East Los Angeles College » Physiology » Physiology 001 - Introduction to Human Physiology » Winter 2021

Physiology 001 - Introduction to Human Physiology » Winter 2021 » Lecture Exam 1

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Question #1

Which of components of a general reflex arc are listed in the order information typically flows through them following a stimulus?

A. Effector, efferent pathway, integrating center, afferent pathway, receptor

B. Receptor, afferent pathway, integrating center, efferent pathway, effector

C. Effector, afferent pathway, integrating center, efferent pathway, receptor

D. Receptor, efferent pathway, integrating center, afferent pathway, effector

E. Integrating center, receptor, afferent pathway, efferent pathway, effector

Question #2

The negative feedback system is much more common than the positive feedback system.

A. FALSE

B. TRUE

Question #3

After spending several days at a high altitude, where oxygen pressure is low, a person will begin to produce more red blood cells, which enhances the ability of blood to carry oxygen to the tissues. What term best describes this type ofresponse?

A. Positive feedback

B. Physiological acclimatization

C. Evolution

D. Feedforward regulation

E. Developmental acclimatization

Question #4

The number of distinct cell types in the human body is about twenty.

A. TRUE

B. FALSE

Question #5

Which of the following situations best represents a homeostatic mechanism?

A. Increasing the size of fast-food restaurant portions causes body weight to increase.

B. As age increases, the amount of calcium in bones tends to decrease.

C. After going outside on a hot day, the core body temperature increases.

D. After eating a large batch of salty popcorn, levels of salt in the urine increase.

E. A person who becomes very nervous begins to sweat profusely.

Question #6

Homeostasis refers to the relative constancy of the external environment.

A. FALSE

B. TRUE

Question #7

Circadian rhythms are biological rhythms with what main characteristic?

A. They repeat approximately every 24 hours, like daily spikes in hormone secretion.

B. They cease to occur when a person is in a dark environment.

C. They are cyclical, like the 28-day female menstrual cycle.

D. They cease to occur when a person is in a dark environment.

E. They are voluntary rhythms, like the time you decide to eat lunch each day.

Question #8

If a protein’s conformation changes it is likely that its function will change as well.

A. TRUE

B. FALSE

Question #9

The carboxyl ion is an anion.

A. FALSE

B. TRUE

Question #10

Which of the following is NOT a type of molecular interaction that determines the tertiary structure of a protein?

A. Van der Waals forces

B. Ionic bonds

C. Hydrogen bonds

D. Covalent bonds between two cysteine amino acids

E. Covalent bonds between purine and pyrimidine bases

Question #11

Which of the following is unique to atoms of each element?

A. The number of protons

B. The number of electrons

C. The number of neutrons

D. The ratio of protons to electrons

E. The number of bonds it can form

Question #12

Molecules that have properties of both polar and nonpolar molecules are called

A. amphipathic.

B. unipolar.

C. hydrophilic.

D. bipolar.

E. hydrophobic.

Question #13

The number of covalent bonds that can be formed by a given atom depends upon the number of electrons present in the outermost orbit.

A. FALSE

B. TRUE

Question #14

Within a single protein, which of the following are you likely to find?

A. You are likely to find all of these within a single protein.

B. Hydrogen bonds

C. Disulfide bridges

D. Ionic bonds

E. Hydrophobic interactions

Question #15

Hydrolysis of glycogen will have what effect on blood glucose level?

A. Increase blood glucose level

B. No effect on blood glucose level

C. Decrease blood glucose level

Question #16

In general, polar molecules will dissolve in polar solvents, while nonpolar molecules cannot.

A. TRUE

B. FALSE

Question #17

NaCl is a molecule formed by the covalent bonding of a sodium atom to a chlorine atom.

A. FALSE

B. TRUE

Question #18

Cholesterol is a phospholipid.

A. FALSE

B. TRUE

Question #19

Glucose cannot be synthesized from fatty acids because the reaction converting pyruvic acid to acetyl coenzyme A is not reversible.

A. FALSE

B. TRUE

Question #20

A. Results in molecules with an even number of carbon atoms only

B. Begins with a molecule of acetyl coenzyme A

C. Requires more energy than is produced by the catabolism of the same fatty acid

D. Takes place in the cytosol of cells

E. The enzymes that catalyze it are in the same location as those that mediate fatty acid catabolism

Question #21

If you add a single cholesterol molecule into the plasma membrane, do you expect that, several hours later, it will be in the same place (i.e., adjacent to the same exact phospholipid molecules).

