Midterm 1 Bio 162
From the superior vena cava, blood flows to the _____.
right atrium
When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?
rising carbon dioxide
The movement of substances from the blood into the proximal tubule is known as _____.
secretion *Secretion is the movement of substances from the blood into the kidney tubules.
An ectothermic organism would have the advantage over an endothermic organism when ______.
food is scarce year-round *Correct! Endothermic organisms require substantial energy to sustain themselves.
Which of the following animals has a three-chambered heart?
frog Correct. Hearts of frogs and other amphibians contain two atria and one ventricle.
_____ cells are the cells that regulate the opening and closing of stomata, thus playing a role in regulating transpiration.
guard
Which of these are symbiotic associations?
mycorrhizae
The primary functions of the _____ are to warm, filter, and humidify air.
nasal cavity
What is the basic functional unit of the kidney?
nephron *Nephrons perform the work required to maintain water and electrolyte balance.
Movement of water across a membrane is best described as ______.
osmosis *Correct. Osmosis often occurs through membrane channels called aquaporins.
Water potential (the potential energy of water) at a given location is determined by _____.
the pressure on water and amount of solutes dissolved in it *Correct. Water potential is the combination of pressure potential and solute potential.
What forces are responsible for capillarity?
adhesion of water molecules to the sides of xylem cells, cohesion of water molecules to each other, and surface tension Submit
What pressure would be required on the plunger to cause water to flow from left to right?
0.1 Map Correct. A decrease in pressure will cause water to flow from left to right.
You have probably noticed that urine is not always the same. The body is capable of adjusting the volume and the osmolarity of its urine output depending on a number of factors. The kidneys are regulated by hormones such as antidiuretic hormone (ADH) and aldosterone. These hormones are secreted in response to changes in the animal's internal water and salt balance. For example, sweating or blood loss can disrupt water and/or salt balance in the body, leading to a hormonal response that returns the system to homeostasis. Mechanisms for adjusting blood volume or osmolarity include increasing water and/or sodium reabsorption in the nephrons and collecting ducts. How do the following stimuli affect water and sodium (Na+) reabsorption in the kidneys?
1) Blood Loss :- B. with blood body loses both water and salt. so it will trigger release of vasopressin and aldosterone which will result in the reabsorption of water and salt from the filterate. 2) ADH secretion :- A. vasopressin increase the permeability of DCT for water which diffuses out from it. 3) Aldosterone release:- B. Aldosterone increase membrane permeability to Na+. as the ions move out actively, water diffuse out due to osmotic gradient resulting from ion movement. 4) alcohol consumption:- C. it actually decreases the water uptake. alcohol decrease the level of ADH. this results in less water uptake and excessive urination leading to dehydration. 5) sweating:- A. water loss by sweating decrease the plasma water level. it will stimulate secretion of ADH and increase water uptake in kidneys. 6) dehydration due to less water uptake:- A. same as above. 7) caffeine consumption:- C. caffeine and other xanthines inhibit Na+ reabsoption and increase glomerular filteration. 8) eating salty foods:- A. salty foods increase the blood salt level. to tackle this, ADH is secreted and secretion of aldosterone is inhibited. this increase water uptake and decrease sodium reabsorption. 9) diabetes insipedus:-C. in diabetes, glucose is present in the filterate and final urine. due to presence of glucose in filterate is no more hypotonis to tissue fluid and so not loose water to it. so there is higher loss of water in urine. this leads to excessive urination, due to lesser water reabsorption, and increased thirst, due to high water loss. 10) severe diarrhea:- B. loss of chiefly water and salts in diarrhea will stimulate both ADH and aldosterone to increase their loss in urine to maintain homeostasis. * Antidiuretic hormone (ADH) and aldosterone are two of the hormones that help to regulate blood osmolarity, blood pressure, and blood volume by acting on the kidney. ADH is released from the posterior pituitary gland in response to increased blood osmolarity. Dehydration, sweating, and eating salty foods can all cause blood osmolarity to rise. To counteract that change, ADH acts on the distal tubules and collecting ducts, causing them to become more permeable to water. As a result, water is reabsorbed, lowering blood osmolarity, concentrating the urine, and reducing urine volume. The chart shows regulation of blood osmolarity. At first, increase in blood osmolarity triggers osmoreceptors in hypothalamus causing release of ADH. ADH acts on the pituitary gland, which increases water permeability of the collecting ducts. Water reabsorption helps prevent further osmolarity increase, leading to normal homeostasis (blood osmolarity of 300 milliosmoles per liter). Besides, the osmoreceptors triggering causes thirst, which urges one to drink water, reducing blood osmolarity to set point and leading to normal homeostasis again. Aldosterone is released from the adrenal glands in response to a drop in blood pressure or blood volume. Blood loss and severe diarrhea can both cause blood pressure and blood volume to drop. To counteract those changes, aldosterone acts on the distal tubules, causing them to reabsorb more Na+ and water. The reabsorption of both sodium and water results in an increase in blood volume and blood pressure without changing blood osmolarity.
