BY 124 - Exam 3
Which of these is responsible for initiating a signal transduction pathway?
A This is a signal molecule. The attachment of a signal molecule to a plasma membrane receptor initiates a signal transduction pathway.
_____ in carbon dioxide in your red blood cells, which causes _____ in pH, causes your breathing to speed up. See Concept 42.6 (Page)
An increase ... a drop Water and carbon dioxide combine, in the presence of the enzyme carbonic anhydrase (found inside red blood cells), to form carbonic acid, which dissociates to hydrogen ion and bicarbonate. The higher concentration of hydrogen ions leads to a drop in pH.
Which secretion is not a barrier that prevents pathogens from entering the body?
Antigens. Antigens are foreign molecules that initiate an immune response.
The video discusses the relationships between the cross-sectional area of blood vessels, blood flow velocity, and blood pressure. Determine which of the following statements are true and which are false.
As blood flows from the aorta through the other vessels, blood pressure increases. False Blood flowing from one aorta into billions of capillaries decreases the velocity and pressure of the blood flow. True Blood flow velocity is inversely related to cross-sectional area. True Blood flow is at its highest velocity in the venae cavae. False The lowest velocity of blood flow occurs in the capillaries. True Blood flows from an area of low pressure to an area of high pressure. False Cross-sectional area, blood flow velocity, and blood pressure are interrelated, and each can affect the other. While cross-sectional area and blood flow velocity are inversely proportional, the relationship of blood pressure to these is impacted not only by the friction of blood's movement within the vascular system, but also by the contraction of the heart and blood vessels. As blood moves away from the contracting heart, less pressure is exerted outward on the vessel walls.
Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____.
B cells ... plasma cells and memory cells The antigen-selected proliferation of B cells produces clones of plasma cells and memory cells.
The words "antigen" and "virus" are interchangeable.
False A virus, like other pathogens, has numerous antigens on its surface, so the words "antigen" and "virus" cannot be used interchangeably.
The structure of fats makes them insoluble in water. The figure below on the left reviews the synthesis and structure of a fat molecule. In order to be absorbed into the body, fats must first be broken down into smaller molecules in the lumen of the small intestine to enhance diffusion into cells, where they are reassembled and packaged into water-soluble globules. The figure below on the right shows how fats are digested and absorbed in the small intestine.
1. A fat molecule is composed of two types of smaller molecules, including only one molecule of glycerol. 2. A fat molecule also includes one, two, or three fatty acid molecules. 3. A fat molecule with only one fatty acid is called a monoglyceride. 4. A fat molecule with three fatty acids is called a triacylglycerol, or a triglyceride. 5. A fatty acid includes a carboxyl group (-COOH) at one end as well as a long hydrocarbon chain. 6. The hydrocarbon chains found in fats store a lot of energy. They also make fats hydrophobic, or insoluble in water.
True or false? One advantage of having a tube-like digestive tract is that digestion of all compounds can take place simultaneously down the tract.
False One advantage of having a tube-like digestive tract is that digestive processes with different requirements (for example, an acidic or basic environment) can be separated within the tract.
True or false? The leukocytes of the innate immune system are B cells, macrophages, and neutrophils.
False The leukocytes of the innate immune system are mast cells, macrophages, and neutrophils.
In addition to testing shmoo formation in the two mutant strains of yeast, the scientists also tested shmoo formation in wild-type yeast. What is the purpose of including wild-type yeast cells in the experiment?
to show normal shmoo formation under the experimental conditions Wild-type yeast cells act as a control for observation of shmoo formation because wild-type cells have both Fus3 and formin present under the experimental conditions.
Which of these is the second of the three stages of cell signaling?
transduction
Among humans, increased interest in food intake normally occurs _____. See Concept 41.5 (Page)
via chemical signals released when the stomach is empty A shrunken, empty stomach releases ghrelin, a protein hormone that sharply increases appetite.
Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?
The large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body. The changes in blood pressure as blood moves through the lungs of land-dwelling vertebrates make it necessary to have separate circuits to the lungs and the rest of the body.
Fus3 kinase and formin proteins are generally distributed evenly throughout a yeast cell. Based on the model in the diagram, why does the shmoo projection emerge on the same side of the cell that bound the mating factor?
