UNIT II, BIO 108
How Enzymes Lower Activation Energy:
The activation energy is proportional to the difficulty of breaking bonds, so the enzyme may stretch or distort the substrate's bonds. The enzyme may help orient two or more reactants quickly. The enzyme's microenvironment may be more conducive to a reaction than the external environment, i.e. contain the ideal pH. The active site may briefly participate in the chemical reaction via side chain interactions, but will subsequently return to its normal state.
If you isolate mitochondria and place them in buffer with a low pH they begin to manufacture ATP. Why?
The high external acid concentration causes an increase in H+ in the inter membrane space leading to increased ATP production by ATP synthetase. Mitochondrial production of ATP requires a concentration gradient of H+, with a high concentration at the inter membrane space and a low concentration in the matrix. The inner membrane is impermeable to H+, but the outer membrane of the mitochondria will allow H+ to pass through. Thus, placing mitochondria in a low pH buffer produces a H+ gradient that can generate ATP through ATP synthetase.
As a result of glycolysis, pyruvate oxidation and the citric acid cycle, only a small portion of the energy of glucose has been converted to ATP. At this point, the majority of the usable energy is contained in:
The majority of the energy is stored in the electron carriers NADH and FADH2. Oxidative phosphorylation can produce 3 ATP for each NADH and 2 ATP for each FADH2.
Active site:
The specific region where the substrate binds to the molecule, akin to the cliché of a key fitting into a keyhole. However, the active site is not as rigid as a keyhole.
Energy Coupling:
The use of an exergonic reaction to power an endergonic one. ATP usually does most energy coupling in cells. Coupling an exergonic reaction with an endergonic one can make the overall reaction exergonic.
C4 plants are more photosynthetically efficient than C3 plants because_________
They have more chloroplasts
CO2 fixation occurs within the stroma. A) True B) False
True
For every CO2 molecule fixed by photosynthesis, one molecule of O2 is produced. A) True B) False
True
If you know the absorption spectrum of a pigment, you can predict the pigment's color. A) True B) False
True
Pyruvate is oxidized when oxygen is present. A) True B) False
True
Pairing f homologous chromosomes can be seen during_______
Zygotene
Rubisco: A) catalyzes the carboxylation of CO2 to ribulose 1,5-bisphosphate. B) initiates photorespiration when the CO2/O2 ratio is low. C) catalyzes the reduction of two molecules of PGAL to form glucose. D) all of the above (a-c). E) a and b, but not c.
a and b, but not c.
ATP can be formed through substrate-level phosphorylation and this process requires A) an input of energy B) a high-energy phosphate group that is transferred directly to ADP C) a concentration gradient of protons D) the protein ATPsynthase E) all of the above
a high-energy phosphate group that is transferred directly to ADP
Light that is visible to humans occupies what part of the electromagnetic spectrum? A) the entire upper half B) the entire lower half C) a small portion in the middle D) the entire spectrum E) visible light is not part of the electromagnetic spectrum
a small portion in the middle
What substance is produced by the oxidation of pyruvate and feeds into the citric acid cycle? A) pyruvate B) glucose C) acetyl-CoA D) O2 E) CO2
acetyl-CoA
The energy required to destabilize existing chemical bonds is called ____ energy.
activation
NADH is produced during A) glycolysis B) the oxidation of pyruvate C) the Krebs cycle D) all of the above E) none of the above
all of the above
Which of the following occurs during the light-dependent reactions of plants? A) electron transport B) chemiosmosis C) splitting of water D) all of the above E) none of the above
all of the above
Which of the following organisms carries out cellular respiration? A) a corn plant B) a dog C) a yeast D) a bacterium E) all of the above
all of the above
Under normal conditions, as electrons flow down the electron transport chain of the mitochondria: A) NADH and FADH2 are oxidized. B) the pH of the matrix increases. C) the electrons lose free energy. D) an electrochemical gradient is formed. E) all of the above.
all of the above.
Coenzyme:
an organic molecule that is a cofactor. Vitamins are important examples because they act either as coenzymes or as raw material for coenzymes.
Both carotenoids and chlorophylls A) are pigments B) absorb photons of all energy ranges C) contain porphyrin rings D) all of the above E) none of the above
are pigments
Noncompetitive inhibitors
bind to a different section of the enzyme and make the conversion less effective.
Enzyme inhibitors
block an enzyme. This is reversible unless if it involves covalent bonding.
Competitive inhibitors
block substrates from entering active sites. Ex. Toxins and poisons.
