Bio Test 2

Which statement is true of enzymes? (a) Enzymes can be either proteins or RNA molecules. (b) When a cell makes an enzyme, it makes many copies. (c) Their substrate specificity involves matching of shapes. Both (a) and (b). (a), (b), and (c).

(a), (b), and (c).

The reaction A → B is unfavorable by itself, but through energy-coupling, cells can use ATP to convert A into B. How is this done?

(c) The unfavorable reaction is replaced by two favorable reactions.

As ATP and NADPH are used, they produce ___ and ___, respectively, which are returned to the light reactions so that more ___ and ___ can be formed

- ADP & NADP+ - ATP & NADPH

In the light reactions of photosynthesis, energy in sunlight is converted into chemical and redox energy in the form of _____ and _____

- ATP - NADPH

energized electrons from photosystem II are passed through another electron transport chain. Their energy is used to pump ___ from the ___ into the _____, creating a concentration gradient.

- H+ - stroma - thylakoid compartment (lumen)

in PSI, ____ is oxidized (which in turn oxidizes _______)

- P700 - the electron transport chain between the photosystems

Electron transport between PS II and the cytochrome complex (through _____) pumps protons from the ____ into the thylakoid space

- PQ - stroma

____ splits water into ___ ___ and ___

- PSII - 1/2 O₂ - H+ - e-

The key function of each of the two photosystems is to ______ and ______

- absorb light - convert the energy of the absorbed light into redox energy (which drives e- transport)

Energized electrons from photosystem I are passed down _____ and added to ___ to form ____

- an electron transport chain - NADP+ to form NADPH

how do animal cells rebuild ATP?

- enzymes convert sugars to fuels that the mitochondria can use - oxidation of one glucose produces ATP (cellular respiration)

pyruvate enters the ____ by passing through the_______

- matrix - inner and outer membranes of the mitochondria

In PS II, the _____ of water releases protons into the ______

- oxidation - thylakoid space

In the light reactions, the energy of sunlight is used to _____ water (the electron donor) to ____ and pass these electrons to _____, producing _____

- oxidize - O₂ - NADP+ - NADPH

In fermentation _____ is reduced and _____ is oxidized.

- pyruvate - NADH

In PS I, the PS I primary electron acceptor is ____ (which in turn reduces other compounds that ultimately reduce ____ to ____)

- reduced - NADP+ to NADPH

the PS II primary electron acceptor is _____ (which in turn reduces the ______).

- reduced - electron transport chain between the photosystems

two photosystems that power linear electron flow from ____ to _____

- water -NADP+

3 roles surface tension, adhesion and cohesion play in transport of water from roots to leaves in xylem

1- generate force ultimately pulling water up thru xylem 2- transmit this force uniformly thru xylem 3- help oppose force of gravity, tending to pull water down

the 4 stages of cellular respiration

1- glycolysis 2- acetyl coA formation 3- citric acid cycle 4- oxidative phosphorylation

Name the 6 Steps of Na+/K+ pump:

1. 3 Na+ ions from the intracellular fluid bind to the pump 2. Pump is phosphorylated after the third phosphate on the ATP (Adenosine TriPhosphate) is hydrolyzed by ATPase. 3. Na+ are released to the extracellular fluid as the pump changes chape. 4. 2 K+ ions from the extracellular fluid bind to the pump 5. The attached K+ ons trigger dephosphorylation of the pump 6> The K+ are released to the intracellular fluid as the pump changes shape due to dephosphorylation

3 outputs of calvin cycle

1. ADP 2. G₃P 3. NADP+

3 things glycolysis/cellular respiration yield

1. CO₂ 2. H₂O 3. ATP

3 inputs of calvin cycle:

1. NADPH 2. CO₂ 3. ATP

3 outputs of light rxns in calvin cycle

1. O₂ 2. ATP 3. NADPH

2 common types of fermentation:

1. alcohol 2. lactic acid

the two forms starch comes in and their differences are?

1. amylose, spiral 2. amylopectin, branches off main chain

4 inputs of light reactions in calvin cycle:

1. light 2. NADP+ 3. ADP 4. water

Complete the following sentences about enzyme function: Enzymes speed reaction rates by ______ and lowering activation energy. Activation energies drop because enzymes stabilize _______. Enzyme specificity is a function of the active site's shape and the chemical properties of _______ at the active site.

1. orienting substrates; 2. the transition state; 3. R-groups

A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7?

100 times

in glycolysis, the 6 carbon sugar is converted into....

2 molecules of pyruvate

to produce 1 G₃P molecule, calvin cycle must take up ___ molecules CO₂

3

one G₃P molecule has _ carbons

3 carbons

in phase 3 of the calvin cycle, the 5 G₃P molecules are converted into __ molecules of ____

3 molecules of R₅P

temperature, pH, phosphorylation

3 things that can change the shape of an enzyme

the net production of one G₃P molecule requires ___ turns of the cycle, with one ___ entering at each turn

3, one CO₂

what does the type of glycosidic linkage (alpha or beta) determine for the polysaccharide?

3d structure of it

CAM plants fix carbon dioxide into ______, just like C4 plants

4 carbon molecules

Glucose (C6H12O6) has a single carbonyl group (-C=O) in its linear form. Based on the number of oxygen atoms in glucose, how many hydroxyl groups (-OH) would you expect glucose to have?

5

how many G₃P molecules enter phase 3?

5

In the first part of Phase 3, __ molecules of G₃P ( __ phosphate groups each) are converted to __ molecules of R₅P (also _ phosphate groups each). Thus there is a net release of _ Pi.

5, 1, 3, 1, 2

The 3 CO₂ molecules are added to 3 RuBP molecules (which contain 15 total carbon atoms), next producing __ molecules of 3-PGA (___ total carbon atoms).

6 molecules, 18 total carbon

In Phase 2, ___ of the ATP and ___ of the NADPH are used in Phase 2 to convert _ molecules of PGA to __ molecules of G₃P. __ phosphate groups are also released in Phase 2 (derived from the 6 ___ used)

6, all (6), 6, 6, 6, atp

in the entire calvin cycle, _ of the 9 phosphate groups are released as Pi

8

in the entire calvin cycle, __ ATP are hydrolyzed to ADP

9

The Calvin cycle requires a total of __ ATP and __ NADPH molecules per G₃P output from the cycle (per __ CO2 fixed)

9, 6, 3

A chemical reaction that has a positive ΔG is best described as a. endergonic. b. spontaneous. c. entropic. d. exergonic. e. enthalpic.

A

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to a. add more of the enzyme. b. add a noncompetitive inhibitor. c. add more substrate. d. heat the solution to 90°C. e. add an allosteric inhibitor.

A

Protein kinases are enzymes that catalyze phosphorylation of target proteins at specific sites, whereas protein phosphatases catalyze removal of phosphate(s) from phosphorylated proteins. Phosphorylation and dephosphorylation can function as an on-off switch for a protein's activity, most likely through a. the change in a protein's charge leading to a conformational change. b. a change in the optimal temperature at which a reaction will occur. c. a change in the optimal pH at which a reaction will occur. d. the excision of one or more peptides. e. the change in a protein's charge leading to cleavage.

A

Which of the following is NOT a way in which an enzyme can speed up the reaction that it catalyzes? a. The active site can provide heat from the environment that raises the energy content of the substrate. b. Binding of the substrate to the active site can stretch bonds in the substrate that need to be broken. c. The enzyme binds a cofactor that interacts with the substrate to facilitate the reaction. d. The active site of the enzyme can provide a microenvironment with a different pH that facilitates the reaction. e. The binding of two substrates in the active site provides the correct orientation for them to react to form a product.

A An enzyme cannot extract heat from the environment to speed a reaction. It can only lower the activation energy barrier so that more substrates have the energy to react.

What's false? (1) Enzymes may change shape when they bind substrates; (2) Enzymes provide no energy for the reaction, except collision energy; (3) Enzymes may release substrates. a. None of the statements is false. b. Statement 1 is false. c. Statement 2 is false. d. Statement 3 is false. e. All three statements are false.

A Enzymes do all these things.

Which fact is most important in explaining how enzymes speed reactions? a. High-energy collisions are less common than low-energy collisions. b. Large molecules collide more energetically than small molecules. c. Every reaction step adds to the time required for the overall reaction. d. It takes less energy to break a hydrogen bond than a covalent bond. e. Very low potential energy tends to make molecules unstable.

A Enzymes provide reaction pathways that have low activation energy requirements. This allows low-energy collisions to cause reactions.

What is the free energy change (\(\Delta G\)) of the hydrolysis of ATP to ADP? a. The free-energy change (\(\Delta G\)) of the hydrolysis of ATP to ADP and Pi may vary considerably with variations in pH, temperature, atmospheric pressure, and concentrations of reactants and products. b. The free-energy change (\(\Delta G\)) of the hydrolysis of ATP to ADP and Pi is approximately -7.3 kcal/mole, but it varies from species to species. c. The free-energy change (\(\Delta G\)) of the hydrolysis of ATP to ADP and Pi is constant at -7.3 kcal/mole.

A The free-energy change (\(\Delta G\)) of the hydrolysis of ATP to ADP and Pi is -7.3 kcal/mole under standard conditions. Standard conditions are defined as a temperature of 298 K (or 250C), 1 atm, pH 7, and equal 1M concentrations present of all reactants and products. In living cells, conditions do not conform to standard conditions, primarily because reactant and product concentrations differ from 1 M. For example, when ATP hydrolysis occurs under cellular conditions, the actual \(\Delta G\) is about -13 kcal/mol, 78% greater than the energy released by ATP hydrolysis under standard conditions.

When a pathway is subject to allosteric feedback inhibition, ... a. an accumulation of effectors slows the pathway. b. the concentration of effectors does not change with time. c. the last enzyme in the pathway is allosteric. d. the effector is made by another pathway. e. an increase in effector concentration speeds the pathway.

