Bio Test 2

__________describes a set of defenses that is customized to each infectious agent, providing a stronger response when an agent has been encountered before.

Adaptive immunity

Which of the following nitrogenous wastes requires the greatest amount of water to excrete?

Ammonia is a toxic substance and requires a great deal of water for its disposal.

How does antigen-antibody binding result in destruction of the antigen?

Antibodies bind the antigen, which then targets the antigen for elimination by innate mechanisms.

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____.

B cells ... plasma cells and memory cells.

What is the primary cell type involved in humoral immunity?

B cells are responsible for antibody production in humoral immunity.

Which of the following inflammatory responses is characteristic of only a systemic response?

Bacteria and toxins enter the bloodstream, and the white blood cell count increases significantly. When bacteria and toxins enter the bloodstream, they are carried throughout the body for a systemic effect and elicit a surge in white blood cell production.systemic=throughout whole body

Freshwater fish excrete a large amount of very dilute urine. What is the best explanation for this?

Because they live in a hypotonic solution, their cells take up an excess of water that must be excreted.

In what ways are neurosecretory cells similar to endocrine cells?

Both release signal molecules into the bloodstream. Endocrine cells release hormones into the bloodstream. Neurosecretory cells release neurohormones into the bloodstream.

Which part of the nephron is most directly involved in the filtration of blood?

Bowman's capsule and the glomerulus make up the blood-filtering part of the nephron.

Cytotoxic T cells kill infected body cells by _____.

Cytotoxic T cells bind to their target cells and release proteins that result in their destruction. Perforin attaches to the infected cell's membrane and produces holes in it through which salts and water can rapidly enter the cell. This destruction is aided by enzymes produced by the T cells, which break down the target cell's proteins.

Which of the following statements regarding innate immunity is correct?

External barriers such as the skin barrier, exoskeleton, and mucous membranes contribute to innate immunity. In addition to those barriers, there are internal defenses such as phagocytic cells and inflammatory cells that help elicit an innate immune response.

A man who has been exposed to the flu virus is tested by his physician. The physician notes that the virus is present but no measurable level of antibodies corresponding to the virus are detected in his body.

He was probably exposed a few days ago and clonal selection has yet to produce plasma cells. After first exposure to an antigen, measurable levels of antibodies (produced from plasma cells) are not seen until about a week after exposure. Thus, it is probable that this man was exposed less than a week ago.

_____ interact with the antigen-class II MHC complex presented by macrophages.

Helper T cells. Specific helper T cells recognize specific antigen-class II MHC complexes. The result of this is an activated helper T cell that stimulates both humoral and cell-mediated immune responses.

Which of the following statements about hormones and the endocrine system is true?

Hormones only affect specific cells having the appropriate receptors. Hormones convey information via the bloodstream to cells throughout the body. Cells are unresponsive to a particular signal if they lack the appropriate receptors.

What is the key difference between active immunity and passive immunity?

In active immunity, a body produces its own antibodies; in passive immunity, a person receives pre-made antibodies. Active immunity lasts for a long time because the body will respond to the same antigen again with the same antibodies. Passive immunity lasts only as long as the antibodies last.

________ describes a set of defenses that is always at the ready and is the same whether a particular infectious agent has been encountered before or not.

Innate immunity

Which of the following is an accurate statement regarding the difference between lipid-soluble and water-soluble hormones?

Lipid-soluble hormones attach to receptors in the cytoplasm; water-soluble hormones attach to membrane-enclosed receptors.

An antigen-presenting cell is a _____.

Macrophages can act as antigen-presenting cells. After breaking up the antigen, parts of it are attached to the macrophage's self proteins and displayed at the cell surface. also B cells.

Which of the following statements regarding the cell mediated response is correct?

Macrophages digest the antigen to break it up into its components, which are then bound by and presented to the cell surface for removal. Macrophages act like the garbage disposals of the immune system, digesting foreign particles and ridding the body of them. After digestion, the macrophage displays the combination of a self protein and foreign antigen called a self-nonself complexon its surface. Helper T cells then recognize and bind to the self-nonself complex displayed on the antigen-presenting cell.

