Biology for AP Courses

Julianne Zedalis, John Eggebrecht

Chapter 25 Animal Nutrition and the Digestive System - all with Video Answers

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Chapter Questions

00:31

Problem 1

When you eat an apple, it is first physically broken down into smaller fragments. What is the term for this process?

a. elimination
b. absorption
c. mastication
d. peristalsis

Aadit Sharma

Numerade Educator

02:19

Problem 2

Which of the following statements is true?

a. The majority of water is reabsorbed by the small intestines.
b. Elimination is a process that occurs via diffusion.
c. Absorption is the process that chemically breaks down food.
d. The small intestines absorb nutrients.

James Thierer

Numerade Educator

00:22

Problem 3

Ruminants and pseudo-ruminants are both able to digest plant materials but have different mechanisms for doing so. Which of the following is a pseudo-ruminant?

a. cow
b. goat
c. crow
d. horse

Aadit Sharma

Numerade Educator

03:02

Problem 4

Which of the following statements about animal digestion is true?

a. Roughage is digested very quickly.
b. Birds eat large quantities at one time.
c. Birds have a four-chambered stomach.
d. In pseudo-ruminants, roughage is digested in the cecum.

James Thierer

Numerade Educator

00:26

Problem 5

Chemical and mechanical digestion begins in the mouth, and food is prepared into a _________, which is then swallowed.

a. bolus
b. trachea
c. peristalsis
d. sphincter

Aadit Sharma

Numerade Educator

03:32

Problem 6

Which of the following statements about digestion is true?

a. Pepsin is converted to pepsinogen with the help of hydrochloric acid.
b. Starch digestion begins in the mouth.
c. Wave-like muscle movements called peristalsis move food from the stomach to the mouth.
d. Amino acids are absorbed through the intestinal lining of the ileum.

James Thierer

Numerade Educator

00:26

Problem 7

Chyme is highly acidic. What is secreted by the pancreas to neutralize chyme?

a. hydrochloric acid
b. bicarbonate
c. bile
d. amylase

Aadit Sharma

Numerade Educator

03:29

Problem 8

How does the liver assist in fat digestion?

a. produces bicarbonate
b. concentrates bile salts
c. produces bile
d. produces pepsin

James Thierer

Numerade Educator

00:33

Problem 9

When you eat food, it is vital that the nutrients be absorbed. How does absorption occur?

a. Food is mechanically and chemically broken down into smaller molecules.
b. Alternating waves of muscular contraction facilitate movement of food.
c. Partially digested food flows into the small intestine and food regurgitation is prevented.
d. Nutrients diffuse across the intestines.

Aadit Sharma

Numerade Educator

03:11

Problem 10

Certain organs control the release of hormones that have vital roles in digestion. Which of the following controls hunger and satiety signals?

a. thymus
b. adrenal cortex
c. thyroid
d. hypothalamus

James Thierer

Numerade Educator

00:21

Problem 11

One cup of which of the following has the most calories?

a. spaghetti with tomato sauce
b. deep-fried zucchini
c. mixed fruit
d. scrambled eggs

Aadit Sharma

Numerade Educator

02:59

Problem 12

Plant materials, such as fruits and vegetables, are difficult to digest because they are difficult to break down. How are humans able to obtain nutrients from fruits and vegetables?

a. Humans produce cellulase, which breaks down cellulose.
b. Intestinal flora have enzymes that break down some of the fiber.
c. Bile is released from the gallbladder to break down fiber.
d. In the stomach, pepsin is produced to break down plant material.

James Thierer

Numerade Educator

00:11

Problem 13

Which statement is not an example of how fat is beneficial?

a. Fat helps absorb lipid-soluble vitamins.
b. Fat helps produce lipid-soluble hormones.
c. Fat has low energy density.
d. Fat makes you feel full faster.

Aadit Sharma

Numerade Educator

03:06

Problem 14

Certain molecules are required by but not produced by the body. Fat- and water-soluble __________ are organic molecules that cannot be produced by the body but are required for many enzymatic functions.

a. minerals
b. vitamins
c. amino acids
d. sugars

James Thierer

Numerade Educator

00:12

Problem 15

What is the result of insufficient amounts of the mineral iodine in the body?

a. muscle weakness
b. poor immune function
c. mood disturbances
d. goiters

Aadit Sharma

Numerade Educator

03:26

Problem 16

Adenosine triphosphate, or ATP, is the source of energy for cells. ATP stores energy in _____________ bonds.

a. carbohydrate
b. glycolysis
c. glycogen
d. phosphodiester

James Thierer

Numerade Educator

00:27

Problem 17

Which of the following statements about glycogen is true?

a. When an individual is sedentary, glycogen is converted to glucose.
b. The liver releases glycogen when blood sugar drops.
c. ATP is produced by excess glycogen and glucose.
d. During glycolysis, glycogen is converted to pyruvic acid.

