Deck 3: Chemistry, biochemistry, and Cell Physiology

Question 1

The __________ structure of proteins involves interactions of amino acids that are found on different subunits.

A)primary
B)secondary
C)tertiary
D)quaternary

Answer 1

D

Question 2

pH is a measure of

A)[H⁺].
B)[OH⁻].
C)ratio of [H⁺] to [OH⁻].
D)ratio of [OH⁻] to [H⁺].

Answer 2

A

Question 3

Metabolic pathways that include synthetic reactions are called

A)anabolic
B)catabolic
C)amphibolic
D)both A and C

Answer 3

D

Question 4

Which of the following bonds are classified as weak bonds?

A)hydrogen bonds,ionic bonds,van der Waals forces
B)hydrogen bonds,ionic bonds,disulfide bonds
C)ionic bonds,van der Waals forces,ester bonds
D)peptide,bonds,disulfide bonds,ether bonds

Question 5

Why is ATP an important molecule?

A)It links major pathways that release energy with those that require energy.
B)It is an energy source that is found in high concentrations in cells.
C)It is an energy source that is always available in large quantities.
D)all of the above

Question 6

Which of the following types of bonds is not based on attraction of one molecule for the other,but instead is based on an uncharged molecule's inability to form a bond with water?

A)van der Waals interactions
B)hydrogen bonds
C)ionic bonds
D)hydrophobic bonds

Question 7

Which of the following statements is true for a strong base?

A)It has a low pᵏ.
B)It has a high pᵏ.
C)It easily donates [H⁺].
D)It dissociates slowly.

Question 8

How can environmental conditions such as salt concentration,temperature,and pH physically affect the enzyme itself?

A)Ions can bind to the active sites of enzymes,preventing the binding of substrate.
B)Changes in temperature change the rate at which molecules interact with the enzyme.
C)All these factors can disrupt the weak bonds that hold the enzyme in its active conformation.
D)These factors affect only the substrate.

Question 9

Diffusion of a solute through a solution is decreased by an

A)increased concentration gradient.
B)increased size of molecule.
C)increased diffusion coefficient.
D)increased diffusion area.

Question 10

Some of the most common buffers in animal cells are effective because

A)they have a pᵏ value that is close to the normal pH of the cell.
B)they can bind with H⁺ in a chemical reaction,forming a new product that can be eliminated from the body.
C)they have very low pᵏ values.
D)both A and B

Question 11

Which of the following types of energy is strictly potential energy?

A)mechanical energy
B)radiant energy
C)chemical energy
D)electrical energy

Question 12

What is the osmolarity of a solution containing 3 M MgCl₂ and 2 M glucose?

A)5 OsM
B)8 OsM
C)11 OsM
D)10 OsM

Question 13

Km in the Michaelis-Menten equation represents

A)the maximum amount of substrate that can be catalyzed by the enzyme.
B)the amount of substrate required for the initial velocity to be half of the maximal velocity.
C)the amount of substrate required to start an enzymatic reaction.
D)a set constant used for all enzymatic reactions.

Question 14

Which of the following carbohydrates is a monosaccharide?

A)sucrose
B)lactose
C)glucose
D)maltose

Question 15

Two compartments are separated by a membrane that is permeable to water and urea.Compartment I contains 1 M NaCl.Compartment II contains 2 M urea.Which of the following is a correct statement of their relationship based on the initial conditions?

A)Compartment I is isosmotic to Compartment II.
B)Compartment I is hyposmotic to Compartment II.
C)Compartment I is hypertonic to Compartment II.
D)both A and C

Question 16

What is the correct relationship between chemical reactions and temperature?

A)All chemical reactions are endothermic,and therefore require warmer temperatures.
B)Warmer temperatures provide the activation energy required to start chemical reactions.
C)Warmer temperatures allow more energy to be released during a chemical reaction.
D)Chemical reactions are not dependent on temperature at all.

Question 17

Which of the following types of regulation involves binding to the active site?

A)competitive inhibition
B)allosteric regulation
C)covalent modification
D)both B and C

Question 18

The correct term(s)for the most abundant liquid in which other molecules are dissolved is/are

A)solvent.
B)solute.
C)solution.
D)both A and C

Question 19

Free energy (ΔG)represents the amount of energy

A)available for use from a reaction.
B)required to start the reaction.
C)that could potentially be released from a reaction.
D)that goes to randomness.

Question 20

Once the activation energy has been transferred to a molecule,

A)it has reached the transition state.
B)it will always return to the substrate conformation.
C)it will always move on to the product conformation.
D)both A and C

Question 21

Glycerol molecules connected to three fatty acids are termed

A)monoacylglycerides.
B)diacylglycerides.
C)triglycerides.
D)cholesterol.

