Positive feedback differs from negative feedback in that

Positive feedback differs from negative feedback in that A) the effector's response increases some parameter (such as body temperature), whereas...

Which process in the nephron is least selective?

Which process in the nephron is least selective?  A) reabsorption B) active transport C) secretion D) salt pumping by the loop of Henle E) ...

Connective tissues typically have

Connective tissues typically have  A) many densely packed cells with direct connections between the membranes of adjacent cells. B) a supporting...

Antidiuretic hormone (ADH) functions at the cellular level by

Antidiuretic hormone (ADH) functions at the cellular level by  A) causing an increase in the number of aquaporin molecules of collecting duct...

Low selectivity of solute movement is a characteristic of

Low selectivity of solute movement is a characteristic of  A) filtration from the glomerular capillaries. B) H+ pumping to control pH. C) secretion...

A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that

A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that  A) they are the body's only means of shedding...

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that A) it is unable to enter nontarget cells. B)...

Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish. Many scientists think that this wide range of functions indicates that prolactin

Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish. Many scientists think...

Ammonia

Ammonia  A) has low toxicity relative to urea. B) is the major nitrogenous waste excreted by insects. C) is soluble in water. D) can be stored...

Interstitial fluid is

Interstitial fluid is  A) the route for the exchange of materials between blood and body cells. B) identical to the composition of blood. C)...

Examine Figure 32.1. Near a goose's abdomen, the countercurrent arrangement of the arterial and venous blood vessels causes

Examine Figure 32.1. Near a goose's abdomen, the countercurrent arrangement of the arterial and venous blood vessels causes A) the blood in the feet...

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless,...

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. ADH can help reduce water loss through its interaction with its target cells in the

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. ADH can help reduce water loss through its...

Fight-or-flight reactions include activation of

Fight-or-flight reactions include activation of  A) the thyroid gland, leading to an increase in the blood calcium concentration. B) the anterior...

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of A) a negative feedback system. B)...

Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more

Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more A) ureters. B) juxtamedullary nephrons. C)...

A human who has no access to fresh water but is forced to drink seawater instead

A human who has no access to fresh water but is forced to drink seawater instead  A) will excrete more water molecules than taken in, because...

The thin horizontal arrows in Figure 32.1 show that

The thin horizontal arrows in Figure 32.1 show that  A) the goose's legs get progressively warmer as the blood moves away from the abdomen to...

Excretory structures known as protonephridia are present in

Excretory structures known as protonephridia are present in  A) cnidarians. B) earthworms. C) vertebrates. D) insects. E) flatworms. Answ...

The nitrogenous waste that requires the most energy to produce is

The nitrogenous waste that requires the most energy to produce is  A) urea. B) uric acid. C) ammonia. D) ammonium. Answer: B ...

The nourishment, insulation, and support for neurons is the result of activity by the

The nourishment, insulation, and support for neurons is the result of activity by the  A) intercalated disks. B) glial cells. C) adipose tissue. D)...

Blood is best classified as connective tissue because

Blood is best classified as connective tissue because  A) its cells are separated from each other by an extracellular matrix. B) its cells can...

For hormones that homeostatically regulate cellular functions,

For hormones that homeostatically regulate cellular functions,  A) the circulating level of a hormone is held constant through a series of positive...

Urea is produced in the

Urea is produced in the  A) liver from NH3 and CO2. B) kidneys from glycerol and fatty acids. C) bladder from uric acid and H2O. D) liver from...

Increased ADH secretion is likely after

Increased ADH secretion is likely after  A) drinking lots of pure water. B) ingestion of ethanol (drinking alcoholic drinks). C) eating a small...

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by A) thyroxine. B) calcitonin. C) growth...

Portal blood vessels connect two capillary beds found in the

Portal blood vessels connect two capillary beds found in the  A) hypothalamus and thalamus. B) hypothalamus and anterior pituitary. C) posterior...

The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of

The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of  A) protonephridia. B) metanephridia. C) ananephredia. D)...

The body's automatic tendency to maintain a constant and optimal internal environment is termed

The body's automatic tendency to maintain a constant and optimal internal environment is termed  A) physiological chance. B) static equilibrium. C)...

