Deck 2: Molecules and Cells in Animal Physiology

Question 1

How does venom permit a slow-moving predator to feed on prey capable of high-speed escape?

A) Venom disrupts sensory systems such that the prey can no longer detect the predator.
B) Venom disrupts the ability of the prey to digest food and thus have the energy to escape.
C) Venom shuts down the ability of the prey to move very far.
D) Venom confuses the prey such that it may run back in the direction of the predator.

Answer 1

C

Question 2

Why have many venomous animals evolved venoms that break down phospholipids?

A) Phospholipids are an important component of venom.
B) Phospholipids are important in sensing predators.
C) Phospholipids are the key to muscular contraction.
D) Phospholipids are the fundamental structure of all cell membranes and intracellular membranes.

Answer 2

D

Question 3

Which molecule is part of a cell membrane?

A) Cholesterol
B) Ubiquitin
C) Cyclic AMP
D) Calmodulin

Answer 3

A

Question 4

A molecule that consists of a polar portion and a nonpolar portion is said to be

A) hydrophilic.
B) hydrophobic.
C) an integral protein.
D) amphipathic.

Question 5

A saturated hydrocarbon tends to

A) be more liquid at colder temperatures compared to an unsaturated hydrocarbon.
B) be more solid at colder temperatures compared to an unsaturated hydrocarbon.
C) contain many double bonds.
D) contain fewer carbon-carbon bonds compared to an unsaturated hydrocarbon.

Question 6

Compared to fish found in lower temperature habitats, fish that inhabit higher temperatures tend to have more

A) saturated phospholipids in their brain synaptic membranes.
B) saturated phospholipids in their brain proteins.
C) unsaturated phospholipids in their brain synaptic membranes.
D) unsaturated phospholipids in their brain proteins.

Question 7

Which membrane protein is responsible for the passive movement of K⁺ across the typical animal cell membrane?

A) Channel
B) Enzyme
C) Transporter
D) Receptor

Question 8

Which molecule is a functional membrane protein?

A) Acetylcholine
B) Cholesterol
C) The Na⁺‒K⁺ pump
D) Calmodulin

Question 9

Choose a feature that is not common to all simple epithelia.

A) microvilli
B) basement membrane
C) nucleus in each cell
E) apical surface

Question 10

A ring of _______ demarcates the apical surface of the cell from its lateral and basal surfaces.

A) tight junctions
B) septate junctions
C) gap junctions
E) microvilli

Question 11

Which of the following is considered a communicating junction?

A) Gap junction
B) Tight junction
C) Septate junction
D) Desmosome

Question 12

When a protein is denatured, which of the following structures is disrupted first?

A) Primary
B) Secondary
C) Tertiary
D) Quarternary

Question 13

If a protein in situ becomes partially denatured because of high temperature, the denaturation can be reversed by a

A) molecular chaperone.
B) proteasome.
C) ubiquitin.
D) peptidase.

Question 14

Which of the following tags proteins for destruction?

A) Proteasome
B) Ubiquitin
C) Molecular chaperone
D) Heat-shock protein

Question 15

How can amino acids in a protein be any closer to one another than their spaced positions in the linear string?

A) Many amino acids break their covalent bonds in the linear arrangement and form closer ionic bonding arrangements.
B) Amino acids in their linear primary structure are constantly breaking and reforming their covalent bonds. When they are not in a bonding arrangement, they can be closer to adjacent amino acids temporarily.
C) As amino acid chains fold into their tertiary structure, this commonly brings some amino acids closer together than their linear spaced positions.
D) Amino acids only form covalent bonds with one another and do not associate with one another at a distance closer than the covalent bond.

Question 16

What drives the ATP protein machine?

A) Na⁺
B) The gradient of H⁺ across the membrane
C) ATP
D) The movement of electrons

Question 17

Why have many venomous animals evolved venoms that disrupt the gating mechanism of the voltage-gated sodium channel?

A) Disrupting the voltage-gated sodium channel would slow the prey's metabolism.
B) Disrupting the voltage-gated sodium channel would slow the prey's ability to manufacture ATP.
C) Disrupting the voltage-gated sodium channel would block oxygen transport.
D) Disrupting the voltage-gated sodium channel would disrupt the nervous system.

Question 18

_______ is(are) the specific set of processes by which complex chemical compounds are broken down to release energy, create smaller chemical building blocks, or prepare chemical constituents for elimination.

A) Metabolism
B) Catabolism
C) Anabolism
D) Biochemical reactions

Question 19

Per gram, the leopard frog can jump farther per jump compared to the western toad because the leopard frog

A) is insensitive to lactic acid.
B) tends to live in warmer climates.
C) has a higher aerobic capacity.
D) creates more lactic acid per unit time.

