What is a control group used for in scientific studies?

Granzymes.

Granzymes are a family of serine proteases that are stored in and secreted from the cytotoxic granules of cytotoxic T lymphocytes (CTL) and natural killer (NK) cells.

They work in synergy with perforin, a pore-forming toxin, to induce apoptosis in target cells.

Perforin is necessary for the delivery of granzyme B to the target cell cytosol where caspase-dependent and -independent pathways to apoptosis are activated.

Perforins (choice A) are pore-forming toxins that work in synergy with granzymes to induce apoptosis in target cells.

Cytokines (choice B) are signaling molecules that regulate immune responses but do not directly induce apoptosis in target cells.

Interferons (choice D) are a type of cytokine that play a role in immune responses but do not directly induce apoptosis in target cells.

The correct answer is choice B.

To amplify specific regions of DNA.

PCR (polymerase chain reaction) is a laboratory technique used to make many copies of a specific region of DNA.

The goal of PCR is to make enough of the target DNA region that it can be analyzed or used in some other way.

PCR has many research and practical applications, including DNA cloning, medical diagnostics, and forensic analysis of DNA.

Choice A is incorrect because PCR does not separate DNA fragments by size. Choice C is incorrect because PCR does not sequence DNA fragments.

Choice D is incorrect because PCR does not analyze protein expression levels.

Innate immunity represents the first line of defense to an intruding pathogen.

The innate immune system is a series of nonspecific defenses that make up the innate immune system.

These defenses are not directed against any one pathogen but instead provide a guard against all infection.

Choice A is incorrect because adaptive immunity is activated when pathogens are able to bypass innate immune defenses.

Choice B is incorrect because antibodies are part of the adaptive immune system and are produced by B cells.

Choice D is incorrect because T cells are part of the adaptive immune system and assist B cells or directly kill infected cells.

Glycogen is the storage form of glucose in the human body.

It is a polysaccharide that is stored primarily in the liver and muscle tissue and can be broken down into glucose when the body needs energy.

Choice A is incorrect because starch is a storage form of glucose in plants, not in the human body.

Choice C is incorrect because fructose is a simple sugar, not a storage form of glucose.

Choice D is incorrect because cellulose is a structural carbohydrate found in plant cell walls, not a storage form of glucose in the human body.

The correct answer is choice A. Golgi apparatus.

The Golgi apparatus is a membrane-bound organelle that is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.

Choice B is incorrect because mitochondria are responsible for energy production.

Choice C is incorrect because ribosomes are responsible for protein production.

Choice D is incorrect because the endoplasmic reticulum is responsible for lipid production and protein production, but not for modifying, sorting and packaging proteins and lipids.

The neuromuscular junction is a type of synapse where neuronal signals from the brain or spinal cord interact with skeletal muscle fibers, causing them to contract.

The activation of many muscle fibers together causes muscles to contract, which in turn can produce movement.

Choice B is incorrect because binding acetylcholine to nAChRs is a process that occurs at the neuromuscular junction, but it is not the function of the neuromuscular junction itself.

Choice C is incorrect because depolarizing the muscle cell membrane is a result of the function of the neuromuscular junction, but it is not the function itself.

Choice D is incorrect because activating voltage-gated sodium channels on the muscle membrane is a result of the function of the neuromuscular junction, but it is not the function itself.

These are the four nucleotide bases found in DNA1.

Choice B) Adenine, Thymidine, Cytidine, Guanine is incorrect because Thymidine and Cytidine are not nucleotide bases found in DNA.

Choice C) Adenosine, Thymine, Cytosine, Guanosine is incorrect because Adenosine and Guanosine are not nucleotide bases found in DNA.

Choice D) Adenosine, Thymidine, Cytidine, Guanosine is incorrect because Adenosine, Thymidine and Cytidine are not nucleotide bases found in DNA.

The correct answer is choice B.

A patient with chronic kidney disease is at risk for developing an increase in the concentration of potassium in the blood.

The kidneys play a pivotal role in the regulation of electrolyte balance.

With progressive loss of kidney function, derangements in electrolytes inevitably occur and contribute to poor patient outcomes123.

Choice A is incorrect because calcium concentration is not regulated in the glomerulus.

Choice C is incorrect because chronic kidney disease can result in either an increase or decrease in sodium concentration in the blood.

Choice D is incorrect because chronic kidney disease does not necessarily result in an increase in magnesium concentration in the blood.

Diffusion.

During hemodialysis, waste products and excess fluids are removed from the blood by diffusion 1.

Diffusion is a separation process in which particles that are dissolved in a solution are relocated from an area of higher concentration in the blood to an area of lower concentration in the dialysate.

Choice A.

Active transport is incorrect because active transport is a process that uses energy to move molecules against a concentration gradient.

Choice B.

Osmosis is incorrect because osmosis is the movement of water molecules across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration.

Choice D.

Facilitated diffusion is incorrect because facilitated diffusion is a process where molecules move down their concentration gradient with the help of carrier proteins.

The correct answer is choice A. Thymus.

The thymus is a primary lymphoid organ located in the mediastinum.

It plays a key role in the maturation and differentiation of T-lymphocytes.

Choice B.

Parathyroid is incorrect because the parathyroid glands are small endocrine glands located in the neck that produce parathyroid hormone, which regulates calcium levels in the blood.

Choice C.

Adrenal is incorrect because the adrenal glands are endocrine glands located above the kidneys that produce hormones such as cortisol and adrenaline.

Choice D.

Pituitary is incorrect because the pituitary gland is an endocrine gland located at the base of the brain that produces hormones that regulate growth, metabolism, and reproductive functions.