Aadit Sharma

Numerade Educator

01:48

Problem 18

What is produced from excess ATP and glucose?

a. glycogen
b. pyruvate
c. peptides
d. essential nutrients

James Thierer

Numerade Educator

00:39

Problem 19

Which of the following is not a reason why ATP is required by animals?

a. ATP is needed to build organic molecules.
b. ATP provides energy for muscle contraction.
c. ATP assists in electrical signal transmission.
d. ATP is the body’s fuel source.

Aadit Sharma

Numerade Educator

01:49

Problem 20

Different macro molecules have varying amounts of energy density. Which of the following is the least energy dense?

a. protein
b. fat
c. fiber
d. carbohydrates

James Thierer

Numerade Educator

00:18

Problem 21

Which of the following does not play a role in masticating food?

a. teeth
b. pharynx
c. saliva
d. tongue

Aadit Sharma

Numerade Educator

02:08

Problem 22

Which of the following statements about the process of digestion is true?

a. Organisms absorb large molecules through digestive cells.
b. The last step of digestion is absorption.
c. Food is only mechanically broken down in the mouth.
d. Food is prepared into a bolus before it is swallowed.

James Thierer

Numerade Educator

00:22

Problem 23

Which of the following enzymes is involved in carbohydrate digestion?

a. pancreatic amylase
b. elastase
c. trypsin
d. pepsin

Aadit Sharma

Numerade Educator

01:19

Problem 24

In protein digestion, what happens in the stomach?

a. Amino peptidase and dipeptidase break peptides into amino acids.
b. Pepsin breaks proteins into peptides.
c. Trypsin, elastase, and chymotrypsin break proteins into peptides.
d. Carboxypeptidase breaks peptides into amino acids and peptides.

James Thierer

Numerade Educator

01:13

Problem 25

Water re absorption is an essential component of processing food. Where is the majority of water reabsorbed?

a. small intestines
b. rectum
c. colon
d. anus

Christina Sorrentino

Numerade Educator

01:32

Problem 26

If you come down with the flu, you might experience emesis. What causes emesis?

a. stomach muscle contractions
b. neural signals that urge elimination
c. inadequate water reabsorption
d. excess water reabsorption

James Thierer

Numerade Educator

00:22

Problem 27

Not all organs involved in processing food are involved in digestion. Which of the following organs is not involved in digestion?

a. mouth
b. anus
c. stomach
d. small intestine

Aadit Sharma

Numerade Educator

02:33

Problem 28

Which of the following statements about digestion of food in the large intestines is true?

a. Mechanical digestion occurs by bacteria.
b. Semi-solid waste is moved by wave-like muscle contractions.
c. Most nutrients are absorbed.
d. Peristaltic mixing occurs.

James Thierer

Numerade Educator

00:18

Problem 29

Taking in food, or __________, is the first step of gaining nutrients from food.

a. digestion
b. ingestion
c. elimination
d. absorption

Aadit Sharma

Numerade Educator

01:22

Problem 30

What is the correct order of processes by which nutrients and energy are obtained from food?

a. digestion ? ingestion ? absorption ? elimination
b. ingestion ? absorption ? digestion ? elimination
c. ingestion ? digestion ? absorption ? elimination
d. ingestion ? digestion ? elimination ? absorption

James Thierer

Numerade Educator

00:22

Problem 31

Gastric control has three phases that assist in digesting food. Which phase is initiated by chyme?

a. intestinal
b. gastric
c. cephalic
d. digestive

Aadit Sharma

Numerade Educator

01:40

Problem 32

Which of the following occurs during the cephalic phase of gastric control?

a. Salivation is triggered.
b. Food is processed by gastric acids and enzymes.
c. Gastrin is produced.
d. Digestive secretions are released.

James Thierer

Numerade Educator

00:21

Problem 33

Hormones are essential for digesting ingested food items. Which hormone controls the release of bile from the gallbladder?

a. pepsin
b. gastrin
c. amylase
d. cholecystokinin

Aadit Sharma

Numerade Educator

00:47

Problem 34

What is the role of gastrin in food digestion and absorption?

a. Gastrin stimulates release of stomach acid.
b. Gastrin stimulates production of bicarbonate.
c. Gastrin stimulates pancreatic juice production.
d. Gastrin stops the release of stomach acid.