Question 20

Which statement regarding enzymes is false?

A) All enzymes are catalysts.
B) Enzymes have substrates and products.
C) Enzymes speed chemical reactions.
D) All catalysts are enzymes.

Question 21

Which reaction is catalyzed by LDH?

A) Pyruvic acid + NADH₂ → lactic acid + NAD
B) Pyruvic acid + NAD → pyruvic acid + NADH₂
C) Pyruvic acid + NAD → lactic acid + NADH₂
D) Lactic acid + NADH₂ → pyruvic acid + NAD

Question 22

The amount of substrate converted to product per unit of time is called the

A) turnover number.
B) saturated speed.
C) V_max.
D) reaction velocity.

Question 23

Turnover number (k_cat) describes what property of an enzymatic reaction?

A) Activation energy
B) Catalytic effectiveness
C) Enzyme‒substrate affinity
D) The transition state

Question 24

The likelihood that an enzyme will form a complex with the substrate during a collision is called the

A) catalytic effectiveness.
B) activation energy.
C) enzyme‒substrate affinity.
D) transition state.

Question 25

An enzymatic reaction is proceeding at subsaturation. Which of the following is not a means by which the enzymatic reaction can be increased?

A) Adding more substrate
B) Adding more enzyme
C) Increasing the catalytic effectiveness
D) Increasing the temperature

Question 26

Refer to the figure shown.
Which of the following represent the best labels for the x axis and the y axis in the figure?

A) x = Substrate concentration; y = Reaction velocity
B) x = Enzyme concentration; y = Reaction velocity
C) x = Time; y = Substrate concentration
D) x = Time; y = Enzyme‒substrate conversion rate

Question 27

Refer to the figure shown.
Which letter in the figure represents high affinity?

A) I
B) II
C) III
D) V

Question 28

Refer to the figure shown.
Which letter in the figure best represents the V_max?

A) VI
B) I
C) III
D) V

Question 29

Refer to the figure shown.
In the figure, which region best represents the K_m of the highest affinity enzyme?

A) I
B) II
C) VII
D) IV

Question 30

Refer to the figure shown.
If more substrate is added to the reaction system of line C in the figure, what would be the most likely outcome?

A) The curve of line C would shift toward line B.
B) The V_max will increase.
C) K_m will decrease.
D) The curve will remain the same.

Question 31

Human LDH-B₄ and rat LDH-B₄ are examples of

A) isozymes.
B) analogous enzymes.
C) isoenzymes.
D) interspecific enzyme homologs.

Question 32

An enzyme-encoding gene is considered to be _______ within a cell if the gene results in the synthesis of the encoded enzyme within that same cell.

A) promoted
B) induced
C) expressed
D) enhanced

Question 33

_______ enzymes are present in a tissue in relatively high and steady amounts regardless of conditions, whereas _______ enzymes are present at low levels (or not at all) in a tissue unless their synthesis is activated.

A) Inducible; constitutive
B) Promotable; constitutive
C) Constitutive; inducible
D) Expressed; promotable

Question 34

Which statement regarding allosteric modulation is true?

A) The binding of an allosteric modulator follows the law of mass action.
B) The binding of an allosteric modulator is irreversible.
C) An allosteric modulator, when present, will always bind to the enzyme it modulates.
D) The binding of an allosteric modulator always increases the catalytic activity of the enzyme.

Question 35

Which of the following is directly involved in covalent modulation?

A) The Na⁺‒K⁺ pump
B) Protein kinases
C) van der Waals interactions
D) Calcium

Question 36

Refer to the figure shown.
How many different enzymes are catalyzing reactions?

A) Two
B) Three
C) Four
D) Five

Question 37

Refer to the figure shown.
According to the figure, a high number of products from the Kreb's cycle could act as _______ and result in _______ of the overall reaction.

A) covalent modulators; inhibition
B) covalent modulators; acceleration
C) allosteric modulators; inhibition
D) allosteric modulators; acceleration

Question 38

A protein kinase catalyzes the phosphorylation of another protein kinase, which in turn catalyzes the phosphorylation of a third protein kinase. This series of multiple enzyme sequences is an excellent example of

A) amplification.
B) a rate-limiting reaction.
C) inducing enzymes.
D) allosteric regulation.

Question 39

The _______ is(are) directly responsible for the amplifying effects during a second messenger cascade.

A) receptors
B) substrates
C) enzymes
D) cell membrane

Question 40

Refer to the figure shown.
Which abiotic factor most likely explains the data in the figure?

