Bio 202 exam #2

What cells produce antibodies?

A lymphocyte is a type of white blood cell that is part of the immune system. There are two main types of lymphocytes: B cells and T cells. The B cells produce antibodies that are used to attack invading bacteria, viruses, and toxins.

What role did helper T cells presumably play in the production of antibodies against the E. coli strain?

After being shown an antigen by a macrophage (or other antigen presenting cell), T-cells activate B-cells that can produce antibodies against the bacteria.

How was Helga's body able to produce antibodies against E. coli O157 if she had never encountered it before?

After identifying the E. coli as a pathogen, Helga's immune system selects among a huge number of B-cells randomly generated by the immune system. B-cells that can produce antibodies against the pathogen are selected and activated

According to Campbell et al. the kidneys of an average human extract 180L of filtrate from your blood stream each day. An average human has only 5L of blood. How is this possible?

Almost all of the 180L of fluid is returned to the blood stream is returned to the bloodstream by osmosis as the renal filtrate goes through the first part of the loop of Henle.

What are antibodies?

Antibodies are specialized, Y-shaped proteins that bind like a lock-and-key to the body's foreign invaders — whether they are viruses, bacteria, fungi or parasites. They are the "search" battalion of the immune system's search-and-destroy system, tasked with finding an enemy and marking it for destruction. Produced by B- lympocytes

How do antibodies facilitate destruction of an invading organism?

Antibodies protect against bacteria that multiply outside cells mainly by facilitating uptake of the pathogen by phagocytic cells that are specialized to destroy ingested bacteria. Through several mechanisms: agglutination, precipitation, opsonization, complement fixation, and neutralization.

How do bacteria and viruses differ?

Bacteria are single-celled, living organisms. They have a cell wall and all the components necessary to survive and reproduce, although some may derive energy from other sources. Viruses are not considered to be "living" because they require a host cell to survive long-term, for energy, and to reproduce.

Blood circulation through fish gills efficiently keeps the internal temperature of fish near the temperature of the water they inhabit. However, fast swimming fish such as tuna and some sharks can have internal temperatures higher than their surroundings. How do they mitigate heat loss through gills?

Because sharks and tuna are endothermic and capable of generating their own heat, in order to mitigate heat loss through their gills, they just simply swim through colder waters and allow their gills to have their blood facilitate heat loss.

Please refresh Rothgar's memory about how blood circulation differs before and after birth.

Before birth, most of the blood flow doesn't go into the lungs. Instead, blood passes through the foramen ovale, which moves blood from the right atrium of the heart to the left atrium, and also through the ductus arteriosus, which moves blood from the pulmonary artery to the aorta. When an infant takes his first breath, these windows close and blood does not flow between the atria. Blood flow begins to go through the heart.

How do capillaries differ from arteries?

Capillaries carry blood away from the body and exchange nutrients, waste, and oxygen with tissues at the cellular level.Arteries carry oxygen rich blood away from the heart and are typically larger than capillaries since they receive blood from the heart which generally has a much higher blood pressure because of its proximity to the heart.

Birds convert nitrogenous waste to uric acid. Why?

Conversion of ammonia into uric acid is more energy intensive than the conversion of ammonia into urea. Producing uric acid instead of urea is advantageous because it is less toxic and reduces water loss and the subsequent need for water

What is osmosis? How does it differ from diffusion? Describe a physiological process in which osmosis plays a role.

Diffusion- The random net movement of a particle from an area of high concentration to an area of low concentration Osmosis-The movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.(i.e. It occurs in the kidneys to recover water from the waste materials of the body. Dialysis as an Example of Osmosis. Kidney dialysis is an example of osmosis.

How do nephrons work? Why do you have nephrons? If a person's nephrons don't work, what can be done?

Each of your kidneys is made up of about a million filtering units called nephrons. Each nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process: the glomerulus filters your blood, and the tubule returns needed substances to your blood and removes wastes. If they don't work, waste builds up in your blood and you'll get sick. Nephron tubules can be repaired, but if the damage is too much, the body may destroy the nephron and cannot generate more nephrons.

What is endothermy? Ectothermy?

