Enzymes Review

Enzymes Review

Khan Academy

You can open this webpage in a new tab.

Copy link

Open in new tab

Multiple Choice

Enzymes are a special type of

• lipid

• carbohydrate

• protein

• nucleic acid

Multiple Choice

Enzymes are a biological catalyst, which means they have ability to

• speed up chemical reactions

• slow down chemical reactions

• stabilize chemical reactions

Dropdown

Enzymes are​

Select answer

, meaning they only work with one type of substrate.

Multiple Choice

The substrate in an enzyme-catalyzed chemical reaction is the same thing as the

• reactant

• product

Hotspot

Which substrate would work with the enzyme on the left side of this drawing?

Labelling

Label the diagram of an enzyme-substrate complex.

Drag labels to their correct position on the image

active site

substrate

enzyme-substrate complex

products

enzyme

Dropdown

Enzymes speed up chemical reactions by​

Select answer

activation energy.

Labelling

Label the catalyzed and uncatalyzed reaction on the graph.

Drag labels to their correct position on the image

catalyzed reaction

uncatalyzed reaction

Hotspot

Which reaction would include the presence of an enzyme?

Dropdown

An uncatalyzed chemical reaction​

Select answer

have an enzyme present.

Multiple Choice

Enzymes denature, which mean they will

• unfold and stop functioning

• unfold but still function

• fold and function better

Multiple Select

Enzymes will denature in the following situations.

CHOOSE THREE

• When placed in an environment that is too hot for its preferred range.

• When placed in an environment that is too cold for its preferred range.

• When placed in an environment that is too acidic for its preferred range.

• When placed in an environment that is too basic for its preferred range.

Labelling

Label the following places on the enzyme activity graph.

Drag labels to their correct position on the image

completely denatured

still folded, but slow

optimal temperature

Match

Match the graph to the correct description.

optimum temperature around 37°C

optimum pH around 4

optimum pH around 9

optimum temperature around 50°C

• optimum temperature around 37°C

• optimum pH around 4

• optimum pH around 9

• optimum temperature around 50°C

Multiple Choice

• reactant

• product

• enzyme

• substrate

Dropdown

The optimal temperature for this enzyme is​ approximately ​

Select answer

°C.

Dropdown

This enzyme will work best at a​ temperature of​ approximately​

Select answer

°C and a pH of approximately​​

Select answer

.

Multiple Choice

• The dipeptide would digest faster.

• The dipeptide would digest slower or not at all.

• The amino acids would combine faster.

• The amino acids would combine slower or not at all.

​Lactose, Lactase, & Lactose Intolerance

​Lactose is the sugar found in cow's milk. It is formed by the combination of glucose and galactose.

​Lactase is the enzyme that breaks down lactose in the digestive tract, specifically the small intestine.

​Lactose intolerance occurs when the body does not produce enough lactase to break down the lactose in milk.

This means the lactose cannot be broken down into glucose and galactose and absorbed by the body.

Dropdown

Based upon the diagram, lactase will have an optimal function at a pH of approximately​​

Select answer

.

Multiple Choice

LACTAID is a digestive supplement that adds lactase to the digestive tract.

An average dose is approximately 18,000 units.

What would happen if you ingest approximately 36,000 units of lactose during a day?

• The lactase would break down and stop functioning, causing symptoms to reoccur.

• The lactase would increase function to saturation (fullness), then stabilize until the lactose was broken down.

• The lactase would begin to double in order to keep up with the demand placed on the body by the lactose.