Muscles are joined to bones by

Muscles are joined to bones by  A) loose connective tissue. B) spindle fibers. C) tendons. D) ligaments. E) Haversian systems. Answer:&nb...

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's A) secretory cell. B) plasma cell. C) endocrine...

The osmolarity of human urine

The osmolarity of human urine  A) can be four times as great as the normal osmolarity of human plasma. B) is always greater than the plasma...

Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long

Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long  A) Bowman's capsules. B) loops of Henle. C)...

Most types of communication between cells utilize

Most types of communication between cells utilize  A) the exchange of cytosol between the cells. B) the release of chemical signals by the cell...

The hypothalamus

The hypothalamus  A) secretes tropic hormones that act directly on the gonads. B) functions only as an endocrine target, by having lots of...

Abnormally reduced somatic growth (dwarfism) can be a consequence of decreased hormone secretion from the

Abnormally reduced somatic growth (dwarfism) can be a consequence of decreased hormone secretion from the A) adrenal gland. B) pancreas. C) anterior...

All hormones

All hormones  A) are lipid-soluble molecules. B) are protein molecules. C) are carried to target cells in the blood. D) elicit the same biological...

In animals, nitrogenous wastes are produced mostly from the catabolism of

In animals, nitrogenous wastes are produced mostly from the catabolism of  A) phospholipids and glycolipids. B) triglycerides and steroids. C)...

In a positive-feedback system where hormone A alters the amount of protein X,

In a positive-feedback system where hormone A alters the amount of protein X,  A) a decrease in A always produces an increase in X, which results...

Coordinating body functions via chemical signals is accomplished by

Coordinating body functions via chemical signals is accomplished by  A) the respiratory system. B) the endocrine system. C) the integumentary...

Fibroblasts secrete

Fibroblasts secrete  A) calcium phosphate for bone. B) chondroitin sulfate. C) fats. D) proteins for connective fibers. E) interstitial flu...

In humans, the transport epithelial cells in the ascending loop of Henle

In humans, the transport epithelial cells in the ascending loop of Henle  A) have 50% of their cell mass made of smooth endoplasmic reticulum. B)...

The type of muscle tissue surrounding internal organs, other than the heart, is

The type of muscle tissue surrounding internal organs, other than the heart, is  A) smooth muscle. B) cardiac muscle. C) skeletal muscle. D)...

Ammonia is likely to be the primary nitrogenous waste in living conditions that include

Ammonia is likely to be the primary nitrogenous waste in living conditions that include  A) a moist system of burrows, such as those of naked...

Compared to the seawater around them, most marine invertebrates are

Compared to the seawater around them, most marine invertebrates are  A) hypoosmotic. B) isoosmotic. C) hyperosmotic. D) hyperosmotic and isoosmotic. E)...

Among the following choices, the most concentrated urine is excreted by

Among the following choices, the most concentrated urine is excreted by  A) desert tortoises. B) frogs. C) birds. D) kangaroo rats. E) huma...

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that A) high amounts...

With its abundance of collagenous fibers, cartilage is an example of

With its abundance of collagenous fibers, cartilage is an example of  A) adipose tissue. B) connective tissue. C) reproductive tissue. D) nervous...

The osmoregulatory/excretory system of an earthworm is based on the operation of

The osmoregulatory/excretory system of an earthworm is based on the operation of  A) metanephridia. B) ananephredia. C) protonephridia. D) nephrons. E)...

You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase I cells on the slide?

You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase...

The process is preceded by replication of the DNA.

The process is preceded by replication of the DNA. A. The statement is true for mitosis only. B. The statement is true for meiosis I only. C. The...

Independent assortment of chromosomes occurs

Independent assortment of chromosomes occurs A. The statement is true for mitosis only. B. The statement is true for meiosis I only. C. The statement...

Centromeres uncouple and chromatids are separated from each other.

Centromeres uncouple and chromatids are separated from each other. A. The statement is true for mitosis only. B. The statement is true for meiosis...

A cell divides to produce two daughter cells that are genetically identical.

A cell divides to produce two daughter cells that are genetically identical. A. The statement is true for mitosis only. B. The statement is true...