James Thierer

Numerade Educator

00:20

Problem 35

The gastric phase assists in processing ingested materials. When does the gastric phase begin?

a. when food is smelled
b. when food reaches the stomach
c. when chyme enters the small intestines
d. when food is ingested

Aadit Sharma

Numerade Educator

02:11

Problem 36

Explain how villi and microvilli aid in absorption.

a. Villi and microvilli increase the surface area of the small intestines, which aids in the absorption of bile salts and vitamin B12.
b. Villi and microvilli increase the surface area of the small intestine, which increases the absorption of nutrients by diffusion.
c. Villi and microvilli form the inner layer of epithelial tissue in the small intestine and increase the absorption of nutrients from chyme.
d. Villi and microvilli absorb food through the small intestine via smooth muscle contractions called peristalsis.

James Thierer

Numerade Educator

00:20

Problem 37

Ruminants, such as this goat, are able to digest large amounts of plant material. How is plant material passed through, digested, and absorbed in the ruminant digestive system?

a. Food is chewed in the mouth, then passes through the esophagus into the rumen and then the reticulum, which contain microbes that break down cellulose and ferment the ingested plant material. The ruminant regurgitates cud from the rumen, and the food is passed into the omasum for water removal and then into the small and large intestines for nutrient and further water absorption. Waste is excreted through the anus.
b. Food is chewed in the mouth, then passes through the esophagus into the rumen and then the reticulum, which contain microbes that break down cellulose and ferment the ingested plant material. The ruminant regurgitates cud from the rumen, and the food is passed into the abomasum for water removal and then into the small and large intestines for nutrient and further water absorption. Waste is excreted through the anus.
c. Food is chewed in the mouth, then passes through the esophagus into the rumen and then
the reticulum, which contain microbes that break down proteins and ferment the ingested plant material. Ruminants regurgitate cud from the rumen, and the food is passed into the omasum for water removal and then into the small and large intestines for nutrient and further water absorption. Waste is excreted through the anus.
d. Food is chewed in the mouth then passes through the esophagus into the reticulum and then the rumen, which contain microbes that break down cellulose and ferment the ingested plant material. The ruminant regurgitates cud from the rumen, and the food is passed into the omasum for water removal and then into the small and large intestines for nutrient and further water absorption. Waste is excreted through the anus.

Aadit Sharma

Numerade Educator

02:49

Problem 38

a. How does a stomach ulcer form?
b. How could you prevent a stomach ulcer from forming in your stomach?

a. a. When the serosa layer of stomach ruptures and does not reform, an open wound is formed. It may be caused by bacteria b. Ulcers can be prevented by eliminating ingesting items that cause degradation of the mucus lining like foods that irritate the stomach.
b. a. When the mucus lining of the stomach ruptures and does not reform, an open wound is formed. It may be caused by a virus. b. Ulcers can be prevented by eliminating ingesting items that cause degradation of the mucus lining, like foods that irritate the stomach.
c. a. When the mucus lining of the stomach ruptures and does not reform, an open wound is formed. It may be caused by bacteria. b. Ulcers can be prevented by ingesting items that will increase the acid content of the stomach.
d. a. When the mucus lining of the stomach ruptures and does not reform, an open wound forms. It may be caused by bacteria. b. Ulcers can be prevented by eliminating ingesting items that cause degradation of the mucus lining, such as foods that irritate the stomach.

James Thierer

Numerade Educator

00:34

Problem 39

How is the gallbladder involved in digestion, even though it is considered an accessory organ?

a. The gallbladder secretes bile to the duodenum, which uses it to break down proteins. It is considered an accessory organ because food does not directly pass through it.
b. The gallbladder secretes bile to the duodenum, which uses it to break down fats. It is considered an accessory organ because food does not directly pass through it.
c. The gallbladder secretes bile to the ileum, which uses it to break down fats. It is considered an accessory organ because food does not directly pass through it.
d. The gallbladder secretes bile to the ileum, which uses it to break down proteins. It is considered an accessory organ because only a very small amount of digestion takes place in the gallbladder.

Aadit Sharma

Numerade Educator

00:46

Problem 40

What is the role of saliva in the digestive system?

a. Saliva contains an enzyme called amylase, which starts the chemical digestion in the mouth by breaking down proteins.
b. Saliva contains an enzyme called lipase, which starts chemical digestion in the mouth by breaking down proteins.
c. Saliva contains an enzyme called maltase, which starts chemical digestion in the mouth by breaking down carbohydrates.
d. Saliva contains an enzyme called amylase, which starts chemical digestion in the mouth by breaking down carbohydrates.

