Bio- unit1- notes from book pt2- ch 3, 32, 16

29 Cystic fibrosis is an inherited condition that affects the lungs and digestive tract (see Chapter 11). In many people with cystic fibrosis, a membrane channel protein is found in the rough endoplasmic reticulum instead of the cell membrane. How could a cell membrane protein end up in the rough endoplasmic reticulum? (Hint: Look at the box about the cooperation of the nucleus, endoplasmic reticulum, and Golgi apparatus in Up Close: Eukaryotic Organelles.)

As the relevant protein is a membrane channel protein, it must pass through the rough endoplasmic reticulum and the Golgi apparatus. If this delivery system is impaired, the protein could be trapped in the rough endoplasmic reticulum and never reach the cell membrane and so be unable to fulfill its function; the result is symptoms of cystic fibrosis.

HYPERTONIC ISOTONIC PEPTIDOGLYCAN GRAM-POSITIVE

Describes a solution surrounding a cell that has a higher concentration of solutes than the cell's cytoplasm. Describes a solution surrounding a cell that has the same solute concentration as the cell's cytoplasm. The macromolecule found in all bacterial cell walls that gives the cell wall its rigidity. Describes bacteria with a cell wall that includes a thick layer of peptidoglycan that retains the Gram stain.

The 1918 flu pandemic killed more people in 1 year than the Black Death killed in the entire 14th century; it killed more people in 25 weeks than AIDS killed in 25 years.

Even more frightening than an epidemic, a pandemic is an exceptionally high number of cases occurring worldwide

Beyond these common features, however—cell membrane, cytoplasm, ribosomes, and DNA—the two cell types are structurally quite different.

For one thing, the DNA in a prokaryotic cell floats freely within the cell's cytoplasm, while in a eukaryotic cell it is housed within a central "command center" called the nucleus. The nucleus is one of many organelles found within eukaryotic cells but not in their simpler prokaryotic cousins

Adaptive immunity or specific -title Barriers Cellular defenses Phagocytes

Physical and chemical barriers like skin, nasal hair, stomach acid, and mucus are part of the first line of defense against pathogens When pathogens get past the bodies barriers, they encounter a variety of cells. Each able to engulf and destroy a variety of different invaders Engulf a verity of pathogens

Antibiotics kill bacteria but leave humans unharmed because bacterial and human cells have --- Of all the ways that prokaryotic and eukaryotic cells differ, the most obvious is the ---of eukaryotic cells compared to their smaller prokaryotic cousins.

different structures complexity

-Unlike cells, which rely on DNA as their hereditary material, viruses can store their genetic information in the form of either DNA or RNA, RNA viruses include the influenza virus and the viruses that cause colds, measles, and mumps. -RNA viruses also cause more serious diseases, like AIDS and polio. -Diseases caused by DNA viruses include hepatitis B, chicken pox, and herpes. Each type of virus has a --- -Some viruses cause more damage than others. The severity of a viral illness typically depends on how ---the body's defenses rally to kill the virus and how well the infected tissue can repair itself. Only one or ---particles are enough to cause an infection.

distinctive protein shell with a characteristic shape. quickly and successfully two

Each year in the United States about 36,000 people die from complications of flu, and more than 200,000 people are hospitalized from flu-related illnesses. Most of these deaths strike young children and the elderly, whose bodies are less able to fight off the infection.

he 1918 flu, by contrast, struck down people in the prime of life: people age 20 to 40 were the hardest hit. The death toll in this age group was so severe that it reduced the average U.S. life expectancy in 1918 by 12 years.

Adaptive immunity or specific Cellular defenses Lymphocytes

lymphocytes set off a chain of events that inactivate invading pathogens and provide long lasting immunity to the specific pathogen's they encounter Mount pathogen specific reactions

Within ---, these virus particles attach to epithelial cells that line the respiratory tract and slip inside the cells. The virus then hijacks the host cells' cellular machinery to replicate its own genetic material. Generally, about ---hours after the virus invades a cell, the cell begins to release newly synthesized viral particles, sending out between 1,000 and 10,000 viruses capable of infecting other cells. Eventually the infected cells die, weakening the respiratory tract.

minutes 10

Antibodies fight infections in several ways. -First, by binding to antigens, they may ---block the infectious organism from infecting other cells, rendering it harmless. -Second, they can ---a pathogen to be digested by phagocytes. -Finally, they can --the pathogen so that complement proteins will bind to it and destroy it. -Each B cell produces antibodies ----for one particular antigen

physically flag mark specific

The human immune system has ---primary lines of defense that coordinate to protect us from pathogens, providing us with immunity, or protection from these threats. -The first includes ---barriers such as the skin and mucous membranes, which block invaders from entering the body. -It also includes a variety of white blood cells called ---that engulf and destroy invaders. -Because we are born with these defense mechanisms, they are referred to collectively as ---. Innate defenses are effective but nonspecific, in that they protect us against a wide variety of invaders but do not target any one in particular. -The second line of defense is ---, which includes the coordinated actions of specialized white blood cells called lymphocytes that take aim at specific pathogens. -Adaptive immunity ---to develop, but it has three main advantages over innate immunity. -First, the adaptive immune system is ---: it is able to recognize particular pathogens—one type of virus, for example—even if it has never encountered that pathogen before. This feature is important because pathogens ---, and many have found ways to evade our innate defenses. -Second, the adaptive immune system is ---: it can mount an immune response to essentially any threat that comes its way. -Finally, the adaptive immune system exhibits ---: once you have chickenpox, the activity of the adaptive immune system means you won't get it again.

two physical and chemical phagocytes innate immunity adaptive immunity takes time specific evolve quickly diverse memory

The lymphatic system is connected by a set of ---(the lymphatic vessels) that weave between blood capillaries and drain fluid (lymph) from tissues. -Lymph contains ---and sometimes ---picked up from tissues. Lymph travels from tissues to ---, where antigen presentation between phagocytes and lymphocytes occurs. -From there, lymph is returned to the ----through veins. In this way, the lymphatic system and the blood circulatory system are connected. -Lymphocytes continually circulate through both the blood and the lymph as they patrol the body looking for invaders

vessels white blood cells pathogens lymph nodes blood circulation

But research in 1933 showed that influenza is caused not by a bacterium but by a ---.

virus

Antibiotics are so common, in fact, that many people routinely take them when hey catch a cold or the flu. But antibiotics are powerless against these illnesses. That's because ---, not bacteria, cause colds and flu. Since viruses are not made of cells—and according to the cell theory are not even considered to be ---—they can't be killed with an antibiotic.

viruses alive

Why is nonspecific immunity important even though another system provides both specificity and memory?

- Because we are born with these defense mechanisms, they are referred to collectively as innate immunity. Innate defenses are effective but nonspecific, in that they protect us against a wide variety of invaders but do not target any one in particular. -These defenses are always present and require little or no time to become active.

What is the structure of a virus, and how do viruses cause disease?

1 all viruses, is a tiny particle made up of nucleic acid surrounded by a protein shell. 2 The nucleic acid serves as the virus's genetic material, while the protein shell (called a capsid) allows the virus to bind to and enter cells. Once inside, the virus then coopts the host cell's machinery to replicate its genetic material and make more viruses. Eventually the multiplied viruses burst from and destroy the host cell

ANTIGEN-PRESENTING CELL B CELLS THYMUS T CELLS

A cell, such as a phagocyte, that digests pathogens and displays pieces of the pathogen on its surface, where they can be recognized by lymphocytes. White blood cells that mature in the bone marrow and produce antibodies during an adaptive immune response. The organ in which T cells mature. White blood cells that mature in the thymus and play several roles in adaptive immunity.

Two types of lymphocyte play crucial roles in adaptive immunity -Like all blood cells, B and T cells develop from ---made in the bone marrow. Some immature ---in bone marrow become B cells (think "B" for "bone"). Other immature lymphocytes migrate from the bone marrow to the thymus, a gland in the chest, where they become ---(think "T" for "thymus"). -Both B cells and T cells eventually travel to the lymph nodes and other organs of the lymphatic system, where they ---for signs of infection.

-B cells and T cells. -stem cells lymphocytes T cells monitor body fluids

What is a major difference between diffusion and active transport?

