Mastering Biology ch 6-9

ATP synthase is a key enzyme of mitochondrial energy conversion. Mitochondrial ATP synthase deficiency is due to a mutation in a gene important for the formation of a subunit in the ATP synthase complex. Scientists could use cells with this gene mutation to investigate which of the following questions?

What effect does the mutation have on the amount of ATP synthesized during cellular respiration?

What can pass through the phospholipid bilayer without the help of a transport protein?

Hydrophobic (nonpolar) molecules Small, uncharged polar molecules large, uncharged polar molecules ions (carbon dioxide, oxygen, water, lipids)

Which of the following describes the process of glycolysis?

It represents the first stage in the chemical oxidation of glucose by a cell.

Which of the following functions is NOT associated with the cytoskeleton in eukaryotic cells?

Movement of RNA molecules from the nucleus to the cytoplasm

The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.

a catabolic pathway

The cell membranes of Antarctic ice fish might have which of the following adaptations?

a high percentage of polyunsaturated fatty acids

Which of the following would increase the electrochemical potential across a membrane?

a proton pump

Which of these is exhibiting kinetic energy?

a space station orbiting Earth

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using

a transmission electronic microscope.

Which of the following statements about the electron transport chain is true?

NADH and FADH2 donate their electrons to the chain.

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.

True

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?

Water will leave the cells, causing them to shrivel and collapse.

Which of these enters the citric acid cycle?

acetyl CoA

Which of these is NOT a product of the citric acid cycle?

acetyl CoA

only channels

allow water molecules and small ions to flow quickly across the membrane provide a continuous path across the membrane

All of the following are part of a prokaryotic cell except

an endoplasmic reticulum.

both channels and carriers

are integral membrane proteins transport solutes down a concentration or electrochemical gradient provide a hydrophilic path across the membrane

Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. As a result, these lipid rafts

are more rigid than the surrounding membrane.

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

cytoskeletal structures

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

embedded in a lipid bilayer.

The presence of cholesterol in the plasma membranes of some animals

enables the membrane to stay fluid more easily when cell temperature drops.

The reaction ADP + P --> ATP is a(n) _____ reaction.

endergonic

Which of these reactions requires a net input of energy from its surroundings?

endergonic

"Conservation of energy" refers to the fact that _____.

energy cannot be created or destroyed but can be converted from one form to another

A(n) _____ reaction occurs spontaneously.

exergonic

The energy for an endergonic reaction comes from a(n) _____ reaction.

exergonic

The following reaction A --> B + C + heat is a(n) _____ reaction. The

exergonic

Select the INCORRECT association

exergonic ... uphill

What molecules belong in space A and B?

glucose and oxygen

Which structure-function pair is mismatched?

microtubule; muscle contraction

Movement of vesicles within the cell depends on what cellular structures?

microtubules and motor proteins

Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the

mitochondria

Which cell would be best for studying lysosomes?

phagocytic white blood cell

What process occurs in structure H? (a chloroplast)

photosynthesis

Mitochondria are found in _____.

plant and animal cells

Chemical energy is a form of _____ energy.

potential

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

In fermentation _____ is reduced and _____ is oxidized.

pyruvate ... NADH

Which of the following is present in a prokaryotic cell?

ribosome

A primary objective of cell fractionation is to

separate the major organelles so that their particular functions can be determined.

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

In the citric acid cycle, ATP molecules are produced by _____.

substrate-level phosphorylation

What process occurs within Box B?

the citric acid cycle

How many NADH are produced by glycolysis?

2

In glycolysis there is a net gain of _____ ATP.

2

Which of the following statements is not true of most cellular redox reactions?

A hydrogen atom is transferred to the atom that loses an electron.

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

ATP

In glycolysis, what starts the process of glucose oxidation?

ATP

Active and passive transport of solutes across a membrane typically differ in which of the following ways?

Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy.

Which of the following is true of the evolution of cell membranes?

All components of membranes evolve in response to natural selection.

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?

Anion and cation.

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Fermentation

Which of the following are common traits of chloroplasts and mitochondria?

Both have their own DNA.

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Carbon dioxide

Both the volume and the surface area for three different cells were measured. These values are listed in the following table: Volume Surface Area Cell 1 9.3 µm3 26.5 µm2 Cell 2 12.2 µm3 37.1 µm2 Cell 3 17.6 µm3 40.6 µm2 Using data from the table above, select the best explanation for why that cell will be able to eliminate waste most efficiently?

Cell 2 since it has the highest surface area-to-volume ratio which facilitates the exchange of materials between a cell and its environment.

Which of the following choices correctly matches a tool and its proper application?

Cell fractionation to study the function of specific organelles

Gaseous hydrogen burns in the presence of oxygen to form water: 2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed?

Hydrogen, polar.

A cell has formed a food vacuole as it ingested a food particle. Which of the following events is associated with the breakdown of that food particle?

Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm.

Frye and Edidin (1970) labeled the membrane proteins of a mouse cell and a human cell with two different markers and fused the cells. In the accompanying diagram, these different markers are indicated with different colors. Based upon the results shown in the diagram, which of the following scientific questions below provided conclusive evidence through this investigation?

Do some membrane proteins move sideways within the phospholipid bilayer?

New biosensors, applied like a temporary tattoo to the skin, can alert serious athletes that they are about to "hit the wall" and find it difficult to continue exercising. These biosensors monitor lactate, a form of lactic acid, released in sweat during strenuous exercise. Which of the statements below is the best explanation of why athletes would need to monitor lactate levels?

During fermentation lactate levels increase, which indicates insufficient oxygen is reaching the muscles causing athletic performance to suffer.