Calculate the partial pressure of oxygen at an atmospheric pressure of 500 mm Hg.
105 mm Hg Correct. This value was determined by multiplying the atmospheric pressure, 500 mm Hg, by 0.21, the fraction of air that is O2.
At an atmospheric pressure of 870 mm Hg with 21 percent oxygen, the partial pressure of oxygen is _____.
182 mm Hg
What characterizes the rates of photosynthesis and transport in a plant on a dry cloudy day?
2. Both the photosynthesis and transpiration rates are low. On a cloudy day with low soil moisture, the photosynthesis rate is low and stomata are closed, so the transpiration rate is low.
True or false? The rate of sugar transport in a plant depends on the rate of photosynthesis, the rate of transpiration, and the difference in turgor pressure between the source and the sink.
2. False While the rate of photosynthesis and the difference in turgor pressure between the source and the sink do influence the rate of sugar transport in the phloem, the rate of transpiration does not; transpiration mainly influences the rate of water transport through the xylem.
What would the graph look like for the following null hypothesis? There is no energy trade-off between reproductive and immune function.
A bar graph of activity with experimental treatments roughly equal to the control *Correct! Equal bar values represent a lack of a difference between the two variables.
Which of the following is most likely to be found in a terrestrial animal with high activity rates?
A four-chambered heart
What would you predict if the curve were steeper than the one pictured?
A larger change in oxygen saturation of hemoglobin to a change in oxygen partial pressure
Which arrow indicates the direction of a gradient of increasing solute concentration in the interstitial fluid surrounding a nephron?
A only *The solute concentration of the interstitial fluid increases along a gradient running from the exterior of the kidney to the center of the kidney.
Which process uses oxygen gas within cells? A. Cellular respiration B. Protein synthesis C. Photosynthesis D. Gene expression
A. Cellular respiration
Which of the following statements best describes the actions of the hormone ADH on the nephron?
ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration. *ADH increases the water permeability of the distal tubule and collecting duct, increasing the amount of water reabsorbed into the surrounding tissue and decreasing the amount lost as urine.
Why is the transport of phloem sap considered an active process?
ATP is used to transport sucrose into companion cells near sources, against a concentration gradient.
How is the time frame of adaptation different from acclimatization? See Section 39.1 (Page 820) .
Adaptation occurs over years to eons, while acclimatization occurs with a change in season. Correct. Adaptation is the production of evolutionary selection. This typically requires many generations of a given organism.
Which lung structure is a tiny sac that functions as an interface between air and blood?
Alveolus
Which of the following is true regarding hormonal regulation of urine volume and composition?
Antidiuretic hormone (ADH) causes a reduction in urine volume. *Correct. ADH creates a concentration gradient that favors water reabsorption.
The dinosaur Apatosaurus (Brontosaurus) is one of the largest terrestrial animals that ever lived−over 20 m in length and weighing over 20 metric tons. Is it more likely that Apatosaurus was homeothermic or poikilothermic? Explain.
Apatosaurus (Brontosaurus) was likely homeothermic, given its huge size. Due to its low surface area/volume ratio, its body temperature would not change much between day and night because it takes a long time to lose or gain heat across such a relatively small surface area.
How is most carbon dioxide transported from tissues to the lungs?
As bicarbonate ions
What might be a consequence of global warming for fishes living in a pond?
As the planets warms, aquatic habitats such as a pond will contain less dissolved oxygen, reducing the ability of fishes to acquire oxygen for their respiratory needs.
Why do salmon rely increasingly on gills for respiration as they get larger?
As the surface-area-to-volume ratio drops with growth, salmon require an adaptation with increased surface area to permit them to acquire adequate oxygen from the environment. Correct. Gills are needed to compensate for increasing size in fishes.
Why does water move up a tree via a pressure gradient and not a solute gradient?
Because xylem cells are dead at maturity Correct. The lack of plasma membranes removes the ability for a solute gradient to form up the tree.
Why might a desert animal have longer loops of Henle than an aquatic one?
