Unit 4 Textbook Questions

Updated through: ch 47.2

What are carnivores, herbivores, and omnivores?

Carnivores primarily eat other animals for their source of organic materials, herbivores eat primarily plants as their source of organic materials, and omnivores get organic materials from both plants and animals.

What are essential nutrients, and are they the same for all animals?

Essential nutrients are the amino acids, fatty acids, vitamins, and minerals that the animal cannot make itself and must obtain from its diet. The list of essential nutrients varies among animal types.

What is the difference between deposit feeders and suspension feeders?

Deposit feeders pick up or scrape particles of organic matter from solid material they live in or on. Suspension feeders ingest small organisms that are suspended in water (bacteria, protozoa, algae, small crustaceans, etc)

Distinguish between intracellular digestion and extracellular digestion

Intracellular digestion takes place within body cells, whereas extracellular digestion takes place outside the cells, either in a pouch or a tube enclosed by the body.

What are the five steps of food processing in a digestive tube?

1. Mechanical processing, to break up the food

2. secretion of enzymes and other substances that aid digestion

3. enzymatic hydrolysis of food molecules into simpler molecular subunits

4. absorption of the molecular subunits into body fluids and cells

5. elimination of undigested materials

What are the two classes of vitamins? Which of the two types is more critical in the diet and why?

Water-soluble and fat-soluble. Fat-soluble vitamins are stored in adipose tissues, while water-soluble vitamins are excreted in the urine, so it is more important to meet daily requirements from water-soluble vitamins.

What are the four layers of the mammalian gut? Which layer is responsible for peristalsis?

mucosa, submucosa, muscularis, and serosa

the muscularis layer (formed from 2 smooth muscle layers) is responsible for peristalsis

How is pepsin produced? What is its function?

Pepsin is secreted from chief cells into the stomach lumen as an inactive precursor molecule, pepsinogen. The pepsinogen is converted to pepsin by the highly acid conditions of the stomach.

pepsin is a digestive enzyme that begins the digestion of proteins by making breaks in polypeptide chains

Distinguish between the functions of the small and large intestines in the process of digestion.

In the small intestine, the digestion of macromolecules into their molecular subunits occurs, and those subunits are absorbed. In the large intestine, water and mineral ions are absorbed from the remaining digestive contents, leaving the undigested remnants, the feces, which are expelled from the body

What differentiates the consequences of secretion of gastrin and cholecystokinin (CCK)?

Gastrin stimulates the secretion of pepsinogen and HCl in the stomach. Pepsin generated by cleavage of pepsinogen digest protein in the swallowed food. Gastrin also stimulates contraction of the stomach and the intestines

Cholecytokinin (CCK), released in the duodenum in response largely to fat content in chyme, inhibits gastric activity. CCK has the opposite effect of gastrin

How do leptin and ghrelin act to decrease food intake?

Leptin is a long-term regulator of food intake. When fat stores increase, leptin secretion by fat cells in adipose tissue increases. As a satiety signal, leptin acts on the hypothalamus to suppress appetite.

Ghrelin is a short-term regulator of food intake. Secreted by the stomach, this hormone is at its highest level before meals, stimulating appetite by acting on the hypothalamus. After food is eaten, ghrelin secretion decreases, causing hunger to abate.

How are the different types of teeth used in feeding?

Incisors nip or cut food

Canines bite and pierce food

Premolars and molars crush, grind, and shear food

What roles do symbiotic microorganisms play in digestion?

Symbiotic microorganisms aid digestion in many herbivores by assisting in the breakdown of plant material. The microorganisms synthesize cellulase, an enzyme vertebrates cannot make, which hydrolyzes the cellulose of plant cell walls into glucose subunits

Mutualistic microorganisms that synthesize essential amino acids and vitamins, and digest particular components of food that otherwise are indigestible, are found in the gut microbiomes of all mammals

Required molecules that animals cannot synthesize are called:

1. nutrients

2. essential nutrients

3. enzymes

4. proteins

5. carbohydrates

2

Which of the following accurately describes a feeding style?

1. Deposit feeders obtain nutrients from organic molecules in solution

2. Deposit feeders scrape organic matter from solid material on which they live

3. fluid feeders digest organisms suspended in water

4. fluid feeders strain food with networks of mucus or bristles and hairs

5. suspension feeders consume sizable food whole or in chunks

2

The order of successive steps in digestion is:

1. absorption follows enzymatic hydrolysis

2. secretion of enzymes follows absorption of digestive material

3. mechanical processing follows enzyme secretion

4. mechanical processing follows enzymatic hydrolysis

5. enzymatic hydrolysis precedes secretion of digestive aids

1

The esophagus, crop, gizzard, and intestine are found in:

1. birds and mammals

2. insects and mammals

3. flatworms and birds

4. earthworms and birds

5. sponges and cnidarians

4

Which of the following is not an essential nutrient in humans?

