get energy from sugars so quickly?

add a small amount of the enzyme sucrase to the solution, so that sucrose may be hydrolyzed w/in seconds

Krebs cycle

breaks down pyruvic acid into carbon dioxide and produces NADH, FADH2, and ATP

excess free energy

can be used for storage

What is reduced in photosynthesis?

carbon dioxide

Which reactions are considered "downhill?"

catabolic

Which reactions release energy?

catabolic

What does delta G represent?

change in free energy

How is potential energy stored?

chemical bonds

Where does glycolysis occur?

cytoplasm of the cell

What is the purpose of water in light reactions?

gives off electrons and protons

What is oxidized in cellular respiration?

glucose

The shorter the wavelength, the ____ the energy of each photon.

greater

primary electron acceptor

in chloroplasts, an acceptor of electrons lost from chlorophyll a; found in the thylakoid membrane

mitochondrial folding

increases the SA, providing space for 1,000s of copies of each component of the ETC in a mitochondrion

thermal energy

kinetic energy associated with the random movement of atoms or molecules

oxidized

loses electrons

inorganic cofactors

metal ions - minerals

Does gylcolysis require oxygen?

nope

does fermentation do ETS?

nope

coenzyme

organic cofactor (vitamins)

obligate anaerobes

organisms that cannot live where molecular oxygen is present

What form is NAD+ in?

oxidized form

The "Final Electron Acceptor" of the mitochondria's ETC is

oxygen

What is reduced in cellular respiration?

oxygen

How is acetyl CoA formed?

pyruvic acid + coenzyme A -- pyruvate is oxidized

What form is NADH in?

reduced form

Exergonic

releases energy

Endergonic

requires/absorbs energy

What does glycolysis mean?

splitting of sugar

When oxygen is released as a result of photosynthesis, it is a direct by-product of?

splitting water molecules

potential energy

stored energy that results from the position or shape of an object

induced fit

substrate binds to the active site of an enzyme, causing the conformation of the active site to change slightly

hydrolysis of sucrose

sucrose + water --> glucose + fructose

Energy

the capacity to cause change

free energy can be thought of as

the instability of a system

3 ways we use ATP

1) Active Transport 2) Muscle Contraction 3) Polymer Synthesis

steps of cellular respiration

1) Glycolysis 2) Krebs Cycle 3) Electron Transport Chain

What 3 things does free energy do?

1) Organize --macromolecules, cells, etc. --maintain the sodium potassium pump 2) Grow --replace dying cells 3) Reproduce --flowers of a plant are used to pass their genes to the next generation *homeostasis *storage

steps of photosynthesis

1) light reactions 2) calvin cycle

How fast can an enzyme typically work?

1,000 substrate molecules/sec

6 G3P

18 carbons

How many FADH2 have are formed from the breakdown of glucose?

2

What is the net yield of ATP in glycolysis?

2 ATP ( Requires 2 ATP, yields 4 ATP)

what does glucose become in glycolysis?

2 pyruvate

How many ATP are made in the ETC?

26-28

Net gain of carbons

3, or one G3P molecule

Regeneration of RuBP

5 molecules of G3P are arranged to become 3 molecules of RuBP (spending 3 ATPs) CO2 reenters the system and repeats the process

How many NADH have are formed from the breakdown of glucose?

6

Photosynthesis equation

6CO2 + 6H2O ------> C6H12O6 + 6O2

formation of ATP requires

7.3 kcal/mol

reaction-center complex

A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor. Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis. Excited by light energy, the pair of chlorophylls donate an electron to the primary electron acceptor, which passes an electron to an electron transport chain.

light-harvesting complex

A complex of proteins associated with pigment molecules (including chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.

The human oral microbiota contains over 700700700 species of bacteria. One species often found in the oral cavity is Streptococcus mutans, an anaerobic bacterium strongly associated with the formation of dental cavities. S. mutans metabolizes glucose and other dietary sugars remaining in the mouth after a meal, producing lactic acid as a byproduct. Over time, high levels of lactic acid can erode tooth enamel, eventually leading to the formation of dental cavities. Which of the following drugs would be most likely to prevent cavities caused by S. mutans?