-Diffusion is the movement from a high concentration of molecules to a low concentration of molecules. Molecules can diffuse across membranes through the phospholipid bilayer or using a special protein. Either kind of diffusion does not need energy from the cell. -Some special proteins move certain molecules across cell membranes only with the help of cell energy (either directly or indirectly). Moving molecules with cell energy is called active transport. The cell energy is the ATP made in the mitochondria. Low to high -simple diffusion= small, uncharged molecules, high to low, no help of transport proteins or input of energy. -facilitated diffusion= large, charged/polar molecules, high to low, with the help of specific transport proteins, no energy -active transport= large molecules, low to high, with the help of specific transport proteins and energy

What is adaptive immunity, and how does vaccination rely on adaptive immunity?

-The second line of defense is adaptive immunity, which includes the coordinated actions of specialized white blood cells called lymphocytes that take aim at specific pathogens. -Vaccines utilize this adaptive immunity and memory to expose the body to the antigen without causing disease so that when then live pathogen infects the body, the response is rapid and the pathogen is prevented from causing disease.

What are the features of the influenza virus that allow it to cause worldwide outbreaks?

-While less lethal flu viruses replicate primarily in the upper respiratory tract, viruses with these four alleles cruise past the mouth, nose, and throat and invade the lungs. Replication of the virus in the epithelial cells lining the lungs killed these cells, and triggered a massive inflammatory response. -The inflammatory response of victims was so massive that it damaged lung tissue, ultimately causing people to suffocate from fluid buildup in the lungs. This aggressive immune response helps explain why victims with the strongest immune systems—people age 20 to 40—were the ones who suffered most. -Another important factor in explaining the large death toll is what came next. Because influenza destroyed the protective layer of cells lining the lungs and upper respiratory tract, bacteria and other pathogens had unimpeded entry into the lungs. Once inside, they grew like mad. Because antibiotics had not yet been discovered doctors had no way of treating these infections -Bacterial pneumonia was responsible for at least half of all deaths during the 1918 pandemic, according to Taubenberger.

1 What does the cell theory state? 2 Which of the following statements best explains why bacteria are considered living organisms? 3 What are the two main types of cells found in organisms? 4 Which of the following is/are not associated with human cells?

1 - 1. That cells are the basic building blocks of life. 2. All living things are made up of cells.3. Every new cell comes from an existing cell. 2 They are made of cells. 3 Prokaryotes and Eukaryotes 4 cell wall

1 Which of the following is found in all viruses? 2 Explain how viruses replicate within humans 3 Why does poliovirus cause long-lasting damage, whereas those infected by influenza virus typically make a full recovery?

1 Capsid, nucleic acid core, proteins such as enzymes., protein shell 2 1.attachment to specific receptors host cell 2.fuse with host cell membrane 3.inject nucleic acid into the host cell 4.genetic info on nucleic acid provides the instructions for the host cell to start to produce viral components (hijacking) 5.new virus particles made therefore new viruses are made (sometimes particles take part of the cell) 6. infect more cells 3 Poliovirus infects and damages nerve cells. As nerve cells do not replicate, they cannot repair themselves. Influenza virus infects cells lining the respiratory tract, which are replaced at high frequency.

Viruses Infect and Replicate in Host Cells stages If a cell does not have receptor molecules to which a specific virus can bind, can that cell be a host for that virus?

1 virus can replicate only within a host cell 2 barrel genes Direct the host cell to synthesize new viral particles 3 ultimately, viral replication kills the host cell either by causing it to burst or by deleting the cell's resources Stages: 1 attachment- A virus particle binds to replicator molecules on the cell surface 2 penetration- The virus enters the host cell and releases its nuclear acids 3 synthesis- The virus hijacks the host cell machinery and resources to mass-produce more viral nucleic acid and proteins 4 Assembly - New virus particles are produced 5 release- New virus particles exit the host cell no

1 What are the shared characteristics of life? 2 What is the smallest living unit? 3 What is the purpose of a cell membrane? 4 What causes you to get sick? 5 How do vaccines work? 6 Should I take an antibiotic if I get a cold? 7 What can you do in the event of a zombie outbreak?

1- (1) Living things grow—they increase in size or cell number. (2) They reproduce, by producing offspring that are similar if not quite identical to themselves. (3) They maintain a relatively stable internal environment in the face of changing external circumstances—producing heat when they're cold, for example—a phenomenon called homeostasis. (4) They sense and respond to their environment, as when a plant grows toward sunlight. (5) And to carry out these various activities, they obtain and use energy, the power to do work 2- cell 3 A phospholipid bilayer with embedded proteins that form the boundary of all cells. provides protection for a cell. It also provides a fixed environment inside the cell, and that membrane has several different functions. One is to transport nutrients into the cell and also to transport toxic substances out of the cell. 4 Viruses spread through tiny droplets in the air that are released when a sick person sneezes, coughs, or blows their nose. You can get sick if you touch your nose, eyes, or mouth after you have touched something contaminated by the virus, such as a toy, countertop, or doorknob 5 The secondary immune response is what confers immunity to a particular infection. It's also how vaccines work. Vaccines are essentially dead or weakened versions of a pathogen administered in order to generate immunity to that pathogen. The goal is to create a primary immune response in the body without causing disease. Thus, if the pathogen is subsequently encountered naturally, the secondary response is already primed. Vaccination is like being infected with a pathogen but not having the disease. 6 no, colds are a virus, not an infection 7

Lymphocytes Are Activated by Antigen-Presenting Cells

1- pathogens ingested by a phagocyte and digested into small pieces es called antigens 2 antigen is displayed bu the phagocyte 3 antigen-specific lymphocyte is able to recognize a specific antigen displayed by a phagocyte 4 binding of the antigen by the lymphocyte leads ti lymphocyte activation, the lymphocyte can now participate against this antigen

12 Water is moving across a membrane from solution A into solution B. What can you infer? 13 Why does facilitated diffusion require membrane transport proteins while simple diffusion does not? 14 Sugars are large, hydrophilic molecules that are important energy sources for cells. How can they enter cells from an environment with a very high concentration of sugar?

12 Solution A must have a lower solute concentration than Solution B. 13 Facilitated diffusion requires membrane transport proteins because the solutes that move by facilitated diffusion are too large or too charged (or both) to cross a membrane by simple diffusion. The transport proteins "facilitate" the movement of these solutes across a membrane. 14 by faciliated diffusion

13 anti-hepatitis C antibodies present in a patient's blood indicate 14 Vaccination against a particular pathogen stimulates what type of response? 15 Will someone who has been exposed to seasonal influenza in the past

13 that the patient has been exposed to hepatitis C at least 2 weeks ago. 14 Primary and Secondary 15 Yes. They will have memory B cells specific for the influenza virus they were exposed to.

ANTIBIOTIC CELL THEORY PROKARYOTIC CELLS EUKARYOTIC CELLS

A chemical that can slow or stop the growth of bacteria; many antibiotics are produced by living organisms. The concept that all living organisms are made of cells and that cells are formed by the division of existing cells. Cells that lack internal membrane-bound organelles. Cells that contain membrane-bound organelles, including a central nucleus.

15 Many foods—for example, bacon and salt cod—are preserved with high concentrations of salt. How can high concentrations of salt inhibit the growth of bacteria? (Think about the high solute concentration of the salty food relative to the solute concentration in the bacterial cells. What will happen to the bacterial cells under these conditions?)

15 In a high-salt environment, water will leave the bacterial cells by osmosis (from the lower-solute-concentration bacterial cells to the higher-solute/high-salt environment in the food). This will cause the cytoplasm of the bacteria to shrivel within the cell wall, thus preventing their growth. This is true for most, but not all, bacteria—some bacteria have mechanisms that enable them to tolerate a high-salt environment.

17 Penicillin interferes with the synthesis of _____. 18 Would phospholipids of the cell membrane be a good target for an antibiotic? Explain your answer.