Which cell type is responsible for the secondary immune response?

Memory cells are rapidly activated upon repeated exposure to the same antigen. Adaptive immune responses will produce memory B and memory T cells in the primary response and these memory cells will initiate the secondary immune response.

Which of these attack cancer cells?

Natural killer cells recognize cancer cells and virus-infected cells and release chemicals that cause the death of these cells.

_________describes the process of engulfing and destroying a foreign particle.

Phagocytosis

B cells that have been stimulated by interleukin-2 develop into _____.

Plasma cells develop from B cells that have been stimulated by the interleukin-2 secreted by helper T cells.

Which is a true statement about memory cells?

Plasma cells live only 4-5 days, but memory cells may last for decades.

What is the main function of the loop of Henle?

Reabsorption of water occurs at the loop of Henle as well as the collecting duct.

Which statement about the endocrine and nervous systems is true?

Some specialized nerve cells, such as neurosecretory cells, perform functions of both systems. nterestingly, neurosecretory cells conduct nerve signals and also make and secrete hormones.

A virus enters your system and successfully invades and infects a cell. At this point it is vulnerable to recognition or attack by _____

T cells

What is a major difference between filtrate in the nephron and urine leaving the bladder?

The filtrate contains amino acids and glucose, but under normal conditions urine does not. Amino acids, glucose, minerals, some vitamins, and other nutrients are reclaimed as the filtrate is refined.

Which of the following is a lymphatic organ?

The spleen, along with the tonsils, lymph nodes, adenoids, and the appendix, is a lymphatic organ.

Which of the following is one way that land animals tend to lose water to their environment?

Water evaporates from moist surfaces of the body.

Glucose, nacl, amino acids are removed from filtrate by _____.

active transport

A characteristic of every animal hormone is that the hormone _____.

acts as a regulatory message or signal between cells. Hormones are secreted into body fluids, usually blood, and communicate regulatory signals throughout the body.

The vertebrate endocrine system consists of more than a dozen major glands. Which of the following is considered to be a major endocrine gland?

adrenal gland.

Passive immunity can be obtained from _____.

an injection of antibodies that recognize invading microbes. Passive immunity can be transferred artificially by injecting antibodies from an animal that is already immune to a disease into another animal, conferring short-term but immediate protection against that disease

In the immune response, the end goal is to disable or kill pathogens that invade the body. But first, antibody proteins or proteins in immune cell membranes must recognize and bind to invaders. This is a challenge, given the vast diversity of pathogensthat can infect us. To meet this challenge, immune proteins _____.

are diverse: each immune protein can bind to only one or a few pathogens, but immune proteins are tremendously diverse, so the system is likely to possess a "match" to nearly any pathogen

Receptors for nonsteroid hormones are located in _____.

association with a cell's plasma membrane.

When a B cell binds to a virus or other pathogen, it _____.

becomes activated, divides rapidly, and thereby mounts a specialized response against the pathogen

The role of cytotoxic T cells is to attack _____.

body cells that have been infected. Cytotoxic T cells kill cancer cells and cells infected by viruses or other intracellular pathogens.

Filtrate is formed as fluid is forced through the walls of the glomerulus and, initially, collects in the structure

bowman's capsule

Steroid hormones, such as the sex hormones, _____.

can diffuse across the phospholipid membrane of cells.

The proliferation of the B lymphocyte to which a specific antigen binds is referred to as _____.

clonal selection. When an antigen binds to a B cell or a T cell, that cell proliferates, forming clones of effector cells with the same specificity.

Antidiuretic hormone (ADH) makes the _____ permeable to water.

collecting duct. Making the collecting duct permeable to water results in the reabsorption of water.

The ________ is a set of proteins that circulate in the blood, stimulating other defenses to help destroy an invader.

complement system

The outer part of the kidney is the ____

cortex

2. An organ that produces and releases hormones is called a ____________

endocrine gland.

Taken together, all of the cells of the human body that produce and secrete hormones are called the-________

endocrine system.