James Thierer

Numerade Educator

00:37

Problem 41

What are the biological benefits of a balanced diet?

a. A balanced diet provides excess energy to be stored in the body and nutrients to maintain good health and increase reproductive capability.
b. A balanced diet allows excess energy to be stored in the body, thereby increasing the rate of metabolic reactions.
c. A balanced diet provides nutrients needed to maintain proper bodily functions, and vitamins and minerals to maintain good health and reproductive capability.
d. A balanced diet provides nutrients needed to maintain proper bodily functions, and vitamins and minerals to maintain good health and increase reproductive capability.

Aadit Sharma

Numerade Educator

01:16

Problem 42

Why is it important to eat carbohydrates, which provide organic carbons?

a. They are needed to provide insulation to mammals.
b. They help to fight infections.
c. They are needed to produce antibodies.
d. They are needed to build cells and tissues.

James Thierer

Numerade Educator

00:31

Problem 43

a. Why is it necessary to consume essential nutrients?
b. What are two examples of fat-soluble essential vitamins, and what are their functions in the human body?

a. a. Essential nutrients are not synthesized by the body and are not necessary for proper body function.
b. Vitamins B and C are two fat-soluble essential vitamins. Vitamin B helps maintain eyesight, and vitamin C is essential for blood clotting.
b. a. Essential nutrients are not synthesized by the body but are necessary for proper body function.
b. Vitamins A and K are two fat-soluble essential vitamins. Vitamin A helps maintain connective tissue, and vitamin K is essential for blood clotting.
c. a. Essential nutrients are synthesized by the body and are necessary for proper body function.
b. Vitamins D and K are two fat-soluble essential vitamins. Vitamin D helps maintain a stable nervous system, and vitamin K is essential for blood clotting.
d. a. Essential nutrients are not synthesized by the body but are necessary for proper body function.
b. Vitamins A and K are two fat-soluble essential vitamins. Vitamin A helps maintain eyesight, and vitamin K is essential for blood clotting.

Aadit Sharma

Numerade Educator

02:03

Problem 44

What happens to glycogen when blood sugar drops?

a. It stimulates the release of insulin, which can regulate the blood sugar level.
b. It is released from the liver and converted to glucose to increase blood sugar levels.
c. It is converted to starch, which breaks down to form glucose and increase blood sugar levels.
d. It is released from the liver and converted to pyruvate, which can then form glucose to increase blood sugar levels.

James Thierer

Numerade Educator

00:33

Problem 45

What is the evolutionary significance of glycogen production?

a. Excess ATP and glucose produce glycogen, which can be used at a later point in time to act
as co-factor if, for example, a good source is scarce.
b. Excess proteins and glucose produce glycogen, which can be used at a later point in time to produce energy if, for example, food is scarce.
c. Excess ATP and glucose produce glycogen, which can be used at a later point in time to produce energy if, for example, food is scarce.
d. Excess proteins and fats produce glycogen, which can be used at a later point in time to act as source of nitrogen if, for example, a good source is scarce.

Aadit Sharma

Numerade Educator

02:56

Problem 46

How can eating too much bread and pasta physiologically promote obesity?

a. Excess blood glucose increases the amount of urea, which is converted into fatty acids. Fatty
acids are stored in areolar cells, which increase the amount of body fat.
b. Excess blood glucose increases the amount of pyruvate, which is converted into fatty acids. Fatty acids are stored in adipose cells, which increase the amount of body fat.
c. Bread and pasta are rich in fats. Their digestion produces fatty acids and glycerol. Fatty acids are stored in adipose cells, which increase the amount of body fat.
d. Bread and pasta are rich in fats. Their digestion produces fatty acids and glycerol. Fatty acids are
stored in areolar cells, which increase the amount of body fat.

James Thierer

Numerade Educator

00:40

Problem 47

How do ingestion and digestion differ?

a. Ingestion is taking food in through mouth, where mechanical digestion begins. Chemical digestion
begins in the stomach, where food is further broken down into smaller molecules that can be absorbed and used by the body.
b. Ingestion is the process of taking in food through the mouth, where mechanical and chemical digestion begins to break down the food into smaller molecules that can be absorbed and used by the body.
c. Ingestion is taking food in through the mouth, where mechanical and chemical digestion begins. Digestion in the stomach breaks down proteins and fats present in food into smaller molecules that can be absorbed and used by the body.
d. Ingestion is the transfer of food from the mouth to the esophagus, where mechanical and chemical digestion begin to break down the food into smaller molecules that can be absorbed and used by the body.

Aadit Sharma

Numerade Educator

03:01

Problem 48

Why are some dietary lipids a necessary part of a balanced diet?

a. Dietary lipids aid in the absorption of water soluble vitamins, including B and C, which are needed for various bodily functions.
b. Dietary lipids aid in the absorption of some minerals, including folic acid, iron, and magnesium, which are needed for various bodily functions.
c. Dietary lipids aid in the absorption of vitamins, including A, B, C, D, E, and K, which are needed for various bodily functions
d. Dietary lipids aid in the absorption of fat-soluble vitamins, including A, D, E, and K, which are needed for various bodily functions.