A drug that prevents the conversion of glucose into pyruvate According to the text, S. mutans causes cavities by producing lactic acid during sugar metabolism. This suggests that S. mutans undergoes lactic acid fermentation, the first step of which is glycolysis, or the conversion of glucose into pyruvate. So, a drug that prevents this conversion would shut down the production of lactic acid in S. mutans, thereby preventing the formation of dental cavities.

chemical energy

A form of potential energy that is stored in chemical bonds between atoms.

cooperativity

A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits.

A researcher proposes a model to explain how enzyme-substrate interactions determine enzyme specificity. The model is based on the idea that substrate molecules form favorable interactions with the amino acid side chains in an enzyme's active site. Based on the model, which of the following statements best explains an enzyme's specificity for a particular substrate molecule?

A molecule with negative charges interacts with positively charged side chains in the enzyme's active site.

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme

photoprotection

A process in which carotenoids absorb and dissipate excessive light energy that would otherwise damage chlorophyll or interact with oxygen forming reactive oxidative molecules that are dangerous to the cell

Catabolic

A process in which large molecules are broken down

Anabolic

A process in which large molecules are built from small molecules

action spectrum

A profile of the relative performance of the different wavelengths in photosynthesis.

Which of the following best explains how the light reactions of photosynthesis generate ATP?

A proton gradient drives the formation of ATP from ADP and inorganic phosphate via ATP synthase. Energy from light excites electrons and initiates their transport through the electron transport chain (ETC). As electrons pass through the ETC, a proton gradient forms across the thylakoid membrane. This gradient drives the synthesis of ATP from ADP and inorganic phosphate via ATP synthase.

allosteric site

A specific receptor site on some part of an enzyme molecule remote from the active site.

Bacteroides is the predominant genus of bacteria found in the human gut microbiota. As anaerobic bacteria, Bacteroides undergo fermentation in the gut, converting otherwise nondigestible carbohydrates into fermentation products that are used by the host for energy. Which of the following toxins would be most likely to disrupt carbohydrate metabolism in Bacteroides species?

A toxin that inhibits the function of an enzyme during glycolysis. According to the text, Bacteroides break down carbohydrates through fermentation. The first step of fermentation is glycolysis, so a toxin that inhibits the function of a glycolytic enzyme would also disrupt carbohydrate metabolism in Bacteroides species.

Acetylcholine (ACh) is an important signaling molecule in the nervous system. After it transmits a signal, ACh is broken down by the enzyme acetylcholinesterase (AChE) in a reaction known as ACh hydrolysis. Which of the following best describes the effect AChE has on the hydrolysis of ACh?

AChE decreases the activation energy of ACh hydrolysis, increasing the rate of this reaction. AChE increases the rate of ACh hydrolysis by lowering the activation energy of the reaction.

Which of the following best indicates that the light reactions of photosynthesis have completed and that the Calvin cycle has begun?

ATP and NADPH accumulate in the stroma. The light reactions of photosynthesis are completed once energy from light is transferred to ATP and NADPH. ATP and NADPH are then transported to the stroma to begin powering the production of carbohydrates from carbon dioxide during the Calvin cycle

energy payoff phase of glycolysis

ATP is produced by substrate-level phosphorylation and NAD+ is reduced to NADH by electrons released from the oxidation of glucose you end up with... 2 ATP + 2 NADH

A researcher claims that a certain herbicide suppresses plant growth by inhibiting chloroplast function. To test the claim, the researcher treats isolated chloroplasts with increasing concentrations of the herbicide. Which of the following statements best clarifies how the data support the researcher's claim?

ATP synthase activity depends on a proton gradient across the thylakoid membrane.

The cytochrome b6f complex is an integral thylakoid membrane protein that forms an electrochemical gradient by pumping protons. In an experiment, researchers apply a toxin to a plant cell that inhibits the cytochrome b6f complex. Which of the following explains the most likely effect of this toxin on the light reactions of photosynthesis?

ATP synthesis will not occur.

ATP and energy coupling

ATP transfers energy from exergonic to endergonic reactions

________________________ bind to a location other than the active site, enhancing the enzyme's activity.

Allosteric activators

substrate-level phosphorylation

As a glucose molecule is gradually broken down, some of the breakdowns steps release energy that is captured directly as ATP. In these steps, a phosphate group is transferred from a pathway intermediate straight to ADP.