17 peptidoglycan- Penicillin stops the ribosome from making peptidoglycan which are a component of the cell wall, not the cell membrane or nuclear envelope. Without peptidoglycan, the cell wall becomes weaker. 18 Phospholipids of the cell membrane would not be a good target for an antibiotic because human as well as bacterial cells have phospholipids in their cell membranes, and thus the proposed antibiotic would harm both bacterial and human cells.- No because all cells have a cell membrane. The antibiotic would need to be able to act specifically on cell membranes of bacteria and not on all cell membranes.

19 A bacterial infection is being treated with an antibiotic that stops bacterial reproduction by blocking DNA replication (bacterial cells cannot reproduce if they cannot replicate their DNA). The physician decides to add penicillin, which inhibits the production of new peptidoglycan. Would this use of penicillin be effective (i.e., will it have any additional impact on treating the infection)? Explain your answer.

19 No. The use of the second antibiotic would not be effective in this situation. If the first antibiotic has stopped the bacteria from reproducing, then they are not synthesizing new cell wall material (peptidoglycan), and thus the second antibiotic would have no additional effect.

20 If bacterial cells were placed in a nutrient-containing solution (one that supports their growth) that had the same solute concentration as the cytoplasm, and which also contained penicillin, would the cells burst? Explain your answer. What if the same experiment were repeated with lysozyme, an enzyme that degrades intact peptidoglycan? What if the two experiments were repeated in solutions that have lower solute concentrations than the cytoplasm, and did not contain growth-supporting nutrients?

20 In the case of bacteria growing in a solution with the same solute concentration as their cytoplasm, they would not burst, even though their newly made cell walls would be weak because of the exposure to penicillin. This is because there is no net flow of water into or out of the cells. In the second case (growing in the presence of lysozyme, which disrupts intact peptidoglycan), again, because the environment has a solute concentration that is the same as that of the cells, there is no net movement of water into or out of the cells. If the two experiments were repeated with solutions with lower solute concentrations than the cells, we would expect water to flow from the solution into the cells. Bacteria need a strong cell wall in order to survive the influx of water without bursting, but in this case, there are no growth-supporting nutrients, so the cells are not actually growing. If the cells are not growing, they are not synthesizing peptidoglycan, so penicillin will have no effect (it weakens peptidoglycan as it is being made). However, as lysozyme can digest intact peptidoglycan, the cell wall will be destroyed, and the cells will burst as the water flows in by osmosis.

21 Fungi are eukaryotic organisms. Scientists have found it more challenging to develop treatments for fungal infections (e.g., yeast infections, athlete's foot, and certain nail infections) than for bacterial infections. Why is this so?

21 As both fungi and humans are eukaryotic organisms, they share many characteristics. This makes it hard to find a target that is present in fungi and not in humans. Many fungal structures are also present in human cells, so interfering with those structures will inhibiting growth of (or kill) the fungus, but will also inhibit (or kill) the human cells.

23 Many patients attempt to pressure their physician to prescribe antibiotics for colds. Is this a good idea? Why or why not?

23 Antibiotics are not effective against colds because colds are caused by viruses. Antibiotics are not effective against viruses. Thus, using an antibiotic to treat a cold will not treat the cold and may increase the chance of antibiotic-resistant bacterial infections in the future.

25 Which of the following is not a cytoskeletal fiber in eukaryotic cells? 26 insulin is a protein hormone secreted by certain pancreatic cells into the bloodstream. Which of the following organelles is/are involved in the synthesis and secretion of insulin?

25 macrotubules - The three main types of cytoskeleton fibers are intermediate filaments, microfilaments, and microtubules. 26 d. all of the aboveThe ribosomes on rough ER make the insulin. The golgi apparatus packages the protein for secretion.

27 Some inherited syndromes, for example Tay-Sachs disease and MERRF (myoclonic epilepsy with ragged red fibers), interfere with the function of specific organelles. MERRF disrupts mitochondrial function. From what you know about mitochondria, why do you think the muscles and the nervous system are the predominant tissues affected in MERRF? (Think about the activity of these tissues compared to, say, skin.) 28 Which organelle would cause the most damage to cytoskeletal fibers in the cytoplasm if its contents were to leak into the cytoplasm?

27 Muscle and nervous tissue are both very active and require large amounts of energy. They rely on mitochondria to provide energy to power their activities. Thus, a condition (such as MERRF) that interferes with mitochondrial function will limit the amount of energy they can provide to cells, and active cells (such as muscle and nervous tissue cells) will not be able to carry out their normal functions. Less active cells will not be affected as dramatically because their energy demands are so much lower. 28 c. lysosome - The enzymes inside the lysosome could be harmful to all contents inside the cell.

4 Both viruses and bacteria can be human pathogens. Describe some key differences between them.

4 -Viruses are the smallest and simplest life form known. They are 10 to 100 times smaller than bacteria. -The biggest difference between viruses and bacteria is that viruses must have a living host - like a plant or animal - to multiply, while most bacteria can grow on non-living surfaces. -Bacteria are intercellular organisms (i.e. they live in-between cells); whereas viruses are intracellular organisms (they infiltrate the host cell and live inside the cell). They change the host cell's genetic material from its normal function to producing the virus itself. -There are some useful bacteria but all viruses are harmful. -Antibiotics can kill bacteria but not viruses.

5 Why do poliovirus, influenza virus, and HIV infections cause different symptoms? 6 Name three components of the innate immune system. For each, provide a brief description of how it offers protection. 7 What are phagocytes, and what do they do? 8 From what you know about innate immunity, would you predict different or identical innate responses to infections from E. coli (a bacterium) and S. aureus (another bacterium)? Explain your answer

5 Each infects a different host cell. Poliovirus infects cells of the nervous system, causing paralysis. Influenza virus infects cells of the respiratory tract, causing respiratory tract symptoms. HIV infects cells of the immune system, causing an immune deficiency. 6 1) Skin provides a barrier to pathogen entry. 2) Enzymes in tears and saliva digest components of pathogens. 3) Phagocytes ingest and destroy pathogens. 7 phagocytes are white blood cells that ingest pathogens and trigger adaptive responses. clotting reactions contain the infection 8 Because innate immunity is nonspecific (it does not uniquely recognize different pathogens), the innate response to E. coli will be the same as the innate response to S. aureus.

5 Bacteria are _____ cells, defined by the _____. 6 Which of the following is/are associated with eukaryotic cells but not with prokaryotic cells? 7 According to the cell theory, all living organisms are made of cells. More specifically, what do all living organisms have in common? For example, do all living organisms carry genetic instructions? Do their cells all have a nucleus? What other features do they have in common?

5 d. prokaryotic; absence of organelles 6 does not have a nucleus or membrane-bound organelles - Both eukaryotes and prokaryotes have a cell membrane, cytoplasm, ribosomes, and DNA 7 Because all living organisms are made of cells, they all have a cell membrane surrounding the cytoplasm. They all carry genetic instructions, in the form of DNA, that they can pass on to their cellular descendants during cellular reproduction. They all have ribosomes, and they all are built from the four classes of organic molecules: proteins, carbohydrates, lipids, and nucleic acids.

The advantage of adaptive immunity is that it "learns" to respond to new invaders and targets them specifically. The downside is that it takes a while for the response to kick in. First-time exposure to a pathogen that has breached our innate defenses will almost certainly cause illness, because the adaptive response takes ---days to develop. Over time an exposed individual will recover as T and B cells are activated and antibody levels increase. This initial slow response is the primary immune response.

7 to 10

8 In the soil of a forest, you find a single-celled organism with a cell wall—could this organism be an animal? Why or why not? Which of the following facts would convince you that the organism is a bacterium and not a plant? 9 The two major components of cell membranes are _____ and _____. 10 If a solute is moving through a phospholipid bilayer from an area of higher concentration to an area of lower concentration without the assistance of a protein, the manner of transport must be 11 Consider the movement of molecules across the cell membrane. a) What do simple diffusion and facilitated diffusion have in common? b) What do active transport and facilitated diffusion have in common?