Catabolic processes A) make complex molecules from simpler ones B) break complex molecules into simpler ones C) occur only in autotrophs D) occur only in heterotrophs E) none of the above
break complex molecules into simpler ones
During what stage of cellular respiration is the most ATP synthesized? A) glycolysis B) oxidation of pyruvate C) Krebs cycle D) fermentation E) chemiosmosis
chemiosmosis
In aerobic cellular respiration, which generates more ATP, substrate-level phosphorylation or chemiosmosis? A) substrate-level phosphorylation B) chemiosmosis C) both generate the same amount of ATP D) neither generates any ATP
chemiosmosis
Most ATP produced in aerobic respiration occurs in the process of: a. glycolysis b. the formation of acetyl-CoA c. the Krebs cycle d. chemiosmosis e. substrate-level phosphorylation
chemiosmosis
During photosynthesis, photons raise electrons to higher energy levels. These excited electrons belong to what compound? A) H2O B) ATP C) RuBP D) glucose E) chlorophyll
chlorophyll
NAD+ is a(n)
coenzyme
Enzyme B requires Zn2+ in order to catalyze the conversion of substrate X. The zinc is best identified as a(n):
cofactor
The First Law of Thermodynamics states that energy can be
converted
What is the cell cycle control system?
cyclical operation of molecule set which triggers and coordinates events in cell cycle
Is the following chemical reaction that is catalyzed by the enzyme malice dehydrogenase endergonic or exorgonic: malic acid + NAD+ -----> oxaloacetic acid + NADH + H+ delta G = +7.1 kcal.
endergonic.
ATP synthase can produce ATP using as a direct energy source:
energy from a proton gradient established in mitochondria The electrons from from NADH and FADH2 flow through the electron transport chain in the inner mitochondrial membrane generating a H+ buildup in the inner membrane space. This proton gradient (gradient of H+) flowing through the membrane enzyme complex ATP synthetase is the direct energy source for producing ATP.
The second law of thermodynamics essentially says_____________.
entropy increases
Oxidizing which of the following substances yields the most energy? A) proteins B) glucose C) fatty acids D) alcohol E) water
fatty acids
In the presence of oxygen, all cells synthesize ATP via the process of glycolysis. Many cells also can metabolize pyruvate if oxygen is not present, via the process of:
fermentation
When energy-depleted elements associated with a proton are accepted by an organic molecule, the process is called A) fermentation B) anaerobic C) aerobic D) catabolism
fermentation
How many carbon atoms are in a molecule of RuBP? A) zero B) one C) two D) three E) five
five
In the chemical equation ^G = ^H - T^S, the term G stands for
free energy
The energy available to do work in a system is called
free energy
What energy-rich organic compound is produced as a result of the Calvin cycle? A) NADPH B) CO2 C) ATP D) H2O E) glucose
glucose
The proper sequence of stages in glycolysis is A) glucose priming, cleavage and rearrangement, oxidation, ATP generation B) cleavage and rearrangement, glucose priming, ATP generation, oxidation C) glucose priming, oxidation, cleavage and rearrangement, ATP generation D) ATP generation, oxidation, glucose priming, cleavage and rearrangement E) oxidation, cleavage and rearrangement, ATP generation, glucose priming
glucose priming, cleavage and rearrangement, oxidation, ATP generation
Calvin Cycle OUTPUTS
glyceraldehyde 3-phosphate (G3P), ADP, NADP+
The initial steps in breaking down glucose are called
glycolysis
Which stage of aerobic respiration requires ATP?
glycolysis The stage of aerobic respiration which requires ATP is glycolysis.
The oxidation of glucose to two molecules each of pyruvate, ATP, and NADH is called ________ and occurs in the ________. A) glycolysis; cytoplasm B) fermentation; cytoplasm C) the Krebs cycle; matrix of the mitochondrion D) anaerobic respiration; cytoplasm E) the respiratory electron transport chain; cristae of the mitochondrion
glycolysis; cytoplasm
High-energy photons A) have long wavelengths B) have short wavelengths C) are more likely to produce red light than blue light D) cannot be absorbed
have short wavelengths
The energy of random molecular motion is called
heat
Cofactors have what effect on enzyme activity
help facilitate enzyme activity
Organisms that do not have the ability to produce or synthesize their own food are called A) anaerobic B) autotrophs C) exergonic D) catabolic E) heterotrophs
heterotrophs
The primary objective of meiosis I is the separation of ______________ and in meiosis II the separation of _________________.
homologous pairs .............. sister chromatids
Which of the following statements are correct? i.Z scheme of light reaction takes place in the presence of PSI only. ii.Only PS I is functional in cyclic photophosphorylation. iii.Cyclic photphosphorylation results into synthesis of ATP and NADPH2. iv. Stroma lamellae lack PSII as well NADP.