A) LDH expression
B) Allele frequencies
C) Temperature
D) Predation

Question 41

Refer to the figure shown.
The figure shows the

A) frequency distribution of two predators on killifish.
B) frequency distribution of two different alleles of the gene for LDH.
C) frequency distribution of two main diets of killifish.
D) temperature tolerance of two subtypes of killifish.

Question 42

Refer to the figure shown.
What is the best explanation for why mammalian and fish LDH-C enzymes are shown to be so distantly related?

A) Many separate gene duplication events created the C version of LDH.
B) The tree is based on LDH-A relationships, so it does not accurately show how closely related the LHD-C versions are to one another.
C) The enzymes were named before the actual evolutionary relationships were known.
D) The tree is separated based on animal phyla, not LDH.

Question 43

Refer to the figure shown.
The diamonds refer to

A) genetic divergence.
B) gene duplication.
C) mutations.
D) speciation.

Question 44

In rats, phosphoenolpyruvate carboxykinase activity per gram of liver significantly increases at birth and remains at this higher level for the life of the animal. This is an example of enzymatic change that takes place over a(n) _______ time frame.

A) acute
B) chronic
C) evolutionary
D) developmental

Question 45

The process of absorbing preexisting light and re-emitting it at longer wavelengths is called

A) bioluminescence.
B) reflection.
C) chromatophoration.
D) fluorescence.

Question 46

The ability of animals to change color in seconds or minutes depends on the function of

A) photocytes.
B) chromatophores.
C) photoproteins.
D) luciferin.

Question 47

Intracellular modification of activity in response to an external signal is an example of

A) transduction.
B) transformation.
C) conversion.
D) covalent modulation.

Question 48

Extracellular signaling molecules initiate their actions on a cell by binding with certain protein molecules of the cell called

A) ligands.
B) peripheral proteins.
C) integral proteins.
D) receptors.

Question 49

Which of the following statements regarding the ligand-gated receptor is false?

A) The naturally occurring ligand can cause the associated protein channel to open.
B) The naturally occurring ligand should bind irreversibly to the receptor until it breaks down.
C) A similarly shaped foreign ligand can attach to the receptor and block the naturally occurring ligand from binding.
D) A ligand can attach to the receptor and activate an intracellular catalytic site on the same molecule.

Question 50

Receptor proteins can bring about all of the following cellular actions except

A) reinforcing the structure of the membrane.
B) opening a protein channel on the membrane.
C) activating an enzyme on the intracellular surface.
D) combining with a ligand to initiate transcription.

Question 51

The α-conotoxin injected into fish by the cone snail binds to and therefore blocks receptor sites on the muscle membrane. This prevents a(n)

A) enzyme from being activated.
B) G protein from being activated.
C) channel from opening into the nucleus.
D) channel from opening.

Question 52

Which reaction does not directly produce an amplification?

A) Activation of a G protein by an activated receptor
B) Formation of cyclic AMP by catalyzing action of adenylyl cyclase
C) Activation of glycogen phosphorylase kinase by active cAMP-dependent protein kinase
D) Opening of a ligand-gated channel on the membrane

Question 53

Which substance is considered a second messenger?

A) IP₃-gated calcium channel
B) Calcium
C) Epinephrine
D) Adenylyl cyclase

Question 54

As a second messenger, calcium typically binds to

A) calmodulin, and the complex activates protein kinases.
B) a G protein to activate general second messengers.
C) cyclic AMP to activate cAMP-dependent protein kinases.
D) inositol triphosphate to activate the endoplasmic reticulum.

Question 55

Steroid hormones bind to _______ and ultimately cause _______.

A) specific intracellular membrane proteins; the opening of ion channels
B) specific intracellular receptor proteins; gene expression
C) specific extracellular receptor proteins; the opening of ion channels
D) specific extracellular membrane proteins; gene expression

Question 56

Provide a specific example of how a membrane protein can be categorized as more than one functional type.

Question 57

Describe what it means for a phospholipid to be amphipathic and how this feature is paramount in the formation of the membrane.

Question 58

Describe how epithelial cells control the transport of substances between the apical and basal sides and thus between different body regions.

Question 59

Define the law of mass action and apply it to a real biochemical reaction.

Question 60

Compare and contrast the factors affecting the rate of an enzymatic reaction in a substrate that is subsaturated and one that is saturated or at V_max.

Question 61

Describe how amplification works in the cell and why it is important.

Question 62

How does the killifish demonstrate the present-day operation of evolutionary forces?

Question 63

Compare and contrast bioluminescence and fluorescence and describe the light production of the hydromedusan jellyfish (Aequorea victoria).

Question 64

List and briefly describe the four types of receptor proteins involved in cell signaling.

Question 65

Describe how a simple ion such as calcium is used as a second messenger.