Bio Test Three

clairebear2018's version from 2018-03-20 03:45

Section 1

Question Answer
Which of these terms is NOT MATCHED with their description?thermal energy: energy stored in molecular bonds, chemical energy: heat energy transfer between objects
Which of these processes is NOT part of the first law of thermodynamics?energy flow can be disrupted by entropy
Which aspect of enzymes is described incorrectly?none of these
In cellular respirationoxygen is used as a reactant - cells tap the energy in food through redox reactions - glucose is oxidized to CO2 - oxygen reduces hydrogen ions to H2O
Which of these is the correct sequence of steps in the process of cellular respiration?glycolysis, acetyl CoA, krebs cycle, electron transport
Which process takes place in animal cells in the absence of oxygen? lactic acid fermentation
Which of the following transport electrons to electron transport chain during cellular respiration?NADH and FADH2
Which of these formulas represents photosynthesis?light energy + 6H2O + 6CO2 > C6H12O6 + 6O2
Which is the correct sequence of reaction during photosynthesis?photosystem II, photosystem I, calvin cycle
The light reactions of photosynthesis supply the calvin cycle withATP and NADPH
During electron transport, the phosphorylation of ADP + P into ATP is called chemiosmosis
In a redox reaction _____ is the total or partial loss of electrons while _____ is the total or partial gain of electronsoxidation ; reduction
On hot, dry days _____, like cactus, close their stomata to conserve water and keep O2 in and CO2 out ; while, _____, like pineapple open their stomata at night, incorporating CO2 into organic acids to be used in the calvin cycle during the dayC3 plants ; CAM plants
Enzymes are specialized proteins that have a specific shaped _____ that binds with the _____ they combine or dismantleactive site ; substrate
A living systems _____ is the energy availability that can do work under cellular conditionsfree energy
In an _____ (spontaneous) chemical reaction energy is released ; while _____ (nonspontaneous) chemical reactions require the input of energyexergonic ; endergonic

Section 2

Question Answer
Metabolismthe totality of an organism’s chemical reactions
Metabolic Pathwaybegins with a specific molecule and ends with a product , each step is catalyzed by a specific enzyme
Catabolic Pathwayrelease energy by breaking down complex molecules into simpler compounds
Anabolic Pathwayconsume energy to build complex molecules from simpler ones , for example, the synthesis of protein from amino acids is an anabolic pathway
Bioenergeticsis the study of how energy flows through living organisms
Energythe capacity to cause change
Kinetic Energyenergy associated with motion
Thermal Energyis the kinetic energy associated with random movement of atoms or molecules
Heatis thermal energy in transfer between objects
Potential Energyis energy that matter possesses because of its location or structure
Chemical Energyis potential energy available for release in a chemical reaction
Thermodynamicsis the study of energy transformations
First Law of Thermodynamics, the energy of the universe is constant. energy can be transferred and transformed, but it cannot be created or destroyed
Second Law of Thermodynamicsduring every energy transfer or transformation, some energy is unusable and is often lost as heat
Entropyis a measure of molecular disorder, or randomness
Spontaneous Processesoccur without energy input; they can happen quickly or slowly, for a process to occur spontaneously, it must increase the entropy of the universe, processes that decrease entropy are nonspontaneous; they will occur only if energy is provided
Exergonic Reactionproceeds with a net release of free energy and is spontaneous
Endergonic Reactionabsorbs free energy from its surroundings and is nonspontaneous

Section 3

Question Answer
Energy Couplingthe use of an exergonic process to drive an endergonic one
Catalysta chemical agent that speeds up a reaction without being consumed by the reaction
Enzymea catalytic protein
The initial energy needed to start a chemical reaction is called the free energy of activation, or activation energy
The reactant that an enzyme acts on is called the enzyme’s substrate
The enzyme binds to its substrate, forming an enzyme substrate complex
Active Siteis the region on the enzyme where the substrate binds
Induced Fitof a substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction
An organic cofactor is called a coenzyme
Competitive Inhibitorsbind to the active site of an enzyme, competing with the substrate
Noncompetitive Inhibitorsbind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective
Allosteric Regulationmay either inhibit or stimulate an enzyme’s activity, occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site
Cooperativity a form of allosteric regulation that can amplify enzyme activity
Feedback Inhibitionthe end product of a metabolic pathway shuts down the pathway
Fermentationis a partial degradation of sugars that occurs without O2
Aerobic Respirationconsumes organic molecules and O2 and yields ATP
Chemical reactions that transfer electrons between reactants are called oxidation-reduction reactions, or redox reactions

