Biochemistry STAAR

Pepsin and trypsin are two of the digestive enzymes that break down protein. A group of students studied the pH requirements of these enzymes. The graph below shows the results. The students found that pepsin functions best in an acid environment and trypsin functions best in a neutral environment. Based on their observations, pepsin most likelyaids in digestion in which part of the human body?

• Pancreas
• Intestines
• Mouth
• Stomach

Which of the following statements about biomolecules is true?

• Simple sugars are made of polysaccharides.
• Glycerol is made of fatty acids.
• Proteins are made of amino acids.
• Nucleotides are made of nucleicacids.

Overheating an enzyme results in the enzyme’s loss of —

• net electrical charge
• ability to catalyze a reaction
• storage of a large amount of chemical energy
• storage of inherited information

Lactose is found in milk products. It is converted by the body into a usable form in aseries of chemical reactions. The diagram shows the series of reactions that convert lactose into a usable form. If Enzyme 2 is denatured, the levels of which substance will increase?

• Lactose
• Glucose-6-phosphate
• Galactose-1-phosphate
• Galactose

Complete the chart by identifying the correct monomer at X.

• enzyme
• fatty acids
• amino acids
• glycerols

Proteins are different from nucleic acids because proteins do not contain —

• a hydrogen (H) atom.
• a carboxylic acid group.
• a carbon (C) atom.
• nucleotides.

Many plants have waxy coatings on some surfaces. This coating reduces water loss because it is not water permeable. This waxy coating is which of the following types of organic molecule?

• carbohydrate
• lipid
• nucleic acid
• protein

One function of the carbohydrate macromolecule is to store energy.Which other macromolecule also functions in storing energy?

• DNA
• protein
• RNA
• lipid

Which of these best represents a fatty-acid molecule?

• A
• B
• C
• d

Enzymes are proteins that help increase the rate of chemical reactions inside cells.These proteins are composed of many simpler molecules called amino acids. Which of the following suggests that the shape of an enzyme determines the enzyme’s function?

• Enzymes are specific to a substrate.
• Enzymes can operate in a wide range of conditions.
• Enzymes are activated by neighboring molecules.
• Enzymes can be found in all life-forms.