To create larger osmotic gradients *Correct! The loop of Henle is an important structure in water reabsorption.
Which of the following statements comparing endotherms and ectotherms is correct? A) Mitochondrial density and enzyme activity are 3—4 times higher in the cells of ectotherms than in the cells of endotherms of similar size. B) Endotherms and ectotherms have about the same mass-specific metabolic rate. C) Both endotherms and ectotherms exchange heat with the environment through convection, conduction, radiation, and evaporation. D) Endotherms can use more of their energy intake for reproduction than ectotherms can.
Both endotherms and ectotherms exchange heat with the environment through convection, conduction, radiation, and evaporation.
In roots the _____ forces water and solutes to pass through the plasma membranes of _____ cells before entering the _____.
Casparian strip ... endodermis ... xylem. The Casparian strip is a waterproof barrier that forces water and solutes to pass through the plasma membranes of endodermis cells.
Which of the following best describes a typical countercurrent heat exchanger?
Cool venous blood is heated by warm arterial blood, allowing heat to be conserved in the body's core. *Correct. This exchange, based on blood moving in opposite directions, conserves heat.
Which of the following best describes a cell in the inner lining of the stomach (in contact with swallowed food)?
Correct. Epithelial tissue lines the surfaces of organs such as the stomach.
Which of the following plant organs may act as a source for translocation of sugars inside a plant?
Correct. Mature leaves photosynthesize, which makes sugars.
Where would oxygen partial pressure be the highest? A) Ocean bottom B) Stagnant pond C) Lake bottom D) Mountain stream
D) Mountain stream Correct! Cold water and heavy mixing creates conditions with high oxygen.
Most mammals are strict homeotherms. Elephants allow their body temperature to vary during the hottest parts of the day, meaning they are ________. Most mammals are strict homeotherms. Elephants allow their body temperature to vary during the hottest parts of the day, meaning they are ________. A) ectothermic B) hibernators C) heat exchangers D) poikilothermic
D) poikilothermic
Why would one predict that if King Kong existed, he would be hairless?
Due to the extreme amount of heat his body would generate, the presence of hair would likely overheat him Correct! The surface area to volume ratio would be so small there would be great demands to cool off the endothermic gorilla.
As blood flows through the glomerulus, what is filtered out?
Electrolytes and wastes *Correct! Cells and macromolecules are too large to be filtered.
Which tissue acts as a filter on the water absorbed by root hairs?
Endodermis Endodermal cells filter solutes from water and allow them to pass through to the vascular tissue.
Which tissue type forms glands?
Epithelial *Correct. This tissue does this as well as lining the surface of organs and covering the outside of the body.
Which of the following does NOT correctly represent blood flow through the heart?
From the right ventricle to the left ventricle
How would the solute potential of agricultural soil change from morning to the middle of the afternoon on a hot dry summer day?
Greatly decreased solute potential over the day
What is the driving force for the filtration of blood by the renal corpuscle?
Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule. *The blood pressure in the glomerular capillaries is higher than in the Bowman's capsule, so water and small solutes are forced out of the blood through capillary pores, leaving the larger components of the blood behind.
_____ bonds are responsible for the cohesion of water molecules.
Hydrogen bonds among water molecules are responsible for the tendency of those molecules to stick together.
Where would you add dots to the figure to represent aquaporins in the correct route?
In the transmembrane route
How might a homeothermic species deal with rising global temperatures?
Individuals with slightly warmer set points will fare better than those with average set points. *Correct! A warmer set point should deal better with warmer temperatures.
What is the function of a circulatory system?
It brings a transport liquid into close contact with all cells in the body.
Based on the structure of the neuron, what would you conclude?
It provides signals to specific cells and tissues. Correct! These neurons serve as "biological wires" for sending signals to specific cells and tissues.
What is the function of the left ventricle?
It pumps oxygenated blood around the body via the systemic circulation.
How might eating salty foods alter urine output?
It would cause more concentrated urine. cause less water to be released in the urine
As an animal gets larger, which of the following occurs?
Its volume grows more rapidly than its surface area.
Osmosis of water into the lumen of the Malpighian tubules in terrestrial insects occurs because of the concentration gradient established by the active transport of _____ into the lumen.
K+ *Correct. This is an action of the potassium pumps in the Malpighian tubules.
Explain why it would be impossible for a gorilla the size of King Kong to have fur. (Your answer should explain how the surface area/volume ratio of a normal-sized gorilla would compare to Kong's; relate this to the role of surface area and volume in heat generation and heat transfer; and consider the function of fur.)