A With this arrangement, feedback inhibition limits the accumulation of effectors.

define centriole

A minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division

enzyme

A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.

Consider the two-step metabolic pathway: A—(enzyme 1)—>B—(enzyme 2)—>C How would inactivating enzyme 1 affect the concentrations of molecules A, B, and C relative to what they would be if the pathway were fully functional

A would increase; B and C would decrease.

atp hydrolysis releases what (2)

ADP and inorganic phosphate

photosynthesis begins in the

ANTENNA COMPLEX

chemiosmosis yields

ATP

most common energy rich substrate

ATP

in glycolysis, one glucose is oxidized into 2 molecs pyruvate, with the production of ___ and ___

ATP & NADH

the calvin cycle uses ____ and ____ produced by the light reactions

ATP and NADPH

exergonic

ATP hydrolysis is highly ______ because there is a large drop in potential energy because charge repulsion is reduced

what enzyme harvests the potential energy of the H+ ions in the lumen

ATP synthase

what phosphorylates ADP to make ATP in the light reactions

ATP synthase

In the second part of Phase 3, 3 ___ molecules are used to convert the _ ___ into _ ___

ATP, 3 R₅P into 3 RuBP

the phosphorylation of enzymes and substrates requires

ATP- from cellular respiration and light dependent reactions

Which of these is an example of negative feedback

After you eat, insulin stimulates the lowering of blood sugar levels.

Select the statement that is incorrect.

All carbohydrates have the general formula Cn(H2O)n.

what is plasmodesmata

An open channel in the cell wall of a plant through which strands of cytosol connect from an adjacent cell.

define basal bodies

An organelle that forms the base of a flagellum or cilium and that is similar to a centriole in structure and function

What about anabolic reactions?

Anabolic reactions will often have a positive ΔG based on an increase in enthalpy and decrease in entropy

Which of the following BEST characterizes gas exchange in animal versus plant metabolism

Animals take in O₂ and release CO₂. Plants take in and release both O₂ and CO₂

identify the chase phase

Any unincorporated radioactively labeled amino acids are washed away and large amounts of the same, but unlabeled, amino acid are added

In an experiment with an enzyme, the 58th amino acid seems to form a covalent bond with a substrate molecule as part of the catalytic process. What would you say?

At some point the bond between the amino acid and the substrate must break.

Which of the following is true for all exergonic reactions? a. The reactions are rapid. b. The reaction proceeds with a net release of free energy. c. The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. d. The products have more total energy than the reactants. e. A net input of energy from the surroundings is required for the reactions to proceed.

B

Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O) is correct? a. The entropy of the universe decreases as the result of this reaction. b. The entropy of the products is greater than the entropy of the reactants. c. The reverse reaction, making glucose from water and carbon dioxide, must be an exergonic reaction. d. The free energy lost in this combustion is less than the energy that appears as heat. e. This is the process of cellular respiration, an anabolic pathway that releases free energy.

B A large molecule (glucose) has been converted into several smaller molecules (water and carbon dioxide); thus, the products have more disorder (greater entropy) than the reactants.

Which type of control agent never speeds an enzyme's action? a. Protein kinase b. Substrate analog c. Allosteric effector d. Regulatory protein e. None of the above.

B Substrate analogs resemble the substrate enough to bind to the active site, but they can't react. Accordingly, they just block the active site and slow the reaction.

In an experiment with an enzyme, the 58th amino acid seems to form a covalent bond with a substrate molecule as part of the catalytic process. What would you say? a. It couldn't happen. Catalysis doesn't alter the enzyme. b. At some point the bond between the amino acid and the substrate must break. c. This is probably a case where the enzyme changes the position of equilibrium. d. There must be an error. Enzymes don't make covalent bonds with substrates. e. This is possible in theory, but it's never been observed.

B To work repeatedly, the enzyme must return to its original state at the end of each catalytic cycle. Some steps may form bonds or break bonds between the enzyme and substrate.

Which is true of the metabolic pathway shown here? enzyme 1 enzyme 2 enzyme 3 A ————————> B ————————> C ————————> D

B is the product of enzyme 1 and the substrate for enzyme 2.

Which statement accurately summarizes a difference between ribonucleotides and deoxyribonucleotides? A. in ribonucleotides the sugar is a pentose; deoxyribonucleotides have a hexose. B. ribonucleotides have a hydroxy,l group bonded to their 2' carbon; deoxyribonucleotides have an H at that same location C. ribonucleoties have a hydroxyl group bonded to their 3' carbon; deoxyribonucleotides have an H at that same location. D. Ribonucleotides contain only purines; deoxyribonucleotides contain only pyrimidines

B. Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location

Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes?

Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.

How do cells replace the energy-rich ATP that is destroyed in energy-coupled reactions?

Both (a) and (b).

A reaction is said to be unfavorable if ... (a) it will be very slow without a catalyst. (b) the free energy change for the reaction is positive. (c) equilibrium favors the reactants, not the products. Both (a) and (b). Both (b) and (c).

Both (b) and (c).

How can "induced fit" influence the specificity of an enzyme?

Both (b) and (c). -It moves the reactive portion of the enzyme closer to the substrate -The enzymes active site changes shape to fit the correct substrate but not other molecules.

Which statement is characteristic of allosteric effectors? a. They bind to the active site. b. Covalent bonds attach them to the enzyme. c. They may not resemble the enzyme's substrates. d. Both (b) and (c). e. (a), (b), and (c).

C The term "allosteric" means "other shape (or structure)."

Enzymes are described as catalysts, which means that they _____. a. increase the free energy of the reactants to make the reaction go faster b. provide activation energy for the reactions they facilitate c. increase the rate of a reaction without being consumed by the reaction d. can alter the free energy change (ΔG) for a chemical reaction e. are proteins

C This permits enzyme molecules to be used repeatedly.

what is the general formula of simple carbs

CN(H₂O)n

in acetyl coA formation, one molecule of ____ is released

CO₂

onserving water simultaneously reduces the amount of ____ available to the plant.

CO₂

cellular respiration produces ____ and ____

CO₂ and atp

the electrons derived from the oxidation of nadph to nadp+ in the calvin cycle are used to reduce ___ to ____

CO₂, G₃P

Lowering the concentration of _____ inside the leaf by fixing it into four-carbon molecules creates a steeper _______, which increases the diffusion of ____ into the plant from the atmosphere. This permits C4 plants to have smaller openings at their guard cells, thus reducing _______.

CO₂, concentration gradient, CO₂, water loss

lower light levels also affect the rate of ___ uptake by the Calvin cycle because

CO₂, cycle needs the ATP and NADPH produced by the light reactions

pyruvate produced in glycolysis is completely oxidized to ___ with the production of ____ _____ and _____

CO₂; NADH, FADH₂; and some ATP

A simple sugar is composed of equal parts carbon and water, which give rise to the general name of any sugar as a ________________.

Carbohydrate

Compare the molecular formula of a carbohydrate (CH2O)n with that of carbon dioxide (CO2). What does the presence of hydrogen atoms in carbohydrates indicate?

Carbohydrates are more reduced than carbon dioxide.

Why do endurance athletes practice "carbohydrate loading," meaning to eat massive amounts of starch in the days leading up to a long race?

Carbohydrates are reduced molecules that can provide the chemical energy required during exercise

Which of the following best explains why "carbs" (carbohydrates) are advertised by manufacturers of candy bars and sports drinks as a "quick energy boost"?

Carbs are reduced molecules that have high-energy electrons.

Using what you have learned about changes in free energy, would you predict the ΔG value of catabolic reactions to be positive or negative?

Catabolic reactions will often have a negative ΔG based on a decrease in enthalpy and increase in entropy

Which of the following statements is true? -Chemical reactions take place slowly over time within cells. -Cells are dynamic, highly integrated structures. -Once organelles in cells are formed, they change relatively little throughout the life of the cell. -Microtubules, once formed, will never shrink in length.

Cells are dynamic, highly integrated structures.

identify the pulse phase

Cells are exposed to a high concentration of a radioactively labeled amino acid for a short period to tag proteins that are being synthesized.

What central theme of biology helps explain why various cells can look so different from each other? -Cells correlate structure with function. -Different cells contain different macromolecules as their genetic material. -All cells need to engage in energy transformations. -Cells must be small in size.

Cells correlate structure with function.

Name the type of reactions and involved components (including functional groups) in the formation of fats?

Condensation reaction; taking away OH from carboxyl group on lipid and taking H away from glycerol

The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct? a. ΔH is the change in entropy, the energy available to do work. b. ΔS is the change in enthalpy, a measure of randomness. c. T is the temperature in degrees Celsius. d. ΔG is the change in free energy.

D

Which of the following best describes enthalpy (H)? a. the total kinetic energy of a system b. the cell's energy equilibrium c. the condition of a cell that is not able to react d. the heat content of a chemical system e. the system's entropy

D

When allosteric effector X binds to enzyme #1, the enzyme stops working. Nevertheless, the speed of the reaction can be altered by adjusting the concentration of X. How? a. There are many copies of the enzyme. b. When X detaches from an enzyme, the enzyme regains full activity. c. X easily escapes from the allosteric site. d. All of the above. e. None of the above.

D Because X leaves an enzyme easily and lets the enzyme go back to work, there are always some working enzymes. The concentration of X determines how many copies are working at each moment. This wouldn't be true if the enzymes couldn't recover.

Which type of control agent exerts noncompetitive inhibition? a. Substrate analog b. Protein kinase c. Allosteric effector d. Both (b) and (c). e. (a), (b), and (c).

D Competitive inhibitors bind to the active site and compete with the substrate for that position. Allosteric effectors don't do that, nor do the phosphoryl groups that are added by protein kinases.

Enzymes speed reactions mainly by ... a. protecting the catalysts. b. raising the kinetic energy of the reactants. c. providing activation energy. d. lowering EA. e. None of the above.