The only formin molecules that get phosphorylated and thus activated are those near the G protein-coupled receptor that binds mating factor. Because the mating factor is diffusing from the direction of the other mating-type yeast, it is the G protein-coupled receptors on that side of the cell that bind mating factor, become activated, and start the phosphorylation cascade that activates Fus3, which activates formin, which leads to localized shmoo formation.
A researcher added a mixture of animal proteins to a physiological buffer solution (pH 7.4) in a test tube incubated at 37°C. The researcher then added purified pepsin to the mixture, but even after several hours, the proteins were not digested. Which of the following would explain this result?
The pH was too high. The pH in the test tube (7.4) was too high to promote enzymatic activity by pepsin, which has an optimal pH close to 2. Therefore, the proteins were not digested.
Which statement about oxygen in fish gills is correct?
The partial pressure of oxygen in blood increases as it flows through gill capillaries. The blood in the gills picks up oxygen as it flows through the capillaries. As a result, the partial pressure of oxygen in the blood increases as it flows through the gill capillaries.
Which event of the cardiac cycle occurs when systolic blood pressure is measured?
The ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria. The systolic blood pressure is the peak blood pressure, resulting from contraction of the ventricles.
The graphs show changes in blood pressure and velocity in the blood vessels of the systemic circuit. Use the graphs to answer the questions. Which letter indicates systolic pressure?
a
Stroke occurs when _____. See Concept 42.4 (Page)
a blood clot enters the cerebral circulation, blocking an artery and causing the death of brain tissue Once deprived of oxygen, brain cells begin to die within a few minutes. Because brain cells rarely divide in adulthood, they cannot be quickly replaced.
Which type of circulatory system is most likely present in organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells?
a closed circulatory system
A physiologist is tracking airflow through an animal's body. The animal inhales once and exhales once. After the animal exhales, the physiologist does not detect any of the initially inhaled air. Which animal is the physiologist likely observing?
a crow
Which of the following is a normal event in the process of blood clotting?
activation of prothrombin to thrombin
A protein kinase activating many other protein kinases is an example of _____.
amplification By activating many other molecules the initial signal is amplified.
Extracellular pathogens such as viruses and bacteria in body fluids are attacked by _____. See Concept 43.3 (Page)
antibodies from plasma cells Antibodies are part of the "humoral" immune responses. Circulating antibodies encounter microorganisms in body fluids and complex with them to "mark" them for further counterattack.
Which letter indicates diastolic pressure?
b (Where there is a dip in the changes in blood pressure)
Which statement best explains why cattle able to survive on a diet consisting almost entirely of plant material?
because cattle have cellulose-digesting, symbiotic microorganisms
The essential nutrients for proper human nutrition include __________.
calcium, sodium, potassium, and other minerals Under no conditions can minerals be synthesized by the body.
Which letter indicates the arteries?
d (Aorta->arteries-> arterioles) (When blood enters the arteries from the aorta, both pressure and velocity begin to fall. As blood leaves the arteries and flows through the arterioles, both pressure and velocity drop rapidly.)
Which letter indicates the vessels in which blood velocity is decreasing the most due to an increase in the total combined cross-sectional area of those vessels?
e
Calcium ions that act as second messengers are stored in _____.
endoplasmic reticula The ER stores calcium ions.
Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?
estrogen Nonpolar molecules can diffuse through the plasma membrane and bind to intracellular receptors.
All animals have innate immunity against foreign pathogens. However, vertebrates are unique in having acquired immunity. Unlike innate immunity, which is a generalized response to a broad range of pathogens, acquired immunity involves white blood cells called lymphocytes that recognize specific pathogens and elicit responses specific to each pathogen that enters the body. Acquired immunity involves both a humoral immune response and a cell-mediated immune response. To review the definitions of these immune responses, see Hint 1. Sort the items into the appropriate bins depending on whether they are involved in the humoral response, the cell-mediated response, or both the humoral and the cell-mediated responses.