ii and iv
Redox reactions (oxidation-reduction) A) do not occur in living systems B) require the presence of oxygen C) involve the loss of electrons termed oxidation D) involve the gaining of energy by an oxidized substance E) both a and b
involve the loss of electrons termed oxidation
ATP formation by glycolysis A) occurs through aerobic respiration B) is an extremely efficient method of acquiring energy by the cell C) requires oxygen D) involves substrate-level phosphorylation E) both a and c
involves substrate-level phosphorylation
Light is required for the light dependent reactions because A) it is the source for electrons B) it splits the water molecule C) it energizes electrons in the reaction center D) it splits ATP molecules which generates the energy necessary to power the light independent reactions E) none of the above
it energizes electrons in the reaction center
What role does O2 play in aerobic respiration? A) it plays no role B) it combines with acetyl-CoA at the start of the Krebs cycle C) it is given off as a by-product during the oxidation of pyruvate D) it combines with H2O to help drive the formation of ATP E) it is the final electron acceptor at the end of the electron transport chain
it is the final electron acceptor at the end of the electron transport chain
During metaphase mitosis chromosomes______
line up at the equator.
Enzymes have what effect on activation energy?
lower the activation energy of a reaction
Most ATP in eukaryotic cells is produced in the: a. mitochondria b. nucleus c. cytoplasm d. rough endoplasmic reticulum e. peroxisome
mitochondria
Compared to retinal, chlorophyll can be described as a pigment that has a A) narrow absorption range but high efficiency B) narrow absorption range but low efficiency C) wide absorption range but high efficiency D) wide absorption range but low efficiency
narrow absorption range but high efficiency
During cell division, sometimes there will be failure of separation of sister chromatids. This is called_______
non disjunction
Which stage of aerobic respiration requires CO2? a. glycolysis b. Krebs cycle c. electron transport chain d. fermentation e. none of the above
none of the above
Cofactors:
nonprotein helpers for catalytic activity.
Transition state:
once the reactants have absorbed enough energy to break bonds. They settle into a new, more stable arrangement, releasing energy (the "downhill movement").
The cell cycle of a germinal cell has
one reduction division followed by division
During chemiosmosis in aerobic respiration, protons are pumped A) out of the cell B) out of the mitochondria into the cell cytoplasm C) out of the mitochondrial matrix into the outer compartment of the mitochondria D) out of the cell cytoplasm into the matrix of the mitochondria E) out of the nucleus and into the mitochondria
out of the mitochondrial matrix into the outer compartment of the mitochondria
The loss of an electron by a molecule is called
oxidation
The final electron acceptor in aerobic respiration is:
oxygen
During which stage of prophase I does the crossing over take place?
pachytene
Manganese is required in_______
photolysis of water during photosynthesis
Which of the following statements accurately describes the relationship between photosynthesis and cellular respiration? A) photosynthesis occurs only in autotrophs; cellular respiration occurs only in heterotrophs B) photosynthesis uses solar energy to convert inorganics to energy-rich organics; respiration breaks down energy-rich organics to synthesize ATP C) photosynthesis involves the oxidation of glucose; respiration involves the reduction of CO2 D) the primary function of photosynthesis is to use solar energy to synthesize ATP; the primary function of cellular respiration is to break down ATP and release energy E) photosynthesis and cellular respiration occur in separate, specialized organelles; the two processes cannot occur in the same cell at the same time
photosynthesis uses solar energy to convert inorganics to energy-rich organics; respiration breaks down energy-rich organics to synthesize ATP
The high concentration of protons in the inner mitochondrial space relative to the mitochondrial matrix represents what type of energy?
potential energy The high concentration of protons in the inner mitochondrial space relative to the mitochondrial matrix represents potential energy.
An example of anaerobic would be A) production of sulfates from H2S B) production of methane by methanogens C) glycolysis by purple bacteria D) utilization of methane by methanogens
production of methane by methanogens
If Delta-G is said to be positive, it means
products of the reaction contain more energy than the reactants
To what category of macromolecules do most enzymes belong?
proteins
During respiration, NADH donates two electrons to the carrier know as ubiquinone. When this happens, ubiquinone: A) becomes oxidized. B) passes the electrons directly to O2 which is reduced to water. C) pumps protons across the inner mitochondrial membrane. D) all of the above. E) a and b, but not c.
pumps protons across the inner mitochondrial membrane.