8 This organism cannot be an animal because animal cells do not have cell walls. Choice c is convincing evidence that the organism is a bacterium and not a plant. - c. The cell wall is made of peptidoglycan. - Plant cell walls are made of cellulose and plant cells are EUKARYOTIC which have a nucleus containing DNA. 9 phospholipids and proteins - DNA is found in the nucleus, not in the cell membrane. - Peptidoglycan is in the cell WALL of prokaryotes, not in the cell MEMBRANE. 10 simple diffusion - ctive and facilitated transport require a protein which eliminates A, B, & D. Solutes do cross phospholipid bilayers 11 a: They both involve the movement of a solute across a membrane from an area of higher solute concentration to an area of lower solute concentration, without the input of any additional energy. b: They both require a transport protein in order to carry a solute across a membrane. and carry large molecules

9 Neutropenia is a deficiency in a type of phagocytic cell called neutrophils. Neutrophils are among the "first responders" to an injury or infection. Would you expect someone with neutropenia to be able to mount an effective inflammatory response? Explain your answer. 10 Why might someone taking anti-inflammatory drugs be more susceptible than others to bacterial infections? 11 Compare and contrast the features of innate and adaptive immunity. 12 B cells, plasma cells, and antibodies are all related. Describe this relationship, using words, a diagram, or both.

9 $$$ 10 The inflammatory response is important in killing and containing pathogens at their sites of entry. Someone taking anti-inflammatory drugs will be more vulnerable to infections because the drugs suppress an important component of his or her innate defenses. 11 Innate immunity is present since birth, always active and nonspecific. It does not have "memory." Adaptive immunity is specific for a particular pathogen and must be turned on when the specific pathogen is encountered— it is not always "on"). Adaptive immunity exhibits "memory," strengthening with repeated exposures to the same pathogen. 12 B cells are lymphocytes that are activated during an adaptive response. Upon activation, they become antibody-producing plasma cells specialized to act against a specific pathogen. The antibodies produced specifically bind to and inactivate their targets.

AUTOIMMUNE DISEASE . PRIMARY IMMUNE RESPONSE SECONDARY IMMUNE RESPONSE .

A misdirected immune response in which the immune system attacks the body's own healthy cells The adaptive immune response mounted the first time a particular antigen is encountered by the immune system. The rapid and strong immune response mounted when a particular antigen is encountered by the immune system subsequent to the first encounter

IMMUNE SYSTEM PATHOGENS IMMUNITY

A network of cells and tissues that acts to defend the body against infectious agents and also helps to heal injuries. Infectious agents, including certain viruses, bacteria, fungi, and parasites, that may cause disease. Protection from a given pathogen conferred by the activity of the immune system.

VACCINE HERD IMMUNITY ANTIGENIC DRIFT . ANTIGENIC SHIFT .

A preparation of killed or weakened pathogen that is administered to people or animals to generate protective immunity to that pathogen The protection of a population from an infection, based on a certain percentage of its members being immune Changes in viral antigens caused by genetic mutation during normal viral replication Changes in viral antigens that occur when viruses of one strain exchange genetic material with other strains

ANTIBODY HELPER T CELL PLASMA CELL MEMORY CELL .

A protein produced by B cells that fights infection by binding to specific antigens on pathogens. A type of T cell that helps activate other lymphocytes including B cells and cytotoxic T cells. An activated B cell that divides rapidly and secretes an abundance of antibodies A long-lived B or T cell that is produced during an immune response and that can "remember" the pathogen

LYMPHOCYTE INFLAMMATION HISTAMINE

A specialized white blood cell of the immune system. Lymphocytes are important in adaptive immunity. An innate immune defense that is activated by infection or tissue damage; characterized by redness, heat, swelling, and pain. A molecule released by damaged tissue and during allergic reactions that promotes inflammation.

PHAGOCYTE INNATE IMMUNITY ADAPTIVE IMMUNITY

A type of white blood cell that engulfs and digests pathogens and debris from dead cells. Nonspecific defenses, such as physical and chemical barriers and specialized white blood cells, that are present from birth and require little or no time to become active. A protective response, carried out by lymphocytes, that confers long-lasting immunity against specific pathogens.

PANDEMIC VIRUS

A worldwide epidemic; an exceptionally high number of cases occurring at the same time. A noncellular infectious particle consisting of nucleic acid surrounded by a protein shell.

What structural features are shared by all cells, and what are the key differences between prokaryotic and eukaryotic cells?

All cells, both prokaryotic and eukaryotic, are surrounded by a cell membrane composed of phospholipids and proteins. nd all cells contain DNA, the molecule of heredity. they fall into one of two fundamentally different categories: prokaryotic or eukaryotic. -Prokaryotic cells are relatively small and lack internal membrane-bound compartments, called organelles -Like all prokaryotic organisms or prokaryotes, bacteria exist as single cells. They include the harmless Escherichia coli that live in our gut and the Lactobacillus acidophilus that make our yogurt, as well as the many bacteria that make us sick. -Eukaryotic cells, by contrast, are much larger and contain many different organelles. -Eukaryotes may be single-celled or multicellular. Plants, animals, protists, and fungi are all examples of eukaryotic organisms

What makes antibiotics special is not just their ability to kill bacteria. After all, bleach kills bacteria just fine. The important thing about antibiotics is that they exert their destructive effects on bacteria without (typically) harming the human or animal host.

Although Fleming didn't know it at the time, penicillin and other antibiotics preferentially kill bacteria because they target what is unique about bacterial cells.

FEVER COMPLEMENT PROTEINS ANTIGEN

An elevated term-113 body temperature. Proteins in blood that help destroy pathogens by coating or puncturing them. A specific molecule (or part of a molecule) to which immune receptors bind and against which an adaptive immune response is mounted.

GOLGI APPARATUS LYSOSOME CYTOSKELETON CHLOROPLAST ENDOSYMBIOSIS

An organelle made up of stacked membrane-enclosed discs that packages proteins and prepares them for transport. An organelle in eukaryotic cells that is filled with enzymes that can degrade worn-out cellular structures A network of protein fibers in eukaryotic cells that provides structure and facilitates cell movement. An organelle in plant and algal cells that is the site of photosynthesis. The scientific theory that free-living prokaryotic cells engulfed other free-living prokaryotic cells billions of years ago, forming eukaryotic organelles such as mitochondria and chloroplasts.

How do different antibiotics target bacteria?

And here's where penicillin comes in: by interfering with the synthesis of peptidoglycan, penicillin weakens the bacterial cell wall, which is then no longer able to withstand the pressure of the incoming water. Eventually, the bacterial cell bursts Some eukaryotic cells, including those of plants and some fungi, have cell walls. However, bacteria are the only ones that have a cell wall made of peptidoglycan—which is why penicillin is such a selective bacteria killer

CHAPTER 3 SUMMARY

Antibiotics are chemicals, originally produced by living organisms, that selectively target and kill bacteria. According to the cell theory, all living organisms are made of cells. New cells are formed when an existing cell divides. There are two fundamental types of cells, distinguished by their structure: prokaryotic and eukaryotic. Prokaryotic cells lack membrane-bound organelles; eukaryotic cells have a variety of membrane-bound organelles, including a central nucleus. All cells are enclosed by a cell membrane made up of phospholipids and proteins. Some cells also have a cell wall surrounding the cell membrane that imparts additional strength. Water crosses cell membranes by osmosis in order to balance the solutes on each side. In a hypotonic solution, water moves into the cell, causing it to swell; in a hypertonic solution, water leaves the cell, causing it to shrivel. Bacteria are surrounded by a cell wall containing peptidoglycan, a molecule not found in eukaryotes. Some antibiotics, like penicillin, work by preventing peptidoglycan synthesis, weakening the cell wall. All cells have ribosomes, complexes of RNA and proteins that synthesize new proteins. Some antibiotics, like streptomycin, work by interfering with prokaryotic ribosomes. The cell membrane is semipermeable: only substances with certain characteristics can cross it freely without help. Small hydrophobic molecules can cross cell membranes by simple diffusion, a process that does not require an input of energy. Large, hydrophilic, or charged molecules are transported across the membrane with the help of membrane transport proteins. Facilitated diffusion is the transport of molecules down a concentration gradient through a transport protein; it does not require an input of energy. Active transport is the transport of molecules up a concentration gradient through a transport protein; it requires an input of energy. Eukaryotic cells contain a number of specialized organelles, including a nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, and chloroplasts, each of which carries out a distinct function. Eukaryotic cells likely evolved as a result of endosymbiosis, the engulfing of one single-cell prokaryote by another. Increased and sometimes inappropriate use of antibiotics has led to the emergence of antibiotic-resistant bacteria. Infections caused by these bacteria are very hard to treat.