humoral response B cells antibodies plasma cells cell-mediated response cytotoxic T cells both helper T cells and cytokines memory cells antigen-presenting cells Acquired immunity involves both a humoral immune response and a cell-mediated immune response to a specific antigen in the body. The two responses are not independent of each other, but rather form an interlinking web. B cells are active in the humoral response. Cytotoxic T cells are active in the cell-mediated response. Helper T cells are active in both responses. Antigen receptors embedded in their plasma membranes enable specific B cells and T cells to recognize and bind to a specific antigen or antigen fragment. After encountering an antigen or antigen fragment it recognizes, the lymphocyte becomes activated, triggering a response called clonal selection (sometimes called clonal expansion). Clonal selection produces effector cells and memory cells of the activated lymphocyte. Plasma cells are the effector cells of the humoral response; they secrete antibodies that neutralize or tag the foreign pathogen for destruction. Active cytotoxic T cells are the effector cells of the cell-mediated response; they kill infected cells displaying the antigen. Activated helper T cells stimulate the effector cells of both responses with cytokines. The memory cells produced by clonal selection contribute to immunological memory. Memory B cells, memory cytotoxic T cells, and memory helper T cells increase the speed and effectiveness of the immune response to an antigen the body has encountered before.
Which letter indicates the vessels in which blood pressure is the lowest?
i
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
inferior vena cava
Choose the list that presents the four stages of food processing in the order in which they naturally occur. See Concept 41.2 (Page)
ingestion → digestion → absorption → elimination This is the order for organisms that require all four steps. Fungi begin the process with digestion and end with absorption.
Thyroid hormones bind to _____ receptors.
intracellular Thyroid hormones are able to pass through the plasma membrane.
An antigen _____. See Concept 43.2 (Page)
is a foreign molecule that evokes a specific response by a lymphocyte Antigen molecules can be a part of any type of organism. Antigen molecules could also be a part of a product of an organism such as pollen or feces.
Voice sounds are produced by the _____.
larynx The larynx houses the vocal cords.
From the pulmonary veins, blood flows to the _____.
left atrium
A signal molecule is also known as a(n) _____.
ligand
Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.
liver ... gall bladder Bile is continuously produced by the liver and is stored in the gall bladder until CCK triggers its release.
The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response.
perforin ... cell-mediated Perforin causes the lysis of pathogen-infected body cells; it is a component of the cell-mediated immune response.
Which of these cells produce and secrete antibodies?
plasma cells Plasma cells are clones of antibody-secreting B cells.
B cells that have been stimulated by interleukin-2 develop into _____.
plasma cells Plasma cells develop from B cells that have been stimulated by the interleukin-2 secreted by helper T cells.
Blood returns to the heart via the _____.
pulmonary veins Pulmonary veins carry oxygenated blood from the lungs to the left atrium.
The micrographs shown below were taken of wild-type, ΔFus3, and Δformin cells after they were stained green, exposed to mating factor, and then stained red. For each micrograph, drag the labels to answer the questions. Labels may be used once, more than once, or not at all.
red and green; yellow; yellow asymmetrical; symmetrical; symmetrical yes; no; no yes; yes; yes yes; yes; yes
The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, there might be a problem with _____. See Concept 41.3 (Page)
regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn" The lower esophageal sphincter "guards" the junction between the esophagus and stomach. In infants, the muscles are weak and regurgitation is quite common.
From the superior vena cava, blood flows to the _____.
right atrium Blood enters the right atrium from the superior and inferior venae cavae.
The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____.
secretin The acidity of the stomach contents triggers the small intestine to secrete secretin; secretin then stimulates the pancreas to secrete bicarbonate to neutralize this acidity.
A signal transduction pathway is initiated when a _____ binds to a receptor.
signal molecule The binding of a signal molecule to a receptor initiates a signal transduction pathway.
A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off.
steroid Steroids bind to intracellular receptors, which can then bind to, and regulate, the expression of genes.
A paleontologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. Which of the following conclusions is best supported by these observations?
the animal was endothermic and had a high metabolic rate
Circulatory systems help to overcome which of the following physiological challenges?
the slow rate at which diffusion occurs over large distances
True or false? The circulatory systems of land-dwelling vertebrates are composed of two pumping circuits: the systemic circulation, which is a lower-pressure circuit to the lung, and the pulmonary circulation, which is a higher-pressure circuit to the rest of the body.