Section 4

Question Answer
Oxidationa substance loses electrons
Reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced)
The electron donor is called the reducing agent
The electron receptor is called the oxidizing agent
Electrons from organic compounds are usually first transferred to NAD+, a coenzyme
NADH passes the electrons to the electron transport chain
Glycolysisbreaks down glucose into two molecules of pyruvate
Citric Acid Cyclecompletes the breakdown of glucose
Oxidative Phosphorylationaccounts for most of the ATP synthesis, it is powered by redox reactions
A smaller amount of ATP is formed in glycolysis and the citric acid cycle bysubstrate level phosphorylation
Before the citric acid cycle can begin, pyruvate must be converted to ____, which links glycolysis to the citric acid cycleAcetyl CoA
Alcohol Fermentation, pyruvate is converted to ethanol in two steps  The first step releases CO2 from pyruvate  The second step produces NAD+ and ethanol
Lactic Acid Fermentation, pyruvate is reduced by NADH, forming NAD+ and lactate as end products, with no release of CO2
Obligate Anaerobescarry out fermentation or anaerobic respiration and cannot survive in the presence of O2
Fatty acids are broken down by _____ and yield acetyl CoA, NADH, and FADH2beta oxidation
Plants and other photosynthetic organisms contain organelles called chloroplasts
Photosynthesisis the process that converts solar energy into chemical energy within chloroplasts

Section 5

Question Answer
Autotrophsare “self-feeders” that sustain themselves without eating anything derived from other organisms
Heterotrophsobtain organic material from other organisms
CO2 enters and O2 exits the leaf through microscopic pores called stomata
A chloroplast has an envelope of two membranes surrounding a dense fluid called the stroma
Thylakoidsare connected sacs in the chloroplast that compose a third membrane system
Chlorophyllthe pigment that gives leaves their green color, resides in the thylakoid membranes
Photosynthesis consists of the ____ (the photo part) and ____ (the synthesis part)light reactions ; calvin cycle
Wavelengthis the distance between crests of electromagnetic waves
Electromagnetic Spectrumthe entire range of electromagnetic energy, or radiation
Visible Lightconsists of wavelengths (380 nm to 750 nm) that produce colors we can see
Light also behaves as though it consists of discrete particles, called photons
Spectrophotometer measures a pigment’s ability to absorb various wavelengths
Absorption Spectruma graph plotting a pigment’s light absorption versus wavelength
Chlorophyll A the key light-capturing pigment
Chlorophyll Ban accessory pigment
Carotenoidsa separate group of accessory pigments
Action Spectrumprofiles the relative effectiveness of different wavelengths of radiation in driving a process
Accessory pigments called ____ may broaden the spectrum of colors that drive photosynthesiscartenoids
Linear Electron Flowthe primary pathway, involves both photosystems and produces ATP and NADPH using light energy
Cyclic Electron Flowelectrons cycle back from Fd to the PS I reaction center via a plastocyanin molecule (Pc)
Carbon enters the cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phospate (G3P)
The Calvin Cycle has 3 phases1. Carbon fixation (catalyzed by rubisco) 2. Reduction 3. Regeneration of the CO2 acceptor (RuBP)

Section 6

Question Answer
C3 Plants), initial fixation of CO2, via rubisco, forms a three-carbon compound (3-phosphoglycerate)
Photorespirationrubisco adds O2 instead of CO2 in the Calvin cycle, producing a two-carbon compound
C4 Plantsminimize the cost of photorespiration by incorporating CO2 into four-carbon compounds
Bundle Sheeth Cellsare arranged in tightly packed sheaths around the veins of the leaf
The production of the four-carbon precursors is catalyzed by the enzymePEP carboxylase
CAM Plantsopen their stomata at night, incorporating CO2 into organic acids that are stored in the vacuoles

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