Which of the following is true of the process of meiosis?

Which of the following is true of the process of meiosis? A) Two diploid cells result. B) Four diploid cells result. C) Four haploid cells result. D)...

Which of the following happens at the conclusion of meiosis I?

Which of the following happens at the conclusion of meiosis I? A) Homologous chromosomes are separated. B) The chromosome number is conserved. C)...

Centromeres of sister chromatids uncouple and chromatids separate.

I. prophase I II. metaphase I III. anaphase I IV. telophase I V. prophase II VI. metaphase II VII. anaphase II VIII. telophase II Centromeres of sister...

Synapsis of homologous pairs occurs; crossing over may occur.

I. prophase I V. prophase II II. metaphase I VI. metaphase II III. anaphase I VII. anaphase II IV. telophase I VIII. telophase II Synapsis of homologous...

Which of the following terms belongs with the words synapsis, tetrads, and chiasmata?

Which of the following terms belongs with the words synapsis, tetrads, and chiasmata? A) haploid B) crossing over C) autosomes D) prophase II E)...

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A) They have twice...

After telophase I of meiosis, the chromosomal makeup of each daughter cell is

After telophase I of meiosis, the chromosomal makeup of each daughter cell is A) diploid, and the chromosomes are composed of a single chromatid. B)...

Which of these statements is false?

Which of these statements is false? A) In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. B) In humans, the 23rd...

In animals, meiosis results in gametes, and fertilization results in

In animals, meiosis results in gametes, and fertilization results in A) spores. B) gametophytes. C) zygotes. D) sporophytes. E) clones Answer:...

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common?

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. alternation...

Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes?

Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes? A) an unfertilized egg cell B) a sperm...

The human X and Y chromosomes are

The human X and Y chromosomes are A) both present in every somatic cell of males and females alike. B) of approximately equal size. C) almost entirely...

How do the two members of a pair of homologous chromosomes differ from each other?

How do the two members of a pair of homologous chromosomes differ from each other? A) their length B) the identity and relative position of the genes...

Which of the following statements about genes is incorrect?

Which of the following statements about genes is incorrect? A) Genes correspond to segments of DNA. B) Many genes contain the information needed...

What is a genome?

What is a genome? A) the complete complement of an organism's genes B) a specific sequence of polypeptides within each cell C) a specialized polymer...

Which of the following is (are) true concerning cyclin-dependent kinase (Cdk)?

Which of the following is (are) true concerning cyclin-dependent kinase (Cdk)? A) Cdk is inactive, or "turned off," in the presence of cyclin. B)...

Which of the following is true concerning cancer cells?

Which of the following is true concerning cancer cells? A) They do not exhibit density-dependent inhibition when growing in culture. B) When they...

Nerve and muscle cells are in this phase

Nerve and muscle cells are in this phase A. G0 B. G1 C. S D. G2 E. M Answer: ...

The "restriction point" occurs here.

The "restriction point" occurs here. A. G0 B. G1 C. S D. G2 E. M Answer: ...

Triggers the cell's passage past the G2 checkpoint into mitosis

Triggers the cell's passage past the G2 checkpoint into mitosis A. PDGF B. MPF C. protein kinase D. cyclin E. Cdk Answer: ...

A protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active

A protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active A. PDGF B. MPF C. protein kinase D....

A protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex

A protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex A. PDGF B. MPF C....

A general term for enzymes that activate or inactivate other proteins by phosphorylating them

A general term for enzymes that activate or inactivate other proteins by phosphorylating them A. PDGF B. MPF C. protein kinase D. cyclin E. Cdk ...

What causes the decrease in the amount of cyclin at a specific point in the cell cycle?

What causes the decrease in the amount of cyclin at a specific point in the cell cycle? A) an increase in production once the restriction point is...

Cells that are in a nondividing state are in which phase?

Cells that are in a nondividing state are in which phase? A) G0 B) G2 C) G1 D) S E) M Answer: ...

If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will

If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will A) move directly into telophase. B) complete the cycle and divide. C)...

The somatic cells derived from a single-celled zygote divide by which process?