How does temperature affect the spontaneity of a reaction?

As temperature increases, the spontaneity of the reaction increases

Trypsin, a proteolytic enzyme found in the small intestine, is essential for digestion. Trypsin functions optimally at approximately 37. degrees. At very high temperatures, the enzyme's activity stops almost completely. Which of the following best explains why trypsin is not active at high temperatures?

At high temperatures, trypsin loses its tertiary and secondary structures. High temperatures can disrupt the interactions between amino acids that help form an enzyme's tertiary and secondary structures. When enough of these interactions are disrupted, the enzyme is denatured and, as a result, can no longer catalyze reactions.

Which of the following is true according to the second law of thermodynamics?

Biological processes that decrease entropy are compensated for by an increase in entropy of the environment.

How do we get energy from ATP?

By breaking the high energy bond between the last two phosphates in ATP energy is released

cellular respiration equation

C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP

combustion of methane

CH4 + 2O2 -> CO2 + 2H2O

RuBisCO catalyzes the joining of carbon dioxide with RuBP during carbon fixation. In an experiment, researchers apply a toxin to a plant cell that inhibits RuBisCO. Which of the following explains the most likely effect this toxin will have on the Calvin cycle?

Carbon dioxide will not be converted into carbohydrates. The toxin inhibits RuBisCO from catalyzing the joining of carbon dioxide with RuBP. This prevents carbon fixation, so the Calvin cycle will not occur. Without the Calvin cycle, carbon dioxide will not be converted into carbohydrates.

Methotrexate is a drug that is commonly used to treat cancers and autoimmune diseases in humans. It functions by binding to the active site of the enzyme DHFR, preventing both DNA synthesis and excess cell proliferation. Which of the following terms best describes methotrexate?

Competitive inhibitor According to the text, methotrexate binds to the active site of DHFR and inhibits its activity. This describes a competitive inhibitor, which functions by binding in place of an enzyme's typical substrate, thereby limiting enzyme activity.

Cyanide poisoning is a type of poisoning caused by exposure to certain cyanide-containing compounds, such as hydrogen cyanide or cyanide salts. Inhalation or consumption of these compounds can cause histotoxic hypoxia, a condition in which cells are no longer able to take up or utilize oxygen during cellular respiration. As a result, ATP production during respiration is significantly reduced. Based on the information above, which of the following is the most likely explanation for how cyanide causes histotoxic hypoxia?

Cyanide inhibits the transfer of electrons to the final acceptor in the electron transport chain. The final electron acceptor in the electron transport chain is oxygen. By inhibiting the transfer of electrons to oxygen, cyanide shuts down the electron transport chain, halting ATP synthesis and causing histotoxic hypoxia.

Cytochromes

Cytochromes are iron-containing carriers that are carrier molecules in the electron transport chain. These carrier molecules hand down electrons to the end of the chain, where they are accepted by oxygen molecules. This system releases energy which is used to pump hydrogens across the inner membrane, setting up a proton gradient responsible for the production of ATP.

A scientist hydrolyzes ATP in a laboratory test tube. He finds that about 3 times as much heat is released than when the same amount of ATP is hydrolyzed in a cell.

Entropy is greater outside of cells than inside them

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Glycolysis

Glycolysis is a series of reactions that extract energy from glucose by splitting it into two three-carbon molecules called pyruvates.

What happens if there is disruptions in free energy?

It can lead to death --like if a human stopped eating --If there's a decrease in free energy, it will affect the plants & the other organisms above them in the food chain

What is the function of NADP+?

It carries electrons to the Calvin cycle

How is metabolic equilibrium prevented?

Materials flow in and out, keeping metabolic pathways from reaching equilibrium & the cell continues to do work A catabolic pathway in a cell releases free energy in a series of reactions. The key is that a product of a reaction then becomes a reactant.

electron carriers (photosynthesis)

NADPH

Photosystem II

One of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P680 reaction-center chlorophyll.

Photosystem I

One of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P700 reaction-center chlorophyll.