Question 22

Electrons can enter the electron transport system via many paths.The first point of commonality in the ETS for all these paths is

A)complex I.
B)complex II.
C)cytochrome c.
D)ubiquinone.

Question 23

Which of the following statements correctly describes fatty acids?

A)Volatile fatty acids are the longest fatty acids.
B)Saturated fatty acids are linear in structure and have one or no double bonds.
C)Medium-chain fatty acids are produced by ruminants when cellulose is fermented.
D)Double bonds in fatty acids create bends/kinks in the chain,thus altering membrane structure.

Question 24

Cells within the adipose tissue that store lipids are called

A)adipocytes.
B)fat bodies.
C)hepatopancreas.
D)blubber.

Question 25

Which of the following is a benefit of using phosphocreatine to store energy (as compared to ATP)?

A)Phosphocreatine can be used by almost any process requiring an input of energy.
B)Phosphocreatine can diffuse more easily to areas needing energy.
C)Phosphocreatine allows muscles to stop using ATP,conserving it for other uses.
D)Phosphocreatine is produced during periods of high muscle activity.

Question 26

All of the following are lipids,EXCEPT

A)steroids.
B)glycogen.
C)triglycerides.
D)phospholipids.

Question 27

The main reason the interior of the cell is negative at rest is because

A)the membrane is more permeable to Na⁺ than any other ion.
B)the membrane is more permeable to K⁺ than any other ion.
C)the Na⁺/K+ pump is electrogenic.
D)it contains a much higher concentration of Cl⁻.

Question 28

When an ion crosses the membrane and binds to a protein to accomplish this feat,it is using

A)passive diffusion.
B)facilitated diffusion.
C)active transport.
D)either B or C

Question 29

Ion channels that open or close based on changes in the membrane potential are called

A)voltage-gated channels.
B)ligand-gated channels.
C)mechanogated channels.
D)porins.

Question 30

__________ is the metabolic pathway that synthesizes glycogen.

A)Gluconeogenesis
B)Glycogenesis
C)Glycogenolysis
D)Glycolysis

Question 31

High concentrations of __________ indicate that a cell has plenty of energy.

A)ADP
B)AMP
C)NAD⁺
D)Acetyl CoA

Question 32

Which of the following statements is true concerning secondary active transporters?

A)A symporter can bind only one particle.
B)An exchanger/antiporter will always be electroneutral.
C)Electrogenic carriers generate a charge difference across the membrane.
D)The direction in which charged particles are transported across the membrane does not affect the electrical gradient.

Question 33

What is the advantage of storing energy as glycogen rather than as lipids?

A)It contains more energy per unit mass.
B)It does not prevent physical functions of a cell.
C)It can be mobilized very rapidly.
D)both A and B

Question 34

Glycolysis is an important metabolic pathway for the production of ATP because

A)it can proceed with or without oxygen.
B)it can produce ATP quickly.
C)it can be used to metabolize fats and carbohydrates equally well.
D)both A and B

Question 35

Lipids used as a major component of biological membranes include

A)phospholipases.
B)sphingolipids.
C)free fatty acids.
D)both A and B

Question 36

Which of the following pairs is correctly matched?

A)monosaccharides / glucose,fructose,sucrose
B)disaccharides / lactose,maltose,galactose
C)polysaccharides / glycogen,starch,chitin
D)glycosylation / addition of lipids to macromolecules

Question 37

__________ enters the TCA cycle and forms NADH and FADH₂,which can then be used for ATP production.

A)Acetyl CoA
B)Glucose
C)Pyruvate
D)A fatty acid chain

Question 38

Which of the following polysaccharides performs a structural role?

A)amylose
B)glycogen
C)chitin
D)amylopectin

Question 39

Cells can regulate the rate of the TCA cycle using all the following ways,EXCEPT

A)controlling the concentration of the substrate.
B)controlling the concentration of the required enzyme.
C)controlling the amount of energy the cell must expend for survival.
D)controlling the catalytic activity of the required enzymes.

Question 40

Production of ATP by the mitochondrial ATP synthase is increased by

A)high levels of ATP.
B)high levels of ADP.
C)low levels of physical activity.
D)low proton motive force.

Question 41

The second law of __________ says that the universe is moving from a state of order to one of disorder.

Question 42

Vesicles that are produced by the ER-Golgi network may be released from the cell using the process of

A)exocytosis.
B)endocytosis.
C)phagocytosis.
D)both B and C

Question 43

Which of the following statements correctly describes the relationship between DNA,RNA,and transcription factors?