James Thierer

Numerade Educator

00:57

Problem 49

What happens to undigested food after the water is reabsorbed?

a. Undigested food is moved through the colon, where intestinal flora aid in digestion by peristalsis, and then stored in the rectum until elimination through the anus.
b. Undigested food is moved through the colon, where intestinal flora aid in digestion by peristalsis; further absorption takes place in the rectum, after which it stores the food until elimination through the anus.
c. Undigested food is moved through the colon, where intestinal flora aid in digestion by segmentation, and then it is stored in the rectum until elimination through the anus.
d. Undigested food is moved through the ileum, where intestinal flora aid in digestion by peristalsis, and then it is stored in the rectum until elimination through the anus.

Aadit Sharma

Numerade Educator

04:34

Problem 50

a. What are micelles?
b. Why are micelles integral to lipid absorption?

a. a. Micelles are lipoproteins designed for the transport of lipids that enter lacteals.
b. Micelles facilitate absorption by microvilli, where the fatty acids and proteins diffuse out to form lipoproteins.
b. a. Micelles are lipoproteins designed for the transport of lipids that enter lacteals.
b. Micelles facilitate absorption by microvilli, where the fatty acids and monoglycerides diffuse out to form triglycerides.
c. a. Micelles are bile salt–surrounded fatty acids and phospholipids.
b. Micelles facilitate absorption by microvilli, where the fatty acids and monoglycerides diffuse out to form triglycerides.
d. a. Micelles are bile salt–surrounded fatty acids and monoglycerides.
b. Micelles facilitate absorption by microvilli, where the fatty acids and monoglycerides diffuse out to form triglycerides.

James Thierer

Numerade Educator

00:24

Problem 51

On a cellular level, why must food be broken down?

a. Large molecules present in intact food pass through the digestive epithelium and enter the cell through the membrane, thereby damaging the nuclear membrane. Hence it must be broken down.
b. Fats present in intact food contain very large molecules, which cannot pass through cell membranes. Fats need to be passed through the digestive epithelium to be utilized.
c. Large molecules present in intact food cannot pass through cell membranes. Nutrients need to be passed through the digestive epithelium to be utilized.
d. Large molecules, if not broken down, produce toxic substances that pass through the epithelium of the digestive tract and are utilized by the cells. This can be lethal to the cell.

Aadit Sharma

Numerade Educator

01:16

Problem 52

What is the importance of neural responses to food stimuli?

a. Neural responses facilitate secretion of fumarase needed for chemical digestion of food as well as other involuntary responses like peristalsis.
b. Neural responses facilitate secretion of enzymes that are needed to digest or break down food as well as other involuntary responses like segmentation in stomach.
c. Neural responses facilitate secretion of enzymes needed to digest or break down food as well as other involuntary responses like peristalsis.
d. Neural responses facilitate secretion of salivary amylase needed to digest or break down food as well as secretion of hormones like secretin and gastrin.

James Thierer

Numerade Educator

00:30

Problem 53

How do hormones regulate digestion?

a. Hormones regulate aspects of digestion such as increasing the peristaltic movements in the esophagus when food is sensed.
b. Hormones regulate digestion by signaling when the stomach is full or empty so that an individual will consume food or stop eating.
c. Hormones like gastrin, secretin, adrenocorticotropic are released from the pituitary to regulate which digestive secretions are released.
d. Hormones regulate aspects of digestion such as which digestive secretions are released as well as when they are released.

Aadit Sharma

Numerade Educator

View

Problem 54

When you are eating a meal, how do you know when you are full?

a. The pituitary gland release hormones when the stomach is full, which therefore reduces hunger.
b. The brain signals when the stomach is full that you are satiated, which therefore reduces hunger.
c. The stomach signals when it is full, which therefore reduces hunger.
d. Low blood sugar levels stimulate a neurotransmitter, which sends a signal to the brain when the stomach is full and therefore reduces hunger.