Which of the following statements provides the best explanation for why living organisms do not violate the second law of thermodynamics?

Organisms require a constant input of energy to maintain order, and some of this energy is released into the environment as heat.

final electron acceptor of ETC in cell respiration

Oxygen

In mitochondria, the rate of ATP synthesis during oxidative phosphorylation is tightly coupled to the movement of electrons through the electron transport chain (ETC). When ADP levels rise and the demand for ATP synthesis increases, electron flow through the ETC also increases. Based on the information above, which of the following best describes an effect of rising ADP levels in mitochondria?

Oxygen consumption will increase. According to the text, rising ADP levels cause more electrons to flow through the ETC. Because the terminal electron acceptor is oxygen, an increase in electron flow will also increase the demand for oxygen. As a result, oxygen consumption will increase when ADP levels rise

Unlike most other cells in the human body, mature red blood cells (RBCs) do not contain a nucleus or mitochondria. This allows RBCs to carry more hemoglobin, and therefore oxygen, through the bloodstream. Based on the information above, which of the following is most likely true about RBCs?

RBCs generate lactate as a waste product. Because RBCs do not contain mitochondria, they generate ATP through fermentation. The type of fermentation that occurs in animal cells is lactic acid fermentation, which produces lactate as a byproduct.

Stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move

mesophyll

Spongy tissue in the interior of the leaf where most chloroplasts are found --densely packed

Which of the following best describes how the Calvin cycle and the light reactions of photosynthesis function together?

The Calvin cycle uses ATP and NADPH generated by the light reactions to synthesize carbohydrates. The light reactions of photosynthesis produce ATP and NADPH. These molecules are then used to power carbohydrate synthesis during the Calvin cycle.

In an experiment, a researcher prepares a reaction mixture by dissolving a substance in a buffered solution. The substance is the substrate of a certain enzyme. The researcher adds a small amount of the enzyme to the reaction mixture and measures the amount of product that is formed over time. Which of the following best predicts the immediate result of adding more substrate to the reaction mixture at the point indicated by the arrow in Figure 1?

The amount of product will increase until the reaction reaches its equilibrium point or until the substrate is used up by the reaction.

Carbon Fixation (Calvin Cycle)

The cycle begins by incorporating CO2 from the air into organic molecules already present in the chloroplast. The cycle then reduces fixed carbon to carbohydrates by the addition of electrons. This requires energy from NADPH & ATP The Calvin Cycle makes sugar.

wavelength

The distance between two corresponding parts of a wave

oxidizing agent

The electron acceptor in a redox reaction.

reducing agent

The electron donor in a redox reaction.

Stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water

Within the tryptophan synthase protein, the active sites of the alpha and beta subunits are connected by a hydrophobic channel. This channel allows the small, hydrophobic indole molecule to diffuse directly from the active site of an alpha subunit to the active site of a beta subunit. Which of the following statements describes a likely effect of the channel on the process carried out by tryptophan synthase?

The indole molecule does not diffuse across the cell membrane before it can be used by the beta subunit

Which of the following statements accurately describes an energy-releasing process that is coupled to an energy-requiring process in the cell?

The movement of motor proteins is powered by the formation of ADP and inorganic phosphate from ATP.

Photophosphorylation

The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.

proton gradient

The product of the electron transport chain. A higher concentration of protons outside the inner membrane of the mitochondria than inside the membrane is the driving force behind ATP synthesis.

oxidative phosphorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

absorption spectrum

The range of a pigment's ability to absorb various wavelengths of light.

Two nutrient solutions are maintained at the same pH. Actively respiring mitochondria are isolated and placed into each of the two solutions. Oxygen gas is bubbled into one solution. The other solution is depleted of available oxygen. Which of the following best explains why ATP production is greater in the tube with oxygen than in the tube without oxygen?

The rate of proton pumping across the inner mitochondrial membrane is lower in the sample without oxygen.

Phlebia tremellosa is a fungus that decomposes organic matter by secreting enzymes into its surroundings. These enzymes break down large biological molecules into smaller molecules that the fungus can absorb. The fungus then uses these small molecules to build its own larger molecules inside its cells. All of these chemical processes release heat into the environment. Living organisms, such as the fungus described above, are highly ordered systems that may appear to contradict the second law of thermodynamics. However, organisms don't actually violate this law. Which of the following statements best justifies the claim that the processes carried out by the fungus are consistent with the second law of thermodynamics?