GRAM-NEGATIVE SIMPLE DIFFUSION TRANSPORT PROTEINS FACILITATED DIFFUSION

Describes bacteria with a cell wall that includes a thin layer of peptidoglycan surrounded by an outer lipid membrane that does not retain the Gram stain. The movement of small, uncharged solutes across a membrane from an area of higher concentration to an area of lower concentration without the aid of transport proteins; does not require an input of energy. Proteins involved in the movement of molecules and ions across the cell membrane. The process by which large, hydrophilic, or charged solutes move across a membrane from an area of higher concentration to an area of lower concentration with the help of transport proteins; does not require an input of energy.

Cell Theory: All Living Things Are Made of Cells Which of the non-human organisms shown have cells of the same structural type as human cells?

Diatoms- algae- Single cell eukaryotes Amoeba- a protist- A single celled eukaryote Bacteria- Single celled prokaryotes Mold- fungus- Single and multicellular eukaryotic cells Elodea - an aquatic plant- A multicellular eukaryote Humans- multicellular eukaryotes Elodea

As Fleming knew, most of the bacterial world falls into one of two categories, Gram-positive or Gram-negative. These names reflect the way bacterial cell walls trap a dye known as the Gram stain (after its discoverer, the Danish scientist Hans Christian Gram).

Gram-positive bacteria retain the dye, while Gram-negative bacteria do not. Fleming found that while penicillin easily killed Gram-positive bacteria like Staphylococcus and Streptococcus—the microbes that cause staph infections and strep throat, respectively—it had little effect on Gram-negative bacteria like E. coli. and Salmonella. It turns out that the cell wall of Gram-negative bacteria includes an extra layer of lipids surrounding the peptidoglycan layer. This extra lipid layer prevents penicillin from reaching the peptidoglycan underneath. The reason for its effectiveness? Streptomycin has a chemical structure that allows it to pass more easily through the outer lipid layer of the Gram-negative bacterial cell wall. Once inside the cell, streptomycin works by interfering with protein synthesis by bacterial ribosomes. Ribosomes are the molecular machines that assemble a cell's proteins.

Innate and Adaptive Immunity

Invading pathogens encounter a Verity of defenses. Physical and chemical barriers are the first line of defense. Pathogens that breach these barriers encounter non-specific cellular defenses. These early lines of defense are known as innate immunity. And are always present and ready to protect against a wide range of pathogens. Adaptive immunity, which relies on the activity of specialized white blood cells, is the next line of defense. Adaptive immunity mounds a unique defense against each specific pathogen it encounters -When pathogens overcome these physical and chemical defenses, they trigger additional innate responses. One of the most important functions of the innate immune system is to promote inflammation in response to tissue damage or infection. -Inflammation is an important line of defense that kills invading pathogens and prevents them from spreading further in the body. -What triggers inflammation? Tissues that have been damaged by injury or by infection release chemicals such as histamine that cause blood vessels to expand and leak fluid into surrounding tissues. -(Aspirin, ibuprofen, and acetaminophen are anti-inflammatory drugs that help reduce fever and pain by interrupting the inflammatory signals received by the brain—which makes you feel better but doesn't treat the underlying cause of those signals.) -Other innate immune defenses include proteins that either attack pathogens directly or prevent them from reproducing. For example, defensive proteins in the blood called complement proteins coat the surface of pathogens, making them more easily destroyed by phagocytes, or directly destroy some bacteria by punching holes in the cell membrane

How safe are vaccines?

Remarkably safe. While any medicine comes with some amount of risk—and vaccines are no different—there is no comparison between the risks posed by vaccines and by the diseases they aim to prevent. For most people, vaccine side effects are nonexistent or very mild. In rare cases, vaccines may cause fever—a consequence of stimulating an immune response against the antigens in the vaccine. In even rarer cases, these fevers can cause seizures

Some Antibiotics Inhibit Prokaryotic Ribosomes If this antibiotic targets ribosomes, why can eukaryotic cells continue to synthesize proteins in its presence?

Ribosomes are responsible for the synthesis of proteins in the prokaryotic and eukaryotic cells but the structure is slightly different in the two types of cell. Anabiotic's that interfere with prokaryotic ribosomes leave eukaryotic ribosome unaffected Prokaryotic ribosomes - no proteins formed - does antibiotic interferes with bacterial ribosomes. But your protein synthesis is interrupted Eukaryotic ribosome -functional proteins -eukaryotic ribosomes are affected by this antibiotic. eukaryotic proteins are still produced b/c the human ribosome has a diff structure, the antibiotic cannot dirsuot its function

LYMPH NODES LYMPHATIC SYSTEM HUMORAL IMMUNITY

Small organs in the lymphatic system where B and T cells may encounter pathogens. The system of vessels and organs that drains fluid (lymph) from the tissues and send it through lymph nodes on its way to the circulation. The type of adaptive immunity that fights free-floating pathogens in the blood and lymph.

Memory Cells Mount an Aggressive Secondary Response Primary responses Secondary

The adaptive immune system's primarily humoral response is slow and produces low level of antibodies. Upon subsequent exposure, memory B cells produce during the primary responses quickly, rapidly dividing and developing into plasma cells that produce high concentration of antibodies Antibody levels rise gradually and Peter on day 12. Alyssa's make sure before the pathogen is cleared by the primary response Antibody levels rise quickly and to a greater extent than the primary response . Antibody concentration remains high longer

22 Bacteria can be characterized as sensitive, intermediately resistant, or fully resistant to different antibiotics. If a strain of bacteria is sensitive to an antibiotic, we can prescribe that antibiotic to treat an infection caused by that strain and have confidence that it will work. If the strain is fully resistant to an antibiotic, that antibiotic cannot treat that infection. In cases of intermediate resistance, it is better to try and find an antibiotic to which the strain is sensitive, as the infection may not respond to antibiotics to which it has intermediate resistance. The table shows the concentrations of antibiotics that determine how a bacterial species will respond to those antibiotics. A sensitive strain will be killed by the concentration of antibiotics shown in the "sensitive" column. A strain with intermediate resistance will only be affected by concentrations in the range indicated in the "intermediate" column. And a fully resistant strain requires concentrations shown in the "fully resistant" column. A hospital patient has a Staphylococcus aureus infection. As part of laboratory testing, the S. aureus from the patient was grown in different concentrations of various antibiotics. For oxacillin, the lowest concentration that inhibited the growth of the strain was 8 µg/ml; for vancomycin, 4 µg/ml; for erythromycin, 16 µg/ml; for tetracycline, 32 µg/ml; and for levofloxacin, 8 µg/ml. Which antibiotic should be used to treat the infection in this patient?

The best option in this case is vancomycin. The strain appears to be resistant to all of the other antibiotics.

Which portion of a phospholipid is found in the middle (the interior) of a membrane?

The hydrophobic tails associate with one another, forming the interior of the membrane.

CHAPTER 32 SUMMARY

The immune system defends the body against infection by pathogens. It also helps to heal injuries and fight cancer. Pathogens are infectious agents that can cause disease; they include certain bacteria, viruses, fungi, and parasites. Viruses are non-cellular; they consist of a genome of nucleic acid (DNA or RNA) contained within a protein shell. The immune system has two main arms: innate immunity and adaptive immunity. Innate immunity is the first line of defense against invaders; adaptive immunity comes into play once innate defenses are breached. The innate immune system includes defenses with which we are born and which are always active: they include barriers such as skin and mucous membranes; antimicrobial chemicals in tears, saliva, and other secretions; and phagocytic cells that engulf and destroy pathogens. The inflammatory response, part of the innate immune system, is triggered by tissue infection or injury. During an inflammatory response, blood vessels swell and leak, marshaling phagocytic cells and protective molecules to the area to contain the infection. Adaptive immunity is conferred by specialized lymphocytes called B and T cells. B cells produce antibodies that recognize specific antigens unique to a pathogen and mark that pathogen for destruction. Cytotoxic T cells destroy infected, foreign, and cancer cells. The immune response can go awry, causing allergies and autoimmune conditions. Allergies are responses to intrinsically harmless substances (for example, pollen), and autoimmune conditions result when the immune system mounts a response against the body's own cells and tissues. At the first exposure to a particular pathogen, a primary immune response is generated that takes time to become fully effective; the primary response also produces memory cells. Memory cells remain in the body and become active at the time of a subsequent exposure to the same pathogen, producing a more rapid and vigorous secondary immune response that fights the pathogen and usually prevents the associated illness. Vaccination elicits a primary immune response. Memory cells produced during the primary response protect against illness following subsequent exposure to the actual pathogen. The adaptive immune response is highly specific for particular pathogens. If the pathogen changes, by antigenic shift or drift, the body must mount a new primary response for each strain of the pathogen. All organisms have ways of defending themselves against infection. The innate immune system is evolutionarily ancient.

