Midterm Review

Changes in external temperatures often result in a person either sweating or shivering, as represented in the diagram below. These responses are one way

• maintain homeostasis

• detect variations

• attract mates

• obtain nutrients

A small lizard spends the morning hours lying in the sunlight until its body temperature rises. Later on in the day, the lizard rests in a shady area until its body temperature cools. This type of behavior is important to

• the DNA in the enzyme mutates and can no longer break down the starch

• enzymes die after working for a long period of constant activity in the body

• the shape of the enzyme changes due to environmental conditions

• as the temperature of the enzyme rises, the pH of the environment changes, deactivating the enzyme

The graph below represents the rate of a chemical reaction involving a particular human enzyme that breaks down starch. The most likely reason the action of the enzyme decreases after 40°C is that

• Sugars

• Fats

• Genetic material

• Enzymes

Which class of molecules is responsible for speeding up chemical reactions?

• the enzyme is digested in those locations

• no protein molecules are located in the small intestine or the mouth

• the enzyme changes to fit different molecules in different locations

• the stomach may have a more suitable environment for the enzyme to work

An enzyme that rapidly breaks down a protein molecule in the stomach may break down that same protein much more slowly in the small intestine or mouth because

• the pH of some enzymes changes as the temperature changes

• enzymes change color in proportion to the rate of activity

• a difference in the pH of an environment changes enzyme activity

• enzyme activity causes acids to change into bases over time

Students did an experiment comparing the activity of four different enzymes, A, B, C, and D. The results are represented in the graph below. A valid conclusion based on the information in the graph is that

• water

• salt

• oxygen

• glucose

An energy-rich organic compound needed by organisms is

• Proteins

• Lipids

• Nucleotides

• Carbohydrates

Glucose molecules are the building blocks of what class of macromolecule?

• 1 and 5

• 2 and 4

• 3 and 2

• 4 and 3

Some structural formulas of organic molecules are shown below. Which structural formulas represent carbohydrate molecules?

• carbohydrates

• lipids

• proteins

• nucleotides

Butter and oil are examples of food composed of

• Lipids

• Carbohydrates

• Nucleotides

• Proteins