Bio Exam 3

True of False: Osmosis refers specifically to the diffusion of water molecules down their concentration gradient.

True

True or False: Receptor-mediated endocytosis is different from phagocytosis and pinocytosis in that cells use it to bring in specific (as opposed to random) large molecules.

True

True or False: Long, thin nerve cells are an example of cells that maintain a good surface area-to-volume ratio is by having an altered shape.

True

True or False: In a complex solution containing many different solutes, the diffusion of the largest solute molecules drives the diffusion of smaller solute molecules.

False

The extracellular structure that holds animal cells together in tissues is called ___________________.

Group of answer choices

the phospholipid bilayer

the fluid mosaic

the extracellular matrix

the cell wall

the extracellular matrix

True or False: NADH is the oxidized form of NAD+

False

True or False: Energy comes in multiple forms and can be converted from one form to another (e.g., kinetic to potential or vice versa).

True

In a redox reaction, the molecule that gains or "accepts" an electron, is known as the ___________________ and, when it gains an electron, it becomes _____________.

Group of answer choices

reducing agent, oxidized

oxidizing agent, oxidized

oxidizing agent, reduced

reducing agent, reduced

oxidizing agent, reduced

In a redox reaction, the ______________ gives up electrons and becomes ________________.

Group of answer choices

reducing agent, reduced

oxidizing agent, oxidized

reducing agent, oxidized

oxidizing agent, reduced

reducing agent, oxidized

Which is the more energetic/energized form of the energy carrier molecule, NAD+ or NADH?

NADH

_________________ is the breakdown of glucose in the absence of oxygen.

Group of answer choices

None of the options provided is correct.

Fermentation

Electron transport

Pyruvate oxidation

Fermentation

How much ATP does fermentation produce?

Group of answer choices

Zero

4

38

2

2

During cellular respiration, chemiosmosis is the movement of ______________  _______________ their electrochemical gradient  (ion concentration gradient) across the __________________________.

Group of answer choices

protons, down, inner mitochondrial membrane

protons, up, cytosol

protons, up, inner mitochondrial membrane

protons, down, matrix

protons, down, inner mitochondrial membrane

Oxidative phosphorylation occurs in two parts.  The first part accumulates hydrogens within the mitochondrial intermembrane space while the second part, called __________________________, uses the established hydrogen concentration gradient to drive ATP synthase.

Group of answer choices

receptor-mediated endocytosis

facilitated diffusion

active transport

chemiosmosis

chemiosmosis

The citric acid cycle occurs within the ___________________ resulting in an accumulation of reduced coenzymes in this region that ultimately feeds the electron transport chain.

Group of answer choices

inner mitochondrial membrane

intermembrane space

mitochondrial matrix

cytosol

mitochondrial matrix

Cellular respiration is the mechanism by which most eukaryotic organisms ______________________________________________.

Group of answer choices

synthesize carbohydrates.

synthesize nucleic acids.

harvest energy from biological molecules.

harvest energy from sunlight.

harvest energy from biological molecules.

Which of the following best explains why two photosystems are required?

Group of answer choices

Electrons need two energy boosts to reach NADP+

Each absorbs different wavelengths to maximize efficiency

One operates only at night

One produces ATP, the other produces oxygen

Electrons need two energy boosts to reach NADP+

In photosynthesis, if electron flow stops, ATP production will eventually stop.

True

A plant is exposed to light that is almost entirely green wavelengths. What is the most likely outcome?

Group of answer choices

No change in photosynthesis

Increased NADPH production

Decreased photosynthetic efficiency

Increased ATP production

Decreased photosynthetic efficiency

A scientist blocks electron flow between Photosystem II and Photosystem I. What is the immediate consequence?

Group of answer choices

CO₂ fixation increases

ATP production increases

Increased oxygen production

NADPH production stops

NADPH production stops

A mutation prevents the oxidation of water in Photosystem II. Which of the following will occur first?

Group of answer choices

RuBP accumulates

NADPH production increases

Oxygen production stops

Calvin cycle accelerates

Oxygen production stops

The Calvin cycle can continue indefinitely without the light reactions.

False

A plant is unable to produce ATP but can still produce NADPH. What process fails first?

Group of answer choices

Oxygen production

Electron transport

Water splitting

CO₂ fixation

CO₂ fixation

True or False: The cytoskeleton is analagous to the human skeleton in that it does things like maintain the overall shape of the cell and the positions of organelles.

True

Sometimes, cells must take up or __________ (expel) large, intact macromolecules that are too large and/or too charged to pass through biological membranes.  These macromolecules cross the membrane inside of small, membrane-enclosed structures called _________________.

Group of answer choices

secrete, vesicles

secrete, receptors

secrete, ligands

endocytose, vesicles

secrete, vesicles

True or False: Tonicity is relative and is meaningless in the absence of a semipermeable membrane.

True

True or False: The reduced form of an energy currency is the more energetic form.

True

True or False: The bulk of the ATP generated in aerobic respiration is generated by oxidative phosphorylation.

True

During the citric acid cycle, the products of pyruvate oxidation are further oxidized in order to reduce NAD+ to NADH and FAD to FADH2 and ____________ is released as a byproduct/waste.

