MCDB 1B Quiz Questions

In order for a cell to be responsive to a lipid-soluble hormone, it must have

A specific receptor in the cytoplasm or nucleus

Answer the following in regards to trypsin and pepsin. What statement(s) is (are) false in regards to these two enzymes: a. Trypsin and pepsin are produced as zymogens b. Pepsin is produced in the stomach, while trypsin is produced in the pancreas c. A competitive inhibitor of pepsin function would likely interfere with the enzymatic function of trypsin. d. Trypsin and pepsin are both hydrolytic enzymes called endopeptidases that cleave covalent peptide bonds within polypeptides. e. Pepsin has optimal peptidase function at acidic pH while trypsin has optimal function at slightly basic pH

A competitive inhibitor of pepsin function would likely interfere with the enzymatic function of trypsin

If the adrenal cortex were surgically removed, an increase in the plasma levels of ________ would likely be observed.

ACTH

The steroid hormones are synthesized from

Cholesterol

What would be the consequence of a mutation that disrupts the function of the secretin receptor in the pancreas? Select one: a. Pepsinogen activation will not be achieved b. alpha cells will increase production of glucagon c. Chyme will damage the small intestine d. beta cells will produce an excess of insulin

Chyme will damage the small intestine

In response to stress, the adrenal gland promotes the synthesis of glucose from noncarbohydrate substrates (lipids via the action of the steroid hormone ________.

Cortisol

As the chyme (food that has been digested in the stomach and mix with gastric juices) is deposited in the duodenum, the endocrine cells of the pancreas release secretin, which in turn activates...

Exocrine cells of the pancreas

Which of the following substances would you expect to see in high concentrations in the blood in response to a prolonged fasting? a. Glucagon b. Aldosterone c. Glycogen d. Insulin e. Glucose

Glucagon

In mice, single-gene mutations lead to obesity. The Ob gene codes for the protein leptin, a satiety factor that signals the brain when enough food has been consumed. The recessive ob- allele is a loss-of-function allele, so ob-/ob- mice do not secrete leptin into veins and capillaries; they do not experience satiety and therefore become obese. Leptin is... a. An paracrine signal that has a receptor on cells in the brain. b. exocrine chemical released from adipose tissue that has receptors on cells in the brain. c. A peptide hormone and that likely has a receptor localized within the cell cytosol d. A hormone that is likely water soluble and binds a receptor on the cell surface. e. Is an example of regulation that employs positive feedback signaling.

Hormone that is likely to be water soluble binds to receptor on cell surface

_______ hormones exit the emitting cell via exocytosis while ________ hormones require a transporter to move through the circulatory system.

Hydrophilic/phobic

Hormones released by the posterior pituitary are produced in the___.

Hypothalamus

Which of the following statements is false for insulin? a. Insulin receptors are always present in the plasma membrane of the vast majority of a healthy human b. The cellular response to insulin is to change the permeability of the plasma membrane to glucose c. Insulin is produced in response to high levels of glucose in the blood, by alpha cells located in the islets of Langerhans d. Insulin is stored inside vesicles in the cells before is released in response to glucose in the blood e. All statements are true for insulin

Insulin is produced in response to high levels of glucose in the blood, by alpha cells located in the islets of Lagerhans

In a healthy person, after a carbohydrate-rich meal, the production of ________ will increase, causing the uptake of ________ from the blood into liver cells. a. insulin; glucagon b. glucagon; glucose c. insulin; glucose d. glucagon;glucogen e. glucagon; protein

Insulin/ glucose

If you were to jog one kilometer a few hours after lunch, which stored fuel would you probably tap? muscle proteins b. Fat from adipose tissue c. All the above d. Blood proteins e. liver and muscle glycogen

Liver and muscle glycogen

A new drug has the ability to inhibit the production of bile salts. What would be the consequences of this inhibition? Select one: a. Aggregation of lipid droplets will decrease b. Fat emulsification will increase c. A lower amount of lipids will be digested d. A higher amount of lipids will be digested

Lower amount of lipids will be digested

The Thyroid stimulating hormone produced by the pituitary is downregulated by the action of the thyroid hormones. This regulation is an example of __.

Negative feedback loop

Which of the following scenarios could potentially affect the digestion of fats?(SELECT ALL THAT APPLY) a. Increase of the pH of the stomach b. None of this options directly affect the digestion of fat c. Gallbladder surgery d. Pharmacological blockage of pancreatic amylase e. Obstruction of the pancreatic duct

Obstruction of the pancreatic duct Gallbladder surgery Increase of the pH of the stomach

Lymphocytes secretion of interleukines activates the secreting lymphocyte and induces production of more interleukines.This is an example of...

