Unit 3 Biology

Everything that the teacher recommended

Cellular Respiration

the metabolic processes whereby certain organisms obtain energy from organic moelcules

Kilocalories

the unit in which energy is measured

Redox Reaction

A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.

Oxidation

The loss of electrons from a substance involved in a redox reaction.

Reduction

any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen)

NAD+

electron carrier involved in glycolysis

NADH

the reduced form of NAD+; an electron-carrying molecule that functions in cellular respiration

Electron Transport Chain

a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP

Glycolysis

first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvate

Pyruvate Oxidation

2nd step in cellular respiration occurs on the way to the mitochondrial matrix. Pyruvate is oxidized into 1 CO2, 1 NADH, 1 acetyl-COA (2 carbons attached to coenzyme A)

Citric Acid Cycle

in cellular respiration, series of chemical reactions that break down glucose and produce ATP; energizes electron carriers that pass the energized electrons on to the electron transport chain

Oxidative Phosphorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain.

Chemiosmosis

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

Substrate-Level Phosphorylation

The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.

Intermediates

the compounds that form between the initial reactant, glucose, and the final product, pyruvic acid

Acetyl CoA

The entry compound for the Krebs cycle in cellular respiration; formed from a fragment of pyruvate attached to a coenzyme.

Oxaloacetate

A four-carbon molecule that binds with the two-carbon acetyl unit of acetyl-CoA to form citric acid in the first step of the Krebs cycle.

Citric Acid

6 carbon; formed in Krebs Cycle; intermediate in the metabolism of carbohydrates

ATP Synthase

large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP (+28 ATP/ cycle)

FADH2

electron carrier produced during the Krebs cycle

Lactic Acid Fermentation

series of anaerobic chemical reactions in which pyruvic acid uses NADH to form lactic acid and NAD+, which is then used in glycolysis; supplies energy when oxygen for aerobic respiration is scarce

Alcohol Fermentation

The conversion of pyruvate to carbon dioxide and ethyl alcohol.

Obligate Anaerobes

Organisms that cannot live where molecular oxygen is present.

facultative Anaerobes

can live with or without oxygen

Autotrophs

organisms that make their own food

Photosynthesis

process by which plants use the sun's energy to convert water and carbon dioxide into sugars

Heterotrophs

an organism that depends on complex organic substances for nutrition

Stomata

the small openings on the undersides of most leaves through which oxygen and carbon dioxide can move

Stroma

thick fluid contained in the inner membrane of a chloroplast

Thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.

grana

stacks of thylakoids

Light Reactions

reactions of photosynthesis that use energy from light to produce ATP and NADPH

Calvin Cycle

cycle in photosynthesis that reduces fixed carbon to carbohydrates through the addition of electrons ("dark cycle")

Carbon Fixation

The incorporation of carbon from carbon dioxide into an organic compound by an autotrophic organism.

Electromagnetic Spectrum

All of the frequencies or wavelengths of electromagnetic radiation

Wavelength

The distance between crests of waves, such as those of the electromagnetic spectrum.

Photon

a quantum of electromagnetic radiation

Chlorophyll

green pigment in plants that absorbs light energy used to carry out photosynthesis

Photosystem II

The first protein complex in the Light-dependent reactions. It is located in the thylakoid membrane of plants, algae and cyanobacteria. The enzyme uses photons of light to energize electrons .

Photosystem I

The second photosystem in the photosynthetic light reactions of algae, plants, and some bacteria. It uses light to reduce molecules.

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.

Photorespiration

A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.

C3 plants

common plants- stoma close during dry weather- get CO2 directly from air- essentially stopping sugar production

C4 Plants

A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end product of which supplies CO2 for the Calvin cycle.

Cam Plants

Store the organic acids made at night in vacuoles and use them for photosynthesis during the day when stomata are closed

what is the term for metabolic pathways that release stored energy by breaking down complex molecules?

catabolic pathways

why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?

electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms wtih a higher affinity for electrons (such as O)

which of the following statements describes the results of this reaction?

c6h12o6+6 o2---> 6 CO2 +6H20 +energy

c6h12o6 is oxidized and o2 is reduced

when a molecule of NADP+ gains a hydrogen atom, the molecule becomes

reduced

which of the following statements describes NAD+

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle

where does glycolysis take place in eukaryotic cells?

cytosol

the ATP made during glycolysis is generated by

substrate- level phosphorylation

the oxygen sonsumed during cellular respiration is involved directly in which process or event?

accepting electrons at the end of the electron transport chain

in addition to ATP, what are the end products of glycolysis

NADH and pyruvate

starting with one molecule of glucose, the energy-containing products of glycolysis are

2 NADH, 2 pyruvate, and 2 ATP

in glycolysis, for each molecule of glucose oxidized to pyruvate

two molecules of ATP are used and four molecules of ATP are produced

why is glycolysis described as having an investment phase and a pay off phase

it uses stored ATP and then forms a net increase in ATP

which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate

acetyl COa

how many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?