In glycolysis the most reduced compound formed is:
pyruvate
The end product of glycolysis is A) NADH B) acetyl-CoA C) lactate D) pyruvate
pyruvate
The final electron acceptor in lactic acid fermentation is: A) NAD+ B) pyruvate C) O2 D) lactic acid E) ATP
pyruvate
Under which condition would you expect the mitochondrial proton gradient to be highest and therefore ATP synthesis to proceed? A) pyruvate (present)-oxygen (present)-ATP levels (high) B) pyruvate (present)-oxygen (present)-ATP levels (low) C) pyruvate (present)-oxygen (absent)-ATP levels (high) D) pyruvate (absent)-oxygen (present)-ATP levels (low) E) pyruvate (absent)-oxygen (absent)-ATP levels (high)
pyruvate (present)-oxygen (present)-ATP levels (low)
Which of the following is a multienzyme complex? A) glyceraldehyde-3-phosphate (G3P) B) NAD+ C) FAD+ D) pyruvate dehydrogenase E) all of the above
pyruvate dehydrogenase
Glycolysis leads to the production of ____________ and two molecules of ATP. In the absence of oxygen, fermentation leads to the production of ______________. Glycolysis plus the citric acid cycle can convert the carbons of glucose to _________ , storing the energy as ATP, _____________ and ___________.
pyruvate, lactic acid, CO2, NADH, FADH2 In glycolysis, glucose with six carbons is converted into two molecules of pyruvate, each with three carbons. In fermentation, pyruvate is reduced by NAD+ producing lactic acid. In the citric acid cycle, the carbons of glucose are converted to CO2 and the H atoms used to reduce NAD+ and FAD forming NADH and FADH2.
At the end of glycolysis, each molecule of glucose has yielded 2 molecules of _______, 2 molecules of ________, and a net of 2 molecules of _________.
pyruvate; NADH; ATP Glycolysis is the conversion of glucose to two molecules of pyruvate, yielding a net 2 ATP and 2 NADH. Recall that 2 ATP were needed to initiate glycolysis and 4 ATP were produced in the pathway, for a net gain of 2 ATP.
Colors of light most useful in photosynthesis are
red, violet, and blue.
In the absence of oxygen, the primary purpose of fermentation is to:
regenerate NAD+ from NADH allowing glycolysis to continue Fermentation allows continued glycolysis by regenerating NAD+ from NADH. NAD+ is limiting, and must be reformed to allow the continuation of the glycolytic degradation of glucose producing ATP.
What pigment is used in human vision? A) chlorophyll a B) beta-carotene C) retinal D) vitamin A E) ferredoxin
retinal
What cellular compartment becomes acidic (high concentration of hydrogen ions) during mitochondrial electron transport?
space between inner and outer mitochondrial membranes Electron transport produces a high concentration of H+ (protons) in the inner membrane space of the mitochondria.
A catalyst will make a reaction
speed up
Water vapor exits and CO2 enters a leaf through the A) stomata B) grana C) porphyrin rings D) photons E) stroma
stomata
In the Krebs cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
The primary form of sugar transported from the site of photosynthesis to the rest of the plant is: A) glyceraldehyde 3-phosphate B) glucose C) fructose D) ribulose 1,5-bisphosphate E) sucrose
sucrose
In the somatic cell cycle, what phase does DNA replication takes place in the________
takes place in S phase
During aerobic respiration, FADH2 is produced in A) glycolysis B) the oxidation of pyruvate C) the Krebs cycle D) the electron transport chain E) fermentation
the Krebs cycle
Hans Krebs discovered (worked out the details of) A) glycolysis B) fermentation C) the oxidation of pyruvate D) the citric acid cycle E) electron transport and chemiosmosis
the citric acid cycle
The most primitive form of metabolism is
the degradation of organic molecules with the released energy stored in ATP
The usefulness of fermentation as a means of deriving energy is limited because A) it cannot generate enough ATP B) it produces too much NH2 C) the end products are toxic to the producer D) it uses more energy than it produces
the end products are toxic to the producer
During what stage of photosynthesis is O2 produced? A) cyclic photophosphorylation B) the light-dependent reactions involving photosystems I and II C) carbon fixation D) the Krebs cycle E) O2 is not produced during photosynthesis
the light-dependent reactions involving photosystems I and II
Which of the following statements about photosynthesis is true? A) the light-dependent reactions can occur only in the light, the light-independent reactions only in the dark B) photorespiration is more efficient at producing glucose than is photosynthesis C) the light-dependent reactions produce the energy-rich compounds that are used to run the light-independent reactions D) all of the above are true
the light-dependent reactions produce the energy-rich compounds that are used to run the light-independent reactions
During what stage of photosynthesis are ATP and NADPH converted to ADP + Pi and NADP+? A) the light-dependent reactions B) the light-independent reactions C) both of the above D) none of the above
the light-independent reactions
In an endergonic reaction, the reactants contain___________free energy than the __________.