Group of answer choices

Water (H2O)

Carbon dioxide (CO2)

Oxygen (O2)

ATP

Carbon dioxide (CO2)

__________________ links glycolysis to the citric acid cycle via acetyl CoA.

Group of answer choices

Oxidative Phosphorylation

Chemiosmosis

Pyruvate oxidation

The TCA cycle

Pyruvate oxidation

True or False: There is more energy stored in NAD+ than there is stored in NADH.

False

Chemiosmosis is driven by a proton gradient that we call the ______________________.

Group of answer choices

mitochondrial force

Hydrogen index

pH scale

proton motive force

proton motive force

If a plant cannot regenerate RuBP, what will happen over time?

Group of answer choices

ATP production stops immediately

Oxygen production increases

G3P production increases

CO₂ fixation stops

CO₂ fixation stops

If the proton gradient across the thylakoid membrane collapses, which process is MOST directly affected?

Group of answer choices

NADPH formation

Water splitting

Carbon fixation

ATP synthesis

ATP synthesis

Why is rubisco considered inefficient?

Group of answer choices

It is not an enzyme

It produces ATP

It can bind molecules other than CO₂

It requires light directly

It can bind molecules other than CO₂

Which best explains the relationship between light reactions and the Calvin cycle?

Group of answer choices

Light reactions supply energy carriers for the Calvin cycle

They operate independently

Calvin cycle produces ATP for light reactions

Both occur in the thylakoid

Light reactions supply energy carriers for the Calvin cycle

A mutation prevents NADP+ from being reduced. What is the most likely consequence?

Group of answer choices

Faster Calvin cycle

Electron transport chain backup

Increased oxygen production

Increased ATP production

Electron transport chain backup

Which of the following is an example of passive transport?

Group of answer choices

Phagocytosis

Receptor-mediated endocytosis

Secondary active transport

Facilitated diffusion

Facilitated diffusion

Most cells in animals are not free-floating.  Instead, they are attached to the extracellular matrix and to each other via ____________________.

Group of answer choices

nucleic acids

phagocytosis

hope

cell junctions

cell junctions

Which of the following best describes simple diffusion?

Group of answer choices

Movement of molecules down aconcentration gradient

Movement of molecules against a concentration gradient

Movement of molecules with the help of carrier proteins

Movement of ions through ion channels

Movement of molecules down a concentration gradient

Cells use energy coupling to do work.  Energy coupling uses a(n) _________________ process to drive a(n) __________________ process.

Group of answer choices

exergonic, intergonic

intergonic, exergonic

exergonic, endergonic

endergonic, exergonic

exergonic, endergonic

Which of the following best describes a metabolic pathway?

Group of answer choices

A process that only occurs in the mitochondria.

A random sequence of chemical reactions in a cell.

A single chemical reaction that produces a large amount of energy.

A series of chemical reactions occurring in a cell, with each step catalyzed by a specific enzyme.

A series of chemical reactions occurring in a cell, with each step catalyzed by a specific enzyme.

When we harvest energy from a catabolic reaction, we can either use it to directly fuel the next reaction in a series, or we can store it in energy currencies like ATP and NAD+/NADH for later use.  During glycolysis, certain intermediate molecules donate a phosphate directly to ADP to produce ATP.  When this happens, we call it ________________________.

Group of answer choices

oxidative phosphorylation

ATP hydrolysis

substrate-level phosphorylation

semiconservative replication

substrate-level phosphorylation

Besides starvation, why else would we breakdown biomolecules?

Group of answer choices

To reuse/reassemble their component parts

More than one of the options provided is correct.

To maintain homeostasis

Because we no longer need them at that moment

More than one of the options provided is correct.

Coenzyme A and oxaloacetate are recycled during ______________________.

Group of answer choices

chemiosmosis

the electron transport chain

the citric acid cycle

oxidative phosphorylation

the citric acid cycle

What is the purpose of fermentation?

Group of answer choices

To generate NADH

To generate pyruvate

To generate ATP

To regenerate NAD+

To regenerate NAD+

Fill in the blanks in the below statement:

Glycolysis produces pyruvate --> Pyruvate is ___________ to acetyl CoA, Acetyl CoA is ___________ to form NADH and FADH2 --> NADH and FADH2 are _____________ to drive ATP synthesis

Group of answer choices

oxidized, reduced, oxidized

reduced, reduced, reduced

oxidized, oxidized, oxidized

reduced, oxidized, reduced

oxidized, oxidized, oxidized

Which experimental result would indicate that a pigment is NOT involved in photosynthesis?

Group of answer choices

It absorbs visible light

It excites electrons

It does not transfer energy to the reaction center

It reflects green light

It does not transfer energy to the reaction center

A researcher artificially increases NADPH levels in a chloroplast. What is the most likely effect?

Group of answer choices

Oxygen production decreases immediately

Calvin cycle activity increases (if ATP available)

Water oxidation increases

Light reactions speed up

Calvin cycle activity increases (if ATP available)

Why is the Calvin cycle sometimes called 'light-independent' even though it depends on light reactions?