King Kong is endothermic, and his huge mass would generate a great deal of heat. His relatively small surface area compared to that of a normal-sized gorilla wouldn't be able to dissipate the heat−especially if the surface were covered with insulating fur.
If ethanol inhibits ADH release, what is predicted?
Large amounts of dilute urine *Correct! Ethanol inhibits water reabsorption.
Which feature is common to gills, lungs, and tracheae?
Large surface area Correct! All have a relatively large surface area for better gas exchange.
Which of the following is an accurate comparison of vertebrate lungs?
Mammals have more alveolar surface area than frogs. Submit Correct. Amphibian lungs are simple sacs that lack the alveoli found in mammalian lungs.
Osmoregulation in all marine fishes (cartilaginous and bony) is accomplished primarily with the use of ______.
Na+/K+-ATPase pumps *Correct. Na+/K+-ATPases actively pump ions to maintain osmotic balance in both cartilaginous and bony marine fishes.
The water potential of phloem sap is lowest in which of the following situations?
Near leaves at the start of spring Correct. The water potential of phloem sap is lowest here because developing leaves are using sucrose faster than they are creating it.
How does a selectively permeable membrane affect diffusion?
Only some molecules move from a higher concentration to a lower concentration *Correct! Selectively permeable means that only certain molecules are able to pass through the membrane.
Why are there no endothermic water-breathing animals?
Oxygen is more difficult to extract from water than from air. Correct! Water breathers cannot extract sufficient oxygen to support the high metabolic rates required for endothermy.
Why is it important that the xylem is adjacent to the phloem?
Pressure from xylem water moves nutrients through the phloem. Correct. This is the basis for the Pressure-Flow Hypothesis.
If a mouse has a mass-specific metabolic rate that is 10 times higher than an elephant, what does that tell you about food needs of a mouse?
Relative to body mass, mice will eat much more food per day Correct. The high metabolic rate of mice will require relatively more effort to find food.
Some animals have no gills when young, but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?
Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.
Which of the following represents the correct sequence of flow through the nephron?
Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct *Urine formation in mammals starts with filtration by the renal corpuscle. The volume and composition of the filtrate is modified as it progresses through the proximal tubule, loop of Henle, and distal tubule. Final adjustments to the filtrate take place in the collecting duct.
Which regions of the nephron function independently of hormonal control for the most part?
Renal corpuscle, proximal tubule, and loop of Henle. *Filtration, reabsorption, and the establishment of an osmotic gradient by these regions of the nephron are largely unregulated.
Which of the following is a true statement about body size and physiology?
Small and large animals face different physiological challenges because an animal's body mass increases cubically while its surface area increases as a squared function.
Which of these membrane proteins is involved in secondary active transport?
Sodium/chloride/potassium cotransporter Correct! This performs secondary active transport.
T/F. The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.
TRUE
What might occur if a mutation reduced the water-repellent quality of suberin?
The apoplastic route of water travel would be allowed. Correct. Suberin is the compound that makes up the Casparian strip that blocks this route.
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 about the oxygen-hemoglobin interaction is true?
The binding of one oxygen molecule to hemoglobin stimulates the binding of other oxygen molecules.
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.
Which of the following statements about the distribution of sap throughout a plant is true?
The mechanism that explains the movement of sugars throughout a plant is called the pressure-flow hypothesis.
Kidney Diagram
The nephron is the functional unit of the kidney, meaning that filtrate is processed in the nephrons. Nephrons are positioned in the renal cortex and can extend into the renal medulla. A nephron consists of a glomerulus and a long tubule that includes Bowman's capsule, the proximal tubule, the loop of Henle, and the distal tubule. Filtration occurs at the glomerulus-Bowman's capsule interface, sometimes called the renal corpuscle. The filtrate then travels through the rest of the nephron and drains into the collecting duct. The filtrate, now called urine, exits the kidney through a ureter that drains into the urinary bladder. Finally, the urine is expelled from the body through the urethra.
What would the oxygen measurements be on either side of the apparatus if there were no fish in it and the two chambers were fully sealed off from one another?
The oxygen levels would be maintained at whatever they started at. *Correct! The two sides are separate and therefore would be at whatever concentration they started at.
Imagine a plant without phloem. For sugars to move from one region of the plant to another, what must happen?
The sugars would be actively transported from cell to cell. Correct. ATP-mediated protein transport is still possible.
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.
Which of the following is true regarding marine fishes?
They actively transport ions across their gills into the seawater. *Correct. Marine fishes must rid themselves of excess electrolytes.