1. Vitamin B6

2. calcium

3. glycogen

4. linoleic acid

5. vitamin K

3

A specialized region of the digestive tract is/are the:

1. submucosa formed by circular and longitudinal layers

2. serosa lining the digestive tract for absorption

3. mucosa composed of thick, elastic connective tissue for movement

4. muscularis, an outer layer that secretes a slippery material to prevent friction with other organs

5. sphincters, which form valves between major digestive organs

5

If the fat in whole milk is ingested:

1. the stomach, with its high pH, will stimulate cells of the duodenum to hasten stomach emptying

2. parietal cells in the stomach will absorb it

3. in the small intestine, bile salts emulsify the fats and then lipase hydrolyzes them

4. lactase deficiency in the small intestine would prevent its digestion

5. microvilli will absorb the fat in the form of chylomicrons directly into the blood of the hepatic portal vein

3

The role of the liver in digestion is to:

1. synthesize aminopeptidase and dipeptidase to digest polypeptides

2. synthesize lipase to form free fatty acids

3. secrete trypsin to break the bonds in polypeptides

4. secrete bicarbonate ions and bile salts to help emulsify fats

5. store bile between meals

4

Which of the following best describes regulation of digestion?

1. GIP inhibits insulin release from the pancreas

2. Gastrin stimulates pancreatic secretion of HCl and pepsinogen

3. Secretin stimulates gastric emptying into the duodenum

4. CCK stimulates gastric activity to activate the duodenum

5. Leptin acts on the hypothalamus to suppress appetite

5

An example of a digestive specialization is seen in:

1. the long intestines characteristic of herbivores

2. the incisors being the dominant teeth in wolves

3. the canine teeth being the dominant teeth in deer

4. salivary lipase being made by humans

5. cellulose being made by humans

1

What is innate immunity?

How do anatomical barriers help prevent infection?

What are the usual characteristics of the inflammatory response, and what processes specifically cause each of those characteristics?

W

What is the complement system?

Why does combating viral pathogens require a different response by the innate immune system than combating bacterial pathogens? What are the two main strategies a host uses to protect against viral infections?

How does adaptive immunity differ from innate immunity?

How, in general, do antibody-mediated and cell-mediated immune responses help clear the body of antigens?

Describe the general structure of an antibody molecule.

What are the principles of the mechanism used for generating antibody diversity?

What is clonal selection?

What is immunological memory?

What is immunological tolerance?

Explain how a failure in the immune system can result in an allergy.

Compare invertebrate and mammalian immune defenses

Which of the following most accurately describes mammal defenses against disease-causing viruses or organisms?

1. the innate immune system and the adaptive immune system operate separately but in an interrelated way in defending against a particular pathogen

2. anatomical barriers are important for adaptive immunity but not for innate immunity

3. The adaptive immune system reacts faster to pathogens than the innate immune system

4. once the adaptive immune system is activated in response to a specific pathogen, the innate immune system stops functioning against that specific pathogen

5. White blood cells are key participants in adaptive immunity but not innate immunity

1

Which of the following is not a component of the inflammatory response?’

1. macrophages

2. neutrophils

3. B cells

4. mast cells

5. eosinophils

3

When a person’s immune system resists infection by a pathogen after being vaccinated against it, this is the result of:

1. innate immunity

2. immunological memory

3. a response with defensins

4. an autoimmune reaction

5. systemic inflammation

2

One characteristic of a B cell is that it:

1. has the same structure in both invertebrates and vertebrates

2. recognizes antigens held on class I major histocompatibility complex proteins

3. binds virus-infected cells and kills them directly

4. makes many different B-cell receptors on its surface

5. has a B-cell receptor on its surface, which is the IgM molecule

5

Antibodies:

1. are each composed of four heavy and four light chains

2. display a variable end, which determines the antibody’s location in the body

3. belonging to the IgE group are the major antibody class in the blood

4. found in large numbers in the mucous membranes belong to class IgG

5. function primarily to identify and bind antigens free in body fluids

5

Place the following steps of recognition of an antigen by lymphocytes in the order in which they would occur:

1. bacteria degraded

2. dendritic cell engulfs bacteria

3. T cells activated

4. antigens bind to class II MHC proteins

5. Plasma cells and memory cells produced

2, 1, 4, 3, 5

An antigen-presenting cell:

