The Chemistry of Life

The graph compares the enzymes, gastric protease that is found in the stomach and intestinal protease that is found in the intestine. The contents of the small intestine have a pH greater than 7. When gastric protease from the stomach enters the small intestine, which of the following will most likely happen?

• Gastric protease activity will remain the same

• Gastric protease activity will increase and then decrease

• Gastric protease activity will increase

• Gastric protease activity will decrease

The graph compares the enzymes, gastric protease that is found in the stomach and intestinal protease that is found in the intestine. Which of the following statements is true about intestinal protease?

• The enzyme functions best in an acidic environment

• The optimum pH is approximately 8

• The optimum pH is approximately 3

• It does not function above pH 6

Which statement about enzymes is not true.

• Each enzyme is specific, because of its shape and catalyzes only certain reactions.

• Enzymes are destroyed when they are used and must be made each time a reaction takes place.

• Most enzymes are proteins

• Enzymes form a temporary bond with the substrate

Most Enzymes are responsible for our metabolism. Which of the following best describes the enzymes found in cells of our body?

• thousands of different kinds of enzymes, each promoting a specific chemical reaction

• one enzyme that promotes photosynthesis and one enzyme that promotes cellular respiration

• one kind of enzyme that promotes thousands of different chemical reactions .

• approximately 100 kinds of enzymes, each promoting a different chemical reactions

Which of the following statements about enzymes is not true?

• An enzyme will increase the amount of product

• They raise the activation energy

• Enzymes can increase the rate of reaction

• They can be used more than once

The Miller-Urey experiment of 1953 was designed to test the hypothesis that lightning supplied the energy needed to turn atmospheric gases into organic molecules such as amino acids. Which of the following describes why the Miller-Urey theory is widely accepted today?

• The process of synthesizing organic molecules from a mixture of gases has been successfully modeled in the laboratory.

• No other alternative hypotheses have been introduced.

• Amino acids spontaneously form from molecules in the atmosphere today.

• Organic molecules are present today in extremely high concentrations.

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What element makes up most of the mass in organisms?

• Oxygen

• Hydrogen

• Carbon

• Water

What type of bond is formed by sharing electrons?

• Ionic bond

• Covalent bond

• Metallic bond

• Semi-ionic bond

A positive ion is called a

• Cation

• Anion

• P-ion

• Dogion

What type of compound will have a partial positive and negative charge?

• Polar covalent

• Non-polar covalent

• Ionic

• Metallic

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