The total amount of entropy in the universe increases when heat is released from the fungus into the environment. According to the second law of thermodynamics, the total amount of entropy, or disorder, in the universe can only increase. As the fungus carries out the various cellular processes needed to keep it alive, it releases heat. This release of heat increases the amount of entropy in the universe, which is consistent with the second law of thermodynamics.

Which of the following best describes what will result when a glucose-fed yeast cell is placed in an anaerobic environment?

The yeast cell will produce ATP through fermentation, generating CO2​ and ethanol as byproducts. Yeasts can make ATP through either oxidative phosphorylation or fermentation, depending on whether or not oxygen is available. In an anaerobic, or oxygen-free, environment, yeasts produce ATP through alcohol fermentation, generating CO2​ and ethanol as byproducts

A group of scientists generated a population of fruit flies with a mutation in a gene encoding a protein subunit of ATP synthase. Analysis showed that this was a null mutation, meaning that no protein product was made from the gene. Which of the following pieces of evidence best supports the claim that the wild type version of the gene described above is not essential for ATP synthase function?

There is no lethal phenotype associated with a null mutation in the gene.

Which of the following forms of energy is correctly paired with its definition?

Thermal energy - the energy in a system due to its temperature

What is the primary function of the light reactions of photosynthesis?

To produce NADPH and ATP

How many NADH are produced by glycolysis?

Two NADH molecules are produced by glycolysis.

When light is absorbed by pigments in photosystem II (PSII), energy is passed inward from pigment to pigment until it reaches the reaction center. Electrons are then boosted to a high energy level and captured by the primary electron acceptor. Which of the following occurs immediately after the electrons from PSII are captured by the primary electron acceptor?

Water is broken down. After the electrons from PSII are excited, an enzyme splits a water molecule into one oxygen atom, two hydrogen atoms, and two electrons. These two electrons replace the excited electrons lost from PSII.

Efficiency of respiration

[7.3 kcal/mol x 32 ATP/glucose] / 686 kcal/mol glucose = 34%

chemical equilibrium

a term that describes a state of maximum stability - the forward & reverse reactions occur at the same rate

energy conversion when light strikes a plant pigment

absorption of a photon causes a transition of the chlorophyll molecule from its ground state to its excited state the photon boosts an electron to a shell where it has more potential energy

what makes up ADP?

adenine (nitrogenous base), ribose (sugar), 2 phosphate groups

what makes up ATP?

adenine (nitrogenous base), ribose (sugar), 3 phosphates

ADP

adenosine diphosphate

ATP

adenosine triphosphate

Respiration also plays a role in ____ pathways of the cell

anabolic

Which reactions are considered "uphill?"

anabolic

Which reactions consume energy?

anabolic

The protein pumps in the mitochondrial ETC are

arranged in order of increasing electronegativity

allosteric activator

binds to the enzyme and induces the enzyme's active form

Energy in food

chemical energy

Riboflavin is a key vitamin that makes up FAD, making it a

coenzyme

NADH

coenzyme that carries electrons in glycolysis and respiration

Cyanide dangers

cripples the ETC by binding to the last complex in the chain, thus blocking oxygen from binding. No new electrons from NADH can be added to the beginning & ATP is not produced

The movement of H+ into the InterMembrane Space causes a

decline in pH in the IMM space

FADH2

electron carrier produced during the Krebs cycle

is photosynthesis endergonic or exergonic?

endergonic; the energy boost is provided by light

What type of reaction is photosynthesis?

endothermic & anabolic

kinetic energy

energy of motion

total energy in a system

enthalpy (H)

Rubisco

enzyme that converts inorganic carbon dioxide molecules into organic molecules during the final step of the Calvin cycle

surroundings

everything outside the system

is cell respiration endergonic or exergonic?

exergonic

ATP hydrolysis is __________________ and is coupled with _________

exergonic / endergonic cell activities like chemosynthesis

Where does the energy for the proton gradient come from?

