MEMBRANES & ENZYMES

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

The diagram below shows the general structure of an amino acid. Which type of molecule is formed from amino acids?

• lipids

• proteins

• carbohydrates

• nucleic acids

Tags

NGSS.HS-LS1-1

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-LS1-3

What process would be used in the digestion of macromolecules we consume in our diet?

• Hydrolysis
• Dehydration Synthesis
• Hydrosynthesis

What is structure A?

• Substrate
• Active site
• Enzyme
• Products

What happens to enzymes at low temperature?

• they denature

• they die

• they slow down; inactive

• no change

Which of these is NOT true?

• Enzymes can denature (change shape) when the temperature gets too high.
• Enzymes can only be used once in a chemical reaction. 
• Extreme pH can denature enzymes.
• Enzymes speed up chemical reactions. 

Tags

NGSS.HS-LS1-7

Which line represents a reaction WITH an enzyme?

• A

• B

Tags

NGSS.HS-PS1-5

Which of the following conclusions can be drawn from this graph?

• The optimum pH of the enzyme is 6.6.
  
• The optimum pH of the enzyme is 5.8
  
• The enzyme’s activity increases as pH increases 5.0 to 9.0
  
• The enzyme’s activity is greater around pH of 8.0 .