BIO 122 Lab exam (Digestive)

Which of the following describes the effect of boiling and freezing?

Boiling denatured the enzyme, but freezing had no effect

In the assay in which fat was digested, ________ is the substrate, and ________ is the hydrolase.

Cream, lipase

Amylase and starch are mixed and placed at 0°C. After the IKI test, the solution turns black. A Benedict's test yields a negative result. Was starch digested? How do you know?

No, the Benedict's test revealed no sugars in solution.

Accessory organs of the digestive system include all the following except ________.

adrenal gland

The building blocks for peptides are _______.

amino acids

When proteins are digested, the following molecules can be absorbed: ________.

amino acids, dipeptides, and tripeptides

One enzyme that you will be studying today, produced by the salivary glands and secreted into the mouth, hydrolyzes starch to maltose. It is __________ .

amylase

This enzyme, produced by the salivary glands, digests carbohydrates.

amylase

Pepsin is classified as _______.

an enzyme and a peptidase

Digestive enzymes ________.

are biological catalysts

Enzymes are __________ that increase the rate of chemical reactions without becoming a part of the product.

catalysts

When BAPNA is hydrolyzed, it _______.

changes from colorless to yellow

Pepsin is secreted by _______.

chief cells

Fat digestion results in ________.

monoglycerides and fatty acids

The end products of digestion of carbohydrates are ________

monosaccharides

When carbohydrates are digested, the following molecules can be absorbed: ________.

monosaccharides

Prior to lipase digestion of triglycerides, the solution would be _______.

more basic

The __________ abuts the lumen of the alimentary canal and consists of epithelium, lamina propria, and muscularis mucosae.

mucosa

Which layer of the alimentary canal is constructed from either stratified squamous or simple columnar epithelium?

mucosa

The lining of the alimentary canal is a ________.

mucosa (mucous membrane)

The enzyme __________ hydrolyzes neutral fats to their component monoglycerides and fatty acids.

pancreatic lipase

This protein-digesting enzyme works optimally at pH 1.5-2.0. What is the enzyme, and where is it produced?

pepsin; stomach

The portion of the stomach closest to the duodenum is called the ________.

pyloric part

When using the Benedict's assay, which color would indicate the most reducing sugar present?

reddish brown

A tooth consists of two major regions, the crown and the __________.

root

Specializations of the small intestine that increase its surface area for maximal absorption of nutrients include all the following except ________.

rugae

As wastes navigate the large intestine, which features do they pass through, in order?

the right colic, left colic, and sigmoid flexures

Which of following does NOT secrete a lipase

the salivary glands >the small intestine the pancreas the stomach

In the laboratory assay on digestion of the protein BAPNA by trypsin, what was the purpose of including a tube with trypsin alone?

to indicate that trypsin did not contribute to the yellow (positive) color

The substrate of lipase is _______

triglyceride

The enzyme __________, produced by the pancreas, is responsible for breaking down proteins.

trypsin

The pancreas produces this protein-digesting enzyme

trypsin

Which test tube had the highest lipase activity?

tube 1

Which test tubes were used to determine the optimal pH for lipase activity?

tubes 1, 5, and 6

The alimentary canal is also called the ________.

gastrointestinal (GI) tract

This fat-digesting enzyme does the major work of digesting fats in the small intestine

lipase

Hexagonal lobules are characteristic of this organ.

liver

Located inferior to the diaphragm, the __________ is the largest gland in the body.

liver

Enzymes are _______.

made of protein and are catalysts

The evidence that trypsin digested protein to amino acids is ________.

the presence of a yellow color in the test tube

The optimal pH for pepsin activity is ______

2

The digestive enzymes tested in the laboratory function best at this temperature

37* C

The walls of the alimentary canal share a common pattern from esophagus to anus. How many tunics (layers) make up the wall?

4

This test detects starch in solution.

IKI (Lugol's iodine) test

The ________ is/are lymphatic tissue seen in the histological section of the ileum.

Peyer's patches

Why is gastric lipase NOT as active as pancreatic lipase?

The pH of the stomach is too low and no bile is present in the stomach.

What is the difference between cellulose and starch?

They are linked differently.

When you use iodine to test for starch, a color change to blue-black indicates a positive starch test.

True

Which of these best describes a lacteal?

a lymphatic vessel designed to help introduce fats to the blood

Pepsin is _______.

a peptidase, an enzyme that digests protein and a protein that digests protein

Amylase is secreted by _______.

both the salivary glands and the pancreas

A(n) __________ is a specimen or standard against which all experimental samples are compared.

control

The __________ traverses down the left side of the abdominal cavity and becomes the sigmoid colon.

descending colon

Maltose is a _______.

disaccharide

triglycerides:

dissolve poorly in water, are lipids, are digested by lipase, are fats

The tube that leaves the stomach (and is the first part of the small intestine) is called the ________

duodenum

Bile..

emulsifies fat, keeping tiny fat droplets suspended in the aqueous contents of the gut

Approximately 25 cm long, the __________ conducts food from the pharynx to the stomach

esophagus

The tube that connects the oral cavity to the stomach is called the ________.

esophagus

Which cells in the small intestine's mucosa secrete mucus?

goblet cells

The mesentery attached to the inferior margin of the stomach is called the ________.

greater omentum

If Benedict's test in the starch assay produces a __________ precipitate, then your test will be recorded as positive for maltose.

green to orange

substrates are held in the active site by

hydrogen and ionic bonds

Adding bile to triglycerides _______.

increases the surface area of the triglycerides

The presence of reducing sugars _______.

is detected using Benedict's reagent

The uvula is an extension of the __________

soft palate

IKI is used to test for the presence of _______.

starch

The substance that the enzyme acts on is called its _______.

substrate

What does a strong IKI result indicate?

substrate is present

The palatine tonsils are located between which two structures?

the palatopharyngeal arch and the palatoglossal arch

Fats, in the presence of litmus (that indicates pH of the solution), are shown to be digested ________.

when the solution in the test tube turns pink (acidic)