1. can be a CD 8⁺ T cell

2. derives from a phagocyte and displays an antigen to a lymphocyte

3. secretes antibodies

4. cannot be a B cell

5. cannot stimulate helper T cells

2

Antibodies function to:

1. deactivate the complement system

2. neutralize natural killer cells

3. clump bacteria and viruses for easy phagocytosis by macrophages

4. eliminate the chance for a secondary response

5. kill viruses inside of cells

3

After Sally puntured her hand with a dirty nail, she received both a vaccine and someone else’s antibodies against tetanus toxin. The immunity conferred here is:

1. both active and passive

2. active only

3. passive only

4. first active; later passive

5. innate

1

Drugs are administered to patients to enhance the immune response when treating:

1. organ transplant recipients

2. anaphylactic shock

3. rheumatoid arthritis

4. HIV infection

5. type I diabetes

4

Why did the existence of vestigial structures make Buffon question the idea that living systems never changed?

What were Lamarck’s contributions to an evolutionary worldview?

How do the concepts of gradualism and uniformitarianism in geology undermine the belief that Earth is only about 6,000 years old?

What observations that Darwin made on his around-the-world voyage influenced his later thoughts about evolution?

How did Darwin’s understanding of artificial selection enable him to envision the process of natural selection?

W

What were the four great intellectual triumphs of Darwin’s theory?

What two problems slowed the acceptance of Darwin’s theory among scientists?

What is the difference between microevolution and macroevolution?

What types of data provide evidence that evolution has adapted organisms to their environments and promoted the diversification of species?

The “father” of taxonomy is:

1. Charles Darwin

2. Charles Lyell

3. Alfred Wallace

4. Carolus Linnaeus

5. Jean Baptiste de Lamarck

4

The wings of birds, the legs of pigs, and the flippers of dolphins provide examples of:

1. vestigial structures

2. homologous structures

3. acquired characteristics

4. artificial selection

5. uniformitarianism

2

Which of the following ideas proposed by Lamarch was not included in Darwin’s theory?

1. Organisms change in response to their environments

2. changes that an organism acquires during its lifetime are passed to its offspring

3. all species change with time

4. new variations may be passed from one generation to the next

5. specific mechanisms cause evolutionary change

2

The belief that evolution is progressive or goal oriented is called:

1. gradualism

2. uniformitarianism

3. taxonomy

4. orthogenesis

5. the modern synthesis

4

If a population of skunks includes some individuals with stripes and others with spots, would you describe the variation as quantitative or qualitative?

What factors contribute to phenotypic variation in a population?

What is the difference between the genotype frequencies and the allele frequencies in a population?

Why is the Hardy-Weinberg principle considered a null model of evolution?

If the conditions of the Hardy-Weinberg principle are met, when will genotype frequencies stop changing?

Which agents of microevolution tend to increase genetic variation within populations, and which ones tend to decrease it?

Which mode of natural selection increases the representation of the average phenotype in a population?

In what way does sexual selection resemble directional selection?

What is a balanced polymorphism?

Why is the allele that causes sickle cell anemia very rare in human populations that are native to northern Europe?

How can a biologist test whether a trait is adaptive?

The reason spontaneous mutations do not have an immediate effect on allele frequencies in a large population is that:

1. mutations are random events, and mutations may be either beneficial or harmful

2. mutations usually occur in males and have little effect on eggs

3. many mutations exert their effects after an organism has stopped reproducing

4. mutations are so rare that mutated alleles are greatly outnumbered by nonmutated alleles

5. most mutations do not change the amino acid sequence of a protein

4

The phenomenon in which chance events cause unpredictable changes in allele frequencies is called:

1. gene flow

2. genetic drift

3. inbreeding

4. balance polymorphism

5. stabilizing selection

2

Which of the following phenomena explains why the allele for sickle-cell hemoglobin is common in some tropical and subtropical areas where the malaria parasite is prevalent?

1. genetic drift

2. heterozygote advantage

3. sexual dimorphism

4. neutral selection

5. stabilizing selection

2

The neutral variation hypothesis proposes that

1. complex structures in most organisms have not been fostered by natural selection

2. most mutations have a strongly harmful effect

3. some mutations are not affected by natural selection

4. natural selection cannot counteract the action of gene flow

5. large populations are subject to stronger natural selection than small populations

3

Phenotypic characteristics that increase the fitness of individuals are called:

1. mutations

2. founder effects

3. heterozygote advantages

4. adaptive traits

5. polymorphisms

4