lab quiz

A(n) __________ is a biological protein that acts as a catalyst, increasing the rate of a chemical reaction without becoming part of the product. a) substrate b) polymer c) enzyme d) monomer

enzyme

Digestive enzymes are hydrolases, meaning they break down organic food molecules by adding __________ to the molecular bonds. a) oxygen b) water (hydrolysis) c) carbon dioxide d) bile

water (hydrolysis)

In the "lock and key" model of enzyme specificity, the "keyhole" where the chemical reactant binds is known as the: a) active site b) product c) substrate d) assay

active site

What is the term for the process where extreme environmental conditions, such as high heat, cause an enzyme to unravel and lose its function? a) Emulsification b) Catalysis c) Denaturation d) Hydrolysis

Denaturation

Which enzyme is responsible for the breakdown of starch into smaller carbohydrates (like maltose) at a neutral pH? a) Pepsin b) Lipase c) Amylase d) Peptidase

Amylase

Pepsin is an enzyme that digests proteins and peptides; it functions optimally in which type of environment? a) Neutral (pH 7) b) Alkaline (pH 9) c) Acidic (pH 2), such as the stomach d) Cold temperatures (0°C)

Acidic (pH 2), such as the stomach

__________ is a substance that performs emulsification, physically breaking large fat globs into smaller droplets to improve the activity of lipase. a) Benedict’s reagent b) Bile c) Trypsin d) Carbonic anhydrase

Bile

To determine if an enzyme is functioning correctly in a lab setting, scientists use a(n) __________, which often involves a color change or a change in optical density. a) catalyst b) substrate c) assay d) reactant

assay

 In the salivary amylase activity, the __________ assay is used to detect the presence of starch, while the __________ assay is used to detect the presence of reducing sugars like glucose. a) IKI; Benedict’s b) BAPNA; IKI c) pH; optical density d) Benedict’s; BAPNA

IKI; Benedict’s

What two monosaccharides are formed when the lactase enzyme hydrolyzes lactose?

Glucose, Galactose

The difference between lactose-tolerant and intolerant individuals was due to a mutation located in

the genetic switch for the lactase gene

What would be the effect of a mutation in the coding region of the lactase gene?

affect the structure and function of the lactase enzyme itself; reduced enzyme activity and leading to congenital lactase deficiency or persistent lactose intolerance

Which discovery supports the hypothesis that evolution of the lactase persistence trait was driven by the use of milk in pastoralist cultures?

Ancient pots used to hold milk are about the same age as the lactase persistence mutations.

Why would measuring blood glucose levels in an individual 20 to 30 minutes after they drink a liter of milk, indicate whether they are able to digest lactose?

The fats and proteins in milk are digested by the body, causing glucose levels in the blood to increase.

measuring the rate of color change as the enzyme hydrolyzes the synthetic substrate BAPNA

The BAPNA assay; pepsin

High temperatures over _____ lead to irreversible denaturation and reduced protein digestion.

45°C–50°C

uses a-glucose linkages for energy storage and is easily digested by humans.

starch

The smaller subunits that result from hydrolysis (chemical reactant).

Substrate

The substance on which an enzyme specifically acts.

Monomer

The type of fat molecule digested by lipase

Triglyceride

A trial used to ensure the assay is working as intended

Control

Enzymes catalyze the conversion of large complex molecules, or __________, into smaller subunits that can be absorbed, known as __________.

Polymers; monomers

A __________ is the smaller subunit resulting from the catalytic action of an enzyme on a specific substrate.

Product

Identify the general class of nutrients that includes complex sugars like starch and simple sugars like glucose.

Carbohydrates

A non-digestible polysaccharide that provides plant structure

Cellulose

A disaccharide often produced when amylase breaks down starch

Maltose

A monosaccharide (simple sugar) that is directly absorbed into the body.

Glucose

A __________ is an enzyme that specializes in breaking down small peptides into individual amino acids.

Peptidase

Identify the enzyme that catalyzes the hydrolysis of fats into monoglycerides and free fatty acids.

Lipase

In the study of lipid digestion, lipase specifically targets __________ (the type of fat found in food) to produce glycerol and __________.

Triglycerides; monoglycerides

__________ is a measurement used in some assays to quantify how a solution changes from transparent to opaque as a reaction occurs.

Optical density

Amylase activity is highly sensitive to temperature and pH, with peak efficiency occurring near ___and a pH of ___

37 C ; 6.7–7.0