False The pulmonary circulation is the lower-pressure circuit to the lung, whereas the systemic circulation is the higher-pressure circuit to the rest of the body.
True or False? The liver is a component of the alimentary canal.
False. The alimentary canal is the tube through which food passes, beginning at the mouth and ending at the anus. The liver is an accessory organ of digestion and not part of the actual canal through which food passes.
Which of the following is an advantage of a complete digestive system?
It allows for specialized regions with specialized functions.
What is the function of a circulatory system?
It brings a transport liquid into close contact with all cells in the body. This transport liquid exchanges gases, nutrients, and wastes with the cells in the body.
Which statement about the gas exchange system in fish is correct?
It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries. Countercurrent exchange in fish gills is very efficient because it enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries.
What do you predict would happen if the yeast had a mutation that prevented the G protein from binding GTP?
No shmoo would form in response to mating factor. If the G protein could not bind GTP, it would not become activated, and so it would not start the phosphorylation cascade.
Which of the following is an example of positive feedback in the lumen of the stomach?
Pepsin digests molecules of pepsinogen, producing more pepsin. Pepsin digests molecules of pepsinogen, producing more pepsin. This is an example of positive feedback because the product of the digestion reaction, pepsin, catalyzes further digestion, producing more pepsin, and so on.
_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm.
Phospholipase C ... IP3 .... Ca2+ Phospholipase C cleaves IP3 from a membrane protein, and IP3 then binds to a calcium channel on the ER.
Which of the following events occurs first when a wound that breaks the skin has occurred?
Platelets release proteins that form clots and decrease bleeding. The first response to broken skin is the release of clotting proteins from platelets in the bloodstream, which decreases bleeding and helps to seal the wound.
Choose the correct statement from the list below.
Proteins that are consumed in the diet are absorbed as individual amino acids following digestion. The building blocks of proteins are amino acids.
Which process is not required for an animal to obtain energy from food?
Excretion. Excretion of wastes is NOT required for an animal to obtain energy from food.
B cells are involved in the humoral immune response. The flowchart below summarizes the steps involved in B cell activation. Drag the labels to their appropriate locations on the flowchart below. (Note that TCR stands for T cell receptor.)
A. Antigen-presenting cell presents antigen on class II MHC B. Helper T cell recognized antigen using TCR and CD4 C. Helper T cell binds to B cell and releases cytokines D. B cell presents antigen on class II MHC molecule E. B cell differentiates not plasma cells and memory cells When a B cell encounters an antigen it recognizes via its antigen receptors, it internalizes part of that antigen and presents a fragment of the antigen with a class II MHC molecule. An activated helper T cell (activated after an encounter with an antigen-presenting cell) can then recognize this class II MHC-antigen fragment complex on the surface of the B cell and bind to it. This interaction, along with cytokines the helper T cell releases, activates the B cell. The B cell then proliferates and differentiates into plasma cells and memory cells. Plasma cells secrete antibodies that neutralize the pathogen or mark it for destruction. Memory B cells aid in the secondary immune response, should the body encounter the same pathogen again.
Cytotoxic T cells are the effector cells in the cell-mediated immune response. The diagram below summarizes the interaction of a cytotoxic T cell and its target cell. Drag the labels to their appropriate locations on the diagram below using the following steps. Use targets of Group 2 to indicate the types of cells shown. Then, use targets of Group 1 to the remaining targets. The labels under the cell on the left should describe what happens to that cell at each step. The labels under the cell on the right should describe what happens to that cell at each step. Note that TCR stands for T cell receptor.
A. Cytotoxic T cell B. Infected cell C. Recognizes cell using TCR and CD8 D. Presents antigen on class 1 MHC E. Releases perforin and granzymes F. Undergoes enzyme attack G. Moves on to destroy another cell H. Undergoes apoptosis Multiple molecules are involved in the activation and action of cytotoxic T cells. A cytotoxic T cell is activated through interaction with antigen-presenting cells and signals from helper T cells. Once a cytotoxic T cell has been activated, it can recognize an infected cell presenting a specific antigen fragment on its surface. The T cell receptor (TCR) recognizes the class I MHC-antigen fragment complex, and the CD8 protein on the cytotoxic T cell binds to the MHC molecule. To kill the infected cell, the cytotoxic T cell secretes perforin and granzymes. Perforin perforates the cell by forming pores, allowing granzymes to enter the cell and break down proteins. This leads to apoptosis, or programmed cell death. Once a cytotoxic T cell has induced apoptosis in a cell, it moves on to attack other infected cells or cancer cells.