the reactants contain less free energy than the products
Proteins and fats can be nutritional sources of energy provided that A) they are converted into glucose B) the enter their own pathways that are separate from the glucose metabolic pathways C) they are degraded completely into atoms before entering a pathway D) they are modified so that they can enter the glucose metabolic pathways E) both b and c
they are modified so that they can enter the glucose metabolic pathways
In sulfur bacteria, how many pigment electrons must get transported during cyclic photophosphorylation to produce one molecule of ATP? A) one B) two C) three D) four E) five
three
The pigment molecules responsible for photosynthesis are located in the A) mitochondria B) cytoplasm of the cell C) stroma of the chloroplast D) thylakoid membrane of the chloroplast E) all of the above
thylakoid membrane of the chloroplast
A cell culture was supplied with radioactively labeled O2. The cells were monitored. In a few minutes the radioactive oxygen atoms were present in which of the following compounds: A) carbon dioxide B) NADH and FADH2 C) water D) ATP E) lactic acid
water
The oxygen that is released as O2 during photosynthesis came from _____________ molecules. A) carbon dioxide B) water C) glucose D) chlorophyll E) ATP
water
Which of the following is the correct sequence for the movement of electrons during the light-dependent reactions of plants? A) P680 à P700 à water à NADP+ B) water à P700 à NADP+à P680 C) P700 à P680 à NADP+à water D) P680 à water à P700 à NADP+ E) water à P680 à P700 à NADP+
water à P680 à P700 à NADP+
How many NADH from 1 pyruvate to to 1 acetyl CoA?
1
How many ATPs from 1 FADH2 by the electron transport chain?
1.5
How many NADH and FADH2, combined total, from 1 glucose through the completion of the Kreb's cycle?
12
To reduce six molecules of carbon dioxide to glucose via photosynthesis, how many molecules of NADPH and ATP are required? A) 6 NADPH and 6 ATP B) 12 NADPH and 12 ATP C) 12 NADPH and 18 ATP D) 18 NADPH and 12 ATP E) 24 NADPH and 18 ATP
12 NADPH and 18 ATP
Set 3 A) 6 oxygen molecules B) 12 water molecules C) 12 oxygen molecules D) reduced cytochromes E) 6 oxygen + 12 water molecules
12 water molecules
Each molecule of FADH2 results in the production of how many ATP molecules during aerobic respiration? A) 2 B) 3 C) 4 D) 18 E) 36
2
How many net ATPs from glucose to pyruvate?
2
The net ATP result of the breakdown of glucose in glycolysis and fermentation is the production of:
2 ATP
In the course of the cell's breakdown of one glucose molecule, the mitochondrion takes up certain reactants and releases certain products. Indicate some of these reactants and products below by selecting the best choice from each numbered set of letters: REACTANTS (materials entering) A) 6 carbon dioxide molecules B) 2 pyruvates C) 1 glucose D) 2 lactates E) 2 PEP
2 pyruvates
How many ATPs from 1 NADH by the electron transport chain?
2.5
Products of glycolysis are
2ADP, 4ATP, 2NADH, 2 Pyruvate
Answer the following questions in reference to a newt (a type of lizard) that has 22 chromosomes. How many combinations are possible when chromosomes assort independently into gametes (ignoring crossing over)?
2^11 (2 to the power of chromosome number divided in half)
Production of one molecule of 3-phosphoglyceraldehyde requires how many turns of the Calvin cycle? A) 1 B) 2 C) 3 D) 6 E) 12
3
one molecule of glyceraldehyde-3-phosphate. How many turns of the Calvin cycle are required?
3
The immediate products of C3 and C4 photosynthesis are, respectfully: A) ribulose 1,5-bisphosphate; malic acid B) malate; carbon dioxide C) 3-phosphoglycerate; oxaloacetic acid D) glyceraldehyde 3-phosphate; phospho-enol-pyruvate (PEP) E) malic acid; glucose
3-phosphoglycerate; oxaloacetic acid
Glycolysis has an efficiency level of approximately A) 2% B) 3.5% C) 21.5% D) 50% E) 78.5%
3.5%
Oxidative respiration in eukaryotes has an efficiency level of approximately A) 2% B) 63% C) 14% D) 36% E) 32%
32%
In aerobic respiration, the energy in 1 mole of glucose is capable of producing how many ATP molecules:
38 x (6.02 x 1023) molecules of ATP
How many NADHs from 1 glucose to 2 acetyl CoAs?
4
Total Atp OUTPUT GLYCOLOSIS
4 ATP
PRODUCTS (materials leaving) A) 4 carbon dioxide molecules B) 2 pyruvates C) 1 glucose D) 2 lactates E) 2 PEP
4 carbon dioxide molecules
A cell divides every minute. At this rate of division it can fill a 100ml beaker in one hour. How much time does it take to fill a 50ml beaker?
59 minutes
A cell divides every one minute. At this rate of division it can fill 100ml of beaker in one hour. How much time does it take to fill a 50ml beaker?
59 minutes
one molecule of glyceraldehyde-3-phosphate. How many molecules of NADPH are required?
