Biomolecules

As food travels through the digestive system, it is exposed to a variety of pH levels. The stomach has a pH of 2 due to the presence of hydrochloride acid (HCl), and the small intestine has a pH ranging from 7 to 9. HCl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. Which of the following most likely happens to pepsin as it enters the small intestine?

• It becomes inactive.

• It begins to replicate.

• It's shape changes to engulf large proteins.

• It's activity increases to digest more proteins.

In living cells, enzymes act as catalysts, which may reduce the amount of activation energy required for a chemical reaction to occur. In the graphs below, pathway x is a solid line representing the uncatalyzed reaction. The dotted line shows the catalyzed reaction. Which graph best illustrates the changes in a reaction when the catalyst reduces the amount of energy required?

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Tags

NGSS.HS-PS1-4

Fats, oils and cholesterol are all types of what?

• cell membranes

• hormones

• lipids

• fatty acids

What will most likely happen if an appropriate enzyme is added to a chemical reaction?

• The reaction rate will increase.

• The equilibrium of the reaction will be maintained.

• The reaction rate will decrease.

• The reaction will stop.

Tags

NGSS.HS-PS1-5

The human body maintains a temperature of around 98.6 degrees at all times. Enzymes are involved in almost every chemical reaction in the body. Which of the following describes the connection between these two statements?

• Enzymes function best at a specific temperature.

• The body needs to be warm to prevent hypothermia.

• The body is kept relatively warm to prevent too much enzyme action.

• There is no connection between the two statements.

Tags

NGSS.HS-PS1-5

The enzyme lactase will break down the sugar lactose into which of the following components?

• monosaccharides

• nucleic acids

• amino acids

• phospholipids

What type of molecule is this?

• Nucleic acid
• Protein
• Carbohydrate
• Lipid

What is the name and importance of the molecule shown in the picture?

• fatty acid tail; makes up the fat found in butter
• phospholipid; makes up cellular membranes
• triglyceride; makes up animal lard
• cellulose; makes up the cell walls of plants

If in any organism a DNA molecule is 24% cytosine, how much adenine will that DNA molecule contain?

• 24%

• 26%

• 48%

• 52%

Which of the following foods is highest in polysaccharides?

• broccoli

• potato

• cheese

• fish