ORGANELLES CELL MEMBRANE CYTOPLASM RIBOSOME

The membrane-bound compartments of eukaryotic cells that carry out specific functions. A phospholipid bilayer with embedded proteins that forms the boundary of all cells. The gelatinous, aqueous interior of all cells. A complex of RNA and proteins that carries out protein synthesis in all cells.

Anti-vaccine movement

The modern antivaccination push really took off in the late 1990s, in the wake of a fraudulent research paper published by a doctor in England, Andrew Wakefield. That paper, which was published in the journal The Lancet, purported to show a link between the MMR (measles-mumps-rubella) vaccine and the development of autism in 8 children. However, numerous subsequent studies failed to confirm the finding, and Wakefield was ultimately accused of scientific misconduct and had his medical license revoked. The paper was retracted. In fact, you could say that vaccines have become victims of their own success. It's precisely because they have been so effective at reducing the burden of illness over the last hundred years that some people have begun to question whether it's really in their best interest to vaccinate their children.

NUCLEUS CELL WALL OSMOSIS HYPOTONIC

The organelle in eukaryotic cells that contains the genetic material. A rigid structure present in some cells that encloses the cell membrane and helps the cell maintain its integrity The diffusion of water across a membrane from an area of lower solute concentration to an area of higher solute concentration. Describes a solution surrounding a cell that has a lower concentration of solutes than the cell's cytoplasm.

ACTIVE TRANSPORT NUCLEAR ENVELOPE MITOCHONDRIA (SINGULAR: MITOCHONDRION) ENDOPLASMIC RETICULUM

The process by which solutes are pumped from an area of lower concentration to an area of higher concentration with the help of transport proteins; requires an input of energy. The double membrane surrounding the nucleus of a eukaryotic cell. Membrane-bound organelles responsible for important energy-conversion reactions in eukaryotes. A network of membranes in eukaryotic cells where proteins and lipids are synthesized.

CELL-MEDIATED IMMUNITY CYTOTOXIC T CELL . ALLERGY

The type of adaptive immunity that rids the body of infected, cancerous, or foreign cells. A type of T cell that destroys infected, cancerous, or foreign cells An immune response misdirected against harmless environmental substances, such as dust, pollen, and certain foods, that causes uncomfortable physical symptoms.

How do solutes and water cross cell membranes, and what determines the direction of movement of solutes and water in different situations?

Water has a tendency to move across cell membranes in order to balance the solute concentrations on each side of the membrane, a process called osmosis. Water will predictably move from the solution with the lower solute concentration to the solution with the higher solute concentration. For example, cells placed in a lower-solute, or hypotonic, solution will tend to take up water and swell. On the other hand, cells placed in a higher-solute, or hypertonic, solution will tend to lose water and shrivel. In an isotonic solution, where the solute concentration is the same as the cell's cytoplasm, there is no net movement of water into or out of the cell. In all cases, water moves in a direction that will tend to even out the solute. Most of the time, water moves to the side with a higher solute concentration.

Features of Prokaryotic and Eukaryotic Cells

Well all cells have a cell membrane, cytoplasm, ribosome, and DNA, there are specific structural differences between prokaryotic and eukaryotic cells. -Eukaryotic cells contain a variety of membrane enclosed organelles while prokaryotic cells do not. All prokaryotic cells have a cell wall surrounding the cell membrane while many eukaryotic cells do not

The environments that many bacteria find themselves in tend to be hypotonic. Water then enters the bacterial cells by osmosis, causing them to swell. This swelling would be fatal to bacteria were it not for the cell wall, which limits how much water can enter the cell.

What makes the bacterial cell wall rigid is the molecule peptidoglycan, a polymer made of sugars and amino acids that link to form a chainlike sheath around the cell. Different bacterial cell walls can have different structures, but all have peptidoglycan, which is found only in bacteria.

The Lymphatic System: Where B and T Lymphocytes Develop and Act Thymus Lymph nodes Lymphatic vessels Spleen Bone marrow B cells T Cells

Where T lymphocytes mature T and B lymphocytes in the lymph nodes respond to foreign invaders in the lymph These vessels drain fluid from tissues and pass it through the lymph nodes on its way back to the circulation T and B lymphocytes in the spleen responding to phone invaders brought in the blood Where are immature white blood cells are produced The B cells develop in the bone marrow and then circulate through the blood and I lymphatic vessels The T cells develop in bone marrow stem cells that migrate to the thymus. Once mature they circulate through the blood and the lymphatic vessels

Because viruses can swap genes so easily, public health officials closely monitor the types of virus that infect animals. Birds are a primary source of potentially pandemic viruses

Wild birds are routinely infected with viruses that live in their gastrointestinal tracts but cause little or no disease in the bird. Sometimes, however, bird flu viruses can jump from wild birds to poultry or other farm animals and become lethal. And since many human populations maintain close contact with poultry, pigs, and other domestic animals, the risk of an animal virus infecting humans is high.

Immunological Memory How were so many people able to fight the infection while others died? Of those who became infected and then recovered, some may have had partial immunity from an earlier influenza infection. Such long-lasting immunity is conferred by the adaptive immune system.

With repeated exposure, our adaptive immune system develops a memory of every pathogen we encounter that gets past our innate defenses. Should we confront the same pathogen again, immunological memory helps our bodies fight off infection before it can take hold.

How Penicillin Was Discovered

a fortuitous observation by Flemming led to the discovery of the 1st anti-biotic. he realized the fungus on his culture plate was somehow the reproduction of bacteria both the bacteria and the mold can grow and divide on the nutrient-rich late. however, bacteria cannot reproduce in areas surrounded by mold. 1 a single bacterial cell lands in the surface of a nutrient-rich plate. 2 nutrients in the plate support the growth and division of the bacterial cells 3 after many rounds of cell division, enough cells accumulate to ve visualized as a noticeable bacterial growth on the plate

16 Marc, a first-year college student, starts out on a backpacking trip in southern New Mexico. It is September, so the daytime temperatures are quite high, and the desert air is very dry. He has a portable water filter to treat river and stream water that he finds on his planned route through the Gila wilderness. On the second day of his weeklong trip his water filter breaks. He is afraid of contracting giardiasis (a protozoal disease spread through water contaminated by animal feces), so he drinks only the small amount of water that he can boil on his camp stove at night. By the fifth night he is feeling weak and thirsty, and starts to hike out. He makes it to a local highway and collapses. A passing motorist calls 911 for an ambulance. a) Given that Marc has sweat a lot, and that sweat causes the loss of more water than solutes, what has happened to the solute concentration of his blood as a result of his dehydration? b) From the solute concentration of his blood, what is likely to be happening to those of his body cells that are in contact with his blood and related fluids (e.g., lymph and cerebral spinal fluid)? c) The paramedics have available three saline solutions. One is a "normal" isotonic saline—0.9% NaCl. One is a hypertonic saline (3% NaCl). The last is a "half normal" saline (0.45% NaCl). Which one would you use to treat Marc? Why?

a: Marc has lost more water than solutes, so his blood now has a higher solute concentration than normal. b: Because his blood has a higher than normal solute concentration, cells in contact with the blood are likely to be losing water (by osmosis) and beginning to shrivel. c: Marc needs to have his blood volume restored, as well as his current concentration of solutes diluted (back to a normal concentration). This means that the "half normal" saline is probably the best bet. It will add volume, but because it has a lower than normal solute concentration when it is added to his concentrated blood, it will cause the solute concentration to return to normal.