A. Cholesterol will migrate away from phospholipids and toward proteins.

B. All of the molecules will move freely in the lipid bilayer.

C. Cholesterol will be excluded from the bilayer and will no longer be associated with phospholipids because they have different properties.

D. Cholesterol will associate with adjacent phospholipid molecules and stay near them.

Question #22

The rate-limiting reaction in a metabolic pathway is one that occurs at a faster rate than the other steps in the pathway.

A. TRUE

B. FALSE

Question #23

What are the products of glycolysis under anaerobic conditions?

A. 2 molecules of pyruvate, 2 molecules of lactate, and 2 ATP

B. 2 molecules of NADH and 2 molecules of water

C. 2 molecules of pyruvate, 2 molecules of water, and 2 NADH

D. 2 molecules of ATP, 2 molecules of water, and 2 molecules of lactate

E. 2 molecules of pyruvate and 36 molecules of ATP

Question #24

The shape of a ligand and the shape of its binding site influence both the specificity and the affinity of binding.

A. TRUE

B. FALSE

Question #25

The deletion of a single base in a gene would alter the structure of the gene's protein more than the substitution of one base for another.

A. FALSE

B. TRUE

Question #26

Which describes the action of a ligand'scompetitive antagonist?

A. It blocks the binding of the ligand to its binding site and prevents activation of the protein.

B. It binds to a different binding site on the protein, altering the protein shape so that a ligand cannot bind.

C. When present, it increases the binding of a ligand to its receptor.

D. It decreases the amount of ligand required to activate the protein.

Question #27

A clinical disease that results in an inability to absorb fats will not result in malnutrition

A. FALSE

B. TRUE

Question #28

Which is NOT true about protein kinases?

A. They remove phosphate groups from proteins.

B. They add phosphate groups to proteins.

C. They perform the opposite function as phosphatases.

D. They use ATP to carry out their reactions.

E. They produce effects similar to allosteric modulation.

Question #29

The cell membrane is composed mainly of

A. proteins and glycocalyx.

B. phospholipids and proteins.

C. cytosol.

D. water.

E. phospholipids and nucleic acids.

Question #30

Enzymes

A. have names generally ending in the suffix "-ose."

B. are broken down during chemical reactions they catalyze.

C. can be carbohydrate molecules.

D. are polymers of ATP that store large amounts of energy.

E. are catalysts in chemical reactions.

Question #31

Which of the following would achieve the absorption of water across the epithelial lining toward the blood vessels of the small intestine?,,,,

A. Facilitated diffusion of glucose to the bloodstream from the lumen

B. Tightening the tight junctions between epithelial cells

C. Active transport of Na + from the lumen to the basolateral side

D. Active transport of H + from the basolateral side to the lumen

E. Opening of aquaporins on the apical membrane

Question #32

In active transport, the affinity of any given binding site for the molecule to be transported changes as the site goes from facing one side of the membrane to facing the other side.

A. TRUE

B. FALSE

Question #33

Regarding the tonicity and osmolarity of solutions, which of the following statements is not true?

A. The term "osmolarity" refers to the osmotic properties of a solution, regardless of its tonicity.

B. Isotonic solutions are always isoosmotic.

C. The term "tonicity" refers to the effect that a solution has on the degree of stretch or shrinking of the cell membrane.

D. Hypoosmotic solutions are always hypotonic

E. Hypertonic solutions are always hyperosmotic.

Question #34

A woman is participating in a competition held by a local radio station. To win, she must drink 8 gallons of pure water within a few hours. As the osmolarity of her body fluids decreases, it is possible that her cells, including cells in the brain, may swell and burst.

A. TRUE

B. FALSE

Question #35

In the body, Na + ions behave as if they are nonpenetrating solutes because they are actively transported out of cells.

A. TRUE

B. FALSE

Question #36

Substance X is a mostly polar molecule and Substance Y is a mostly non-polar molecule of a similar size. Which will diffuse from the extracellular fluid to the intracellular fluid faster if they are in equal concentrations outside and inside the cell?

A. Substance Y will diffuse faster.

B. Substance X and Substance Y will diffuse at the same rate, as they are of equal size and concentration.

C. Substance X will diffuse faster.

Question #37

Endocytosis of any kind requires metabolic energy.