Compare the relative abundance of Actinobacteria in the microbiome of a healthy adult's intestinal tract to that of a healthy adult's stomach. Which statement best represents the relative abundance of Actinobacteria in each?
Actinobacteria are abundant in the stomach, but rare in the intestinal tract of healthy adults. Researchers have found that Actinobacteria are abundant in the stomachs but quite rare in the intestinal tracts of healthy adults. The environments of the gut and stomach are quite different, leading to variability in the microbiome community of each.
The graph here shows a comparison of the stomach microbiomes of healthy adults versus adults infected with Helicobacter pylori, a type of bacteria that has been linked to the formation of stomach ulcers. Which statement best represents the bacterial community composition of a healthy adult's stomach?
Actinobacteria are the most abundant bacteria in the stomach of healthy adults, followed by Firmicutes, and roughly equal amounts of Bacteroidetes and Proteobacteria. Individuals uninfected with H. pylori have a diverse stomach microbiome, composed primarily of Actinobacteria (45%), Firmicutes (33%), Bacteroidetes (10%), Proteobacteria (10%), and Fusobacteria (2%). Individuals infected with H. pylori have a much less diverse stomach microbiome, composed primarily of Proteobacteria (95%).
Remember that molecules that are soluble in water are hydrophilic. Molecules that are not soluble in water are hydrophobic. During their digestion and absorption in the small intestine, fats are packaged into hydrophilic forms.
Because fats are hydrophobic, unique processes are used to digest and absorb them into the body. Bile salts keep fat from coalescing into large droplets in the lumen of the small intestine. Smaller droplets expose more surface area to the enzyme lipase, which is secreted by epithelial cells to break down triglycerides into monoglycerides and fatty acids. Monoglycerides and fatty acids are small hydrophobic molecules that can diffuse directly across the plasma membrane of small intestine epithelial cells. Other nutrients absorbed during digestion (amino acids, sugars, etc.) typically require membrane proteins and enter epithelial cells via facilitated diffusion or active transport. In small intestine epithelial cells, monoglycerides and fatty acids are combined to form triglycerides again. These triglycerides are packaged into chylomicrons through the addition of a coat of proteins, phospholipids, and cholesterol. Chylomicrons are hydrophilic, which allows them to be transported in lymph and blood. Chylomicrons enter lacteals first, and eventually make their way into the blood.
What role does a transcription factor play in a signal transduction pathway?
By binding to DNA it triggers the transcription of a specific gene.
The binding of signal molecules to _____ results in the phosphorylation of tyrosines.
C The binding of signal molecules to tyrosine-kinase receptors activates tyrosine-kinase enzymes, which phosphorylate tyrosines.
Choose the correct statement from the list below.
Carbohydrate digestion begins in the mouth with salivary amylase. Carbohydrate digestion begins with the action of salivary amylase in the mouth
Which of these receptor molecules would allow Na+ to flow into the cell?
D This is an ion-channel receptor.
Which of these receptors is NOT a membrane receptor?
E This receptor is not associated with the plasma membrane.
Select the correct statement about essential nutrients.
Essential nutrients must be obtained from diet.
By copying and sequencing bacterial DNA in samples obtained from human intestinal tracts and stomachs, researchers have characterized the bacterial community that makes up the human gut at different life stages and under different disease conditions. Locate the pie chart showing the microbiome of a healthy adult's intestinal tract. Which statement best represents the bacterial community composition of a healthy adult's intestinal tract?
Firmicutes are the most abundant bacteria in the intestinal tract of healthy adults, followed by Bacteroidetes and a small amount of Actinobacteria and Proteobacteria. The healthy adult's intestinal tract is primarily composed of Firmicutes (approximately 75%) followed by Bacteroidetes (approximately 20%). The remainder is Actinobacteria and Proteobacteria (5%).
