PGY 206- homeostasis and cell physiology

Q. Researchers compare heart disease rates between people who exercise regularly and those who do not, without assigning exercise habits. The study is best classified as:

A. Experimental

B. Randomized clinical trial

C. Observational association study

D. Placebo controlled trial

C

Q. A study reports a link between acetaminophen exposure and autism that disappears when siblings are compared. This finding most strongly suggests:

A. Acetaminophen is safe in all contexts

B. The environment does not influence autism

C. Shared genetic or environmental factors may explain the original association.

D. Acetaminophen exposure causes autism

C

Q. Which statement best describes the current health status of Kentuckians compared with the rest of the United States? Life expectancy is______.

A. higher, despite lower overall rates of chronic disease

B. lower, mainly due to higher rates of chronic disease

C. higher, because life expectancy is mainly due to genetic factors

D. lower, because life expectancy is mainly due to genetic factors

B

Q. Which combination of conditions is most directly associated with Kentucky’s high obesity rate?

A. Asthma, autoimmune disease, and infection

B. Type 2 diabetes, heart disease, and stroke

C. Cancer alone

D. Neurodegenerative diseases

B

Q. Which statement best describes a set point in a homeostatic system?

A. A fixed value around which a variable is regulated

B. The minimal value of a variable before it catabolizes itself for energy

C. A target value around which a variable is regulated

D. The maximum value a variable can reach

C

Q. Which of the following is a homeostatic-regulated variable?

A. Insulin

B. Blood glucose concentration

C. Glucose uptake by the liver

D. The feeling of hunger

B

Q. During the regulation of body temperature, which pairing is most accurate?

A. Sensor: sweat glands; Effector: hypothalamus

B. Sensor: muscles; Effector: thermoreceptors

C. Sensor: hypothalamus; Effector: skin blood vessels

D. Sensor: thermoreceptors; Effector: sweat glands

D

Q. In type 1 diabetes, blood glucose homeostasis is disrupted because insulin ____, impairing the _____ of the homeostatic feedback loop.

A. is excessive; effector

B. is ineffective; sensor

C. is not produced; integrating center

D. fluctuates; afferent pathway

C

Q. Positive feedback occurs when a change in a variable triggers response that moves the variable in the _____ direction as the initial change, thereby ____ the response.

A. opposite; stabilizing

B. same; amplifying

C. same; stabilizing

D. opposite; amplifying

B

Q. Unlike negative feedback, positive feedback _____ and is therefore generally _____ for maintaining homeostasis.

A. restores set point; beneficial

B. amplifies deviations; destabilizing

C. reduces variability; essential

D. maintains constancy; stabilizing

B

Q. Which description best captures the structure of the phospholipid bilayer?

A. A rigid layer of proteins that blocks all solutes

B. Two layers of phospholipids with hydrophilic heads facing inward

C. Two layers of phospholipids with hydrophobic tails facing inward

D. A single layer of phospholipids embedded in protein

C

Q. Which component of the nucleus is most directly involved in ribosome production?

A. Chromatin

B. Nuclear envelope

C. Nuclear pores

D. Nucleolus

D

Q. Which part of the primary RNA transcript is used to generate messenger RNA?

A. Ribosomal RNA

B. Introns

C. Exons

D. All of these are used to make the final mRNA

C

Q. What is the primary function of the ribosome during translation?

A. Synthesizing mRNA from DNA

B. Matching tRNA anticodons to mRNA codons and forming peptide bonds

C. Transporting amino acids across the nuclear membrane

D. Modifying proteins after translation

B

Q. Which cellular structure is made of proteins assembled into long filaments?

A. Plasma membrane

B. Cytoskeleton

C. Ribosome

D. Golgi apparatus

B

Q. Binding Ca 2+ to a protein most commonly alters the protein’s ____, leading to a change in it's _____.

A. concentration; synthesis

B. gene; transcription

C. shape; activity

D. location; degredation

C

Q. Which of the following is most likely to be made of a chain of amino acids?

A. Glycogen

B. Phospholipid

C. Actin filament

D. DNA

C

Q. Which organelle is most directly responsible for modifying and packaging proteins for secretion?

A. Rough endoplasmic reticulum

B. Golgi aparatus

C. Smooth endoplasmic reticulum

D. Lysosome

B

Q. Engulfment of large particles such as bacteria is ____, whereas release of substances from the cell via vesicle fusion with the plasma membrane is _____.