Positive feedback

Constipation can result from the consumption of a substance that ________. a. speeds up movement of material in the large intestine b. decreases water reabsorption in the small intestine c. promotes water reabsorption in the large intestine d. More than one option is true e. stimulates peristalsis

Promotes water reabsorption in the large intestine

Kwashiorkor is a syndrome caused by malnutrition. Which molecule of the organism will be consumed to remediate the deficiency?Select one: a. None of the above b. Fat c. Glycogen d. All of the above e. Proteins

Proteins

People overusing certain antacids are prone to indigestion (having difficulties digesting certain food). Why? Select one: a. A raise in pH causes less pepsinogen being activated b. A lowering in pH causes a lower rate of pepsin conversion to pepsinogen c. none of the listed options explains this consequence. d. A lowering in acidity causes a reduction in secretion of pepsinogen e. A raise in acidity causes excessive pepsinogen activation

Raise in pH causes less pepsinogen being activated

Which of the following is not true of a hormone? a. All listed statements are true for hormones b. One hormone can have different effects on different cells c. All hormones are distributed through the body via the circulatory system d. Some hormones can enter a cell's nucleus. e. Steroid hormones affect the gene expression of all the cells that they enter

Steroid hormones affect the gene expression of all the cells that they enter

Different body cells can respond differently to the same polypeptide hormones because ________.

Target cell's response is determined by the components of its signal transduction pathways

The function of chylomicrons is to ________ a. None of the options are functions of the chylomicrons b. digest nucleic acids in the intestine c. break down carbohydrates in the mouth d. transport lipids from the intestine to other organs e. move proteins across plasma membranes of cells

Transport lipids from the intestine to other organs

Pituitary peptide hormones that affect other target glands are called hormones.

Tropic

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes ________. a. use water molecules when breaking bonds (hydrolysis) b. More than one option is true c. are catalyzed by the same type of enzyme (peptidases) d. require adenosine triphosphate (ATP) as an energy source e. require the presence of hydrochloric acid to lower the pH

Use water molecules when breaking bonds (hydrolysis)

A person that develops a malfunction in their large intestine will have problems with a. Water reabsorption b. Secretion of bile and enzymes c. Digesting proteins and other nutrients d. Absorption of nutrients from food

Water reabsorption

Neurons have different shapes and sizes depending on their role. A bipolar cell in the retina of the eye collects information from a few inputs and transmits it a short distance to one or more closely spaced neurons. What shape would you predict it to have? Select one: a. A few dendrites and a short axon with one or more terminals b. Numerous dendrites and a long axon c. A long axon with many axon terminals d. A dense field of dendrites and a single axon e. Dendrites and a highly branched axon

a. A few dendrites and a short axon with one or more terminals

Which of the following statements is false with respect to epinephrine? a. All statements are true for epinephrine b. Epinephrine can elicit a response from more than one cell type through binding to different membrane bound receptors c. Epinephrine can cause vasodilation (increase of blood flow) d. Epinephrine can cause the breakdown of glycogen in the liver e. Epinephrine can cause vasoconstriction (decrease of blood flow)

a. Cause vasoconstriction/dilation, can elicit response from more than one cell type through binding to different membrane bound receptors, and breakdown glycogen

When you decide to mark a particular answer to this question, your nervous system sends the command to your hand to do so. That command is carried into your hand by axons of Select one: a. efferent neurons. b. ganglion cells. c. sensory neurons d. interneurons e. afferent neurons.

a. efferent neurons

Which statement is correct? a. When the inside of a neuron becomes more negative in comparison to its resting condition, its plasma membrane is said to be depolarized. b. At resting potential, most of the sodium channels are closed. c. Once voltage-gated sodium channels open and close, they can be triggered again only after a delay of 1-2 seconds. d. During an action potential, the voltage changes from the resting potential of +50 mV to -60mV, then rapidly returns to the resting potential.

b. At resting potential, most of the sodium channels are closed.

In order to maintain the resting potential of the nerve cell membrane, the sodium‒potassium pump keeps the concentration of Select one: a. K+ and Na+ inside the cell lower than in the extracellular fluid. b. K+ inside the cell greater than in the extracellular fluid, and the concentration of Na+ inside the cell lower than outside the cell c. negative ions higher outside the cell by pumping negative ions across the membrane. d. Na+ and K+ inside the cell greater than outside the cell. e. Na+ inside the cell greater than outside the cell, and the concentration of K+ inside the cell lower than outside the cell.

b. K+ inside the cell greater than in the extracellular fluid, and the concentration of Na+ inside the cell lower than outside the cell

The electrochemical gradient of a given ion determines the movement of that ion across a plasma membrane. Based on your knowledge of the normal intra- and extracellular concentrations of Na+ and K+ ions across a resting membrane, when both Na+ and K+ voltage-gated channels are opened in response to an action potential you would expect that Select one: a. Na+ will move out of the cell but K+ flow will cease. b. Na+ and K+ will both move out of the cell. c. Na+ will move into the cell, whereas K+ will move out of the cell. d. Na+ and K+ will both move into the cell. e. Na+ will move out of the cell, whereas K+ will move into the cell.

c. Na+ will move into the cell, whereas K+ will move out of the cell.