In a marine environment, animals that are osmoconformers __________.

experience no net water loss or gain by osmosis

t or f The words "antigen" and "virus" are interchangeable.

false. A virus, like other pathogens, has numerous antigens on its surface, so the words "antigen" and "virus" cannot be used interchangeably.

n each nephron of the kidney, the glomerulus and Bowman's capsule _______

filter the blood and capture the filtrate. Using hydrostatic pressure, plasma is forced through the walls of the glomerulus, becoming filtrate as it crosses, and collecting within Bowman's capsule.

Which best describes the function of the kidneys?

filtering blood, removing wastes and regulating water balance

What is the correct sequence of filtrate processing in the nephron?

filtration, reabsorption, secretion, excretion. The blood is first filtered to take out waste particles, but some nutrients and vital chemicals are also lost and must be reabsorbed. The nephron then secretes any remaining wastes so that they, along with those previously filtered and not reabsorbed, can be excreted.

An antigen is a(n) _____.

foreign molecule that evokes an immune response. Antigen molecules can belong to any type of organism, or to products of organisms such as pollen or feces.

Many birds, insects, and terrestrial reptiles excrete nitrogenous wastes in the form of uric acid, which __________.

forms solids that are relatively water-insoluble and nontoxic. Uric acid, which is relatively nontoxic, precipitates out of solution and is excreted as a paste or dry powder. An animal must expend more energy to excrete uric acid than to excrete urea, but the higher energy cost is balanced by the great savings in body water.

How can active immunity be obtained?

from a vaccine. A vaccine represents a form of active immunity because a person's own immune system is stimulated to produce antibodies rather than receiving them. The vaccine does not confer immediate immunity by using previously formed antibodies but rather allows the body to form its own antibodies.

People with diabetes have trouble regulating the levels of ___________in the blood

glucose

A __________ is a chemical substance used for communication that is produced at one site in the body and then carried in the blood to another.

hormone

the ____ is a collection of cells and organs that protect an organism's body from agents that can cause disease.

immune system

When glucose levels get too high in the blood, the pancreas releases ____________, whereas when glucose levels get too low, the pancreas releases ____________.

insulin; glucagon

What happens to glucose in the filtrate as it passes through the proximal tubule?

it is reabsorbed

A signal molecule is also known as a(n) __

ligand

T and B cells are types of _____.

lymphocytes.

Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium?

macrophage

The primary nitrogen-containing compound excreted by kidneys of mammals is __________.

mammals, most adult amphibians, and many marine fishes and turtles excrete mainly urea.

Some viral diseases are dangerous only when a person is infected for the first time; subsequent infections produce only mild symptoms or go entirely unnoticed. This pattern can be explained by the action of _____.

memory cells that trigger a secondary immune response

hat can white blood cells do that helps them carry out their defensive functions more effectively?

migrate into and out of blood vessels. Phagocytic white blood cells move from the circulatory system to the site of injury. Some macrophages migrate throughout the body.

As filtrate moves down the loop of Henle, the surrounding interstitial fluid becomes _____ concentrated than the filtrate, so _____ leaves the filtrate.

more ... water

Under the influence of antidiuretic hormone (ADH), _____ is produced and the body preserves water

more concentrated urine.

Effector B cells _____.

multiply and make antibodies that circulate in blood and lymph. B cells that make antibodies are called effector B cells. These effector B cells are highly effective at combatting an existing infection, even though they only last for 4-5 days before dying off.

Which of these is the functional unit of a kidney?

nephron

5. A nerve cell that can communicate via both hormones and electrical signals is called a __________

neurosecretory cell.

How do nonsteroid hormones differ from steroid hormones?

nonsteroid hormones act via signal transduction pathways; steroid hormones do not act via signal transduction pathways. Since they do not enter the cell, nonsteroid hormones act via signal transduction pathways.

Steroid hormone-receptor complexes act in _____.

nucleus. Steroid hormone-receptor complexes bind to DNA, where they affect transcription.

An aquatic animal that has the same solute concentration as its environment is a(n) _____.

osmoconformer. Osmoconformers have body fluids with a solute concentration equal to that of the surroundings. Most marine invertebrates, including jellies, molluscs, squids, and sea stars, are osmoconformers. These animals have body fluids with a solute concentration equal to that of seawater.