A. pinocytosis; endocytosis

B. endocytosis; phagocytosis

C. phagocytosis; exocytosis

D. pinocytosis; exocytosis

C

Q. In a 70-kg adult, total body water is approximately ____ L, and extracellular fluid volume is approximately ______L.

A. 28; 14

B. 42; 14

C. 42; 28

D. 35, 21

B

Q. A person undergoing cancer treatment is most likely to suffer a ____ than normal hemocrit.

A. lower

B. higher

A

Q. Plasma differs from interstitial fluid primarily because plasma contains _____, and severe dehydration would most likely cause hematocrit to ____.

A. more proteins; increase

B. more ions; decrease

C. fewer proteins; increase

D. fewer cells; decrease

A

Q. Which statement best defines passive transport?

A. Movement of molecules using ATP

B. Movement of molecules against their concentration gradient

C. Movement of molecules driven by gradients without energy input

D. transport requiring membrane pumps

C

Q. Which molecule is most likely to diffuse directly across the lipid bilayer?

A. Na+

B. Glucose

C. O2

D. Ca++

C

Q. A red blood cell placed in a hypotonic solution will:

A. shrink

B. remain unchanged

C. swell and potentially lyse

D. actively pump out water

C

Q. Which statement correctly distinguishes primary from secondary active transport?

A. Primary active transport uses ion gradients, while secondary active transport uses ATP directly

B. Primary active transport moves solutes down their gradients, while secondary moves them up

C. Primary active transport uses ATP directly, while secondary active transport uses stored energy in gradients

D. Both primary and secondary active transport require ATP binding to the transporter

C

Q. If primary active transport of the NA/K pump is disrupted, Na+/glucose transport activity will _____.

A. Increase

B. Decrease

C. Reverse

D. Not change

B

Q. Which stem cell type can give rise to both embryonic and extraembryonic tissues?

A. Pluripotent

B. Multipotent

C. Totipotent

D. Induced pluripotent

A

Q. Which list correctly identifies the four major tissue types in the human body?

A. Muscle, epithelial, connective, nervous

B. Bone, muscle, epithelium, blood

C. Nervous, skeletal, cardiac, smooth

D. Epithelial, endocrine, immune, connective

A

Q. When luminal glucose concentration is high, glucose is absorbed across epithelial cells primarily by:

A. Simple diffusion across the lipid bilayer

B. Paracellular diffusion driven by osmotic pressure

C. Na/glucose cotransport across the apical membrane

D. Endocytosis into vesicles

C

Q.Introducing a competitive inhibitor will _____ the apparent affinity of the receptor by requiring _____ ligand to achieve the same response.

A. increase; less

B. increase; more

C. decrease; more

D. decrease; less

C

Q. Intracellular receptor signaling is generally longer-lasting than membrane receptor signaling because it:

A. Uses second messengers

B. Alters gene expression and protein synthesis

C. Activates ion channels

D. Requires ATP

B

Q. Binding of Ca2+ or the addition/removal of phosphate groups (phosphorylation) can_____ a protein’s confirmation, thereby _____ its function.

A. disrupt; inhibiting

B. stabilize; amplifying

C. change; altering

C

Q. During gene expression, DNA is_____ to produce RNA, and introns are _____ before the RNA is translated into protein.

A. transcribed; removed

B. translated; removed

C. replicated; spliced

D. replicated; retained

A

Q. Glucose is transported by glucose transporters, membrane carrier proteins. Which of the following characteristics limits the max rate of glucose transport?

A. competition

B. saturation

C. diffusion coefficient

D. specificity

C

Q. During translation, each mRNA ____ is recognized by a complementary _____, which delivers the correct amino acid to the ribosome.