D Enzymes always lower EA, though they may have other effects as well. With a lower EA, more collisions can produce the transition state.

How can "induced fit" influence the specificity of an enzyme? a. It can not influence the specificity of an enzyme. b. It moves the reactive portion of the enzyme closer to the substrate. c. The enzyme's active site changes shape to fit the correct substrate but not other molecules. d. Both (b) and (c). e. None of the above.

D The active site of the enzyme will change shape to make a better fit with only the appropriate substrate, which can bring the reactive portion of the enzyme closer to the substrate.

Which molecules do not normally cross the nuclear membrane? -mRNA -Proteins -DNA -Nucleotide triphosphates

DNA

Chromatin is composed of

DNA and protein.

ribosomes bound to the surface of the endoplasmic reticulum synthesize which 3 proteins?

DNA polymerase, ribosomal protein, actin

Lactose the, sugar in milk, is a _______________, because it can be split into two monosaccharides

Disaccharide

The second law of thermodynamics states which of the following?

Disorder always increases in the universe.

Allosteric enzyme regulation is usually associated with a. lack of cooperativity. b. the need for cofactors. c. activating activity. d. competitive inhibition. e. an enzyme with more than one subunit.

E

Which of the following would be unlikely to contribute to the substrate specificity of an enzyme? a. A positive charge on the substrate is attracted to a negative charge in the active site of the enzyme. b. A hydrophobic group on the substrate interacts with several hydrophobic amino acids on the enzyme. c. A similar shape exists between a pocket on the surface of the enzyme and a functional group on the substrate. d. The enzyme has the ability to change its configuration in response to the substrate binding. e. The enzyme has an allosteric regulatory site.

E The allosteric site is distinct from the active site, and does not affect the substrate specificity of the enzyme.

Which statement is true of enzymes? a. Enzymes can be either proteins or RNA molecules. b. When a cell makes an enzyme, it makes many copies. c. Their substrate specificity involves matching of shapes. d. Both (a) and (b). e. (a), (b), and (c).

E There are many copies of each enzyme; they're usually proteins but sometimes they are RNA; and they only attack substrates that fit the shape and charge of the active site.

Which of the following is a basic structural difference between plant cells and animal cells?

E.All of the above apply.

secretory proteins are created in the

ER

Bound (free) ribosomes synthesize which three proteins?

ER protein, insulin, lysosomal enzyme

steps of the secretory path

ER, cis golgi, medial golgi, trans golgi, cell membrane

If a reaction is endergonic, then which of these statements is true?

Energy must be added for the reaction to proceed.

Which of the following represents a major difference between prokaryotic cells and eukaryotic cells?

Eukaryotic cells tend to have much more extensive inner membrane systems and larger numbers of intracellular organelles than do prokaryotes.

Dairy cattle were unknown in Thai culture until recently, and 97% percent of Thai people are lactose intolerant as adults. Which explanation for such widespread lactose intolerance is most likely correct?

Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful.

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.

False

why is more ATP made per molecule of NADH than per molecule of FADH2?

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae

in the calvin cycle, CO₂ is converted into

G₃P

in the entire calvin cycle, the ninth phosphate appears in the _____

G₃P output from the cycle

The total energy in a molecule, its enthalpy, is given by the letter ____.

H

the inner membrane creates a _____ during electron transport

H+ gradient

Which fact is most important in explaining how enzymes speed reactions?

High-energy collisions are less common than low-energy collisions.

Where do the excited electrons flowing through photosystem I originally come from?

H₂O

in light reactions, light energy is used to oxidize ____ to _____

H₂O to O₂

What would happen if the Na+/K+ pump was not working?

If it doesn't work the Na+/K+ gradient won't be set up which interrupts secondary active transporters and would not make the inside of the cell negative

How allosteric regulation can change an enzyme's catalytic activity?

In allosteric activation, a regulatory molecule binds to a location other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.

Which statement most accurately explains how allosteric regulation can change an enzyme's catalytic activity

In allosteric activation, a regulatory molecule binds to a location other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.

Consider a situation in which the enzyme is operating at optimum temperature and pH, and has been saturated with substrate. What is your best option for increasing the rate of the reaction?

Increase the enzyme concentration.

Peptidoglycan forms sheets that stiffen the cell walls of bacteria. How is the formation of sheets possible?

Individual strands are joined by peptide bonds - a type of covalent bond.

Which of the following best describes how gramicidin functions?

It forms a channel in the membrane.

Which of the following is not true of osmosis?

It is an energy-demanding or "active" process.

What is the most important factor in explaining why diffusion occurs spontaneously?

It leads to an increase in entropy.

What is the most important factor in explaining why osmosis occurs spontaneously?

It leads to an increase in entropy.

What is the function of the nuclear pore complex?

It regulates movement of materials across the nuclear envelope.

What is the most likely role of a cell that contains an extensive smooth ER?

It synthesizes large quantities of lipids.

A ____________ cannot be hydrolyzed any further.

Monosaccharide

Describe how high and low turgor pressure develops:

Movement of sugar into phloem creates high turgor pressure in the phloem at the source. Movement of sugar out of the phloem creates low turgor pressure into the phloem at the sink

____ is the compound that functions as the electron acceptor in glycolysis

NAD+

in acetyl coA formation, _____ is reduced to _____

NAD+ to NADH

the reduced form of the electron acceptor in glycolysis is........

NADH

light rxns are dependent on the calvin cycle because

NADP+ and ADP produced by cycle are inputs to light rxns

PSI yields

NADPH

the calvin cycle oxidizes the light reactions product ____ to ____

NADPH to NADP+

what 2 things are used to drive the calvin cycle

NADPH, ATP

The light-independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

NADPH\

Is this a permanent change?

NO

Can an enzyme make a nonspontaneous reaction occur spontaneously? Why or why not?

No, because enzymes do not affect the overall ΔG of a reaction.

What's false? (1) Enzymes may change shape when they bind substrates; (2) Enzymes provide no energy for the reaction, except collision energy; (3) Enzymes may release substrates.

None of the statements is false.

what does an NLS do?

Nuclear Localization Signal: allows things in/out the nucleus

what is induced fit

On binding substrates, some active sites change shape for a better match

Which of the following molecules would you expect to have the most free energy per gram?

One with carbon and hydrogen atoms only

Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results? -Only one of the two fusion proteins possesses a nuclear localization signal. -The cytoplasmic protein contains a nuclear localization signal. -Nucleoplasmin does not have a nuclear localization signal. -One of the fusion proteins entered the nucleus by passive transport.

Only one of the two fusion proteins possesses a nuclear localization signal.

PSII releases

O₂

lower light levels mean a lower rate of ___ production

O₂

In PS II (the first photosystem in the sequence), _____ is oxidized (which in turn oxidizes water)

P680

oxidants in PSII and PSI

P680+ and P700+

In each photosystem, this redox reaction moves an electron from the special chlorophyll pair (____ in PS II and ____ in PS I) to that photosystem's __________

P680, P700, primary electron acceptor

Energized electrons from ___ are used to reduce NADP+.

PS1

oxidation of electron transport chain between the two photosystems: a. PSI b. PSII c. both

PSI

reduction of NADP+: a. PSI b. PSII c. both

PSI

ANTENNA COMPLEX DONATES ENERGY FROM EXCITED ELECTRONS TO

PSI & PSII

H₂O enters photosynthesis in

PSII

oxidation of water: a. PSI b. PSII c. both

PSII

reduction of electron transport chain between the two photosystems: a. PSI b. PSII c. both

PSII

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place? -Osmosis -Active transport -Passive transport

Passive Transport

Which processes establish a gradient of protons to drive ATP synthesis?

Photosystem II and mitochondrial electron transport chain reactions

_____ are surface appendages that allow a bacterium to stick to a surface. -Flagella -Cell walls -Pili -Ribosomes -Mitochondria

Pili

A carbohydrate that yields many monosaccharides when hydrolyzed is a _______________.

Polysaccharide

What is the function of a bacterium's capsule? -DNA storage -adhesion -protein synthesis -propulsion -protection

Protection

Why does relative enzyme activity shown in Figure 8.15a appear to drop off, when other studies have shown that reaction rates tend to increase at higher temperatures?

Protein denaturation

what manufactures cellular membranes by adding membrane proteins and phospholipids to its own membrane

RER: As membrane proteins grow from ribosomes on rough ER, the proteins are embedded into the rough ER membrane.

Which of these is NOT a lipid?

RNA

How do current models of enzyme function differ from Fischer's lock-and-key model?

Rather than enzymes being rigid, we now believe they undergo an induced fit upon substrate binding.

_____ are the sites of protein synthesis. -Peroxisomes -Ribosomes -Mitochondria -Microfilaments -Golgi apparatuses

Ribosomes

protein sythesis occurs in the

Rough ER

How does carbon fixation differ between C3 and C4 plants?

Rubisco is the primary enzyme that catalyzes carbon fixation in C3 plants, and phosphoenolpyruvate carboxylase can catalyze carbon fixation in C4 plants.

at the end of the calvin cycle, ___ is converted to ___ without the addition or loss of any carbon atoms

R₅P to RuBP

A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume?

Solution A: 1.4% (m/v) starch

A semipermeable membrane is placed between the following solutions. Which solution will increase in volume?

Solution D: 12.4% (m/v) NaCl

Why do plants require sunlight?

Sunlight energy can be used by plants to reduce the carbon atoms in carbon dioxide

What can change the shape of an enzyme?

Temperature, pH, and phosphorylation are among the factors that can affect protein structure.

What will happen to a red blood cell (rbc), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?

The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc.

How does pH affect enzyme-catalyzed reactions?

The concentration of protons affects the folded structure of the enzyme.

If exergonic reactions occur spontaneously, what keeps molecules from breaking apart and cell chemistry from racing out of control?