What hypothesis was being tested with the Δformin strain?
Formin is required for the signal transduction pathway leading to shmoo formation.
Choose the correct statement from the list below.
Free fatty acid absorption occurs in the small intestine. Fat digestion is not complete until pancreatic lipases finalize fat digestion in the small intestine.
Are both Fus3 kinase and formin required for directional cell growth during mating in yeast? When a yeast cell binds mating factor molecules from a cell of the opposite mating type, a signaling pathway causes it to grow a projection toward the potential mate. The cell with the projection is called a "shmoo" (because it resembles a 1950s cartoon character by that name).Researchers sought to determine how mating factor signaling leads to growth of this cell projection on one side of the cell—in other words, to asymmetric cell growth. Previous work had shown that activation of Fus3, one of the kinases in the signaling cascade, caused it to move to the membrane near where the mating factor bound its receptor. The researchers' first experiment identified one of the phosphorylation targets of Fus3 kinase as formin, a protein that directs microfilament construction. Based on this information, the researchers developed the working model shown below for the signaling pathway that leads to the formation of shmoo projections in yeast cells. To determine if Fus3 and formin were required for shmoo formation, the researchers generated two mutant yeast strains: one that lacked the gene for making Fus3 kinase (a strain called ΔFus3) and one that lacked the gene for making formin (Δformin). The researchers exposed the mutant strains to mating factor and observed whether or not the cells formed shmoos. Data from D. Matheos et al., Pheromone-induced polarization is dependent on the Fus3p MAPK acting through the formin Bni1p, Journal of Cell Biology 165:99-109 (2004). A model helps scientists form testable hypotheses. What hypothesis was being tested with the ΔFus3 strain?
Fus3 is required for the signal transduction pathway leading to shmoo formation.
Which of the following is an adaptation of the avian lung that best helps meet the metabolic demands of flight?
Gas exchange occurs during both inhalation and exhalation.
How do hydrogen ions (H+) and chloride ions (Cl-) get into the lumen of the stomach?
H+ is actively transported from parietal cells into the lumen, while Cl- diffuses from parietal cells into the lumen.
A man who has been exposed to the flu virus is tested by his physician. The physician notes that the virus is present but no measurable level of antibodies corresponding to the virus are detected in his body. What might this mean?
He was probably exposed a few days ago and clonal selection has yet to produce plasma cells. After first exposure to an antigen, measurable levels of antibodies (produced from plasma cells) are not seen until about a week after exposure. Thus, it is probable that this man was exposed less than a week ago.
_____ interact with the antigen-class II MHC complex presented by macrophages.
Helper T cells Specific helper T cells recognize specific antigen-class II MHC complexes. The result of this is an activated helper T cell that stimulates both humoral and cell-mediated immune responses.
What is one function of mucus in the lumen of the stomach?
It protects the epithelium from being digested by gastric juice. A layer of mucus lines the lumen of the stomach, protecting the epithelium from being digested by the substances in gastric juice, especially pepsin.
What is the function of the left ventricle?
It pumps oxygenated blood around the body via the systemic circulation.
How do cells involved in the innate immune response detect the presence of pathogens?
Leukocytes recognize unique molecules on pathogens. Pattern-recognition receptors on leukocytes recognize and bind to unique molecules on the pathogens, such as the amino acid N-formylmethionine in bacteria. This receptor binding leads to activation of the innate immune response.
The video covered the relative pressures in different blood vessels throughout the vascular system. Rank the blood vessels from lowest blood pressure to highest blood pressure.
Lowest mean pressure venae cavae veins capillaries arterioles aorta Highest mean pressure As blood moves through the vascular system from the heart, the pressure decreases. The impact of the initial ventricular contraction results in the highest pressure in the aorta. The blood pressure decreases as blood flows from the aorta into the other vessels. Therefore, the lowest pressure is in the venae cavae, which carry deoxygenated blood back to the heart.
Tissues are immunogically "typed" before an organ transplant to make sure that the donor and recipient match as closely as possible in their _____. See Concept 43.3 (Page)
MHC (major histocompatibility complex) proteins Nonidentical MHC proteins are antigenic and likely to cause transplant rejection when unmatched.
Which of the following cells can engulf a pathogen?