A. TRUE

B. FALSE

Question #38

"Osmosis" refers to the movement of what substance across semipermeable membranes?

A. Water

B. Solutes

C. Charged particles

D. Glucose

E. Lipid molecules

Question #39

The component of the plasma membrane that acts as a selective barrier to diffusion of polar molecules is the integral proteins.

A. FALSE

B. TRUE

Question #40

The final equilibrium state reached by a molecule that enters a cell by facilitated diffusion is the same as that for a molecule that enters the cell by diffusion.

A. TRUE

B. FALSE

Question #41

Activated calmodulin functions to activate or inactivate cytosolic enzymes.

A. TRUE

B. FALSE

Question #42

At very low concentrations, epinephrine causes an artery to dilate. At higher concentrations epinephrine causes the same artery to constrict. How can these different effects be explained?

A. There are two types of receptors for epinephrine that use the same second-messenger system.

B. There are two types of epinephrine receptors with different affinities for epinephrine that use two different second-messenger systems.

C. At higher concentrations epinephrine can pass through the plasma membrane and directly stimulate contraction within the cell.

D. There is one type of epinephrine receptor that uses two second-messenger systems.

Question #43

An adipose (fat) cell responds to the presence of the hormone epinephrine by increasing cytosolic cyclic AMP production, which leads to the catabolism of both glycogen and fat. What is the most likely explanation for this phenomenon?

A. Epinephrine is binding to two types of receptors in the plasma membrane.

B. Cyclic AMP-dependent protein kinase activates two kinds of enzymes.

C. The activated receptor complex stimulates production of two different second messengers.

D. Cyclic AMP directly activates enzymes that catabolize glycogen and fat.

Question #44

Drug Y is a drug that is used to increase the force of contraction achieved by heart muscle tissue. In the absence of the drug, epinephrine increases heart contractility through a signaling pathway that involves a receptor and cAMP. Which of the following are plausible mechanisms of action for Y?,,

A. Increasing the expression of Camp

B. Inhibiting phosphodiesterase activity

C. Acting as an agonist on the receptor for epinephrine, a hormone that increases heart contractility

D. Decreasing the activity of cAMP-dependent protein kinase

E. Increasing the availability of phosphodiesterase molecules

Question #45

Cyclic AMP activates allosteric proteins.

A. TRUE

B. FALSE

Question #46

With regard to the action of hormones and neurotransmitters on cellular receptors, which of these describes "amplification"?

A. Some cellular receptors have such low affinity for chemical ligands that it can require a million or more molecules to activate them.

B. Only hydrophilic first-messenger molecules can activate second-messenger molecules within the cell cytosol.

C. When the extracellular concentration of a chemical messenger reaches a very high level, it overwhelms transporter molecules and the chemical floods into the cell.

D. A single first-messenger molecule activates multiple second-messenger molecules, each of which activate thousands of enzymes.

Question #47

A. Sodium

B. Cyclic AMP

C. Protein kinase

D. Glucose

E. Thyroid hormone

Question #48

What is a role of calcium ions in the second-messenger cascade involving phospholipase C, diacylglycerol, and inositol trisphosphate?

A. It binds to the endoplasmic reticulum and causes therelease ofinositol trisphosphate

B. It splits and activates G-protein subunits.

C. It is the first messenger that binds to the integral membrane protein receptor.

D. It phosphorylates cell proteins.

E. Along with diacylglycerol, it activates protein kinase C.

Question #49

Designing a drug that blocked the release of eicosanoids would be an effective therapy for both pain and inflammation.

A. FALSE

B. TRUE

Question #50

Naloxone (Narcan) is an antagonist to the opioid receptor, the same receptor to which heroin is an agonist. If both heroin and naloxone were in the bloodstream, what would the user experience?

A. An increase in the effects of heroin

B. A decrease in the effects of heroin

C. A new set of effects unlike those of heroin alone

D. The same effects from heroin plus additional effects of naloxone

Question #51

Homeostatic control systems and acclimatization are examples of biological adaptations.

A. FALSE

B. TRUE

Question #52

regulation describes regulation of cellular activity by messengers from nearby cells.

A. muscle cell

B. collagen cells

C. epithelial cells

D. Paracrine

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