The energy needed to start a chemical reaction is called the energy of activation (EA). This required energy input represents a barrier that prevents even energy-releasing exergonic reactions from occurring without some added energy.

What often happens to an enzyme after it binds to its substrate?

The enzyme changes shape.

Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why is this logical?

The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific

Which of the following statements about the nuclear envelope is false? -The nuclear envelope is continuous with the Golgi apparatus. -Molecules pass into and out of the nucleus through nuclear pores. -Nuclear pores are made up of a group of proteins that are collectively called the nuclear pore complex. -The nuclear envelope is composed of two lipid bilayers.

The nuclear envelope is continuous with the Golgi apparatus.

Which of the following can vary among monosaccharides?

The number of carbon atoms

define autophagy

The process of self-digestion by a cell through the action of enzymes originating within the same cel

How are proteins transported throughout the endomembrane system? -The protein contains a molecular zip code that allows the protein to be shipped to the correct cellular compartment. -The cell sends the proteins to the cellular compartment that currently has the least amount of proteins in it. -The cell always synthesizes a protein in the compartment in which it will be used. -Every protein will have a nucleic acid attached to it, which tells the cell in which compartment it will be used.

The protein contains a molecular zip code that allows the protein to be shipped to the correct cellular compartment.

Which of the following scenarios would you predict to be responsible for activating this enzyme?

The sugar binds to the enzyme and changes the conformation of the active site.

How do cells use ATP to raise the energy level of reaction substrates?

The terminal phosphate of ATP is bound to the substrate

Mitochondria are separated into two compartments, the matrix and the intermembrane space, by their inner and outer membranes. How does the presence of two compartments contribute to the function of mitochondria?

The two compartments permit different but complementary functions to be accomplished in the organelle.

How do the α and β forms of glucose differ?

Their ring structures differ in the location of a hydroxyl group.

Which statement most accurately explains why ATP hydrolysis is highly exergonic?

There is a large drop in potential energy because charge repulsion is reduced

The term carbohydrate is appropriate because of which of the following characteristics of sugars?

They all have the general formula (CH2O)n.

Phospholipid bilayer membranes are selectively permeable; in which way are they "selectively permeable"?

They allow some things to cross while restricting others.

Which aspect of phospholipids is most important to the formation of bilayers?

They are amphipathic.

Which of the following is not a characteristic that chloroplasts and mitochondria share?

They are both part of the endomembrane system.

What do phospholipids and triglycerides have in common?

They both have a glycerol backbone.

The small intestine is the site of digestion and absorption of nutrients. A single layer of epithelial cells lines the small intestine. In the duodenum (the first section of the small intestine), these epithelial cells secrete large quantities of digestive enzymes. Which of the following features would be typical of these epithelial cells?

They contain large quantities of rough endoplasmic reticulum.

Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules. Why?

They do not have a polar or charged region.

Which statement is true for all redox reactions?

They involve the transfer of electrons.

Suppose some blood cells were in an isotonic solution. What would happen to them?

They would remain the same size.

free ribosomes create proteins that function in the cytoplasm or in environments that are in direct contact with the cytoplasm

This includes the nucleus which is considered to be in contact with the cytoplasm

In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules? -To make the proteins bigger -To give the protein molecules energy -To make the proteins easy to see -To target the proteins to the nucleus

To make the proteins easy to see

Why is ATP a good source of energy for biological reactions?

Triphosphate chains are unstable.

Which of the following is the best explanation for why vegetable oil is a liquid at room temperature while animal fats are solid?

Vegetable oil has more double bonds than animal fats.

When is the overall free energy change ΔG in a reaction most likely to be negative (meaning that the reaction is exergonic)?

When products have lower potential energy and higher entropy than reactants

When does feedback inhibition occur?

When the product of a pathway feeds back to interact with an enzyme early in the same pathway to inhibit its func

allosteric effectors

_______ _____ may not resemble the enzyme's substrates

competitive inhibition

___________ __________ occurs when the regulatory molecule is similar in size and shape to the enzyme's natural substrate and inhibits catalysis by binding to the enzyme's active site

cofactor

a _____ such as a vitamin, binds to an enzyme and plays a role in catalysis

Steroids are ________.

a class of lipid with four-ring structure.

A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____. -a membrane-bound nucleus -carbohydrates -a plasma membrane -ribosomes

a membrane-bound nucleus

The term phospholipid can best be described by which of the following?

a nonpolar lipid molecule that is made amphipathic by the addition of a phosphate

A glycosidic linkage is analogous to which of the following in proteins?

a peptide bond

Which of the following crosses lipid bilayers the fastest?

a small, nonpolar molecule like oxygen (O2)

Which of the following crosses lipid bilayers the slowest?

a sodium ion

Which of these is exhibiting kinetic energy?

a space station orbiting Earth

active site

a substrate binds to an enzyme at the ____ ____, where the reaction occurs

GLUT-1 is an example of what?

a transport protein that facilitates diffusion of a large molecule across cell membranes

The process of photosynthesis probably originated in: a. prokaryotes b. in fungi c. three separate times d. in plants

a.

Why might adding inorganic phosphate to a reaction mixture where glycolysis was rapidly proceeding help sustain the metabolic pathway? A. the metabolic intermediates of glycolysis are phosphorylated b. it increases the energy levels of the electrons that are transfered to the electron transport chain where ATP is produced. c. it would increase the oxygen sypply available for aerobic respiratioin because each phosphate group has four oxygen atoms as constituents d. it would increase the amount of glucose available for catabolism.

a.

sodium-potassium pumps: a. move 2 P ions and 3 Na ions while consuming an ATP for each cycle b. move 3 P ions and 2 Na ions while producing an ATP for each cycle

a.

which of the following would enable you to detect aneuploidy? A. karyotyping b. autosomy c. syngamy d. synapsis

a.

which statement most accurately sumarizes a feature of passive transport? A. it is a spontaneous process b. it involves no change in free energy c. no membraine protein are involved d. it makes the cell interior and exterior more different from one another

a.

The term phospholipid can best be described by which of the following? A. a nonpolar lipid molecule that is made amphipathic by the addition of a phosphate b. a polar lipid molecule that fully repels water c. a nonpolar lipid molecule that is made polar by the addition of a phosphate d. a polar lipid molecule that fully interacts with water

a. a nonpolar lipid molecule that is made amphipathic by the addition of a phosphate

Imagine that you've set up a genetic screen to identify E. coli mutants that cannot metabolize the amino acid tryptophan. Beginning with a master plate containing many colonies, you prepare replica plates on medium with glucose or tryptophan as the only energy source. You would look for colonies that _____. a. can grow only on the plates with glucose b. can grow on both types of media c. cannot grow on either type of media d. can grow only on the plates with tryptophan

a. can grow only on the plates with glucose

Spherocytosis is a defect associated with a defective cytoskeletal protein in red blood cells. What do you suspect is one consequence of defective cytoskeletal proteins in red blood cells?

abnormal cell shape

in the citric acid cycle, _____ is fully oxidized

acetyl coA

in the citric acid cycle, 2 carbons from the ____ are _____ to two molecules of CO₂

acetyl group of acetyl coA, oxidized

What three distinct elements make up the cytoskeleton in eukaryotic cells? -flagella, cilia, and centrosomes -carbohydrates, lipids, and nucleic acids -actin filaments, intermediate filaments, and microtubules -ATP, TTP, and CTP

actin filaments, intermediate filaments, and microtubules

transition state

activation energies drop because enzymes stabilize the ________ ______

endo and exo cytosis are both forms of what kind of transport

active

in the area of the sink, sucrose is unloaded from the phloem by

active transport

mineral ions are pumped into the xylem by

active transport

Which of the following means of transport would most likely be used for moving a medium-sized molecule (like a monosaccharide or an amino acid) from a low concentration on the outside of a cell to a high concentration on the inside of a cell?

active transport through a "pump" protein

A kinase is an enzyme that ______

adds a phosphate group to target molecules

______ in leaves and stems opposes the force of gravity

adhesion of water to plant cells

the terminal position of the carbonyl group on a sugar makes it an.........

aldose

Which of the following can change the shape of an enzyme?

all of the above

what type of glycosidic linkage is starch?

alpha

two types of glycosidic linkages (2)

alpha and beta

glycogen is linked by what kind of bonds?

alpha glycosidic linkage

The polymerization of amino acids into a protein is an example of _____.

an anabolic pathway

denatured

an enzyme is ______ when it loses its native conformation and its biological activity

specific

an enzyme is considered ______ because of its ability to recognize the shape of a particular molecule

catalyst

an enzyme is considered a ____ because it speeds up chemical reactions without being used up

when properly aligned the enzyme and substrate form

an enzyme substrate complex

what occurs in substrate level phosphorylation?

an enzyme transfers a P group from one molecule to ADP to form ATP

water and ions moving along a cell wall continuum is called

apoplastic

The "heat" in chili peppers is due to a molecule called capsaicin. Suppose you breed chili peppers that have low amounts of capsaicin over many generations in order to make them milder (have less capsaicin). What process is occurring? A. environmental change b. heritable variation c. artificial selection d. natural selection

artificial selection

A function of cholesterol that does not harm health is its role _____.

as a component of animal cell membranes

The oxaloacetate quickly is converted into _____ or ____ acid (both of which are also _____ molecules).

aspartic, malic, 4 carbon

Function of the nucleolus (MB)

assembles ribosomes

In cells, what is usually the immediate source of energy for an endergonic reaction?

atp

In the Calvin cycle, the energy outputs from the light reactions (____ and ____) are used to power the conversion of ____ into ______

atp and nadph, co2 into the sugar g3p

You will notice that C4 photosynthesis uses an _____ to fix the carbon dioxide. This energy expense is compensated by the reduction of photorespiration in conditions limiting the availability of _____

atp molecule, co2

Catabolite activator protein (CAP) activity is controlled by the cAMP at the _____ level. A. translational b. post-translational c. transcriptional

b.