A. exon; ribosome

B. codon; tRNA

C. anticodon; amino acid

D. codon; tRNA

B

Q. A common misconception is that homeostasis means _____, when in reality it reflects _____ around a set point.

A. dynamic balance; instability

B. a fixed value; dynamic constancy

C. negative feedback; positive feedback

D. no change; oscillation

B

Q. Water moves through the semi-permeable membrane from a _____ solute compartment to _____ solute compartment by ____.

A. high: low: passive diffusion

B. high: low: active transport

C. low: high: passive diffusion

D. low: high: active transport

C

Q. Oxygen moves through the plasma membrane by:

A. vesicle-mediated transport

B. active transport

C. facilitated diffusion

D. passive diffusion

D

Q. A decrease in cell size is called_____, while replacement of one mature cell type with another is called _____.

A. hypertrophy; dysplasia

B. hyperplasia; dysplasia

C. atrophy; hyperplasia

D. atrophy; metaplasia

D

Q. A pluripotent stem cell has the potential to develop into:

A. both embryo and extra-embryo structure (placenta)

B. extra-embryo structure (placenta only)

C. embryo (every cell type in the body) but not extra-embryo (placenta)

D. cells of the nervous system only

C

Q. Opening K+ channels at rest will cause K+ to move_____ the cell, making the membrane potential more______.

A. into; negative

B. out of; negative

C. into; positive

D. out of; positive

B

Q. Which of the following cell organelles is responsible for the detoxification of toxins and alcohols?

A. Peroxisomes

B. Golgi apparatus

C. endoplasmic reticulum

D. lysosome

A

Q. In which direction does one cycle of the Na-K pump move 3 Na ions across the plasma membrane?

A. Either direction

B. There is no Na movement

C. From outside to inside

D. from inside to out

D

Q. An increase in membrane potential away from resting levels in the negative direction is called______, whereas a return toward resting membrane potential is called _____.

A. depolarization; hyperpolarization

B. depolarization; repolarization

C. repolarization; depolarization

D. hyperpolarization; repolarization

D

Q. The life expectancy in KY is about _____ years shorter than the rest of the USA.

A. ten

B. zero

C. five

D. fifteen

C

Q. Researchers compare the grades of students who drink caffeine with those who do not. This study is best classified as:

A. Placebo-controlled trail

B. Randomized clinical trial

C. Observational association study

D. Experimental

C

Q. Homeostasis of the body is maintained by:

A. negative feedback mechanism

B. positive feedback mechanism

C. neutral feedback mechanism

D. explosive control mechanism

A

Q. In which of the following solutions would red blood cells swell and burst?

A. 50 NaCl + 200 mM glucose

B. 100 mM NaCl + 100 mM glucose

C. 150 NaCl + 100 mM glucose

D. 50 NaCl + 100 mM glucose

D

Q. Blood clotting and uterine contractions during childbirth are examples of _____ feedback because the response _____ until a specific endpoint is reached.

A. negative; terminates the response

B. positive; restores the set point

C. negative reduces the stimulus

D. positive; amplifies the stimulus

D

Q. Plasma membranes are ____, allowing some substances to pass while restricting others, primarily due to the _____ of the lipid bilayer.

A. freely permeable; embedded proteins

B. impermeable; hydrophilic heads

C. rigid; cholesterol content

D. selectively permeable; hydrophobic core

D

Q. Movement of substances through cells is called _____ transport, whereas movement between cells is called _____ transport.

A. paracellular; transcellular

B. facilitated; diffusion

C. passive; active

D. transcellular; paracellular

D

Q. Which of the following substances is routinely in the cytoplasm of eukaryotes?

A. mRNA

B. nucleoli

C. DNA

D. chromatin

A

Q. Which option lists the three major classes of membrane receptors?

A. Ligand-gated channels, GPCRs, enzyme-linked receptors

B.  GPCRs, intracellular receptors, nuclear receptors

C.  GPCRs, intracellular receptors, nuclear receptors

D. Kinases, phosphatases, transcription factors

A