What is a benefit for a shark of osmoconforming? See Section 40.2 (Page 841) .
They don't lose water to their environment. *Since they have a similar concentration of solutes in their body fluids as in their environment, water doesn't leave them by osomosisosmosis.
How does a shark help balance water and electrolytes living in an ocean environment?
They maintain a high concentration of urea in their blood. Submit *Correct! This creates a smaller osmotic gradient and hence less water loss.
How do CAM plants avoid losing very much water despite living in deserts?
They open their stomata only at night. Correct. This reduces water loss due to cooler temperatures.
An insect acclimated to a warm, dry environment would be expected to show which of the following?
Thick cuticle *Correct. A thick cuticle limits water loss.
What is the function of the Loop of Henle in mammalian kidneys?
To create the kidney's osmotic gradient that permits the reabsorption of water and various solutes *Correct. This gradient is critical for the eventual production of highly concentrated urine. Return to Assignment
Why did the experiment use different individuals in repeated trials?
To reduce biasing results from a single odd individual Submit
Why would spiracles be located on the underside of a desert grasshopper?
To reduce water loss via evaporation *Correct! The underside of the grasshopper is shaded from solar heat.
True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.
True (Enzyme activity depends on conditions within a cell, such as temperature and pH, which must be kept within a certain narrow range.)
Why is uric acid advantageous for nitrogenous waste excretion?
Uric acid is insoluble in water. *Correct! Because it is insoluble, its elimination does not involve much water loss.
Which of the following statements about blood circulation in the body is true?
Valves prevent the backflow of blood into the atria and ventricles.
Which of the following occurs in response to a drop in blood pressure?
Veins constrict.
Which of the following is a disadvantage of external gills?
Vulnerable to predation
Which of the following statements about xylem transport is true?
Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves. Water and minerals that are taken up in the soil are transported from roots to leaves by the xylem.
The kidneys of terrestrial mammals conserve water in the body by concentrating urine. The osmolarity of human blood is 300 mOsm/L, but human urine is generally about 1200 mOsm/L. The loop of Henle and the collecting duct are instrumental in maintaining osmotic gradients that make the concentration of urine possible. Complete the diagram below using the following steps: Place the pink labels, which indicate interstitial fluid osmolarity in mOsm/L, onto the correct pink targets. (Note that the numbers inside the nephron and collecting duct indicate the osmolarity of the filtrate at those different points.) Place a red arrow to indicate active transport or a purple arrow to indicate passive transport onto the remaining targets. Do H2O, NaCl, and urea experience active transport, passive transport, or both? Keep in mind that the nephron's epithelium exhibits varying permeability to water and solutes along its length. Labels can be used once, more than once, or not at all.
Water is reabsorbed in the kidney because of the osmotic gradient established in the interstitial fluid. The osmolarity of the interstitial fluid increases deeper into the medulla. As a result, water diffuses out of the descending limb of the loop of Henle and out of the collecting duct, flowing from areas of lower osmolarity in the filtrate to areas of higher osmolarity in the interstitial fluid. This water diffuses into blood vessels surrounding the nephron, called the vasa recta, returning to the bloodstream and therefore not diluting the osmotic gradient. The osmotic gradient in the interstitial fluid is maintained mostly by NaCl and urea. In the thin portion of the ascending limb of the loop of Henle, NaCl diffuses out of the nephron. In the thick upper portion of the ascending limb, NaCl is actively transported out of the nephron. (The ascending limb is impermeable to water, which helps maintain high osmolarity in the interstitial fluid.) Urea diffuses out of the lower portion of the collecting duct and is responsible for the high osmolarity in the inner medulla. After traveling through the nephron and the collecting duct, urine is more concentrated than other body fluids and excretes urea and other wastes with a minimal loss of water. The ability of mammalian kidneys to conserve water in this way is a key terrestrial adaptation.
What would happen if this cell were moved from pure water to a seawater solution?
Water would move out of the cell. Correct. Because the solute potential would be lower outside the cell, water would move in that direction.
You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm
In contrast to acclimatization, adaptation involves _______.
a change in allele frequency over many generations *Correct. Adaptation is a genetic change in a population caused by natural selection exerted by the environment.
A homeostatic set point is best described as _____.
a normal or target value for a controlled variable *Correct. Animals have a set point for blood pH, body temperature, and many other variables.
Which of the following aquatic habitats has the highest oxygen content per unit area?
a shallow river fed by a waterfall Correct. Waterfalls are highly oxygenated aquatic environments because of the exposure of the water to air and the incorporation of air bubbles. Also, shallow streams tend to be better oxygenated than deep ones.
