Biology 30S Unit #2 Digestion Name: ____________________ Mr. Wasylkoski Kelvin Highschool

BIOLOGY 30S: DIGESTION UNIT TEST

ANSWER KEY

This unit test has 4 sections. Section 1: Multiple Choice, Section 2: Short Answer, Section 3:

Diagram, Section 4: Long Answer. Please carefully read each question and answer it to the

best of your ability. Once you have completed Section 1: Multiple Choice, fill in the bubble

sheet below with your answers. USE PENCIL!

Final Mark: /60

Section 1: Multiple Choice.

Please answer the following multiple choice questions about Digestion. Select one answer

per question. If you change answers please clearly indicate you did you so. Fill in the bubble

sheet on the front page to state your answer.

1 Mark Each

1. The purpose of HCI in the stomach is to convert:

a. trypsin to trysinogen

b. trysinogen to trypsin

c. lipase to lipids

d. pepsinogen to pepsin

2. CCK is released by the ___________ in response to ___________. It travels to the

___________ to stimulate the release of___________.

a. gall bladder; fat; duodenum; liver; bile

b. duodenum; fat; gall bladder; bile

c. stomach; mountain dew; liver; bile

d. pancreas; protein; duodenum; pepsin

3. The tooth has an inner layer of tissue called the ___________.

a. dentin

b. enamel

c. gingiva

d. root

4. The taste buds are located along the sides of the ___________ on the tongue.

a. microvilli

b. papillae

c. rugae

d. none of the above

5. The small intestine uses ___________ to absorb nutrients.

a. villi

b. rugae

c. papillae

d. none of the above

6. The enzyme found in saliva that breaks down starch is called:

a. pepsin

b. trypsin

c. amylase

d. lipase

7. One major function of the large intestine is to:

a. break down starch

b. absorb water

c. produce bile

d. produce insulin

8. When blood glucose drops, the ___________ releases ___________ which travels to the

___________ causing ___________ to breakdown, releasing glucose into the

bloodstream.

a. pancreas; insulin; muscles; protein

b. pancreas; glucagon; liver; glycogen

c. liver; insulin; pancreas; glycogen

d. liver; glucagon; pancreas; lipids

9. Bile is produced in the ___________ and stored in the ___________.

a. stomach; liver

b. intestine; stomach

c. liver; gall bladder

d. gall bladder; colon

10. Lipids are also known as:

a. Carbohydrates

b. fats

c. nucleic acids

d. proteins

11. A human is an omnivore and has large ___________ used for tearing food. In addition,

the molars and premolars are quite ____________.

a. incisors; flat

b. incisors; sharp

c. canines; flat

d. canines; sharp

12. Feces is stored in the ___________ until it is released from the body.

a. anus

b. rectum

c. ileum

d. duodenum

13. The ileocecal valve controls movement of nutrient deficient contents from the

___________ to the ___________.

a. esophagus; stomach

b. small intestine; large intestine

c. oral cavity; esophagus

d. pancreas; liver

14. The innermost lining of the esophagus or stomach is called the:

a. submucosa

b. mucosa

c. rugae

d. none of the above

15. The muscular contractions that occur all along the digestive tract and which move food

along are called:

a. elimination

b. peristalsis

c. hypotension

d. swallowing

16. Which specific layer is found in the stomach but not in the esophagus:

a. mucosa

b. submucosa

c. rugae

d. all of the above

17. Which of the following is not a normal component of gastric juice?

a. rennin

b. secretin

c. hydrochloric acid

d. pepsinogen

18. Trypsin is released by the ___________ and acts in the ___________ to break down

___________.

a. stomach; duodenum; carbohydrates

b. pancreas; duodenum; proteins

c. liver; stomach; carbohydrates

d. gall bladder; liver; proteins

19. Unlike glucose and amino acids, fats entering the villus (villi) move into the

a. artery

b. vein

c. lacteal

d. capillary

20. The small intestine has 3 regions. The second region is called the:

a. ileum

b. duodenum

c. jejunum

d. colon

Section 2: Short Answer. Please answer 4 of the following 6 short answer questions. The first 4

questions you answer will be marked. If you choose to have a question not marked, draw a line

through it.

5 Marks Each.

1. Where does protein digestion take place? What chemicals are required? Explain your

answer.

Protein digestion takes place in both the stomach and small intestine. The primary

chemical involved in protein digestion in the stomach is HCl, which is present in gastric juice.

HCl converts pepsinogen into pepsin which breaks down amino acids (proteins) into smaller

peptides. In the small intestine, pancreatic juices play a major role in protein digestion.

Pancreatic juices activate trypsinogen into the digestive enzyme trypsin, which further breaks

down (or cleaves) peptide bonds in amino acids (breaks down protein).