Macrophages. Macrophages are leukocytes that can engulf and digest a pathogen.
Which of the following is a difference between vitamins and minerals?
Vitamins are organic molecules, but minerals are inorganic molecules.
Which structure is not part of the alimentary canal?
Salivary glands. The salivary glands are not part of the alimentary canal but contribute digestive enzymes to break down food in the mouth.
Which event occurs first during atrial and ventricular diastole?
The atria and ventricles are relaxed, and blood flows into the atria. Diastole is the relaxation phase of the cardiac cycle during which the chambers of the heart are relaxed and blood can enter them passively.
Which of the following statements best describes the events of apoptosis?
The cell's DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell's parts are packaged in vesicles that are digested by specialized cells.
Fluorescent dyes were used in the experiment to distinguish the old and new cell walls of the yeast cells. First, the existing cell walls of each strain were stained with a green fluorescent dye. These green-stained cells were then exposed to mating factor and then stained with a red fluorescent dye that only labels new cell wall growth. Growth of the cell on all sides (symmetric growth) is indicated by a uniform yellow color, resulting from merged green and red stains. This occurs normally in wild-type cells that have not been exposed to mating factor. The image below shows the fluorescence pattern in wild-type yeast cells that have been exposed to mating factor. Note the asymmetric growth. When designing an experiment, scientists make predictions about what results will occur if their hypothesis is correct. One of their hypotheses was that Fus3 kinase is required for the signal transduction pathway leading to shmoo formation. If this hypothesis is correct, what result should be observed in the ΔFus3 strain?
The ΔFus3 strain should not form shmoos, and the cells should not have a red zone in their walls. If Fus3 kinase is critical to shmoo formation, then cells that don't produce Fus3 kinase should not be able to form shmoos.
One of their hypotheses was that formin is required for the signal transduction pathway leading to shmoo formation. If this hypothesis is correct, what result should be observed in the Δformin strain?
The Δformin strain should not form shmoos, and the cells should not have a red zone in their walls. If formin is critical to shmoo formation, then cells that don't produce formin should not be able to form shmoos.
The partial pressure of oxygen at a particular point in the bloodstream is 100 mm Hg. Under what circumstance will there be a net diffusion of oxygen from the water into the bloodstream at this location?
There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is greater than 100 mm Hg. Oxygen diffuses from where its partial pressure is higher to where its partial pressure is lower. So, if the partial pressure of oxygen at a particular point in the bloodstream is 100 mm Hg, then the partial pressure in the adjacent water would have to be greater than 100 mm Hg for there to be net diffusion into the bloodstream.
Which is a true statement about memory cells?
They have a longer lifespan than plasma cells. Plasma cells live only 4-5 days, but memory cells may last for decades.
Which of the following statements best describes the role of mast cells in the inflammatory response?
They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream. Mast cells release chemicals that dilate nearby capillaries, increasing their permeability and allowing blood components to enter the region from the bloodstream, thus causing localized swelling.
The epithelium that lines the stomach has many deep infoldings, or pits. In what way do these pits function as glands?
They secrete gastric juice into the main chamber of the stomach. Glands are structures that secrete hormones into the interstitial fluid or secrete other substances onto body surfaces or into body cavities. The pits in the stomach wall function as glands by secreting gastric juice into the main chamber of the stomach.
The site of inflammation may become swollen due to the increased numbers of cells and fluids at the site and painful due to signals from pain receptors.
True The site of inflammation may also become red due to increased blood flow at the site; the inflammatory response continues until all invaders are eliminated and the wound is repaired.
Which of the following statements about blood circulation in the body is true?
Valves prevent the backflow of blood into the atria and ventricles. Valves are flaps of tissue that close when the ventricles contract to prevent the backflow of blood into the atria and also when the ventricles relax to prevent the backflow of blood from exiting vessels to the ventricles.
As detailed in the video, what is the effect of total cross-sectional area on the velocity of blood flow?
Vessels with higher total cross-sectional area have lower blood velocity. Blood flows about 500 times slower through the capillaries than it does through the aorta. This lower velocity is due to the same amount of blood that left the aorta moving through a larger total area in the capillaries.