Most of the CO2 from the catabolism of glucose is released during ______ a. glycolisis b. the Krebs cycle c. chemiosmosis d. electron transport

b.

The energy of electron transport serves to move (translocate) protons to the outer mitochondrial compartment. How does this help the mitochondrion to produce energy? A. The protons receive electrons from the NAD+ and FAD that are accepted by electrons in glycolysis and the Krebs cycle. b. The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in the mitochondria. c. The hydrogen ions (protons) are transferred to oxygen in an energy-releasing reaction. d. The protons pick up electrons from the electron transport chain on their way through the inner mitochondrial membran

b.

The proteins of the electron transport chain active in the light-dependent reactions a. are part of the reaction centre of photosystem I b. are membrane proteins present in the thylakoid c, have hydrophilic exterior surfaces d. are free proteins present in the thylakkoid lumen

b.

Which one of the following is not a component of each monomer used to make proteins? A. a carboxyl group, COOH b. a phosphorous atom, P c. a side chain, R d. an amino functional group, NH2

b. a phosphorous atom, P

Compare the molecular formula of a carbohydrate (CH2O)n with that of carbon dioxide (CO2). What does the presence of hydrogen atoms in carbohydrates indicate? A. carbohydrates are more oxidized than co2 b. carbohydrates are more reduced than co2 c. every c atom in carbohydrate is bonded to 4 different atoms d. carbohydrates contain a carbonyl functional group

b. carbohydrates are more reduced than carbon dioxide

which trerm describes a trait that increases an individual's ability to survive in a particular environment? A) fitness b) adaptation

b_ adaptation

_____ is/are identical in structure to centrioles. -Basal bodies -Microfilaments -Chromatin -Mitochondria -Nuclear envelopes

basal bodies

what type of glycosidic linkage is cellulose?

beta

at what point is light energy converted to chemical energy in photosynth

between chemiosmosis and atp

as water evaporates from the cell walls, it is lost first from the regions _____

between the microfibrils

Which of the following is most likely to receive a fabricated organ made from his own cells? -pancreatic cancer patient -lung cancer patient -bladder cancer patient -thyroid cancer patient

bladder cancer patient

If a fabricated windpipe is not receiving proper oxygen and nutrients, which of the following failed to properly regenerate? -blood vessels -white blood cells -keratin -mucus producing cells

blood vessels

Where do scientists obtain adult stem cells? -saliva -bone marrow -skin -pancreas

bone marrow

flagella are found in pro, euk, or both?

both

light absorption: a. PSI b. PSII c. both

both

plasma membranes are found in pro, euk, or both?

both

reduction of primary electron acceptor: a. PSI b. PSII c. both

both

ribosomes are found in pro, euk, or both?

both

Proteins destined for secretion are made on ribosomes

bound to the ER

glycogen is highly....

branched

As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy? A. it is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem I. b. it exciteds electrons of the reaction center of photosystem I. c. it is used to establish and maintain a proton gradient d. it is lost as heat

c.

In the energy-yielding phase of glycolysis, energy is extracted in the form of a. NADH b. pyruvate c. ATP and NADH d. ATP

c.

Mitochondria are separated into two compartments, the matrix and the intermembrane space, by their inner and outer membranes. How does the presence of two compartments contribute to the function of mitochondria? A. it enables mitochondrial DNA and ribosomes to remain seperated from the functional compartment of the mitochondria. b. the double-membrane feature of mitochondria is what enables them to glycosylate proteins c. the 2 compartments permit different but complementary functions to be accomplished in the organelle

c.

What can you infer about high-molecular-weight proteins that cannot be transported into the nucleus? A. they are foreign proteins b. they are defective proteins c. they lack nuclear localization signals (NLS) d. they have been tagged for destruction

c.

different ratios occur in crosses with single gene pairs or two gene pairs. What type of ratios are likely to occur in crosses dealing with a single gene pair? A. 1:1:1:1, 1:4:6:4:1 b. 9:3:3:1, 1:2:1 c. 3:1, 1:1, 1:2:1, d. 4:1, 1:1, 1:4:1

c.

what is a major difference between meiosis II and mitosis? A. homologues align on the metaphase plate in meiosis II b. sister chromatids separate in mitosis and homologues separate in meiosis II c. in meiosis II sister chromatids separate d. crossover takes place in meiosis II

c.

what is a major difference between mitosis and meiosis I? a. dna replication takes place prior to mitosis, but not before meiosis I. b. only meiosis I results in daughter cells that contain identical genetic information c. sister chromatids separate in mitosis, and homologues separate in meiosis I. d. sister chromatids separate in mitosis and homologues separate in meiosis II

c.

what is the site of synthesis of proteins for export (secretion from the cell)? A. ribosomes that attach to the Golgi complex b. ribosomes that attach to the outer mitochondrial membrane c. ribosomes that attach to the endoplasmic reticulum d. free ribosomes

c.

which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not? A. cholesterol and phospholipids are primarily hydrophilic; fats are primarily hydrophobic. B. cholesterol and phospholipids are primarily hydrophobic; fats are primarily hydrophilic c. cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophilic d. cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophilic

c. cholesterol and phospholipids contain both hydrophobic regions; fats are primarily hydrophilic

What type of interaction is directly responsible for the formation of secondary structure? A. peptide bonds between nonadjacent amino acids b. peptide bonds between adjacent amino acids c. hydrogen bonds between sections of the polypeptide backbone d. hydrogen bonds between side chains of amino acids

c. hydrogen bonds between sections of the polypeptide backbone

Which statement is most accurate regarding similarities and differences between proteins and nucleic acids? A. proteins and nucleic acids both have a sugar-phosphate backbone and are formed by condensation reactions. B. nucleic acids have directionality, proteins do not c. proteins and nucleic acids both have a backbone and are formed by condensation reactions. d. proteins are formed by hydrolysis reactions; nucleic acids are formed by condensation reactions

c. proteins and nucleic acids both have a backbone and are formed by condensation reactions

Mitochondrial DNA codes for about 13 proteins (depending on the species of organism). These 13 proteins account for a small proportion of the proteins present in mitochondria. The remaining proteins are coded for by nuclear DNA. What is the most likely explanation for how these proteins find their way to the mitochondria? a. mRNAs that are manufactured in the nucleus, but translated by mitochondrial ribosomes b. random transport vesicles c. signal sequences d. attachments of ribosomes to outer mitochondrial pores and direct deposition into the inner mitochondrial compartment

c. signal sequences

what do phospholiipids and triglycerides have incommon? A. they both contain serine or some other organic compound b. they both have a phosphate c. they both have a glycerol backbone d. they both have three fatty acids.

c. they both have a glycerol backbone

Can the atomic mass of an element change? A. no it is fixed. If it changes at all then you have formed a different element. B. yes, adding or losing electrons will substantially change the atomic mass. C. yes, adding or losing neutrons will change the atomic mass without forming a different element. d. yes. adding or losing protons will change the atomic mass without forming a different element.

c. yes. Adding or losing neutrons will change the atomic mass without forming a different element.\

_____ is the most water-efficient of the types of photosynthesis.

cam metabolism

simple sugars are equal parts ___________ and ____________.

carbon and water

3 key phases of the calvin cycle

carbon fixation, reduction, regeneration

In C3 and CAM plants _____ and ______ occur in the same cells

carbon fixation, the calvin cycle

what are carbs made up of? (2)

carbon oxygen and hydrogen atoms

In roots the _____ forces water and solutes to pass through the plasma membranes of _____ cells before entering the _____.

casparian strip, endodermis, xylem

energy of activation

catalysts speed reactions mainly by lowering

plasmodesmata are a type of ____, and ___ and ___ can pass through them

cell junction, water and ions

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?

cell wall

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell? -capsule -pili -cell wall -flagella -nucleoid region

cell wall

endo and exo cytosis both require

cellular energy

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

cellular respiration

oxygen and sugar are inputs for......

cellular respiration

cells walls are only in plant cells and are made of

cellulose fibrils

The generation of transpirational pull in leaves depends on the interaction of water with the _____ in _____

cellulose microfibrils in mesophyll cell walls

PSII produces a proton gradient for

chemiosmosis- H+ gradient drives atp synthase enzyme

When an insect is crushed, it creates a crunching sound. What carbohydrate is the most likely source of this sound?

chitin

Which polysaccharide is an important component in the structure of many animals and fungi?

chitin

PSI and PSII have ____ molecules

chlorophyll

chloroplasts contain the pigment ______

chlorophyll

makes sugar by converting light energy into chemical energy

chloroplast

Which of the following eukaryotic organelles are found only in algal and plant cells? -chloroplasts -mitochondria -nucleus -Golgi apparatus

chloroplasts

animals lack what organelle

chloroplasts

how to plant cells rebuild ATP?

chloroplasts use light energy to link ADP with Pi (photosynthesis)

The _____ is composed of DNA and protein. -chromatin -centriole -mitochondrion -ribosome -flagellum

chromatin

the material chromosomes of euk. organisms are made of

chromatin

a ___ such as a vitamin binds to an enzyme and plays a role in catalysis

cofactor

_____ tends to keep water molecules that are away from surfaces from separating.

cohesion

_______ in leaves, stems, and roots transmits that force.

cohesion btw water molecules

Examples of secretory proteins

collagen, insulin, and digestive enzymes of the stomach and intestine

secretory protein examples

collagen, insulin, and digestive enzymes of the stomach and intestine

sucrose is loaded by active transport into nearby ______ of the phloem and then diffuses through channels into the _________ in the veins of the leaves

companion cells, seive tube members

The eukaryotic cell overcomes the problem of its larger size by _____. -only living in multicellular organisms -only living in non-extreme environments -always containing a cell wall -compartmentalizing cellular functions into various organelles

compartmentalizing cellular functions into various organelles

An enzyme inhibitor that is roughly the same shape as the substrate and binds at the active site is termed a(n) _____ inhibitor.