6
Set 3 A) 6 oxygen molecules B) 12 water molecules C) 12 oxygen molecules D) reduced cytochromes E) 6 oxygen + 12 water molecules
6 oxygen molecules
Number of mitotic divisions required to produce 128 cells from a single cells is_______
7
How much energy is released when one of the high-energy bonds in ATP is broken? A) 730 cal/mole B) 7.3 cal/mole C) 7.3 kcal/mole D) 73 kcal/mole E) 730 kcal/mole
7.3 kcal/mole
one molecule of glyceraldehyde-3-phosphate. How many molecules of ATP are required?
9
Which of the following statements about enzymes is true? A) some substrates can make enzymes change shape slightly B) all enzymes have the same pH optimum C) the active sites of all enzymes have the same three-dimensional shape D) all of the above E) none of the above
A some substrates can make enzymes change shape slightly
In glycolysis, the activation of glucose is accomplished by:
ATP
The universal energy currency for all cells is
ATP
Conversion of ATP to ADP:
ATP + H2OADP + P
Explain how ATP is able to power both transport and mechanical work?
ATP Hydrolosis = change in shapes/binding affinities proteins/enzymes a)direct phosphorylization b) indirect (non-covalent bonding of ATP/hydrolytic products along cytoskeleton
As protons flow through the ______ , energy is released and exploited to combine ADP and inorganic phosphate to form ATP.
ATP synthase As protons flow through the ATP synthase, energy is released and exploited to combine ADP and inorganic phosphate to form ATP.
induced fit.
Active site is not as rigid as a keyhole. It can change shape to best fit around the substrate, which is a phenomenon known as induced fit.
Mitotic spindle is mainly composed of which protein?
Actomyosin
90% of photosynthesis in the world is carried out by_________
Algae
Enzyme-substrate complex:
An enzyme is bound to a substrate.
The light reaction of photosynthesis does not include A) chemiosmosis B) oxygen liberation C) charge separation D) electron transport
B) oxygen liberation
In the first step of glycolysis, the enzyme hexokinase uses ATP to transfer a phosphate to glucose to form glucose-6-phosphate. The product continues to be oxidized forming pyryvate in glycolysis and is a precursor to acetyl-CoA for the citric acid cycle. Suppose that a cell has only glucose available for energy and that the activity of hexokinase is suddenly stopped in this cell. Which of the following conditions will occur? A. The cell will continue to produce energy from mitochondrial electron transport. B. The cell will continue to produce ATP using the citric acid cycle. C. The cell will ultimately be unable to produce ATP. D. The cell will be forced to switch to fermentation to produce ATP. E. The use of oxygen by the cell will increase.
C. The cell will ultimately be unable to produce ATP Because energy production requires that glucose first be metabolized in glycolysis, the loss of hexokinase would block ATP production in the cell.
Which of the following organisms have the greatest problem with photorespiration? A) C4 plants B) heterotrophs C) C3 plants D) CAM plants E) purple sulfur bacteria
C3 plants
Which of the following is mismatched? A) Photosystem I - uses the P700 molecule in its photocenter B) PGA - a 3-carbon compound C) antenna complex - contains hundreds of pigment molecules D) CAM plants - open their stomata during the day and close them at night to avoid photorespiration E) C4 plants - expend ATP to concentrate CO2 in bundle-sheath cells to avoid photorespiration
CAM plants - open their stomata during the day and close them at night to avoid photorespiration
In aerobic respiration carbohydrates are ultimately broken down into: a. acetyl-CoA b. CO2 c. O2 d. H2O e. heat
CO2
Calvin Cycle INPUTS
CO2, ATP, NADPH
Products of the Krebs cycle include:
CO2, NADH, FADH2
The dark reaction in photosynthesis is limited by A) CO2, temperature, and light B) CO2, light, and water C) water, temperature, and CO2 D) oxygen, water, and temperature
CO2, temperature, and light limit the dark reaction.
A microtubule is involved in the________
Cell division
Zygotic meiosis occurs in
Chamlymydomonas
What are Homologous chromosomes (homologs)?
Chromosomes w/ same length, centromere position and staining pattern. They carry the same genes. One chromosome of each pair is from a different parent.
Daughter cells that form as a result of meiosis are not similar to the of parent cell because
Crossing over
When molecules are reduced they gain A) energy B) electrons C) hydrogen protons D) all of the above E) none of the above
D
Why do drastic changes in the temperature or pH of a system alter enzyme activity? A) they change the three-dimensional shape of the enzyme B) they disrupt hydrogen and ionic bonds in the enzyme C) they disrupt hydrophobic interactions in the enzyme D) all of the above E) none of the above
D) all of the above
The actions of an enzyme can be affected by all of the following except A) p/PH B) temperature C) allosteric inhibitors D) availability ATP E) cofactors
D) availability ATP
What must be true for a reaction to occur spontaneously?