Endothermy - physiological generation and regulation of body temperature by metabolic means : the property or state of being warm-blooded. Ectothermy - Any so-called cold-blooded animal; that is, any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface

How is filtration different from secretion?

Filtration involves the transfer of soluble components, such as water and waste, from the blood into the glomerulus. ... Secretion involves the transfer of hydrogen ions, creatinine, drugs, and urea from the blood into the collecting duct, and is primarily made of water. Blood and glucose are not normally found in urine.

Describe the different adaptive strategies used by fish, mammals and birds for getting rid of nitrogenous wastes. How do the different strategies fit the lifestyle of the organism?

Fish- must conserve water and so their kidneys excrete little water. Waste/Ammonia is loss through secretion by the gills. Works in marine life. Mammals- excrete urea as well as excess salts and water in one go. Works for mammals that don't have gills or live in water.Birds- produce uric acid. Less toxic than urea and better for smaller animals.

Bob (a human) tells his parents he can't go to college in Minnesota because he is ectothermic. His parents don't understand. Please translate for them. Should his parents accept his explanation?

He means his body does not produce enough internal heat to regulate his body temperature. He is either mistaken or a liar.

What is interferon?

Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses. IFNs) are proteins produced by a variety of cells in the inflammatory response to infections. Their production is triggered by the immune system in response to pathogens or cytokines.

What are the loops of Henle?

Loop of Henle, long U-shaped portion of the tubule that conducts urine within each nephron of the kidney of reptiles, birds, and mammals. ... The principal function of the loop of Henle is in the recovery of water and sodium chloride from urine. The part of the nephron that extends from the cortex of the kidney into the medulla and back.

Compare the vessels of the lymphatic system to veins. How are they similar? How are they different?

Lymphatic vessels are similar to veins in that they contain valves to prevent backflow, and use the contraction of nearby skeletal muscles to help move lymph along. They are quite unlike in terms of what they carry (lymphatic fluid vs. blood). They are also quite different in that lymphatic vessels are sealed at one end, whereas veins form a full circuit with the other blood vessels. ... Both veins and lymphatics are valved to create directional flow of liquid.

What role did macrophages presumably play in the production of antibodies against the E. coli strain?

Macrophages presumably were among the first immune cells to attack the E. coli. After engulfing and destroying the bacteria, the macrophages used MHCII complexes to display bits of bacterial protein to helper T-cells, which then activated the appropriate B-cells.

Compare the roles of cytotoxic T-cells to Natural killer cells. How does each contribute to the function of the immune system?

NK cells were first noticed for their ability to kill tumour cells without any priming or prior activation (in contrast to cytotoxic T cells, which need priming by antigen presenting cells). They are named for this 'natural' killing.

What are osmoconformers? How do they differ from osmoregulators?

Osmoregulators are either marine or freshwater organisms that tightly regulate their internal osmolarity in a constant value. Moreover, their osmolarity does not depend on the osmolarity of the external environment. Osmoregulators are the commonest type of aquatic animals. Osmoconformers are exclusively marine organisms that match their internal osmolarity to the osmolarity of the outside environment. However, their ionic composition may be different from that of the outside seawater. Their internal environment is isotonic to the external environment. Generally, most marine invertebrates are osmoconformers. The main difference between osmoregulators and osmoconformers is that osmoregulators tightly regulate their body osmolarity as a constant, while osmoconformers match the osmolarity of their body to their outside environment.

Compare the lungs to the kidneys.

Physiologically, the lungs and kidneys are intricately related, not least as homeostatic organs controlling the cellular electrolyte and acid-base status that guarantee the best microenvironment for cellular function. Lungs have Alveoli, Kidneys have Nephrons. (they have similar functions.)

In the case study about Baby Joe, Baby Joe was unable to produce the RAG protein. How did lack of Rag protein cause Baby Joe to be sick?

RAG protein is needed to randomly rearrange the genes for antibodies and T-cell receptors, a necessary step in producing B and T cells with different specificities.

Rothgar's immune system will encounter many more pathogens (disease causing rganisms) than just E. coli O157. How can Rothgar's immune system produce antibodies capable of attacking the wide variety of pathogens he will encounter? Explain.