24 Briefly describe the structure and function of each of the following eukaryotic organelles: a. mitochondrion. b nucleus. c endoplasmic reticulum. d chloroplast

a: Mitochondria are rod-shaped organelles. They are surrounded by a double membrane (they have both an inner and outer membrane). They are important in the reactions that extract energy from food and convert it to an immediately usable form. b: The nucleus is a large organelle that stores the genetic instructions (DNA). The nucleus has a double membrane (the nuclear envelope) that has pores that permit the movement of molecules into and out of the nucleus. c: The endoplasmic reticulum is an extensive network of membrane tubes. The endoplasmic reticulum is connected to the nucleus and has a variety of critical functions in the cell, including protein synthesis, lipid synthesis, and drug detoxification. d: Chloroplasts are organelles found in plant cells. They are enclosed by a double membrane and appear green because of the pigments involved in photosynthesis. Photosynthesis is the process by which energy from sunlight and carbon dioxide from the air are used to synthesize sugars.

The phagocytes of innate immunity we encountered earlier play an important role in ---: the antigens that activate lymphocytes are remnants of pathogens that ---have swallowed and chewed up; when these cells are done chewing, they post little bits of the invaders—antigens—on their surface, where they present them to ---. This process is called antigen presentation, and the cells that do this vital work are called ---, or APCs. Lymphocytes have receptors on their surface that can bind to antigens on the surface of APCs. A lymphocyte with a receptor that matches the antigen perfectly will bind to it, and that interaction will activate the lymphocyte. Each lymphocyte will recognize only one antigen, but since our bodies can produce billions of unique lymphocytes, each with a unique receptor, chances are good that at least one will match. This specificity is the basis of adaptive immunity

adaptive immunity phagocytes lymphocytes antigen-presenting cells

When the immune system attacks harmless antigens from outside the body, like those in dust, pollen, or certain types of food, an ---results. When the immune system attacks the body's own healthy cells, a more serious ---can occur. Multiple sclerosis, lupus, and rheumatoid arthritis are all autoimmune diseases, caused by a body at war with itself.

allergy autoimmune disease

Cytotoxic T cells are activated by ---they encounter on the surface of phagocytes that have engulfed pathogens. As with ---, helper T cells assist in the process: they provide a growth signal to killer T cells to multiply. Activated cytotoxic T cells divide and patrol the body on the lookout for infected cells displaying the antigens that activated them. When such cells are found, the cytotoxic T cells bind to the antigens and release chemicals that kill the rogue cells. As with B cells, some of the dividing cytotoxic T cells become long-lived memory cells, ready to recognize the same antigens in the future In addition to targeting virally infected body cells, cytotoxic T cells also target foreign cells (from a transplanted organ or tissue, for example) and even cancer cells that the body recognizes as genetically altered. Note that while both humoral and cell-mediated immune responses destroy invaders, there is a key difference between them: humoral immunity produces antibodies that bind to antigens on free-floating pathogens in blood and lymph; cell-mediated immunity marshals cytotoxic T cells that bind to and destroy infected or altered cells in body tissues.

antigens humoral immunity

Mitochondria and chloroplasts are about the same size and shape as ---. Both mitochondria and chloroplasts have circular strands of ---, just like prokaryotic cells. They also contain ribosomes that are similar in structure to ---—so similar, in fact, that some antibiotics that target prokaryotic ribosomes can affect the ribosomes in eukaryotic mitochondria, which accounts for both the toxicity and the side effects of these antibiotics.

bacteria DNA prokaryotic ribosomes

Prokaryotic cells carry out similar functions of energy conversion and protein transport, but they don't contain these processes within separate organelles; everything occurs in the ---.

cytoplasm

New influenza viruses are constantly being produced by two mechanisms: mutation and ---. Because influenza viruses replicate their genetic material so rapidly and don't "proofread" the replicated copies, mistakes often occur, leading to mutations. ---is the gradual accumulation of mutations that cause small changes in the antigens on the virus surface. Antigenic drift explains why there can be different types, or strains, of influenza circulating at the same time. Two important antigens on the influenza virus are ---. Hemagglutinin is a viral protein that binds to receptors on host cells and enables the virus to ---host cells and it gradually changes and caused by point mutations that occur when the virus replicate.; the neuraminidase protein helps newly-formed viruses ---host cells. also, rapid change and caused by gene exchange btw 2 different viruses that simultaneously infect the same cell A person's immune system mounts an adaptive response specifically to these two antigens. together, antigenic drift and antigenic shift create an increasing ---over time until one of the variants is able to infect human cells so efficiently that it sweeps through the population and causes a pandemic.

gene swapping Antigenic drift hemagglutinin and neuraminidase enter exit variety of strains

B and T cells cooperate to produce two main types of adaptive immunity. -One type, called ---, targets free-floating threats in the blood and lymph. These threats may include virus particles, bacterial cells, and bacterial toxins. Humoral immunity produces ---—proteins that circulate in body fluids and help to fight infections by binding to specific antigens on pathogens. Antibodies are produced by ---. Like all lymphocytes, B cells have ---on their surface that recognize specific antigens. When a B cell encounters an antigen on a pathogen, it ---to it with its receptor. The B cell then internalizes the pathogen, digests it, and presents these antigens on its surface. (B cells are a type of antigen-presenting cell.) To begin producing antibodies that recognize and bind to that antigen, the B cell needs the assistance of specialized T cells called ---. These cells also have ---that can recognize antigens. When an activated helper T cell meets a B cell that has encountered the same pathogen, the helper T cell releases ----that trigger the B cell to divide. That B cell will divide repeatedly to create an army of ---—cells that secrete many copies of an antibody specific to that particular antigen. Some of the dividing B cells will become memory cells, which remain in the bloodstream and "remember" the infection; The second type of adaptive immunity is ---immunity, which targets infected or altered body cells—for example, cells infected with the influenza virus. This response requires a type of T cell called a ---. These important cells, also called killer T cells, are the immune system's elite fighting force; they are ones that actually kill body cells that are compromised by foreign invaders.

humoral immunity antibodies B cells receptors binds helper T cells receptors signaling molecules plasma cells cell-mediated cytotoxic T cell

normal lungs v. pneumonia ling

normal- clear, lots of space Bad lungs- cloudy, willed with pathogens, fluids, inflammatory cells, and derbies making it harder to breath. bacterial lung infections were responsible for at least half of all deaths resulting from the 1918 pandemic

Viruses are considered to be nonliving because even though all viruses have genes, viruses are --- Lacking the cellular machinery for replicating genetic material and synthesizing proteins, viruses cannot reproduce independently—they must infect a host cell in order to reproduce

not made of cells.

-The nucleus is the defining organelle of eukaryotic cells (from the Greek eu, meaning "good" or "true," and karyon, meaning "nut" or "kernel"). It is surrounded by the ----, a double membrane made of two lipid bilayers dotted by small openings called pores. The nucleus encloses the cell's ---and acts as a kind of control center. Important reactions for interpreting the genetic instructions contained in DNA take place in the nucleus. ----are the cell's "power plants"—they use oxygen to extract energy from food and convert that energy into a useful form. All ---—including plants—have mitochondria. Humans who inherit or develop defects in their mitochondria usually ---—an indication of just how important these organelles are. -The endoplasmic reticulum (ER) is a vast network of membranes that serves as a kind of ---for the manufacture of proteins and lipids. The "rough" ER is studded with ribosomes making ---; the "smooth" ER makes lipids -Newly-made proteins travel from the ER to the Golgi apparatus, an organelle that packs the protein "---" into vesicles and then ships them to specific destinations, such as the cell membrane, other organelles, and the bloodstream. -The nucleus, ER, and Golgi apparatus thus work together to make and ---to specific locations in and out of the cell. -Eukaryotic cells also contain lysosomes, which ---molecules. Lysosomes can be thought of as the cell's ---centers. -In addition to these membrane-bound structures, a vast network of protein fibers called the cytoskeleton allows cells to ----, much the same way the human skeleton does. -Finally, in addition to the above organelles, plant cells contain chloroplasts, which carry out ---; they also have a cell wall made of cellulose

nuclear envelope DNA Mitochondria eukaryotes die assembly line proteins lipids cargo transport proteins digest and repurpose recycling move and maintain their shape photosynthesis

What are the key eukaryotic organelles and their functions?

nucleus - The organelle in eukaryotic cells that contains the genetic material. endoplasmic reticulum -A network of membranes in eukaryotic cells where proteins and lipids are synthesized ribosome - A complex of RNA and proteins that carries out protein synthesis in all cells. Golgi apparatus - An organelle made up of stacked membrane-enclosed discs that packages proteins and prepares them for transport. mitochondrion - Membrane-bound organelles responsible for important energy-conversion reactions in eukaryotes.