competitive

a ____ inhibitor has a structure so similar to the substrate that it can bond to the enzyme just like the substrate

competitive

An enzyme inhibitor that is roughly the same shape as the substrate and binds at the active site is termed a(n) _____ inhibitor. What do they do?

competitive; Competitive inhibitors prevent substrate binding by mimicking the substrate and competing for the active site.

water moves through the root ____ to the _____

cortex, vascular tissue

the inner membrane of mitochondria have infoldings called what

cristae

Hydrogen bonds tend to pull water molecules at the surface together, reducing the _____ of the surface.

curvature

In C4 and CAM plants carbon dioxide fixation occurs in the

cytoplasm

As opposed to C3 photosynthesis, C4 photosynthesis and CAM photosynthesis first fix carbon dioxide into four-carbon compounds in the

cytoplasm of the mesophyll cells

what provides the cell with structural support?

cytoskeleton: made of microfilaments

area outside of the chloroplast is called...

cytosol

glycolysis occurs in the...

cytosol

glycolysis and cellular respiration occurr in

cytosol and mitochondria

Motor proteins require energy in the form of ATP. ATP hydrolysis results in a conformational change that allows the protein to move along microtubular tracks (pathways). What structural component of the motor protein contains the ATP binding site and, therefore, changes shape to enable movement? a. the stalk b. the portion of the molecule that binds to the vesicle being transported c. a location midway between the vesicle binding site and the protion of the molecule that binds to microtubular tracks d. the portion of the molecule that binds to the microtubular track along which the vesicle is being transported

d.

What is a major difference in the extracellular matrix (ECM) between plant and animal cells? A. plant ecm components are released extracellularly by the gogli stacks, whereas lysosomes function in this capacity in animal cells b. Plant and animal ECMs are quite similar in structure and function. c. Plant ECM is composed primarily of proteins, whereas animal ECM is mainly carbohydrates. d. Plant ECM is primarily carbohydrate in nature, whereas animal ECM is largely protein based.

d.

which of the following events takes place in the electron transport chain? A. the breakdown of an acetyl group to carbon dioxide b. substrate-level phosphorylation c. breakdown of glucose into 2 pryvate molecules. D. the extraction of nrg from hi-nrg electrons remaining from glycolysis and the Krebs cycle

d.

Which statement most accurately explains why ATP hydrolysis is highly exergonic? A. ATP contains the carbohydrate ribose, which stores a large amount of chemical energy b. energy is released when a phosphate group is added. C. there is a large increase in potential energy because charge repulsion is reduced, accompanied by a large increase in entropy. d. there is a large drop in potential energy because charge repulsion is reduced, accompanied by a large increase in entropy.

d. ****Potential energy drops because ATP's four negative charges become spread between two molecules as opposed to being clustered on one molecule; products are also more disordered than reactants.

What type of functional group results when the alcohol group on glycerol reacts with the carboxylic acid group on a fatty acid? A. peptide bond b. glycosidic bond c. hydrocarbon d. ester

d. ester

Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of this amino acid. A. relative to the amino acids found in organisms, its interactions with water will be intermediate. B. it is hydrophilic c. relative to the amino acids found in organisms, its interactions with water will be very high d. it is hydrophobic

d. it is hydrophobic

In humans, xeroderma pigmentosum is a disorder of the nucleotide excision repair mechanism. These individuals are unable to repair DNA damage caused by ultraviolet light. Which of the following are the most prominent types of mutations in individuals suffering from xeroderma pigmentosum? a. methylation of purines b. telomere shortening c. mismatch errord d. pyrimidine dimers

d. pyrimidine dimers

higher relative humidity of air around leaf, effect on transpirational pull?

decreases

less curvature of water surface on mesophyll cells, effect on transpirational pull?

decreases

lower rate of evaporation from surface of mesophyll cells, effect on transpirational pull?

decreases

thicker film of water on surface of mesophyll cells, effect on transpirational pull?

decreases

Enzymes speed up chemical reactions by ____.

decreasing the activation energy

Enzymes speed up chemical reactions by ____.

decreasing the activation energy, which stabilizes the transition state and increases rate of reaction.

an enzyme is _____ when it loses its native conformation and its biological activity

denatured

when proteins move from the ER to the Golgi, the Golgi...

detects chemical tags proteins, alters their structure, releases them in other vesicles targeted for different destination

what other than store calcium does the smooth er do?

detoxification and lipid synthesis

lactose is a....

disaccharide

In ATP synthesis in both the chloroplast and mitochondria, _______ is coupled to the formation of a proton (H+) gradient across a membrane.

electron transport

Which term describes the degree to which an element attracts electrons?

electronegativity

Redox reactions involve the gain or loss of _____.

electrons

how does PSI replenish its lost e-?

electrons leaving the first electron transport chain

_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.

electrons passing along the electron transport chain

far from the nucleus

electrons tend to have more potential energy when they are in electron shells .....

Which tissue acts as a filter on the water absorbed by root hairs?

endodermis-filter solutes from water and allow them to pass through to the vascular tissue.

The collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

endomembrane system

phosphorylation of enzymes and substrates drives ____ which enables cells to ____

energetic coupling, enables cells to do work

starch is a ____ molecule found in _____

energy storage, plants

In animals the role of carbohydrate polymers is primarily

energy storage.

a chloroplast is covered by 2........

envelope membranes

R-groups

enzyme specificity is a function of the active site's shape and the chemical properties of ______ at the active site

orienting substrates

enzymes speed reaction rates by _____ ______ and lowering activation energy

What type of functional group results when the alcohol group on glycerol reacts with the carboxylic acid group on a fatty acid?

ester

lysosomes are found in pro, euk, or both?

euk

mitochondria are found in pro, euk, or both?

euk

nucleolus are found in pro, euk, or both?

euk

centrioles are only found in

euk. animal cells

cell walls, chloroplasts, and vacuoles are only found in

euk. plant cells

why is photosynthesis important

every chemical reaction decreases free energy

which requires fusion with the plasma membrane endo or exo?

exo

where is chitin found?

exoskeletons, cell walls of fungi and algae

the beta glycosidic linkage of cellulose allows it to do what?

extensive H bonding between hydroxyl groups of parallel cellulose molecules

Ideally, the best scaffold for growing a replacement tissue or organ would be made of what? -silicon -plastic -cotton -extracellular matrix

extracellular matrix

The process shown in this animation is referred to as _____.

facilitated diffusion

exergonic ---> uphill... correct? If false, what's wrong?

false - downhill

what happens instead of glycolysis when oxygen is not present?

fermentation

the electron transport chain after PSI ends with

ferredoxin

What is the name of the currently accepted model of membrane structure, and where does it place membrane proteins?

fluid-mosaic; embedded within the membrane and on the surfaces of the membrane

what does an irreversible inhibitor do

forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity

When ATP is hydrolyzed into ADP and inorganic phosphate, _____.

free energy is released

Proteins that function in the nucleus, such as DNA polymerase, are synthesized by

free ribosomes in the cytoplasm

Function of the Mitochondria (MB)

generates ATP

glycogen is a polymer of.......

glucose

in glycolysis, the carbon containing compound that functions as an e- donor is....

glucose

Which of these best reflects the following relationship: monosaccharide versus polysaccharide?

glucose versus glycogen

The primary energy storage molecule in animals is?

glycogen

the linkage in polysaccharides is.....

glycosidic linkage

cisternal maturation occurs in the

golgi

protein modification and sorting occurs in the

golgi

An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum.

golgi aparatus

thykaloids stack to form

granum

If hot, dry conditions require the plant to conserve water, _____ close the _______

guard cells, stomata

What are the byproducts of cellular respiration? (3)

heat CO₂ water

Which of these are by-products of cellular respiration?

heat, carbon dioxide, and water

Which of the following sugars might have the formula C6H12O6?

hexose

fructose is a_____ that is a ______

hexose, ketose

glucose is a.....

hexose- aldose (has terminal carbonyl group)

on sunny days, when photosynthesis rates are high, phloem transport rates are high or low?

high

cohesion and adhesion are the result of

hydrogen bonds

Peroxisomes produce WHAT as a by-product of their metabolic processes.

hydrogen peroxide

2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed?

hydrogen, polar

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

hydrolysis

how are disaccharides and polysaccharides formed back into individual monosaccharides?

hydrolyzation

Basal bodies and centrioles have

identical structures

lower

if a reaction is exergonic, the products have _______ free energy than the reactions

allosteric activation

in ______ ________ a regulatory molecule binds to a location other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate

cooperativity

in ______, if one substrate is bound, then the next binds more easily

Carbohydrates have been shown to form

in biotic and abiotic conditions, including outer space.

One function of peroxisomes is alcohol detoxification. In which of the following locations would you expect to find large quantities of peroxisomes?

in liver tissue of people who drink large quantities of alcohol

larger diameter of somatal pores, effect on transpirational pull?

increases

The primary difference between C3 , C4 , and CAM photosynthesis is in the

initial fixation of CO₂

The only cytoskeletal fibers not associated with intracellular movement or whole cell locomotion are the...

intermediate filaments

Many cell organelles, most notably the nucleus are anchored by (............) which are assembled from a diverse class of proteins.

intermediate fillaments

Endocytosis moves materials _____ a cell via _____. out of ... membranous vesicles -into ... membranous vesicles -into ... facilitated diffusion -out of ... diffusion -into ... a transport protein

into ... membranous vesicles

what do beta linkages do to each molecule?

invert them oppositely, producing straight unbranched molecules

what happens to the SA of a cells plasma membrane when endocytosis occurs

it decreases

what happens to the SA of a cells plasma membrane when exocytosis occurs

it increases

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

it is acquired by a reactant in an endergonic reaction

an enzyme is considered specific because

its ability to recognize the shape of a particular molecule

why is the citric acid cycle cyclic and not linear?

its easier to move electrons and produce CO₂ from compounds with 3 or more C atoms than from a 2c compound like acetyl coA

ribulose is a....

ketose- essential to carbon fixation in green plants

In muscle cells, fermentation produces what? (2)

lactate & NAD+

main sources in a plant are its

leaves

Both the _____ and the _____ are the same in all types of photosynthesis.

light reactions, calvin cycle

One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water.

lipid

In marshes and other wet areas where vegetation is rotting, the water surface often has an oily sheen due to insoluble compounds. What are these molecules?

lipids

Enzymes speed reactions mainly by ...

lowering EA.