Ronald Prasad

Numerade Educator

00:35

Problem 55

Simple cuboidal epithelial cells line the ducts of certain human exocrine glands. Various materials are transported into or out of the cells by diffusion. (The formula for the surface area of a cube is 6 × S2, and the formula for the volume of a cube is S3, where S = the length of a side of a cube.) Which of the following cubeshaped cells would be most efficient in removing waste by diffusion?

a. 10 µm
b. 20 µm
c. 30 µm
d. 40 µm

Aadit Sharma

Numerade Educator

01:35

Problem 56

Celiac disease is dangerous in affected individuals, because ingesting gluten damages the villi of the small intestines. Why is this potentially life threatening?

a. The villi aid in mechanical digestion of food particles. When they are damaged, nutrients cannot be digested properly in the body.
b. Villi increase the surface area of the small intestine, which aids in the absorption of bile salts. This nutrient cannot be absorbed when they are damaged.
c. Villi decrease the surface area of the small intestine available for absorption. Nutrients cannot properly enter the bloodstream when they are damaged.
d. Villi increase the surface area available for nutrient absorption. When villi are damaged, nutrients cannot properly enter the bloodstream.

James Thierer

Numerade Educator

00:34

Problem 57

One of the key features of villi and microvilli in the digestive system is their finger-like projection shape. Which of the following is an example of how the shape of microvilli can enhance nutrient absorption?

a. Nutrients can enter the bloodstream through the blood vessels that are located in middle of the
microvilli.
b. Larger microvilli have more surface area over which more nutrients are absorbed.
c. The microvilli projections aid in mechanical digestion of food particles.
d. The finger-like projections prevent large particles of food from passing through the digestive system.

Aadit Sharma

Numerade Educator

01:48

Problem 58

Microvilli greatly increase the efficiency of nutrient uptake in the small intestines. How do the size and shape of microvilli promote this efficiency?

a. They have a greater surface area-to-volume ratio than larger cells. The finger-like projection
shape provides more surface area over the small intestines from which they absorb nutrients and contains blood vessels so nutrients passing through them can enter the bloodstream readily.
b. They have a greater surface area-to-volume ratio than larger cells. The finger-like projection
shape is present in the middle of microvilli, which have more surface area over the small intestines from which they absorb nutrients and also contains blood vessels so nutrients can enter
the blood easily.
c. They have a greater surface area-to-volume ratio than larger cells. The finger-like projections prevent large particles of food from passing through the digestive system and also contain blood vessels so nutrients passed through them can readily enter the bloodstream.
d. They have a greater surface area-to-volume ratio than larger cells. The finger-like projections aid
in mechanical digestion of food particles and contain blood vessels so nutrients passing through them can enter the bloodstream readily.

James Thierer

Numerade Educator

00:51

Problem 59

Birds have several unique physical differences from other vertebrates, and several pertain to how birds process food. Some differences are obvious, such as the presence of a beak and no teeth, whereas other differences can be observed in their internal features. For example, birds have a monogastric digestive system like most other vertebrates, but their digestive system structure differs from that of most other monogastric vertebrates. Which of the following is true about how birds process food?

a. Beak emergence coincided with insect inclusion in the bird diet.
b. The gizzard is the primary site of mechanical digestion.
c. Birds excrete nitrogenous waste and feces through separate openings.
d. Birds digest plant material more slowly than ruminants.

Aadit Sharma

Numerade Educator

01:42

Problem 60

As shown in this figure, the oral cavity has several components that contribute to ingestion and the initial stages of digestion. How do the components of the oral cavity work together to complete the first step of food processing?

a. The teeth and jaw mechanically chew the food, and saliva from the salivary glands moistens the
food and begins chemical digestion. The tongue then physically moves the food to the pharynx, where peristalsis moves the food into the stomach.
b. The teeth and jaw mechanically chew the food, and saliva from the salivary glands moistens the
food and initiates mechanical and chemical digestion. The tongue then physically moves the food to the pharynx, where peristalsis moves the food into the stomach.
c. The teeth and jaw mechanically chew the food, and saliva from the salivary glands moistens the
food and begins chemical digestion. The tongue then physically moves the food to the larynx, where peristalsis moves the food into the stomach.
d. The teeth and jaw mechanically chew the food, and saliva from the salivary glands moistens the
food and initiates mechanical and chemical digestion. The tongue then physically moves the food to the pharynx, where segmentation moves the food into the stomach.

James Thierer

Numerade Educator

00:47

Problem 61

Most mammals have a monogastric digestive system, which means they have one stomach chamber. Ruminants and pseudo-ruminants consume a large amount of plant material and have polygastric digestive systems, which means they have more than one stomach chamber. Why is an increased number of stomach chambers beneficial for ruminants and pseudo-ruminants?

a. Microbes in the chambers break down and ferment plant material.
b. Extended exposure to stomach acid breaks down more cellulose.
c. Increased amounts of peristalsis crush more of the plant fibers.
d. Having more stomach chambers increases exposure for nutrients to be absorbed.