Would an amphibian that lacks lungs and breathes entirely through its skin likely be larger or smaller than an amphibian that has lungs? See Section 39.3 ( page 827) . a) Smaller because its larger surface area to volume ratio would allow it to breathe sufficiently through its skin alone b) Smaller because its smaller surface area to volume ratio would allow it to breathe sufficiently through its skin alone c) Larger because its larger surface area to volume ratio would allow it to breathe sufficiently through its skin alone d) Larger because its smaller surface area to volume ratio would allow it to breathe sufficiently through its skin alone.
a) Smaller because its larger surface area to volume ratio would allow it to breathe It would have a smaller volume that requires oxygen relative to the surface area of skin over which it can acquire it.
The large surface area in the gut directly facilitates _____.
absorption
By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.
acidic If not carried by hemoglobin, hydrogen ions would reduce the pH, or increase the acidity, of the blood.
Air-breathing insects carry out gas exchange _____.
across the finest branches of the trachea and cell membranes
Glucose is removed from filtrate by _____.
active transport *The reabsorption of glucose requires the expenditure of energy.
Bony fishes excrete what type of nitrogenous waste?
ammonia *Correct. Ammonia diffuses across gills or is excreted in urine.
Most carbon dioxide is carried from the body tissues to the lungs _____.
as bicarbonate ions (HCO3 -) Most carbon dioxide released from body tissues combines with water to form carbonic acid, which then breaks up into hydrogen and bicarbonate ions.
Which of the following actions is not a function of the epithelium? a) Regulates the excretion of waste. b) Allows the internal environment to alter its conditions to match those of the external environment. c) Controls the exchange of nutrients between the internal and external environments. d) Creates an internal environment that is different from the external environment.
b) Allows the internal environment to alter its conditions to match those of the external environment. (The epithelium allows the internal environment to remain constant even if the external environment changes.)
Which of the following has the highest surface area/volume ratio? mouse bacterium elephant human
bacterium *Correct! Although the measures are small in a bacterium, the ratio of surface area to volume is greater than the other options.
When water moves from soil into the vascular tissues inside the root, it can take three possible pathways. Of these, the apoplastic route is _____.
between cells and through cell walls Correct. Water can move through the apoplast, but must enter the symplast at the endodermis to enter the xylem.
The majority of carbon dioxide is carried in blood as _____.
bicarbonate dissolved in plasma Correct. The bicarbonate forms after carbon dioxide reacts with water, forming carbonic acid that dissociates into bicarbonate and hydrogen ions.
In Gila monsters, the organ in which water from urine is reabsorbed into the bloodstream is the _____.
bladder
Which of the following is an example of a connective tissue?
blood
Which of these is NOT one of the four major categories of tissue? muscle epithelial connective blood nervous
blood *blood is a type of connective tissue
Hemoglobin and hemocyanin _____.
both transport oxygen
How do plants that are adapted to dry and salty soils normally tolerate the low water potential in the environment?
by lowering the solute potential inside their cells Correct. Lowered solute potential will draw water into the cells.
You inject an animal with a drug that loosens the tight junctions between epithelial cells. What do you predict will immediately occur? a) Muscles will no longer contract. b) Nerves will no longer conduct electrical signals. c) Excess water will enter into the organism. d) Nothing will happen.
c) Excess water will enter into the organism. *Correct! Epithelial tissue allows the passage of materials into and out of the organism.
Which of these mechanisms is/are passive?
capillarity and transpiration
Which barrier(s) must O2 and CO2 cross to pass between air and blood inside lungs?
capillary wall, extracellular fluid, epithelial cells
Which do you predict would have the largest difference in mass-specific basal metabolic rate? dog and cat lion and cat cat and mouse lion and dog
cat and mouse
What is the force behind the process known as "transpiration" in plants?
cohesion-tension Correct. The pull of water evaporating from the leaves is the force that moves water through plants.
The transport of a water column up a very tall tree can be explained by _____.
cohesive and adhesive forces of the water column under evaporative tension Correct. The pull of evaporation, combined with the tendency of water to form polar bonds, moves water.
Antidiuretic hormone (ADH) makes the _____ permeable to water.
collecting duct *Making the collecting duct permeable to water results in the reabsorption of water.
In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.
combined with hemoglobin In the blood most oxygen is transported attached to hemoglobin.