Rothgar's bone marrow stem cells continually produce new B-cells. Each new B-cell randomly rearranges the gene for antibodies so that each newly maturing B-cell produces antibodies with different specificity.

Most fish do not convert toxic ammonia to urea or uric acid. How do they get away without detoxifying ammonia? Why do fish make ammonia? Why do humans make ammonia?

Since fish can easily get rid ammonia by diffusion from their gills, the ammonia does not build up in their blood. Ammonia is the end product of protein catabolism and is stored in the body of fish in high concentrations relative to basal excretion rates. The human body makes ammonia when the body breaks down foods containing protein into amino acids and ammonia, then converting the ammonia into urea.

If Helga encounters the same strain of E.coli again, she will probably not get very sick. Why not? Explain.

Some of the B-cells activated during her immune response will become memory B-cells. These memory B-cells will quickly produce antibodies if the E. coli is encountered again.

Compare the roles of cytotoxic T-cells to B-cells. How does each contribute to the function of the immune system?

The major function of the helper T cells is to activate cytotoxic T cells and B cells. ... The cytotoxic T cells destroy pathogens by phagocytosis. B cells produce and secrete antibodies, activating the immune system to destroy the pathogens.

What are MHC proteins?

The major histocompatibility complex is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules.

dependent variable

The measurable effect, outcome, or response in which the research is interested.

Jeremiah, a freshwater fish, looked through the glass of his aquarium and pined for Sally the brilliantly colored saltwater fish in the next tank. Unfortunately, the biggest obstacle to their romance was not the glass wall of their fish tanks. Rather, they will be forever kept from swimming together by osmosis.What is osmosis? Why is it such a big deal for fish? How do saltwater fish differ from freshwater fish in how they deal with osmosis?

The movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration. Osmosis is a big deal for both saltwater and freshwater fish. Saltwater fish must take in a lot more water to prevent the salt in the water around it from pulling the water outside of their bodies. Diffusion in their bodies allow them to live in a state of constant osmosis. If placed in freshwater. They would explode.

The kidneys of desert animals have longer loops of Henle than organisms living in wet areas. What are the loops of Henle? What does the length of the loop have to do with their function?

The part of a kidney tubule that forms a long loop in the medulla of the kidney, from which water and salts are reabsorbed into the blood..Longer the loop, more salt and water gets reabsorbed...

While thinking of children, he also remembers that children have a larger thymus (proportionally) that adults, but he can't remember what the thymus does. What does the thymus do?

The thymus gland produces hormones and also is a part of the immune system by training and developing T-lymphocytes/T cells.

Why were they important for the immune response to the E. coli O157?

These proteins are important for the immune response to the E. coli because they will are the structures which will bind to the antigens derived from pathogens and display them on the cell surface for recognition by the appropriate T-cells. While they will not play much of a role this time, they will allow for the body to respond quickly to the virus should it be encountered in the future.

How does the immune system of humans defend against viruses?

Virally infected cells produce and release small proteins called interferons, which play a role in immune protection against viruses. Interferons prevent replication of viruses, by directly interfering with their ability to replicate within an infected cell The acquired immune system, with help from the innate system, produces cells (antibodies) to protect your body from a specific invader. These antibodies are developed by cells called B lymphocytes after the body has been exposed to the invader. The antibodies stay in your child's body.

independent variable

a variable (often denoted by x ) whose variation does not depend on that of another. I.e Time or age

Dr. Clueless told his class that T-Cell receptors are cells in the lymph nodes that welcome T-cells to the lymph nodes, and provide all that the T-cells need to relax after spending a hard week traveling through the blood stream destroying bacteria by phagocytosis. Accroding to Dr. Clueless the lymph nodes are expansions of the arteries where immune cells congregate during their time off.What is wrong with Dr. Clueless's information? Is anything correct? Explain

a, b., and c among other factual errors.A. T-cells don't destroy bacteria by phagocytosis, they destroy infected human cells.B. Lymph nodes are not expansions of the arteriesC. T-cell receptors are proteins produced by T-cells, not a welcoming committee