As shown in the diagram detailed in the video, which type of blood vessel has the greatest total cross-sectional area throughout the whole body?
capillaries The capillaries are tiny blood vessels where oxygen exchange between the blood and surrounding tissues occurs. Each capillary has a very small individual cross-sectional area. However, people have billions of capillaries in their bodies. The sheer number of capillaries means that, despite their small individual size, the total cross-sectional area of capillaries is the highest of any type of blood vessel. You can see from the graph that capillaries have a total cross-sectional area of about 4500 cm2 .
The human respiration rate is most closely correlated to the blood levels of which compound during most daily activities?
carbon dioxide
Different types of food are eaten by various groups of animals, but it is usually true that _____. See Concept 41.4 (Page)
cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine The ruminants are "front-end" fermenters, with mutualistic microbes residing in chambers or sections of the stomach.
Innate immunity and acquired immunity are both _____. See Concept 43.1 (Page)
characteristics of all vertebrate animals Only vertebrate animals have fully developed acquired immunity to supplement their innate immunity.
The presence of fatty acids and amino acids in the chyme from the stomach triggers the small intestine to secrete a hormone known as _____.
cholecystokinin, or CCK The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete CCK. CCK then stimulates the gall bladder to release bile and the pancreas to secrete pancreatic enzymes.
What is apoptosis?
controlled cell suicide
Lysine is an essential amino acid for animals. An animal that lacked lysine in its diet ________.
could not make many necessary proteins
Which of these acts as a second messenger?
cyclic AMP
Which letter indicates the vessels in which blood travels the most slowly?
f
Which of the following are the only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart?
fishes
Ticks are parasites that obtain nutrients by ingesting blood from a host animal. Ticks would be classified as ________.
fluid feeders
In which of the following organisms does blood flow from the pulmocutaneous circuit to the heart before circulating through the rest of the body?
frogs
Which letter indicates the venules?
g (*From heart*Aorta-> arteries-> arterioles-> capillaries-> venules-> vein->Venae Cavae *to heart*)
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid?
grasshoppers Within an open circulatory system, such as that operating in insects, the body fluid (hemolymph) bathes the organs directly as it is pumped between open spaces in the body.
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid? See Concept 42.1 (Page)
grasshoppers Within an open circulatory system, such as that operating in insects, the body fluid, called hemolymph, bathes the organs directly as it is pumped between open spaces in the body.
Which letter indicates the vessels in which blood velocity is increasing the most due to a decrease in the total combined cross-sectional area of those vessels?
h
The figure shows how fats are absorbed from the lumen of the small intestine and ultimately reach the blood. Key events occur in the lumen, in small intestine epithelial cells, and in lacteals, which are vessels of the lymphatic system. Drag each statement into the appropriate bin depending on whether the event occurs in the lumen of the small intestine, in a small intestine epithelial cell, or in a lacteal.
lumen of small intestine Lipase breaks triglycerides down into monoglycerides and fatty acids. epithelial cell Chylomicrons leave this structure by exocytosis. Monoglycerides and fatty acids are reassembled to form triglycerides. Triglycerides are coated with phospholipids, cholesterol, and proteins to form chylomicrons. lacteal This structure contains lymph. Chylomicrons are transported in this structure to veins.
Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium?
macrophage
Which of these cells is responsible for the rapidity of the secondary immune response?
memory cells Memory cells are responsible for the rapidity of the secondary immune response and for long-term immunity.
A primary reason for needing a new vaccine for influenza each year is that _____. See Concept 43.4 (Page)
mutation in the influenza virus is frequent The virus that causes one year's flu outbreak has a high rate of mutation, resulting in antigenic variation that the immune system cannot recognize.
The primary functions of the _____ are to warm, filter, and humidify air.
nasal cavity
Secretin stimulates the _____ to secrete _____.
pancreas ... bicarbonate The acidity of the stomach contents triggers the small intestine to secrete secretin, which in turn stimulates the pancreas to secrete bicarbonate to neutralize this acidity.
Cholecystokinin (CCK) stimulates the _____ to secrete _____.
pancreas ... pancreatic enzymes The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete CCK. CCK then stimulates the pancreas to secrete enzymes that play a role in the digestion of these nutrients.