Which of the following statements concerning graded potentials is true? Select one: a. They travel long distances in order to generate an action potential. b. They are caused by ionic currents spreading over long distances c. They allow a cell to integrate inputs and respond proportionally. d. They are equivalent to the resting potential of the cell membrane

c. They allow a cell to integrate inputs and respond proportionally.

Hormones, autocrine and paracrine signals belong to a number of distinct chemical groups. Which of the following is not one of these groups? a Carbohydrates b. Proteins c. Amines d. Steroids e. All of the listed molecules could be hormones

carbs

which is true about nodes of ranvier Select one: a. The speed of the action potential is the same here as in all other axons in the nervous system. b. Na+ channels remain open here until the action potential has reached the axon terminal. c. The depolarization caused by the opening of voltage-gated channels does not always cause an action potential here. d. A loss of signal will occur as the action potential travels to each adjacent node. e. Na+ channels will inactivate at this node and enter a refractory state.

e Na+ channels will inactivate at this node and enter a refractory state.

The nodes of Ranvier are regularly spaced gaps in the myelinated axon. All of the following about them are true except: Select one: a. Voltage-gated ion channels are clustered at the nodes. b. Action potentials can only be fired at the nodes. c. Action potentials cannot be propagated through the myelinated membrane adjacent to the nodes. d. The nodes do not contain myelin e. Positive charges flow along the outside of the myelinated axon in between the nodes

e. Positive charges flow along the outside of the myelinated axon in between the nodes

In a thin section through brain tissue you see a cell that is wrapped around the axon of a neuron, forming concentric layers of plasma membrane. This cell most likely Select one: a. A Shwannn Cell b. supplies nutrients to neurons. c. recycles neurotransmitter in the synapses. d. gives structural support to the axon. e. insulates the axon for rapid conduction of action potentials.

e. insulates the axon for rapid conduction of action potentials.

If a physical or chemical stimulus causes a change in a cell's membrane potential, a direct effect of that change may be Select one: a. an increase in pumps b. increased permeability of the plasma membrane to certain ions. c. an increase in the number of K+ ions needed to reach equilibrium. d. an increase in the lipid composition of the membrane. e. an increase in Na+ concentration outside the cell.

increased permeability of the plasma membrane to certain ions.

Select the option that makes the following sentence true: __________ is secreted by ___________ to ____________ a. Bile / stomach / emulsify fats b. Trypsin / the pancreas / digest proteins c. Secretin / the pancreas/ neutralize HCl d. Amylase/ endocrine glands in the mouth/ digest carbohydrates e. HCl / chief cells / sterilize food

trypsin/ pancreas/ digest proteins

Steroid hormones a. are produced only by the adrenal cortex b. are water-soluble c. act by modifying gene expression in their target cells d. May cause a cytoskeletal rearangement in the cytoplasm of the cells e. Require to contact cell surface receptors to cause a cell to change its gene expression

Act by modifying gene expression in their target cells

Hormone X activates the cAMP second messenger system in its target cells. The greatest response by a target cell would come from ________.

Applying a molecule of hormone X to the extracellular fluid surrounding the cell

Which signals travel the shortest distance from the emitting cell to the target cell?

Autocrine

Testosterone is an example of a chemical signal that affects the very cells that synthesize it, the neighboring cells in the testis, along with distant cells outside the gonads. Thus, testosterone is an example of ________. I) an autocrine signal II) a paracrine signal III) a hormone IV) a Neurohormone a. only I and III b. only II and III c. only I and II d. Only III and IV e. I, II, and III

Autocrine/paracrine signal and a hormone

A disease in which antibodies destroy myelin produced by oligodendrocytes would most likely cause which of the following? a. The dendrites of peripheral nerves would not process information from other neurons. b. Neurons in the brain and spinal cord would conduct action potentials more slowly. c. The blood-brain barrier would be weakened and toxins would easily pass into the brain. d. Action potential conduction in neurons in the peripheral nerves would be slower. e. Neurons in the brain would be deprived of nutrients

B. Neurons in the brain and spinal cord would conduct action potentials more slowly.