Q: Which of the following equations correctly represents the relationship between surface area and volume for a spherical cell, and explains why diffusion is sufficient for single-celled organisms?

$$\text{Surface Area} = 4\pi r^2$, $$\text{Volume} = \frac{4}{3}\pi $$r^3$$, so $$\frac{\text{Surface Area}}{\text{Volume}} = \frac{3}{r}$$

Question 1

Which of the following best describes the primary function of bile in the digestive system?

Accepted Answer

Bile neutralizes stomach acid and emulsifies fats to aid in lipid digestion.

Question 2

A patient has a blockage in their bile duct. Which of the following digestive processes would be most directly affected?

Accepted Answer

Emulsification and digestion of dietary fats

Question 3

Which structure in the small intestine is primarily responsible for increasing the surface area for absorption?

Accepted Answer

Villi and microvilli

Question 4

After nutrients are absorbed in the ileum, which blood vessel transports them directly to the liver for processing?

Accepted Answer

Hepatic portal vein

Question 5

Which of the following best explains why single-celled organisms do not require a circulatory system?

Accepted Answer

Their small size allows diffusion to supply all their needs across the cell membrane.

Question 6

A person has a disease that damages the microvilli in their small intestine. Which of the following is the most likely consequence?

Accepted Answer

Decreased absorption of nutrients due to reduced surface area

Question 7

Which of the following is NOT a function of the mammalian circulatory system?

Accepted Answer

Producing digestive enzymes for the duodenum

Question 8

If the colon fails to absorb water efficiently, which of the following conditions is most likely to result?

Accepted Answer

Diarrhea

Question 9

Which of the following best describes the path of a glucose molecule from the gut to the body’s cells?

Accepted Answer

Ileum → hepatic portal vein → liver → general circulation → body cells

Question 10

Which of the following equations correctly represents the relationship between surface area and volume for a spherical cell, and explains why diffusion is sufficient for single-celled organisms?

Accepted Answer

$$	ext{Surface Area} = 4\pi r^2$, $$	ext{Volume} = \frac{4}{3}\pi $$r^3$$, so $$\frac{	ext{Surface Area}}{	ext{Volume}} = \frac{3}{r}$$

Question 11

A patient has a genetic disorder that prevents the formation of lacteals in their villi. Which nutrient absorption would be most directly impaired?

Accepted Answer

Fatty acids and glycerol

Question 12

Which of the following best explains why the hepatic portal vein is critical in nutrient processing?

Accepted Answer

It transports absorbed nutrients directly from the gut to the liver for detoxification and storage.

Question 13

Which of the following scenarios best illustrates the importance of the colon in water balance?

Accepted Answer

A person with a colon infection experiences frequent, watery stools due to reduced water absorption.

Question 14

Which of the following is a correct sequence of events for the elimination of waste from the digestive system?

Accepted Answer

Colon absorbs water → faeces stored in rectum → expelled through anus

Question 15

Which of the following best describes the role of the circulatory system in distributing heat?

Accepted Answer

Blood circulates heat produced by metabolism to maintain a stable internal temperature.

Question 16

A person is unable to produce pancreatic enzymes. Which of the following digestive processes would be most affected?

Accepted Answer

Digestion of starch, proteins, and lipids in the duodenum

Question 17

Which of the following is a correct statement about the absorption of digested food in the small intestine?

Accepted Answer

Most digested food enters blood capillaries in the villi, while fat digestion products enter lacteals.

Question 18

Which of the following best explains why the surface area to volume ratio is important for diffusion in single-celled organisms?

Accepted Answer

A high surface area to volume ratio allows efficient exchange of materials across the cell membrane.

Question 19

Which of the following is NOT transported by the mammalian circulatory system?

Accepted Answer

Cellulose

Digestive System and Circulatory System in Mammals

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