2

carbon dioxide is released during which of the following states of cellular respiration

oxidation of pyruvate to acetyl CoA and the citric acid cycle

during aerobic respiration, electrong travel downhill in which sequence?

food>NADH>electron transport chain> oxygen

where are the proteins of the electron transport chain located?

mitochondrial inner membrane

the primary role of oxygen in cellular respiration is to

act as an acceptor for electrons and hydrogen

inside an active mitochondrion, most electrons follow which pathway?

citrtic acid cycle>NADH> electron transport chain>oxygen

during aerobic respiration, H20 is formed. where does the oxygen atom for the formation of the water come from?

molecular oxygen (O2)

when hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembranespace, the result is the

creation of a proton-motive force

how many oxygen molecules (O2) are required each time a molecule of glucose (c6h12o6) is completely oxidized to carbon dioxide and water via aerobic respiration?

6

which of the following produces the most ATP when glucose is completely oxidized to carbon dioxide and water

oxidative phosphorylation

the synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of

an endergonic reaction coupled to an exergonic reaction

if a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized by carbon dioxide and water, how many ATP molecules can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water

12

in liver cells, the inner mitochondrial membranes are about 5 times the area of the outer mitochondrial membranes. What purpose must this serve?

it increases the surface for oxidative phosphorylation

which catabolic process may have been used by cells on ancient Earth before free oxygen became available

glycolysis, pyruvate oxidation, the citric acid cycle, tand oxidative phosphorylation, using an electron acceptor other than oxygen

in the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of

ATP, CO2, AND ethyl alcohol

which statement best supports the hjypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on earth?

glycolysis is widespread and is found in the domains bacteria, archea, and eukarya

you have a friend who lost 7kg of fat on a regiment of strict diet and exercise. how did the fat leave her body

it was released as CO2 and H2O

the chemical reaction for phoyosynthesis is 6 CO2 +12 H2O +light energy --> c6h12o6 + 6 o2 + 6 H2O

during the light reactions of photosynthesis, water is split, removnig electrong and protons, and oxygen gas is released

experimental evidence shows that the process of glycolysis is present and citrually identical in organisms from all three domains, archea, bacteria, and eukarya. which of the following hypotheses could be best supported by this evidence

glycolysis is a universal energy releasing process and therefore suggests a common ancestor for all forms of life

what is the relationship between wavelength of light and the quantity of energy per photon?

they are inversely related

which of the following are products of the light reactions of photosynthesis that are utilized in the calvin cycle

ATP and NADPH

where does the calvin cycle take place

stroma and chloroplast

in any ecosystem, terrestrial or aquatic, what group is always necessary

autotroph

when oxygen is released as a result of photosynthesis, it is a direct by product of

splitting water molecules

a plant has a unique photosynthetic pigment. the least of this plant appear to be reddish yellow. what wavelenghts of visible light are being absorbed by this pigment

blue and violet

which of the events listed below occurs in the light reactions of photosynthesis

light is absorbed and funneled to reaction-center chlorophyll a

which statement describes the functioning of photosystem II

the electron vacancies in P680 are filled by electrons derived from water

what are the products of linear photophosphorylation

ATP and NADPH

what does the chemiosmotic process in chloroplasts involve

establishment of a proton gradient across the thylakoid membrane

in a plant cell, where are the ATP synthase complexes located

thylakoid membrane and inner mitochondrial membrane

which of the following statements best describes the relationship between photosynthesis and respiration

photosynthesis stores energy in complex organic molecules, whereas respiration releases it

where are the molecules of the electron transport chain found in plant cells

thylakoid membranes of chloroplasts

reduction of oxygen to form water occurs during

respiration only

reduction of NADP+ occurs during

photosynthesis

generation of proton gradients across membranes occurs during

both photosynthesis and respiration

the reactions that produce molecular oxygen take place in

the light reactions alone

what is the primary function of the calvin cycle

synthesize simple sugars from carbon dioxide

the NADPH required for the calvin cycle comes from

reactions initiated in photosystem I

reactions that require CO2 take place in

the calvin cycle alone

which of the follownig statements best represents the relationships between the light reaction and the calvin cycle

the light reactions provide ATP and NADPH to the calvin cycle, and the cycle returns ADP, Pi and NADP+ the the light reactions

the pH of the inner thylakiod space has been measure, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?

the pH within the thylakoid is less than that of the stroma

compared to C3 plants, C4 plants

can continue to fix CO2 even at relatively low CO2 concentration and high oxygen