exergonic redox reactions along the electron transport chain

What type of reaction is respiration?

exothermic & catabolic

reduced

gains electrons

Downhill route of electrons in cell respiration

glucose --> NADH --> electron transport chain --> oxygen

What is the carbohydrate produced directly from the Calvin Cycle?

glyceraldehyde 3-phosphate (G3P) --takes 3 turns of the Calvin Cycle to net 1 G3P

Which of the following processes results in an increase of entropy?

glycolysis

When does substrate level phosphorylation occur?

glycolysis and the citric acid cycle

second law of thermodynamics and evolution

increase in organization as more complex individuals result from evolution, but the total entropy of the universe still increases

What happens to energy that is lost during transformations?

it is converted into thermal energy and released as heat -- unable to do work

systems that are high in free energy are

less stable & tend to move toward a more stable one w/ less free energy

Enzyme

lowers the activation energy needed to start a reaction

proteins in glycolysis

must be digested into individual amino acids & have their amino groups removed --waste excreted as NH3 or other waste products

lipids & metabolic pathways

must be digested to glycerol and fatty acids -- glycerol --> converted to glyceraldehyde phosphate --during beta oxidation, fatty acids are broken into 2 carbon fragments that enter Krebs as acetyl CoA --one gram of fat generates 2x as much ATP as one gram of carbohydrate

Cyanide is a toxin that can affect cellular respiration. It functions by binding to an allosteric site on the enzyme cytochrome c oxidase, disrupting the electron transport chain. Cyanide is able to bind to cytochrome c oxidase whether or not the enzyme is bound to a substrate. Which of the following terms best describes cyanide?

noncompetitive inhibitor

Cofactors

nonprotein enzyme helpers

spontaneous reaction

occurs naturally and favors the formation of products at the specified conditions --leads to an increase in entropy w/o an input of energy --"energetically favorable" --ex) rusting of a car

After strenuous exercise, a muscle cell would contain decreased amounts of ___ and increased amounts of ___

oxygen; lactic acid

The H+ concentration gradient in photosynthesis is used to do

photophosphorylation

Chemosynthesis

process in which chemical energy is used to produce carbohydrates

Hydrolysis of ATP

releases energy by transferring its third phosphate from ATP to some other molecule

energy investment phase of glycolysis

requires 2 ATP

Which of the following correctly describes the immediate source of energy that drives ATP synthesis in the mitochondrion?

the H+ concentration gradient across the cristae membrane

alcoholic fermentation

the anaerobic process by which yeasts and other microorganisms break down sugars to form carbon dioxide and ethanol

Metabolism

the combination of chemical reactions through which an organism builds up or breaks down materials

What is oxidative phosphorylation?

the e- movement from cytochrome to another until they combine w/ oxygen and hydrogen ions (H+) to form water

What supplies the electrons that are lost from PS I after it is energized by a photon?

the electrons from PS II

Acetyl CoA

the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme

activation energy

the minimum amount of energy required to start a chemical reaction

RuBP

the molecule that reacts with CO2 during carbon fixation. --has 5 carbons

free energy

the portion of a system's energy that can perform work (when temperature and pressure are uniform throughout the system)

energy transformation

the process of changing one form of energy to another

reduction stage of calvin cycle

the reducing pwr of NADPH donates electrons to the low-energy acid 1,3-bisphosphoglycerate to form G3P

Thermodynamics

the study of energy transformations

heat

thermal energy in transfer from one body of matter to another

Electrons become energized during photosynthesis when

they are struck with a photon of light and move to a higher energy level

The light reactions occur in the ________ and the Calvin cycle take place in the ________

thylakoid membrane / stroma

What is not an energetics function of the accessory pigments in the chloroplast?

to absorb different wavelengths than the chloroplasts

purpose of electron transport chain

to create a protein gradient that drives the production of ATP

How many times does the Krebs cycle occur for each molecule of glucose?

twice -- 3 NADH each time -- 1 FADH2 each time -- Carbon is lost as CO2 -- 1 ATP formed each time

What is oxidized in photosynthesis?

water

saturated enzyme

when every active site is continuously occupied by a substrate where adding more substrate does not increase the reaction rate at all