Aadit Sharma

Numerade Educator

01:42

Problem 62

This figure shows the majority of the digestive tracts of two organisms that consume different food sources. a. Which digestive tract belongs to the herbivore? b. How did you determine this?

a. a. The digestive tract shown at the bottom belongs to the herbivore. b. Herbivores have a shorter intestinal tract, which allows stronger smooth muscle contractions called peristalsis in a shorter area, providing more opportunity for nutrients to be obtained and absorbed.
b. a. The digestive tract shown at the top belongs to the herbivore. b. Herbivores have a longer intestinal tract, which provides more opportunity for nutrients to be obtained and absorbed, since plant material is difficult for animals to break down.
c. a. The digestive tract shown at the bottom belongs to the herbivore. b. Herbivores have a longer intestinal tract, which provides more opportunity for the nutrients to react with the intestinal enzymes for better absorption, since plant material is difficult for animals to break down.
d. a. The digestive tract shown at the bottom belongs to the herbivore. b. Herbivores have a shorter intestinal tract, which provides more opportunity for nutrients to be obtained and absorbed, since plant material is difficult for animals to break down.

James Thierer

Numerade Educator

00:24

Problem 63

The ruminant digestive system has evolved several differences from the traditional mammalian monogastric digestive system because they consume large amounts of plant material. Which of the following is NOT a component of the ruminant digestive system that has evolved to more efficiently digest plant fibers?

a. omasum
b. abomasum
c. reticulum
d. gizzard

Aadit Sharma

Numerade Educator

01:34

Problem 64

This figure shows the three main components of the large intestine. How do these three parts contribute to processing as food material passes through the large intestine?

a. The cecum receives semi-solid waste from the small intestine and absorbs water, vitamins, and minerals. Then the colon further digests some material. The rectum stores the fecal matter until it is excreted.
b. The cecum receives semi-solid waste from the small intestine. Then the colon digests some materials. The rectum absorbs water and some vitamins and minerals and then stores the fecal matter until it is excreted.
c. The cecum receives semi-solid waste from small intestine. Then, the colon absorbs water and some vitamins and minerals, and further digests some material. The rectum stores the fecal
matter until it is excreted.
d. The cecum receives semi-solid waste from the small intestine. The colon is the only region where absorption of vitamins takes place in the digestive system. The rectum stores the fecal matter until it is excreted.

James Thierer

Numerade Educator

00:32

Problem 65

This figure shows involuntary muscle movement in part of the digestive system. What stimulates this involuntary response?

a. smelling food
b. seeing food
c. chewing food
d. swallowing food

Aadit Sharma

Numerade Educator

01:36

Problem 66

This image shows the digestive system of a ruminant animal. How does this polygastric digestive system enhance digestion efficiency in ruminants?

a. Multiple stomach chambers in ruminant animals contain microbes that have cellulase, which breaks down plant material. Plant material is difficult to digest because animals lack cellulase to break down cellulose.
b. Multiple stomach chambers in ruminant animals allow stronger smooth muscle contractions, which break down plant material. Plant material is difficult to digest because animals lack cellulase to break down cellulose.
c. Multiple stomach chambers present in ruminant animals contain cellulase, which break down plant material. Plant material is difficult to digest because animals lack cellulase to break down cellulose.
d. Multiple stomach chambers in ruminant animals allow the food to stay in the stomach for a longer time so that peristaltic movements and the action of enzymes on food particles occurs for a longer time.

James Thierer

Numerade Educator

00:49

Problem 67

An experiment to measure the rate of respiration in mice at $10^{\circ} C$ and $25^{\circ} \mathrm{C}$ was performed using a respirometer, an apparatus that measures changes in gas volume. Respiration was measured in mL of $O_{2}$ consumed per gram of organism over several five-minute trials, and the following data were obtained.

$$\begin{array}{|c|c|}\hline \text { Organism } & {\text { Temperature $\left(^{\circ} \mathrm{C}\right)$ }} & {\text { Average respiration $\left(\mathrm{mL} 0_{2} / \mathrm{g} / \mathrm{min}\right)$ }} \\ \hline \text { Mouse } & {10} & {0.0518} \\ \hline \text { Mouse } & {25} & {0.0321} \\ \hline\end{array}$$
According to these data, mice at 10°C demonstratedgreater oxygen consumption per gram of tissue than mice at $25^{\circ} C.$ Which of the following statements best explains the observation?

a. The mice at 10°C had a higher rate of ATP production than the mice at 25°C.
b. The mice at 10°C had a lower metabolic rate than the mice at 25°C.
c. The mice at 25°C weighed less than the mice at 10°C.
d. The mice at 25°C were more active than the mice at 10°C.