Delta G must be negative
At which stage of the cell cycle are histone proteins synthesized in a eukaryotic cell?
During S phase
Which of the following are mismatched A) anabolic reactions-expend energy B) reduction-gain of an electron C) endergonic reaction-anabolism D) exergonic reaction-catabolism E) activation energy-entropy
E) activation energy-entropy
The major production of ATP during aerobic metabolism occurs when electrons from __________ and _____________ are transferred to _______________.
E. FADH2, NADH, O2
Which of the following statements about mitochondria is false? A. They contain an inner and an outer membrane. B. The region enclosed by the inner membrane is termed the matrix. C. They contain DNA and ribosomes. D. They are an important site for energy production in cells. E. They contain stacked internal thylakoid membranes.
E. They contain stacked internal thylakoid membranes. Stacked thylakoid membranes (granum), exist only in plastids, such as plant chloroplasts, not in mitochondria.
During a heart attack, blood flowing to the heart muscle is interrupted by blockage of a coronary artery. How would you expect the metabolism in the heart to change? A. oxidative phosphorylation would slow down in the mitochondria B. the rate of production of lactic acid would be stimulated C. the use of glucose by the muscle tissue would increase D. the production of water by mitochondria would be inhibited E. all are expected metabolic changes
E. all are expected metabolic changes Arteries carry oxygenated blood. If the flow of blood through the coronary artery to the heart is blocked, the heart is being deprived of oxygen. All of the above answers are expected effects of an insufficient oxygen supply to the cells, and resulting fermentation.
chromatid
Each of a pair of identical DNA molecules after DNA replication, joined at the centromere.
During the oxidation of glucose, a net gain of ATP only occurs under aerobic conditions. A) True B) False
False
Light-driven electron transport in the chloroplast pumps H+ into the intermembrane space between the outer and inner membranes. A) True B) False
False
Define Zygote:
Fertilized diploid egg.
What takes place prior to the reformation of the nuclear envelope during M phase of the cell cycle?
Formation of the contractile ring, and formation of the phragmoplast
The final product of the Calvin cycle is A) RuPB B) PGA C) ATP D) G3P
G3P The final product of the Calvin cycle is G3P (glyceraldehyde 3-phosphate).
∆G = ∆H - T∆S
G=Free energy ∆= change H=total energy (enthalpy). S= = entrophy. T = temp in Kelvin (K)
ic and myl, were good and did the drill, from ATP to ADP, so one would have its fill, am-end to pi, that how you synthesize, glutamine from onia, and ATP'O Hydrolized
Glutamaic Acid + ATP >>>>Glutamyl + ADP Glutamyl + ammonia
The earliest photosynthesizers probably used what as a source of hydrogen? A) H2S B) H2O C) CO2 D) C6H12O6
H2S
ETC IN & OUT
IN = 10 NADH, 2 FADH2, 32ADP, 6 O2 OUT= 10NAD+, 2 FAD, 32 ATP, 6 H2O
Krebs Cycle IN & OUT
IN = 2 Acetyl CoA, 2 ADP, 6NAD+, 2FAD OUT= 6NADH, 2FADH, 2 ATP, 4 CO2
Krebs Cycle IN & OUT
IN =2 Acetyl CoA, 2 ADP, 6NAD+, 2FAD OUT = 4 CO2, 2 ATP, 6 NADH, 2 FADH2
ETC IN & OUT
IN=10 NADH, 2 FADH2, 32ADP, 6 O2 OUT=10NAD+, 2 FAD, 32 ATP, 6 H2O
Light Reactions INPUTS &OUTPUTS
INPUTS= NADP+,Light, Water, ADP OUTPUTS=ATP, NADPH, O2
Dinitrophenol (DNP) is an uncoupler, or has the ability to separate the flow of electrons and the pumping of H+ ions for ATP synthesis. This means that the energy from electron transfer cannot be used for ATP synthesis. Fifty years ago, DNP was given as a drug to help patients lose weight. Why does this work? Why would this be dangerous?
If electron transport doesn't produce ATP, then much more sugar must be metabolized for energy needs. Very low production of ATP would be lethal. In oxidative phosphorylation, the flow of electrons from NADH and FADH2 to oxygen results in the pumping of H+ from the matrix to the inner membrane space. This gradient of H+ can produce ATP by flowing through ATP synthetase in the mitochondrial inner membrane. Dinitrophenol disrupts the H+ gradient reducing ATP synthesis. Under these conditions, much of our food that we eat could not be used for ATP synthesis are we lose weight. However, too much inhibitor and we could make too little ATP for life. The difference between weight loss and death is only a small concentration change in dinitrophenol, making the drug dangerous.