2. Where does fat digestion take place? What chemicals are required? Explain your answer.

Fat digestion takes place both in the stomach and the small intestine. When present in

the stomach, muscles churn, partially breaking down and separating larger fat

globules, mixing them into chyme. Next stop is the small intestine, or the duodenum.

This is the primary digestion site of fats in the body. Once in the duodenum, fats

(lipids) are introduced to bile that is secreted from the gallbladder. This bile acts as an

emulsifier that separates fat globules into smaller droplets while keeping it combined

with other digestive juices. By now, pancreatic juices have been released and mixed

with the chyme. These pancreatic juices contain the enzyme pancreatic lipase, which

further breaks down fat globules into glycerol or other alcohols.

3. What are the 5 functions of the liver?

Bile production

Filtration

Regulating blood sugar balance

Waste management

Synthesis and storage

4. Think about diarrhea and constipation (sorry!). How does each occur in the large

intestine and what is the result of their occurrence?

Diarrhea occurs when the large intestine fails to absorb enough water from the feces.

This causes an excess amount of water to remain within the fecal matter, causing a

runny stool.

Constipation occurs the large intestine absorbs too much water from the feces. This

results in an extra dry stool, which may prove difficult to pass.

5. List the three different parts of the small intestine and describe their function.

1. Duodenum

The majority of digestion occurs here. The duodenum receives chyme from

the stomach and together with pancreatic juices and bile, chyme is further

broken down.

2. Jejunum

The second or “middle” section of the small intestine, the jejunum contains

villi which are responsible for absorbing nutrients into the blood stream.

3. Ileum

The third or “final” section of the small intestine, the ileum absorbs any

remain nutrients or bile acids left in the chyme.

6. You were asked to research a digestive disorder for a research assignment. State your

topic and write a brief description of the symptoms and treatments for your disorder.

Topic too broad to fully elaborate.

Section 3: Diagram

10 Marks

1. Label the following diagram.

Section 4: Long Answer

10 Marks

1. After a long day of test writing at school you walk home and make your favourite meal. In great detail, describe the pathway of that meal and the processes of digestion it undergoes when it enters and eventually exits your body.

The start of your foods journal through the digestive system begins with the sense of

smell. Upon smelling food your salivary glands begin to produce saliva, which moisten the

oral cavity. When food enters the mouth, salivary glands produce even more saliva. Teeth

begin to mechanically digest your food by chewing, at the same time; the tongue mixes the

food with saliva, starting the process of chemical digestion through salivary amylase. This

creates a ball of food called a bolus.

This bolus is then passed to the back of the mouth with help from the tongue, causing

the pharynx to close the epiglottis and force the tongue to press against the roof of the

mouth which creates a seal. From here, bolus is moved through the pharynx and enters the

esophagus. The bolus moves through the esophagus (and rest of the digestive system)

through a series of muscle contractions called peristalsis. At the end of the esophagus is the

cardiac sphincter, which allows for the passing of bolus from the esophagus into the stomach,

while simultaneously stopping “food” and gastric juices from leaving the stomach.

Once the bolus is in the stomach a combination of mechanical and chemical digestion

takes place. Mechanical digestion of the bolus involves churning, in which the stomach itself

contracts and moves its contents against its rigid walls (rugae), this helps break up the food

and mix it with the gastric juices. Chemical digestion uses gastric juices, which are secreted by

the stomach walls (lining). This gastric juice contains HCl (breaks up protein), an enzyme

called pepsin (speeds up digestion of proteins) and rennin (used to help digest milk via

separation – whey and curds). The bolus at this point is referred to as chyme.

From here, chyme is passed through the pyloric sphincter and enters the first part of

the small intestine, the duodenum. Once in the duodenum the majority of digestion takes

place here. The chyme is further digested by a combination of mechanical and chemical

digestion. Bile’s (emulsification of fats), intestinal juice, and pancreatic juices (trypsin

breaking down protein) all play a factor in digestion while in the duodenum. Once the chyme

is broken down further, it moves to the jejunum where villi and microvilli absorb nutrients

into the blood stream. Absorption continues into the final section of the small intestine, the

ileum, where the remainder of nutrients is absorbed, along with any bile that remains.

The remaing chyme (now officially waste), enters the first part of the large intestine,

the cecum. As waste moves through the large intestine it passes through the ascending colon,

transverse colon, descending colon and sigmoid colon. During this process, the large intestine

removes water from the waste and it begins to harden, The waste is now referred to as stool.

The stool is stored in the sigmoid colon until a mass movement occurs (you gotta go!). The

stool is then passed to the rectum and passed through the anus. This completes the digestive

process.