Proteins in sieve-tube elements must be encoded by nuclei in what cells?
companion
Most of the carbon dioxide produced by humans is _____.
converted to bicarbonate ions by an enzyme in red blood cells
A valuable nutrient such as glucose is reabsorbed from the proximal tubule into the blood through what process?
cotransport with sodium *Correct. This transport system is established by the movement of Na+ along its concentration gradient.
Which of the following statements describes a negative feedback response? a) The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions. b) The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot. c) A person who loses 3 pounds continues to diet to lose an additional 10 pounds. d) After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.
d) After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels. *The actions of insulin reverse the internal conditions of high blood sugar levels in the body.
Some plants growing in arid climates have small leaves and thick waxy cuticles on the upper epidermis. This is an adaptation for _____.
decreasing water loss from leaves Correct. Plants in arid climates also often have stomata only on their lower leaf epidermis.
When would you observe a positive root pressure?
during guttation Correct. Guttation is driven by the force of water moving into the stele, and being pushed upward by the cell walls.
The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the _____.
fishes
True or false? The pressure inside the human chest cavity is always positive, so the lungs stay relatively inflated even upon exhalation.
false
True or false? Root pressure can move water a long distance up the xylem because of the higher water potential of the xylem in comparison to the water potential in the surrounding cells.
false Root pressure can move water a short distance up the xylem because of the lower water potential of the xylem in comparison to the water potential in the surrounding cells.
True or false? The driving force for the unloading of oxygen from hemoglobin into tissues is the difference in PCO2 levels between the blood and body tissues.
false. The PCO2 levels affect the diffusion of carbon dioxide; the driving force for the diffusion of oxygen from hemoglobin into tissues is the difference in PO2 levels between the blood (100 mm Hg when oxygenated) and body tissues (40 mm Hg at rest).
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.
The movement of substances out of the glomerulus and into Bowman's capsule is referred to as _____.
filtration *Blood pressure is the force behind the filtration of substances out of the glomerulus and into Bowman's capsule.
Which term best describes an animal that, although generating a significant amount of heat through metabolism, does not maintain a constant body temperature? Which term best describes an animal that, although generating a significant amount of heat through metabolism, does not maintain a constant body temperature? A) homeothermic ectotherm B) homeothermic endotherm C) heterothermic ectotherm D) heterothermic endotherm
heterothermic endotherm
When comparing a mouse to an elephant, the mouse has a _____ surface-area-to-volume ratio and a _____ mass-specific basal metabolic rate.
higher higher *Correct. Because volume increases much faster than surface area as an animal gets larger, the mouse has a higher surface-area-to-volume ratio; also, small animals have higher relative metabolic rates than large animals.
How does their urine compare to that of individuals with normal aquaporins?
higher volume and lower osmolarity *Without aquaporins in the collecting duct, water cannot be reabsorbed, which would result in increased urine volume and decreased urine osmolarity.
A shift to the right of the oxygen-hemoglobin equilibrium curve represents _____.
increased oxygen delivery to a tissue Correct. A shift to the right—representing a pH decrease—makes hemoglobin more likely to release oxygen to tissues with low pH.
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
inferior vena cava
When the mammalian brain compares the actual temperature of the body to the preferred temperature of the body, which general component is being used?
integrator
Which component of a homeostatic system sends instructions based on sensory information? a) Integrator. b) Set point. c) Sensor. d) Effector.
integrator *An integrator sends instructions to an effector based on sensory information.
Voice sounds are produced by the _____.
larynx
From the pulmonary veins, blood flows to the _____.
left atrium
Compared with a smaller cell, a larger cell of the same shape has _____.
less surface area per unit of volume
A drug that inhibits chloride pumping out of the ascending limb of Loop of Henle would result in _____.
less water removed from the descending limb *Correct! The gradient would be less steep.
In which region of the nephron is a steep osmotic gradient created?
loop of Henle *The steep osmotic gradient created along the loop of Henle allows water and salts to be returned to the body.
Which of the following organisms would lose the most water by osmosis across its gills?
marine bony fish *
Under the influence of antidiuretic hormone (ADH), _____ is produced.
more concentrated urine *Under the influence of ADH more concentrated urine is produced and the body conserves water.
As filtrate moves down the loop of Henle, the surrounding interstitial fluid becomes _____ concentrated than the filtrate, so _____ leaves the filtrate.
more...water *The increasing solute concentration of the interstitial fluid results in water leaving the filtrate by osmosis.
According to the pressure-flow hypothesis, what mechanism causes the movement of phloem sap from sources to sink tissues?
pressure potential differences between source and sink. These differences cause a flow of sugars in the phloem.