A new drug was found to decrease Hepatitis B virus. The drug is an analogue of one of the nucleic acid bases of DNA and probably works by being incorporated into the virus and disrupting viral genes during viral DNA replication. However, patients in a clinical trial of the drug began to experience drastic overproduction of lactic acid and liver failure leading to death. The most likely explanation for the problem:
Incorporation of the drug into mitochondrial DNA disrupts the ability of mitochondria to make ATP. The key concept is that lactic acid is produced only when there is exertion for the muscles or when mitochondrial function is inhibited. The drastic overproduction of lactic acid and liver failure due to a drug that acts like a nucleotide would only occur if this analogue was incorporated into mitochondrial DNA, disrupting mitochondria function. Tragically, that is exactly what happened in this case.
The electron transport chain in cellular resp is located predominantly in the:
Inner membrane of the mitochondria
Consider the hypothetical biochemical pathway H -- I -- J-- K-- L. Which step most likely evolved first? A) H -- I B) I -- J C) I -- H D) J -- K E) K -- L
K -- L
Which stage of aerobic respiration produces ATP and NADH and releases CO2?
Krebs cycle The stage of aerobic respiration which produces ATP and NADH, and releases CO2 is the Krebs cycle.
Explain why in anaerobic cells the ratio of pyruvate/ lactate is much less than 1 while under aerobic conditions the ratio of pyruvate/ lactate is much greater than 1.
Lactate is produced from pyruvate only under anaerobic conditions. The glycolytic pathway produces pyruvate, which in the presence of oxygen will be further metabolized in the citric acid cycle to produce NADH and FADH2 for oxidative phosphorylation in the mitochondria. Normally, lactic acid will be low under these conditions. In the absence of oxygen (anaerobic), pyruvate must be converted to lactic acid, the only reaction that can regenerate NAD+ allowing further glycolysis. The production of lactic acid only under anaerobic conditions explains why pyruvate/lactate is much less than 1 in anaerobic cells and much greater than one in aerobic cells.
Stroma in the chloroplast of higher plants contain
Light independent reaction enzymes
What is MPF? What does MPF do?
MPF (cyclin CDK complex) triggers cell passage from G2 phase >>M
Where in the leaves of C4 plants does Carbon Dioxide fixation occur?
Mesophyll cells
chromosomes
Molecules of DNA complexed with specific proteins responsible in eukaryotes for storage and transmission of genetic information.
What substance is regenerated by fermentation? A) O2 B) NAD+ C) acetyl-CoA D) ATP E) glucose
NAD+
Which of the following is a reduced compound?
NADH
The final output of the Krebs cycle includes all of the following except A) NADP B) FADH2 C) ATP D) CO2
NADP
Which of the following is not a product of fermentation? A) CO2 B) O2 C) ethanol D) lactate E) all of the above are products of fermentation
O2
The terminal electron acceptor during mitochondrial respiration:
O2 The electron transport in the inner membrane of the mitochondria is a series of protein complexes that receive electrons from NADH and FADH2. Transferring electrons through the protein complexes results in the pumping of protons into the inner membrane space, and the final acceptor is oxygen, generating water.
During meiosis chiasmata are observed at
Pachytene
Photosynthesis takes place in the membranes of small sacs called A) thylakoids B) grana C) photosystems D) photons
Photosynthesis takes place in the membranes of small sacs called thylakoids.
Trematol is a metabolic poison derived from the white snake root. Cows eating this plant concentrate the poison in their milk. The poison inhibits liver enzymes that convert lactic acid to other compounds for metabolism. Why does physical exertion increase symptoms of poisoning by trematol? Why does the pH of the blood decrease in a person who has digested trematol?
Physical exertion would increase the production of latic acid by fermentation, and the build up of lactic acid decreases blood pH when liver enzymes are blocked. During exertion, our muscles produce lactic acid from pyruvate by fermentation, allowing the regeneration of NAD+ for continued ATP production by glycolysis. Because lactic acid metabolism is blocked by tremetol, the acid would build up in our blood, decreasing the pH.
Cell plate formation is present in____________.
Plant cells
chromatin
Protein/DNA complex making the chromosome.
Electrons from excited chlorophyll molecule of photosystem II accepted first by
Quinone
What is a commonly used material for the study of mitosis in a laboratory?
Root tip
DNA replication occurs in_____
S phase
In a somatic cel cycle, DNA synthesis takes place in the_________
S phase
In the cell cycle DNA synthesis takes place during________
S phase
Which stage is known for DNA replication?
S-phase
Which aspect of mitosis is affected by colchicine in inducing polyploidy?
Spindle formation
kinetochore
Structure forming at centromere during Mitosis for binding microtubules.
Kranz anatomy is one of the characteristics of the leaves of_______
Sugar cane
The pairing of homologous chromosomes is called
Synapsis