Name and give the functions of at least three organelles present in both plant and animal cells. plant cells also have

nucleus, - Control Center of the Cell. "information Central", the Nucleus contain DNA and with it Coded instructins for making protiens and other materials endoplasmic reticulum- freely suspended in the cytoplasm also bound to the Endoplasmic Reticulum, Internal membrane system this is where the lipid(fat)components of the CELL MEMBRANE are built or made along with proteins RESPONSIBLE FOR TRANSPORT OF MATERIALS THROUGH THE CELL. ribosome, - made in the Nucleolus, for Protein Systhesis (building), protein factories, contain Ribosomal RNA rRNA and protein, found freely suspended in the cytoplasm also bound to the Endoplasmic Reticulum Golgi apparatus,- THEY ARE FLATTENED MEMBRANE STACK LOCATED NEAR THE NUCLUES, helps BUILD PROTEINS, mitochondrion, responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations. lysosome- A MEMBRANE BOUND SAC OF HYDROLYTIC ENZYMES (ENZYMES THAT DIGEST MACROMOLECULES., BREAK DOWN FOOD PARITICLS (LIPID CARBS AND PROTIENS) THE MAIN LOCATION OF WHAT INTRACELLULAR DIGESTION. IT CONTINUOUSLY BREAKS DOWN AND RECYCLES PARTS. THS LYSOSOMES BREAKS DOWN ORGANELLES THAT HAVE OUT LIVED THEIR USEFULNESS., mitochondrion - Membrane-bound organelles responsible for important energy-conversion reactions in eukaryotes. cytoskeleton - The cytoskeleton supports the cell, gives it shape, organizes and tethers the organelles, and has roles in molecule transport, cell division and cell signaling. REMEMBER- all cells have a cell membrane, ribosomes, DNA, and cytoplasm plants - large water vacuole, cell wall, and chloroplasts

Like an army, the immune system defends the body from different kinds of invaders—principally infectious agents, or ---, such as viruses, bacteria, and parasites that enter the body and cause disease. In addition, the immune system plays an important role in helping us heal from injuries, and even protects us as against ----, which can be thought of as treasonous cells that go over to the other side. The immune system basically reacts against anything it encounters as foreign, or "nonself," and tries to destroy it

pathogens cancer

Membranes: All Cells Have Them Cell membrane - also known as the plasma membrane, is a double layer of lipids and proteins that surrounds a cell. It separates the cytoplasm (the contents of the cell) from the external environment. gives the cell its structure and regulates the materials that enter and leave the cell. It is a selectively permeable barrier, meaning it allows some substances to cross, but not others structure of cell membrane: -The cell membrane is a flexible yet durable structure composed of ----. -A phospholipid has two main parts: a ---"head" and a ---"tail." -In the watery context of a cell, the hydrophobic tails of phospholipids cluster together in the middle of the membrane away from water, while the hydrophilic heads face outward, toward the water. -When arranged in this way, the phospholipids form a two-ply structure called a ---. -Proteins sit nestled in the lipid bilayer, where they perform a variety of functions such as relaying ---across the membrane and ---nutrients in and wastes -The cell membrane is ---, meaning that only substances with certain characteristics can cross it easily without help. -With its densely packed collection of hydrophobic phospholipid tails, the lipid bilayer is largely ---to large molecules, like glucose, and hydrophilic or charged substances, like sodium ions, and only weakly permeable to water. -In fact, the only things that do cross the lipid bilayer easily and without assistance are small, uncharged molecules like oxygen (O2) and carbon dioxide (CO2) gas, which cross by ---. -To move glucose molecules across the membrane, the cell makes use of ----proteins. -Transport proteins sit in the membrane bilayer with one of their ends outside the cell and the other inside it. -By acting as a channel, carrier, or pump, transport proteins provide a passageway for large or hydrophilic molecules to cross the membrane. They are also very specific: -Transport proteins can move substances either with or against their concentration gradient—either "---" across the membrane. -When a substance moves "downhill" by a transport protein from an area of higher concentration to an area of lower concentration, the process is called ---. -like simple diffusion, facilitated diffusion requires no additional energy besides that stored naturally in the concentration gradient. -In addition to glucose, ions and water also move across the cell membrane by facilitated diffusion. ----, the movement of water across membranes discussed previously, relies on both simple diffusion and facilitated diffusion through transport proteins.

phospholipids and proteins hydrophilic hydrophobic bilayer signals transporting semipermeable impermeable simple diffusion transport -downhill" or "uphill facilitated diffusion -Osmosis

To respond to and remember specific pathogens, our adaptive immune system must be able to ---them, that is, to distinguish one from another. The particular identifying detail of a pathogen that lymphocytes recognize is called an ---. An antigen could be a piece of a viral protein, a component of a bacterial cell wall, or a toxin made by the bacterium. Each antigen matches with molecular precision the exact shape of a receptor found on a ---. When a lymphocyte finds an antigen "match," it becomes activated—that is, it turns on specific immune response genes and begins to ---.

recognize antigen lymphocyte divide

How do antibiotics get past this barrier/ cell membrane? -Antibiotics move across membranes in a number of ways. Some antibiotics, like tetracycline, are small hydrophobic molecules that can cross the cell membrane directly by ----. -Others, including penicillin and streptomycin, pass through membranes by ---using transport proteins. -just because an antibiotic makes it inside a bacterial cell, however, doesn't mean it will ---there. -Some bacteria have transport proteins that can actively pump the antibiotic back ---of the cell. -This bacterial counteroffensive measure is an example of ---, in which proteins pump a substance "uphill" from an area of lower concentration to an area of higher concentration. -Unlike facilitated diffusion, active transport requires an input of ---. -Active transport keeps the ----in the bacterial cell low, but the cell must expend energy to keep pumping the antibiotic out against its concentration gradient. -Eukaryotic cells use active transport for several important purposes—for example, to maintain ---across the membranes of nerve cells and to import certain nutrients "uphill" against their concentration gradient -Pumping antibiotics out of the bacterial cell is one way in which bacteria can ---the destructive power of an antibiotic. -Others include ---the antibiotic with enzymes. Why would bacteria have such built-in mechanisms for counteracting or resisting drugs?

simple diffusion facilitated diffusion stay out active transport chemical energy antibiotic concentration ion gradients resist chemically breaking down -Microorganisms like these have evolved chemical defenses as a way to protect themselves from other organisms. In turn, their combatants have evolved countermeasures that give them resistance. Humans thus find themselves embroiled in a battle originally waged solely between microorganisms.

Some Important Features of Innate Immunity physical barriers phagocytes chem defenses inflammation

skin, mucous membranes these ingest and destroy pathogens. also, trigger inflammation and adaptive immune responses stomach acid, tears, saliva, complement proteins, fever 1- pathogens get past physical barriers 2- pathogens and damaged cells release histamines and other molecules that increase blood flow and attract white blood cells to infected areas 3 blood vessels leak, causing surrounding tissues to swell with fluid containing clotting factors and white blood cells 4 phagocytes ingest pathogens and trigger adaptive responses. clotting reactions contain the infection

The Immune System Defends against a Variety of Pathogens Can eukaryotic organisms cause disease in humans?

the immune system can protect the body against many specific pathogens. virus, bacteria, and parasites can all be detected as forge-triggeing a verity of defenses Many single-cell eukaryotes can cause severe diseases to humans. The human body is a rich source of nutrients that the parasites require for survival, as long as they can overcome the obstacles of human innate and adaptive immunity.