The best definition of an endotherm is an animal that ______.
produces adequate heat to warm its own tissues
Blood returns to the heart via the _____.
pulmonary veins
A woman standing and watching the stars on a cool, calm night will lose most of her body heat by _____. convection radiation evaporation conduction
radiation
An animal warming up in the sun is gaining heat via _____.
radiation *Correct. Radiation is the transfer of heat between two bodies not in direct physical contact.
Which term describes a steady state in which the internal conditions of an organism are kept within a narrow range without regard to the external conditions?
regulatory homeostasis *Regulatory homeostasis involves adjusting the internal conditions of an organism to stay within a narrow range without regard to the external conditions.
Which component of a homeostatic system perceives changes in some parameter of the environment? a) Sensor. b) Integrator. c) Set point. d) Effector.
sensor *A sensor perceives changes in some parameter of the environment.
How would this curve likely differ for a person whose family has lived atop a mountain for thousands of years?
shift to the left
How would this curve likely differ for a person whose family has lived atop a mountain for thousands of years?
shifted to the left These people would have a hemoglobin with a higher affinity for oxygen.
Which of the following actions acts to warm a homeothermic body? a) Sweating. b) Panting. c) Dilating blood vessels. d) Shivering.
shivering *Shivering generates metabolic heat and warms the body.
45) A moth preparing for flight on a cold morning may warm its flight muscles via _____. A) acclimatization B) torpor C) evaporative cooling D) shivering thermogenesis
shivering thermogenesis
Which term describes an area where sugars are used or stored?
sink A sink is an area where sugars are used or stored; typically, these are the roots and fruits of a plant.
Electrical impulses that trigger contraction of cardiac muscle cells in vertebrates originate in the _____.
sinoatrial node
Which of these is reabsorbed from filtrate?
sodium chloride, glucose, water and amino acids *All of these, as well as bicarbonate ions, are reabsorbed from the filtrate.
bone is an example of
supportive connective tissue *Correct. Like all supporting connective tissue, bone has a firm extracellular matrix and offers structural support and protection.
The study on male crickets showed a trade-off between ______.
spermatophore production and lytic activity *Correct. Crickets traded off the level of their immune response, measured by lytic activity, for increased reproductive effort, measured by spermatophore production.
In what season would a desert locust cuticle have the most wax?
summer *The solar heat that promotes evaporation is highest in the summer.
Which of the following best describes smooth muscle cell structure and control?
tapered, involuntary *Correct. Smooth muscle cells are tapered and are controlled by involuntary movement.
Circulatory systems compensate for _____.
the slow rate at which diffusion occurs over large distances
Which of the following respiratory systems is NOT closely associated with the blood supply?
the tracheal system of an insect
Which of the following is an advantage that ectotherms have over endotherms of the same size?
they require much less food
_____ provide(s) the major force for the movement of water and solutes from roots to leaves.
transpiration, the evaporation of water from leaves, exerts a pull that bears the primary responsibility for the movement of water and solutes from roots to leaves.
True or false? The lungs of humans form from the embryonic foregut.
true
The most abundant solute in urine is _____.
urea *Nitrogenous wastes, such as urea, are the primary solute found in urine.
Which of the following drains urine from the kidneys to the bladder?
ureter *Correct. This is the name of the tube that drains urine to the bladder.
A blood vessel that takes blood to the heart is a(n) _____.
vein
Which of the following is the correct sequence of blood flow in birds and mammals?
vena cava → right atrium → right ventricle → pulmonary artery
Air moves in and out of the tracheal system of an exercising insect by ______.
ventilation of the tracheae due to contraction of muscles around the tracheae Correct. The muscles compress and dilate the tracheae, producing pressure changes in gases.
To view the animation, click here. Then click on the image to start the animation. This is an animation of the movement of water and ions through the root
via the apoplastic route. The animation illustrates water and ions moving along a cell wall continuum.
According to the pressure-flow hypothesis, which direction are sucrose and water flowing when roots are sources and leaves are sinks?
water and sucrose flow up the stem, Sucrose flows from a higher pressure to a lower pressure via a flow of water obtained from the xylem
The descending limb of the loop of Henle is permeable to _____, and the thin ascending limb is permeable to ______.
water; Na+ and Cl− *Correct. The descending limb is impermeable to solutes; the thin ascending limb is impermeable to water.
When is it a source?
when it germinates -sucrose stored inside the seem is released to the growing embryo, which cannot yet make enough sucrose to feed itself.