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

ER → Golgi → vesicles that fuse with plasma membrane

Which stage of glucose metabolism produces the most ATP?

Electron transport and chemiosmosis

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

Electronegativity.

Which of these is NOT a product of glycolysis?

FADH2

Which molecule is metabolized in a cell to produce energy for performing work?

Glucose

In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced?

Glucose is consumed, and carbon dioxide is produced.

Which step of the cellular respiration pathway can take place in the absence of oxygen?

Glycolysis

The oxidation of glucose in the presence of oxygen involves glycolysis, pyruvate oxidation, and the citric acid cycle (Krebs cycle). Some energy is captured in glycolysis when glucose is converted to pyruvate (pyruvic acid). In the citric acid cycle (Krebs cycle), more energy is captured in the form of reduced electron carriers, NADH and FADH2. Select the best explanation for why the eventual reoxidation of NADH and FADH2 is crucial for the continuation of the citric acid (Krebs) cycle.

In order for the cycle to continue, oxidized electron carriers must be available.

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?

Ionic

The formulation of a model for a structure or for a process serves which of the following purposes?

It functions as a testable hypothesis.

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.

A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?

It is stored in NADH and FADH2

Three lab groups carried out an experiment to identify the correct molarities for five solutions. Each unknown contained one of the following sucrose concentrations: 0.0 M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, and 1.0 M. Each data entry represents the average of 3 sample replications of 1 cm3 sweet potato cubes expressed as percent change in mass after an overnight (24 hr) soak in the unknown solutions. From the data given, which statement most accurately describes what is occurring in response to a particular unknown solution. Unknown Percent change in mass (%) Group 1 Group 2 Group 3 A 6.6 7.8 7.5 B 3.1 3.7 2.9 C -2.7 -3.5 -2.5 D 0.7 0.5 1.1 E -11.6 -12.3 -12.6 F -5.2 -6.2 -4.9

Osmosis of water molecules from unknown solution A likely caused the increase in mass observed.

Which of the following statements is true of the bonds in a water molecule?

Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.

Suppose that the cell shown in this figure is secreting insulin, a protein hormone, via exocytosis. Which statement most accurately describes why this mechanism of transport is ideal for insulin secretion?

Proteins are large molecules that cannot be transported efficiently across the membrane via transport proteins.

Which one of the following statements about the endomembrane system is correct?

Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system.

In facilitated diffusion, what is the role of the transport protein?

Transport proteins provide a hydrophilic route for the solute to cross the membrane.

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

True

In a biological reaction, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, a substance that resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the amount of succinate molecules to those of malonic acid reduces the inhibitory effect if malonic acid. Select the correct identification of the molecules described in the reaction.

Succinate is the substrate, and fumarate is the product in the reaction.

Which of the following statements about the chemiosmotic synthesis of ATP is correct?

The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane.

Which statement about the citric acid cycle is correct?

The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.

Gaucher disease is the most common of lipid storage diseases in humans. It is caused by a deficiency of an enzyme necessary for lipid metabolism. This leads to a collection of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow. Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells would be involved in Gaucher disease.

The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids.

Which statement correctly describes the nuclear envelope of a eukaryotic cell?

The nuclear envelope is continuous with the endoplasmic reticulum.

Biological systems use free energy based on empirical data that all organisms require a constant energy input. The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following statements is an important consequence of this first law?

The organism must ultimately obtain all the necessary energy for life from its environment.

A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?

The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.

Which of the following statements about osmosis is correct?

The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.

Which one of the following statements about the redox reactions of the electron transport chain is correct?

The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane.

Cell membranes are asymmetrical. Which of the following is the most likely explanation?

The two sides of a cell membrane face different environments and carry out different functions.

Which of the following statements about a typical plasma membrane is correct?

The two sides of the plasma membrane have different lipid and protein composition.

Why are lipids and proteins free to move laterally in membranes?

There are only weak hydrophobic interactions in the interior of the membrane.

Which of the following is true of integral membrane proteins?

They are usually transmembrane proteins.

Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?

both flagella and motile cilia

What molecules belong in spaces E and F?

carbon dioxide and water

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

cell-cell recognition

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

cellular respiration

Which of the following correctly matches an organelle with its function?

central vacuole ... storage

Which structure is not part of the endomembrane system?

chloroplast

The advantage of light microscopy over electron microscopy is that

light microscopy allows one to view dynamic processes in living cells.

What process occurs in Box A? (glucose -> pyruvate)

glycolysis

Which of these are by-products of cellular respiration?

heat, carbon dioxide, and water

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

hydrolysis

In muscle cells, fermentation produces _____.

lactate and NAD+

What organelle is indicated by the letter C? (animals)

mitochondrion

Which structure is common to plant and animal cells?

mitochondrion

What molecule is indicated by the letter D?

oxygen

Which of the following is a major cause of the size limits for certain types of cells?

the need for sufficient surface area to support the cell's metabolic needs

The permeability of a biological membrane to a specific polar solute may depend on which of the following?

the types of transport proteins in the membrane

What is energy coupling?

the use of energy released from an exergonic reaction to drive an endergonic reaction

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?

transforming the energy in glucose and related molecules in a chemical form that cells can use for work

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

two ATP

Which of the following best describes the structure of a biological membrane?

two layers of phospholipids with proteins either crossing the layers or on the surface of the layers

only carriers

undergo a change in shape to transport solutes across the membrane transport primarily small polar organic molecules

The electrons stripped from glucose in cellular respiration end up in which compound?

water

Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?

whether or not the cell is partitioned by internal membranes

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

γ-phosphate (the terminal phosphate)