A)There is only one transcription factor for each region of DNA encoding RNA.
B)Transcription factors must always bind close to the transcription start site.
C)Phosphorylation is one way of regulating interactions between proteins required for transcription of DNA.
D)Transcription factors carry out the process of transcription themselves.

Question 44

The term that describes a macromolecule that has unfolded as a result of an increase in temperature is _________.

Question 45

__________ are the sections of DNA used to encode RNA.

A)Chromosomes
B)Exons
C)Introns
D)Genomes

Question 46

The products of glycolysis are ATP,NADH,and __________.

Question 47

The __________ is formed by water molecules that surround water-soluble molecules in a solution.

Question 48

The extracellular matrix performs a variety of functions,including mediation of interactions between cells.__________ is a glycosaminoglycan (GAG),which provides protection and acts as a shock absorber.

A)Collagen
B)Chondroitin sulfate
C)Hyaluronan
D)Fibronectin

Question 49

Variations in proteins can arise from a SINGLE gene using

A)alternative splicing.
B)different alleles.
C)duplication of genetic material during crossover.
D)mobile elements or jumping genes.

Question 50

Energy is stored temporarily in reducing equivalents such as __________,and then released later in oxidation reactions.

Question 51

The cytoskeleton is composed of a variety of fibers,including

A)macrotubules.
B)large filaments.
C)microfilaments.
D)all of the above

Question 52

In order to ensure that some proteins are properly folded,the cells use __________,such as heat shock proteins.

Question 53

The energy of movement is termed __________ energy.

Question 54

All metabolic pathways in a cell,tissue,or organism can be referred to as the __________.

Question 55

__________ is the process of forming acetoacetyl CoA from two acetyl CoA molecules.

Question 56

Reversible enzymatic reactions eventually reach the point of __________,where the reactions in the forward and reverse directions are occurring at the same rate.

Question 57

Fatty acids with no double bonds are termed __________,and have a linear structure.

Question 58

Transmembrane gradients are often referred to as____________________ gradients.

Question 59

Molecules that can be positive or negative,depending on the pH of the solution,are called __________.

Question 60

Proteins may be degraded by proteosomes because

A)they have become damaged.
B)they are labeled with ubiquitin.
C)they are proteins which are rapidly degraded as part of the cell's control of protein levels.
D)all of the above

Question 61

Winding DNA around __________ serves two major purposes: protection and compression.

Question 62

The __________ describes how phospholipids,proteins,and other biological molecules come together to form a flexible cell membrane.

Question 63

A water molecule is held together by polar covalent bonds.Because the electrons are not shared equally in this arrangement,water exhibits many unique characteristics that are beneficial for life (e.g.high surface tension).Discuss several of these characteristics and explain how they are beneficial to living organisms.

Question 64

RNA is degraded by enzymes called __________.

Question 65

Proteins,carbohydrates,and lipids all perform vital functions for an organism.Discuss some of these vital functions and what could happen to an animal if one of these biological molecules were removed from their diet.

Question 66

Organisms typically release more CO₂ during periods of high activity.Based on your knowledge of the TCA cycle,explain how this occurs.

Question 67

When the potential of a cell membrane becomes less negative,or gains more positive charges,the term __________ is applied.

Question 68

Your book refers to the process of diffusion and mentions that both chemical and electrical gradients may influence this process.Explain why Na⁺ would be influenced by both chemical and electrical gradients,but glucose would not.

Question 69

Steroid hormones use __________ as a precursor molecule.

Question 70

The ratio between oxygen consumption and carbon dioxide production is termed the __________.

Question 71

Temperature and pH can have profound effects on the ionization states of molecules.Explain how they can cause these effects and why ionization is important physiologically.

Question 72

What is the role of molecular chaperones?

Question 73

Proteins form enzymes,transporters,channels,and many other critically important components of cells.Thus,it is essential that cells be able to regulate the amount of each protein that is available for use.What mechanisms are available to the cell for this regulation of protein levels?

Question 74

An __________ protein is one that spans the entire membrane or is fixed in it.

Question 75

The Na⁺/K⁺ ATPase pump plays only a minor role in directly generating the resting membrane potential.(The electrogenic contributions are minimal. )However,the cell's membrane potential would not be possible without it.Explain how this can be true.

Question 76

There are multiple ways that particles may cross a cellular membrane.Discuss the salient features of passive diffusion,facilitated diffusion,and active transport.

Question 77

We know that fatty acids are an important source of energy for tissues.List the ketone bodies and explain why fatty acids sometimes need to be converted to ketone bodies before they can be used.Briefly summarize the two main steps in ketone metabolism.

Question 78

Release of energy from many biological molecules requires oxygen,and yet some species are able to survive in conditions having little or no oxygen (hypoxia or anoxia).What adaptations allow them to do this?