Terrestrial animals are __________.

osmoregulators that do not exchange quantities of water by osmosis with the environment. They have to drink quantities of water or get it in their food to survive.

A is an agent in the environment that has the potential to cause disease.

pathogen

The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response

perforin ... cell-mediated. Perforin causes the lysis of pathogen-infected body cells; it is a component of the cell-mediated immune response.

Which of these cells produce and secrete antibodies?

plasma cells. Plasma cells are clones of antibody-secreting B cells.

Which of the following is a function of the human kidney?

processing of blood to form filtrate material, from which metabolic wastes are discarded

n terms of molecular classes, antibodies are _____.

proteins. composed of amino acids

If you are dehydrated, which of the following would increase in your kidneys?

reabsorption

Following tissue damage or the entry of microorganisms, an inflammatory response may be initiated by the _____.

release of histamine by mast cells. At the injury site, mast cells (white blood cells that reside in connective tissue) release histamine, which induces neighboring blood capillaries to dilate and become leaky.

The _____ are the major blood vessels transporting blood to the kidneys.

renal arteries. The word "renal" refers to a kidney. Recall that arteries transport blood away from the heart. Renal arteries transport blood to the kidneys.

Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____.

renal pelvis ... ureter ...urinary bladder

Functions of the lymphatic system include _____.

return of fluid to the circulatory system and fighting infections

The active movement of ions and drugs from capillaries into tubules is called ___________.

secretion

The movement of substances from the blood into the proximal tubule is known as _____.

secretion

Steroid hormones such as estrogens and androgens are produced by the __________.

sex organs. other organs too tho.

A signal transduction pathway is initiated when a _____ binds to a receptor.

signal molecule

A cell that releases interferon is _____.

signaling other cells that it has been infected by a virus. Interferons are proteins that interfere with viral infections. Virus-infected body cells secrete interferon proteins, which induce nearby uninfected cells to produce substances that inhibit viral replication. In this way, interferons limit the cell-to-cell spread of viruses in the body.

What is reabsorbed from filtrate?

sodium chloride, glucose, water, amino acids, and bicarbonate ions

Antibodies are _____.

specialized proteins that attach to pathogens and disable them or mark them for destruction by immune cells

. A___________ is a cell that has receptors for a specific hormone and will therefore be affected by that hormone.

target cell

The immune system is initially capable of mounting responses to particular microorganisms because _____.

the body contains an enormous diversity of B and T cells, each with a specific kind of antigen receptor. An enormous diversity of B cells and T cells develops in each person. Researchers estimate that every one of us has millions of different kinds enough to recognize and bind to virtually every possible antigen. A small population of each kind of lymphocyte lies in wait in our body, genetically programmed to recognize a specific antigen.

Helper T cells are part of _____.

the cell-mediated immune response. Cell-mediated immunity depends on the action of cytotoxic T lymphocytes, whose action is enhanced by the additional stimulatory proteins secreted by helper T cells.

During a secondary immune response, _____.

the generation of effector cells begins with memory cells produced during the primary immune response. The capacity to quickly generate secondary responses is termed "immunological memory."

The primary reason steroid hormones usually act slowly is that _____.

they turn genes on or off and it takes time for gene products to build up or become depleted.

The antigen-binding sites of an antibody molecule are found in the _____.

tip of each arm of the Y shaped antibody. Antigen binding sites are at the tips of the arm of the Y shaped antibodies and are called variable regions as these regions show structural variety. This accounts for the diversity of lymphocytes and gives the humoral immune system the ability to react to virtually any kind of antigen.

Which of these is the second of the three stages of cell signaling?

transduction

The difference between neurotransmitters and hormones has become blurred in recent years, but a chemical is currently classified as a hormone if it _____

travels in the blood and has an effect on a remote tissue. Chemical messengers (hormones) that affect target cells convey information via the bloodstream to target cells throughout the body.

The most abundant solute in urine is _____.

urea (and other nitrogenous wastes