Group of answer choices

It does not directly require photons

It produces light

It uses oxygen instead of light

It only occurs in darkness

It does not directly require photons

If ATP synthase is inhibited, what happens to the proton gradient?

Group of answer choices

It decreases immediately

It disappears completely

It increases because protons cannot flow back

It has no change

It increases because protons cannot flow back

If a plant is exposed to very high-energy radiation (e.g., UV), what is the most likely effect?

Group of answer choices

Increased ATP production

Increased photosynthesis

Damage to pigment molecules

Faster carbon fixation

Damage to pigment molecules

In which of the following cell types would you expect to see cells connected to one another via tight junctions?  Select all that apply.

Group of answer choices

Cells that line the stomach

Blood cells

Cells that line the bladder

Cells of the heart

Cells that line the stomach

Cells that line the bladder

In cellular respiration, diffusion of protons from the intermembrane space back into the mitochondrial matrix drives the synthesis of ATP via ATP synthase during ____________________.

Group of answer choices

respiratory transport

the citric acid cycle

electron transport

chemiosmosis

chemiosmosis

During electron transport, _____________ from the oxidation of NADH and FADH₂ pass from one membrane-associated “carrier” to the next in a series and _____________ are pumped into the intermembrane space.

Group of answer choices

protons, electrons,

electrons, protons

protons, protons

electrons, electrons

electrons, protons

In ______________ reactions, energy is absorbed. In _________________ reactions, energy is released.  Most catabolic reactions are _____________________ reactions.

Group of answer choices

endergonic, exergonic, endergonic

exergonic, endergonic, exergonic

exergonic, endergonic, endergonic

endergonic, exergonic, exergonic

endergonic, exergonic, exergonic

A plant is placed in light but deprived of CO₂. What happens?

Group of answer choices

Electron transport stops immediately

Oxygen production stops

Light reactions stop immediately

ATP and NADPH accumulate

ATP and NADPH accumulate

Why are accessory pigments like beta-carotene important?

Group of answer choices

They replace chlorophyll

They fix carbon

They expand the range of light absorbed

They produce ATP directly

They expand the range of light absorbed

During photosynthesis, energy from photons is temporarily stored in excited electrons.

True

True or False: Facilitated diffusion requires energy from ATP.

False

When oxygen acts an an electron acceptor at the end of the electron transport chain, it is ____________________.

Group of answer choices

oxidized

reduced

reduced

The proton motive force that is generated during aerobic respiration is generated by _______________________.

Group of answer choices

the sodium potassium pump

glycolysis

electron transport

the glucose transporter

electron transport

Glycolysis results in 2 net ATP because the first reaction in the series is ______________________.

Group of answer choices

endergonic

hydrolytic

a redox reaction

exergonic

endergonic

• Glycolysis: Results in the production of pyruvate

• Pyruvate Oxidation: Results in the production of Acetyl CoA

• Citric Acid Cycle: Where most of the NADH is produced

• Oxidative Phosphorylation: Where energy carriers are reduced to drive ATP synthesis

Which of the below statements INCORRECTLY describes NAD+?

Group of answer choices

NAD+ is the oxidized form of NADH.

NAD+ is the reduced form of NADH.

NAD+ is used as an electron carrier during cellular respiration.

NAD+ is an example of an energy currency.

NAD+ is the reduced form of NADH.

______________ are our bodies preferred energy source.

Group of answer choices

Proteins

Nucleic acids

Carbohydrates

Lipids

Carbohydrates

A build up of the products of respiration, e.g., ATP and NADH, can regulate aerobic respiration by inhibiting activity of enzymes involved in the citric acid cycle.  This type of inhibition is known as ___________________________.

Group of answer choices

feedback inhibition

allosteric inhibition

transcriptional regulation

translational regulation

feedback inhibition

Most of the NADH produced during aerobic respiration is produced by ________________________.

Group of answer choices

electron transport

glycolysis

fermentation

the citric acid cycle

the citric acid cycle

Once an electron reaches the end of the electron transport chain, it will combine with oxygen and protons within the mitochondrial matrix to form __________.  Another way of saying this is: 

2H+  +  2e-  + 1/2 O₂  -->  _______________

 

 

 

Group of answer choices

salt (variable chemical formulae)

water (H2O)

more protons (H+)

Carbon dioxide (CO2)

water (H2O)

What is the effect of surface area on diffusion?

Group of answer choices

Larger surface area increases the rate of diffusion

Larger surface area decreases the rate of diffusion

Surface area has no effect on diffusion

Surface area only affects active transport

Larger surface area increases the rate of diffusion

Electron transport is _______________________ chemiosmosis.

Group of answer choices

unrelated to

coupled to

the same thing as

coupled to

Gluconeogenesis is the ____________ of smaller, carbon-containing, non-carbohydrate molecules into glucose.

Group of answer choices

adaptation

reduction

oxidation

phoshorylation

reduction

Which scenario would MOST directly reduce oxygen production?

Group of answer choices

Removing CO₂

Preventing water oxidation

Inhibiting the Calvin cycle

Blocking ATP synthase

Preventing water oxidation