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 cube-shaped cells would be most efficient in removing waste by diffusion?
Figure 25.22
10 µm
20 µm
30 µm
40 µm
56.
Celiac disease is dangerous in affected individuals, because ingesting gluten damages the villi of the small intestine. Why is this potentially life threatening?
The villi aid in mechanical digestion of food particles. When they are damaged, nutrients cannot be digested properly in the body.
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.
Villi decrease the surface area of the small intestine available for absorption. Nutrients cannot properly enter the bloodstream when they are damaged.
Villi increase the surface area available for nutrient absorption. When villi are damaged, nutrients cannot properly enter the bloodstream.
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?
Nutrients can enter the bloodstream through the blood vessels that are located in middle of the microvilli.
Larger microvilli have more surface area over which more nutrients are absorbed.
The microvilli projections aid in mechanical digestion of food particles.
The finger-like projections prevent large particles of food from passing through the digestive system.
58.
Microvilli greatly increase the efficiency of nutrient uptake in the small intestines. How do the size and shape of microvilli promote this efficiency?
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.
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.
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.
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.
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?
Beak emergence coincided with insect inclusion in the bird diet.
The gizzard is the primary site of mechanical digestion.
Birds excrete nitrogenous waste and feces through separate openings.
Birds digest plant material more slowly than ruminants.
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?
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.
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.
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.
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.
61.
This figure shows the majority of the digestive tracts of two organisms that consume different food sources.
Figure 25.23
Which digestive tract belongs to the herbivore? How did you determine this?
i. The top digestive tract belongs to the herbivore. ii. 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.
i. The bottom digestive tract belongs to the herbivore. ii. 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.
i. The bottom digestive tract belongs to the herbivore. ii. 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.
i. The top digestive tract belongs to the herbivore. ii. 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.
62. This figure shows the three main components of the large intestine.
Figure 25.24
How do these three parts contribute to processing as food material passes through the large intestine?
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.
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.
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.
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.
63.
This figure shows the digestive system of a ruminant animal. How does this polygastric digestive system enhance digestion efficiency in ruminants?
Figure 25.25
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.
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.
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.
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.
65.
Figure 25.26
According to these data, mice at 10 °C demonstrated greater oxygen consumption per gram of tissue than mice at 25 °C. Which of the following statements best explains the observation?
The mice at 10 °C had a higher rate of ATP production than the mice at 25 °C.
The mice at 10 °C had a lower metabolic rate than the mice at 25 °C.
The mice at 25 °C weighed less than the mice at 10 °C.
The mice at 25 °C were more active than the mice at 10 °C.
64. An experiment to measure the rate of respiration in mice at 10 °C and 25 °C was performed using a respirometer, an apparatus that measure changes in gas volume. Respiration was measure in milliliters of O2 consumed per gram of organism over several 5-min trials, and the following data were obtained.
65.
ATP is essential for organisms because it provides energy to cells. How does ATP provide this energy on a physiological level?
When energy is needed, ATP is converted to ADP and a phosphate group. Energy is released from the breaking of the phosphodiester bonds.
When energy is needed, ATP is converted to ADP and a phosphate group. Energy is released from the breaking of the glycosidic bonds.
When energy is needed, ATP is formed from ADP and a phosphate group. Energy is released from the breaking of the phosphodiester bonds.
When energy is needed, ATP is formed from ADP and a phosphate group. Energy is released from the breaking of the phosphoanhydride bonds.
66.
An omnivore comes across potatoes, avocados, kale, and eggs and craves only the eggs. In what nutrient is the animal likely deficient?
carbohydrates
protein
fiber
fatty acids
67.
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?
Carbohydrates are broken down into glucose, which provides energy as ATP through metabolic pathways. ATP helps to maintain connective tissue.
Carbohydrates are broken down into glucose, which is essential for blood clotting.
Carbohydrates, along with proteins, help maintain connective tissue and are essential to blood clotting.
Carbohydrates are broken down into glucose, which provides energy as ATP through metabolic pathways. ATP is required for proper cellular function.
68.
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 rabbit has not eaten recently and its blood sugar drops.
There is an overabundance of food available to a rabbit.
A rabbit spots a coyote and flees in response.
A young rabbit with an adequate food source is developing into an adult rabbit.