A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of eukaryotic cells.

lysome

When a lysosomal protein-containing vesicle buds from the Golgi apparatus, it is a

lysome

Which organelle plays a role in intracellular digestion?

lysosome

Which organelle plays a role in intracellular digestion? -chloroplast -Golgi apparatus -plasmodesma -ribosome -lysosome

lysosome

autophagy is done by

lysosome

macromolecule digestion occurs in the

lysosome

Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis. The asbestos fibers can be inhaled. Cells will phagocytose the foreign material but are unable to degrade it. As a result, asbestos fibers build up in which of the following intracellular organelles?

lysosomes

the golgi sythesize

lysosomes and lipids

ribosomes deposit their contents in organelles and outside the cell through

membrane fusion

What happens in lateral diffusion in the cell membrane?

membrane lipids and proteins move sideways in the bilayer

In C4 and CAM photosynthesis, carbon dioxide is fixed in the cytoplasm of the _____, not inside the chloroplasts. Carbon dioxide enters these cells by _______

mesophyll cells, diffusion from the stroma

During muscle contractions, myosin motor proteins move across tracks of.....

microfilaments

The extension of pseudopodia in amoeba is due to the regulates assembly and destruction of....

microfilaments

WHAT are a component of the cytoskeleton.

microfilaments

Centrosomes are sites where protein dimers assemble into .....

microtubules

In Eukaryotic flagella, the fibers that slide past one anotherdue to the activity of dynein protiens are...

microtubules

The cilia and flagella of eukaryotic cells are composed of _____. -microtubules -intermediate filaments -tonofilaments -microfilaments -pili

microtubules

Which of these are hollow rods that shape and support the cell? -chloroplasts -microtubules -peroxisomes -microfilaments -plasma membrane

microtubules

what are hollow rods that shape and support the cell

microtubules

You have a distant cousin, age 4, who is always tired and fatigued and is not able to play games and sports like other healthy children. He is most likely to have an enzyme deficiency or defect associated with which intracellular organelle

mitochondria

its matrix contains enzymes that function in cellular respiration

mitochondria

where is atp made

mitochondria

which organelle is extensive in muscle cells

mitochondria

Which of these organelles carries out cellular respiration? -chromatin -mitochondrion -smooth endoplasmic reticulum -ribosomes -nucleolus

mitochondrion

Function of the Golgi Apparatus (MB)

modifies and sorts proteins

a ______ cannot be hydrolyzed any further

monosaccharide

the smallest unit of a carb is...

monosaccharide

for glucose in a solution, why does equilibrium favor the ring formation?

more stable than straight chain formation

Sodium-potassium pumps:

move two potassium ions and three sodium ions while consuming an ATP for each cycle

secretion

moved out of cell

Cystic fibrosis (CF) is a membrane-transport disease that is caused by an allele found primarily in Caucasian populations. What mechanism fails in CF patients?

movement of chloride ions across cell membranes

The most common pattern of membrane traffic is?

movement of newly synthesized proteins from rough ER

water and ions can travel into the root by the apoplastic route-- ____________-- or by the symplastic route-- ___________

moving between cells along cell wals, moving from cell to cell through plasmodesmata

Which of the following is a correct match of cell type with structure?

muscle cell ... has proteins that slide back and forth

Which of the following is a correct match of cell type with structure? -nerve cell ... closely joined -skin cell ... has a large volume -intestinal cell ... closely joined -muscle cell ... has proteins that slide back and forth -skin cell ... has long extensions

muscle cell ... has proteins that slide back and forth

in oxidative phosphorylation, ____ and _____ are oxidized in the electron transport chain

nadh and fadh2

the electrons derived from this oxidation reaction in the light reactions are used to reduce ____ to _____

nadp+ to nadph

are conducting cells in xylem alive

no

ferredoxin to NADP+. Is energy input required?

no

in reducing 3PGA to G₃P, are carbon atoms added or removed?

no

is co2 or o2 involved in glycolysis?

no

plastoquinone to P700+. Is energy input required?

no

larger air space in leaf interior, effect on transpirational pull?

no effect

are bound substrates always converted to products?

no sometimes they escape

water to P680- energy input required?

no, p680 is already very high energy

are all enzymes made of proteins?

no- some can be RNA

a ____ inhibitor binds to the enzyme on a place that isnt the active site

noncompetitive

what is the double membrane that encloses the nucleus called?

nuclear envelope

Molecules move into and out of the nucleus through the _____. -nucleoid -nucleolus -chromatin -nuclear pore complexes

nuclear pore complexes

Where is a bacterial cell's DNA found? -ribosomes -nucleus -peroxisome -nucleoid region -capsule

nucleiod region

Where is a bacterial cell's DNA found?

nucleoid region

Ribosomal subunits are manufactured by the _____. -nucleolus -peroxisome -smooth endoplasmic reticulum -rough endoplasmic reticulum -lysosome

nucleolus

Ribosomes are manufactured by the

nucleolus

Which of these is rich in unsaturated fats?

olive oil

proteins destined for lysosomes are made

on ribosomes on the ER

One of several formed bodies with specialized functions, suspended in the cytoplasm of eukaryotic cells.

organelle

hat name is given to the process by which water crosses a selectively permeable membrane?

osmosis

when the sugar concentration in the phloem rises near the source, water enters the phloem from the xylem by

osmosis

in acetyl coA formation, pyruvate is _____ into acetyl coA

oxidized

photosynthesis produces ____ and _____

oxygen and sugar

The Casparian strip is a waterproof barrier that forces water and solutes to

pass through the plasma membranes of endodermis cells.

C4 plants have a special carbon acceptor molecule, ______. ______, a highly efficient enzyme, reacts with carbon dioxide and ___ to produce oxaloacetate, a ______ compound that gives C4 photosynthesis its name.

pep, pep carboxylase, pep, 4 carbon

If you were going to develop a new antibiotic, you would probably need to become an expert on which of these carbohydrates?

peptidoglycan

Which of the following carbohydrates contains a peptide bond?

peptidoglycan

main constituent of bacterial cell walls is?

peptidoglycan

Which of these organelles produces H2O2 as a by-product? -flagellum -centrioles -mitochondrion -peroxisome -nucleus

peroxisome

A white blood cell engulfing a bacterium is an example of _____. -phagocytosis -pinocytosis -facilitated diffusion -receptor-mediated endocytosis -exocytosis

phagocytosis

the engulfing of microorganisms or other cells and foreign particles by phagocytes

phagocytosis

Lysosomes help in the hydrolysis of macromolecules for example:

phagocytosis and autophagy

water reaches the veins in the leaf, where some is used to transport sugar in the ____. the remaining water molecules pass out of the _____ tissue and into the ______.

phloem, vascular, mesophyll

In C3 plants the conservation of water promotes _____.

photorespiration

This use of ATP in the C4 process makes the C4 pathway more efficient in conditions with little ______

photorespiration

CO₂ provides carbon for

photosynthesis

most of the biomass of carbs is created by.....

photosynthesis

The _____ is a selective barrier, regulating the passage of material into and out of the cell. -lysosome -plasma membrane -nucleus -chloroplast -nuclear envelope

plasma membrane

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

plasma membrane

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell. -plasma membrane -nucleoid region -ribosome -pili -cell wall

plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell's chemical composition.

plasma membrane

Chemical energy is a form of _____ energy.

potential

The buildup of hydrogen ions inside the thylakoid compartment stores _____

potential energy

The mechanism that explains the movement of sugars throughout a plant is called the ________

pressure flow hypothesis

nucleoid are found in pro, euk, or both?

pro

Function of the rough ER (MB)

produces secretory proteins

The cell wall found in bacterial cells functions to _____. -regulate what passes in and out of the cell -maintain the position of the nucleus -synthesize phospholipids -protect the cell and provide shape and rigidity

protect the cell and provide shape and rigidity

What is the function of a bacterium's capsule?

protection

A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.

protein

The ribosome functions in the synthesis of _____. -carbohydrates -proteins -nucleic acids -lipids

proteins

once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called......

pyruvate

Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?

pyruvate, ATP, NADH

A protein that binds selectively to a specific molecule (such as an intercellular mediator or antigen) and initiates a biological response.

receptor

electrons

redox reactions involve the gain or loss of ....