The somatic cells derived from a single-celled zygote divide by which process? A) meiosis B) mitosis C) replication D) cytokinesis alone E) binary...

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle was the nucleus with 6 picograms of DNA?

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to...

Movement of the chromosomes during anaphase would be most affected by a drug that

Movement of the chromosomes during anaphase would be most affected by a drug that A) reduces cyclin concentrations. B) increases cyclin concentrations. C)...

Which of the following is false regarding the bacterial chromosome?

Which of the following is false regarding the bacterial chromosome? A) It consists of a single, circular DNA molecule. B) DNA replication begins...

During which phases of mitosis are chromosomes composed of two chromatids?

During which phases of mitosis are chromosomes composed of two chromatids? A) from interphase through anaphase B) from G1 of interphase through metaphase C)...

The correct sequence of steps in the M phase of the cell cycle is

The correct sequence of steps in the M phase of the cell cycle is A) prophase, prometaphase, metaphase, anaphase, telophase. B) prophase, metaphase,...

Chromosomes first become visible during ________ of mitosis.

Chromosomes first become visible during ________ of mitosis. A) prometaphase B) telophase C) prophase D) metaphase E) anaphase Answer: ...

Which of the following organisms does not reproduce cells by mitosis and cytokinesis?

Which of the following organisms does not reproduce cells by mitosis and cytokinesis? A) cow B) bacterium C) mushroom D) cockroach E) banana tree...

How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?

How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle? A) The daughter...

Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants

Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants A) the spindles contain microfibrils in addition...

Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with

Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with A) a single...

All of the following occur during mitosis except the

All of the following occur during mitosis except the A) condensing of chromosomes until they become visible. B) uncoupling of chromatids at the centromere. C)...

All of the following occur during prophase of mitosis in animal cells except

All of the following occur during prophase of mitosis in animal cells except A) the centrioles move toward opposite poles. B) the nucleolus can no...

A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei containing how many chromosomes each?

A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei containing how many chromosomes each? A) 12 B)...

If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus (its de-polymerization) which stage will mitosis be arrested?

If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus (its de-polymerization)...

Centromeres uncouple, sister chromatids are separated, and the two new chromosomes move to opposite poles of the cell.

Centromeres uncouple, sister chromatids are separated, and the two new chromosomes move to opposite poles of the cell. A. telophase B. anaphase C....

This is the longest of the mitotic stages

This is the longest of the mitotic stages A. telophase B. anaphase C. prometaphase D. metaphase E. prophase Answer: ...

Centrioles begin to move apart in animal cells.

Centrioles begin to move apart in animal cells. A. telophase B. anaphase C. prometaphase D. metaphase E. prophase Answer: ...

Two centrosomes are arranged at opposite poles of the cell.

Two centrosomes are arranged at opposite poles of the cell. A. telophase B. anaphase C. prometaphase D. metaphase E. prophase Answer: ...

If there are 20 chromatids in a cell, how many centromeres are there?

If there are 20 chromatids in a cell, how many centromeres are there? A) 10 B) 20 C) 30 D) 40 E) 80 Answer: ...

The centromere is a region in which

The centromere is a region in which A) chromatids are attached to one another. B) metaphase chromosomes become aligned. C) chromosomes are grouped...

Chromosomes become visible during

Chromosomes become visible during A) metaphase. B) prophase. C) interphase. D) prometaphase. E) anaphase. Answer: ...

Signal transduction pathways benefit cells for all of the following reasons except

Signal transduction pathways benefit cells for all of the following reasons except A) they help cells respond to signal molecules that are too large...

The cleavage of glycogen by glycogen phosphorylase releases ________.

The cleavage of glycogen by glycogen phosphorylase releases ________. A) glucose-1-phosphate B) cellulose C) galactose-1-phosphate D) fructose-1-phosphate E)...

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.

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. A) ion B)...

Which example below is a protein that can hold several other relay proteins as it binds to an activated membrane receptor?

Which example below is a protein that can hold several other relay proteins as it binds to an activated membrane receptor? A) active transcription...

The response of a particular cell to a signal depends on

The response of a particular cell to a signal depends on A) its particular collection of signal receptor proteins. B) its relay proteins. C) the proteins...