Aadit Sharma

Numerade Educator

02:27

Problem 68

ATP is essential for organisms because it provides energy to cells. How does ATP provide this energy on a physiological level?

a. When energy is needed, ATP is converted to ADP and a phosphate group. Energy is released from the breaking of the phosphodiester bonds.
b. When energy is needed, ATP is converted to ADP and a phosphate group. Energy is released from the breaking of the glycosidic bonds.
c. When energy is needed, ATP is formed from ADP and a phosphate group. Energy is released from the breaking of the phosphodiester bonds.
d. When energy is needed, ATP is formed from ADP and a phosphate group. Energy is released from the breaking of the phosphoanhydride bonds.

James Thierer

Numerade Educator

00:27

Problem 69

An omnivore comes across potatoes, avocados, kale, and eggs and craves only the eggs. In what nutrient is the animal likely deficient?

a. carbohydrates
b. protein
c. fiber
d. fatty acids

Aadit Sharma

Numerade Educator

01:21

Problem 70

Carbohydrates often get a bad reputation for their role in promoting weight gain when consumed in excess. However, carbohydrates are necessary for biological functions. Why is it important to consume carbohydrates?

a. Carbohydrates are broken down into glucose, which provides energy as ATP through metabolic pathways. ATP helps to maintain connective tissue.
b. Carbohydrates are broken down into glucose, which is essential for blood clotting.
c. Carbohydrates, along with proteins, help maintain connective tissue and are essential to blood clotting.
d. Carbohydrates are broken down into glucose, which provides energy as ATP through metabolic pathways. ATP is required for proper cellular function.

James Thierer

Numerade Educator

00:41

Problem 71

Excess ATP is combined with excess glucose and stored as glycogen in the liver and skeletal muscle. Under what circumstance would glycogen storage in skeletal muscle prove beneficial for a rabbit?

a. A rabbit has not eaten recently and its blood sugar drops.
b. There is an overabundance of food available to a rabbit.
c. A rabbit spots a coyote and flees in response.
d. A young rabbit with an adequate food source is developing into an adult rabbit.

Aadit Sharma

Numerade Educator

05:21

Problem 72

E. coli colonize the human gastrointestinal tract. The temperature of that environment is tightly regulated. However, the pH ranges from the highly acidic stomach (pH 4.5) to the relatively basic lower intestine (pH 9). Over the entire pH range of the environment the pH of the E. coli cytoplasm is maintained in a narrow range between 7.2 and 7.8. Wilks and Slonczewski (Journal of Bacteriology, 189, 2007) used a fluorescent dye to follow the recovery of cytoplasmic pH after an acid shock comparable to what occurs in the human stomach. They found that the pH within the cell recovered in approximately 2 minutes.

Rapid restoration of cytoplasmic pH does not occur in the presence of ATPase inhibitors. Construct an explanation for the mechanisms that maintain homeostasis with a model of exchange of hydrogen ions (H+) between the cell and its extracellular environment.

James Thierer

Numerade Educator

16:02

Problem 73

We need an explanation of the common experience that an "upset stomach" (functional dyspepsia) or constipation can result from stress. Irritable bowel syndrome is a chronic gastrointestinal disease and is treated with the neurotransmitter serotonin. Serotonin receptors are located on the cell membranes of neurons and activate second messenger cascades that regulate gene expression. In humans most serotonin is synthesized in neurons that enervate smooth muscle cells lining the gastrointestinal tract. There is an association of serotonin with a sense of well-being.

A. Based on these data, justify the claim that timing of the passage of food in the gastrointestinal tract is regulated by serotonin.

The effect of serotonin on smooth muscle is a clue but it doesn't provide a mechanism connecting stress to the symptoms of functional dyspepsia. Serotonin is synthesized by all Bilateria (animals with bilateral symmetry, including humans) and is released as a response to stress (Puglisi-Allegra and Andolini, Behavioral Brain Research, 277, 2015). Serotonin is also synthesized by plants to regulate root growth.

B. Describe the role for serotonin that is indicated across domains.

C. Evaluate the effect that stress produces in serotonin production, the association of stress with functional dyspepsia, and the role of serotonin in the regulation of expression in smooth muscle cells in terms of evidence of a negative feedback produced by serotonin as a medication.

D. Justify your evaluation of the stress and the role of serotonin as a response to the stress in the form of a feedback loop diagrammatically.

Quorum sensing coordinates bacterial expression, stimulating virulence factors, and behavior, inducing the formation of biofilms. Knecht et al. (EBioMedicine, 9, 2016) have demonstrated that serotonin functions as a quorum sensing messenger among bacteria in the gastrointestinal tract of mice.

E. Construct an explanation of the effect of serotonin as a treatment of functional dyspepsia.

Ronald Prasad

Numerade Educator