Is the electron acceptor reduced or oxidized?

reduced

in oxidative phosphorylation, O₂ is ____ to water

reduced

why is closing the stomata a tradeoff

reduces water loss but slows down photosynthesis and may cause plant to overheat

function of microfilaments (MB)

responsible for cell locomotion and the cell's structural characteristics

In a bacterium, where are proteins synthesized?

ribosomes

In a bacterium, where are proteins synthesized? -ribosomes -nucleus -peroxisome -nucleoid region -capsule

ribosomes

Proteins destined for secretion are made on

ribosomes bound to the rough ER

proteins destined for lysosomes are made on

ribosomes bound to the rough ER

What is the site of synthesis of proteins for export (secretion from the cell)?

ribosomes that attach to the endoplasmic reticulum

The surface area of a root is enormously expanded by thousands of _____ and _____

root hairs, symbiotic mycorrhizae

Mycorrhizae are mutualistic associations of ____ and ____

roots and fungi

function and structure of Intermediate filaments

rope-like structure anchor organelles and intercellular junctions called desmosomes. specialized for bearing tension

what organelle is found extensively in the pancreas (produces insulin)

rough ER

Which of these manufactures cellular membranes by adding membrane proteins and phospholipids to its own membrane? -lysosomes -nucleolus -rough endoplasmic reticulum -Golgi apparatus -ribosomes

rough endoplasmic reticulum

CO₂ is fixed by ____ to start calvin cycle

rubisco

in C3 photosynthesis, carbon dioxide is captured by the ____ enzyme and added to ____ inside the chloroplast. This produces ____, a three-carbon compound that gives the C3 process its name.

rubisco, rubp, 3-PGA

a reaction is unfavorable if it spontaneously...

runs in the direction of the reactants

proteins from rough ER can go where?

secred outside the cell; to create lysosomes; to replace proteins in the plasma membrane

function of microtubules

serve as intracellular highways for transporting vesicles and organelles; required for cellular locomotion via flagella and cilia

when the noncompetitive inhibitor is bonded to the enzyme, the ______ of the enzyme is distorted

shape

Root pressure can move water a ____ distance up the xylem because of the ____ water potential of the xylem in comparison to the water potential in the surrounding cells.

short, lower

an area where sugars are used or stored

sink. ex- roots and fruits

whats an allosteric enzyme?

small molecules can change its activity by noncovalent bonding to other parts of the enzyme (allosteric sites)

Where is calcium stored?

smooth ER

Where is calcium stored? -mitochondria -centrioles -smooth endoplasmic reticulum -rough endoplasmic reticulum -microtubules

smooth endoplasmic reticulum

Calcium ions are stored in the

smooth er

lipid sythesis occurs in the

smooth er

poison detoxification occurs in the

smooth er

what is a substrate analog?

something that looks like a substrate

an area of sugar production is called a

source

the difference in turgor pressure between the ___ and the ____ causes the flow of the solution into the ____

source, sink, phloem

Where would you most likely find an integral membrane protein?

spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell.

PSII does what to yield e-

splits water

where does the oxygen generated from photosynthesis come from?

splitting of water- hydrogen ions and oxygen are released into the thylakoid compartment

how does PSII replenish its lost e-?

splitting water

Cell walls are used by many different organisms for protection from their environment and structural support. These cell walls must obviously be insoluble in water; otherwise, they would dissolve the first time the organism got wet. Which of the following carbohydrates would you expect to be the most soluble in water?

starch

space inside chloroplast is called....

stroma

thykaloids are surrounded by fluid called

stroma

where is calvin cycle located?

stroma

cellulose is a ____ molecule found in _____

strucutral, cell walls

most commonly transported sugar in plants

sucrose

the Calvin cycle (sometimes called the dark or carbon reactions), which uses the products of the light reactions to produce _____

sugar

carbohydrates are more commonly known as...

sugars

_____ in leaves generates the force that pulls water through the xylem.

surface tension

The transport of water and mineral nutrients from the roots to the leaves in plants depends on three properties of water

surface tension, adhesion, cohesion

the water surface between the microfibrils becomes more curved, which increases the ____ and ____

surface tension, transpirational pull

during which process of meiosis does crossover take place?

synapsis

Function of the Smooth ER (MB)

synthesizes lipids

What is the major structural difference between starch and glycogen?

the amount of branching that occurs in the molecule

what is the major structural difference between starch and glycogen?

the amount of branching that occurs in the molecule

What is a transition state?

the complex formed as covalent bonds are being broken and re-formed during a reaction

transition state

the complex formed as covalent bonds are being broken and re-formed during a reaction

NADH and FADH2 are both electron carriers that donate their electrons to....

the electron transport chain

what happens at the end of phase 2 of the calvin cycle?

the end of Phase 2, 1 of the 6 R₃P molecules is output from the cycle, removing 3 of the 18 carbons

A reaction is said to be unfavorable if... (2)

the free energy change of the reaction is positive and the reaction favors the reactants

Over the past several decades, natural selection has caused populations of Staphylococcus aureus (an infectious wound bacterium) to evolve resistance to most antibiotics. If antibiotic use were stopped, what would you predict would happen to theseS. aureus populations? a. They will go extinct without the antibiotic b. the frequency of resistant forms will definately increase in these populations c. the populations will begin colonizing new environments d. the frequency of nonresistant forms will increase in these populations

the frequency of nonresistant forms will increase in these populations

The rate of O₂ production by the light reactions varies with _____ because _____

the intensity of light, because light is required as the energy source for O₂ formation

in the mesophyll, some h2o molecs are used in photosynthesis, while excess h2o molecs evaporate from the mesophyll cell surfaces into ____. when the stomata are open, the water molecules pass out of the leaf.

the interior of the leaf

Integral membrane proteins stay in membranes because of

the locations of their polar and nonpolar amino acids.

acetyl coA formation and the citric acid cycle occur in.....

the matrix

In order to best eliminate the chance for rejection, a tissue or organ should be made from cells obtained from which of the following? -a cadaver -a donor pig -a sibling -the patient

the patient

anabolic pathway

the polymerization of amino acids into a protein is an example of an _______ _______

What is the difference between an aldose sugar and a ketose sugar?

the position of the carbonyl group

Suppose that the concentration of CO₂ available for the Calvin cycle decreased by 50%, how would O₂ production be affected

the rate of O₂ production would decrease because the rate of adp and NADP+ production by the calvin cycle would decrease

reductant in PSII and PSI

the reduced primary electron acceptors

Which of the following do starch and cellulose have in common?

the size of their monosaccharide subunits

What region of a steroid is hydrophilic?

the terminal hydroxyl group

Electrons tend to have more potential energy when ____.

they are in electron shells far from the nucleus

what happens to the phosphate groups on ATP in a watery environment and what does this cause

they are partially ionized; several negative charges packed into a small space

bound ribosomes make proteins destined for locations separated from the cytoplasm by a cellular membrane

they will ultimately reside in or pass through the endomembrane system

membraneous sacs in chloroplasts are called

thykaloids

where do protons accumulate during ATP synthesis in the light reactions?

thylakoid space (lumen)

where are light reactions located?

thylakoids

Oxygen holds electrons more ______ than hydrogen does

tightly

The CAM adaptation is to fix carbon dioxide at different ____ rather than in different ____. In CAM plants the stomata are

times, locations, closed during the day

In mitochondrial electron transport, what is the direct role of O2?

to function as the final electron acceptor in the electron transport chain

What is the function of the reactions in a fermentation pathway?

to generate NAD+ and NADH, so glycolysis can continue

What is a purpose of the cell wall for both prokaryotes and plant cells?

to protect the cell from the effects of a hypotonic environment

what does the pulse chase experiemnt allow scientists to do?

track the movement of proteins through the endomembrane system

C4 plants differ from C3 and CAM plants in that C4 plants _____

transfer fixed carbon dioxide to cells in which the Calvin cycle occurs

what do protein kinases do

transfer one of ATP's phosphates to enzymes that are being controlled-

Beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____.

transferring of information from DNA to messenger RNA

loss of water from leaves through the stomata is called

transpiration

the loss of water through _____ in the leaves pulls water up to the leaves through the ____.

transpiration, xylem

how do molecules and ions get into the leaves of plants

transpiration- evaporation of water from leaves pull them up

A tiny membranous sac in a cell�s cytoplasm carrying molecules produced by the cell.

transport vesicle

in endo and exo cytosis,

transported substances never physically cross the plasma membrane

true or false- enzymes provide no energy for the reaction besides collision energy

true

osmosis increases the ______ in the phloem and starts the flow of materials into the phloem

turgor pressure

the overall reaction reduces entropy

under what conditions could some exothermic reactions be nonspontaneous

what regulates cytoplasm composition, creates internal pressure, stores cell compounds

vacuole

In C4 plants, the chloroplasts are concentrated in the ______ which leads to less _____ and _____

vascular bundle sheath cells, photorespiration, water loss

the electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the phososystem II replacement electrons come?

water

when the concentration of sucrose in the phloem near the sink is lowered,

water moves out of the phloem by osmosis and back into the xylem

what holds an enzyme and substrate together before a reaction occurs?

weak noncovalent forces

protein kinase and allosteric effector

what 2 types of control agents exert noncompetitive inhibition?

the enzyme changes shape

what often happens to an enzyme after it binds to its substrate?

slows

when a pathway is subject to allosteric feedback inhibition, an accumulation of effectors _______ the pathway

when products have lower potential energy and higher entropy than reactant

when is the overall free energy change in a reaction most likely to be negative (exergonic)

what is cooperativity?

when no subsstrate is bound to active sites, they are malformed so it takes a hard collisioin to bind first substrates. then the others become easier

complex

when properly aligned, the enzyme and substrate form an enzyme substrate (ES)

Under what circumstances does membrane transport always require energy?

whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane

what distinguishes surface tension, adhesion and cohesion from each other

where hydrogen bonds are found

the terminal phosphate

which part of the ATP molecule is released when it is hydrolyzed to provide energy for biological reactions

electronegativity

which term best describes the degree to which an element attracts electrons

substrate analog

which type of control agent never speeds an enzyme's action?

triphosphate chains are unstable

why is ATP a good source of energy for biological reactions

Can changes in potential energy be released as heat?

yes

P700 to FD (ferredoxin). Is energy input required?

yes

are phloem cells alive

yes

are simple sugars carbs?

yes

does a control agent ever speed up an enzyme

yes

is ATP produced in citric acid cycle?

yes

is peptidoglycan found only in bacteria?

yes

p680+ to PQ (plastoquinone). Is energy input required?

yes

when a cell makes an enzyme does it make many copies

yes

are complex sugars carbs?

yes, dont have formula cn(h2o)n

do enzymes react chemically with substrates?

yes- there can be an H transfer

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?

γ-phosphate (the terminal phosphate)