Review

DNA is a nucleic acid that consists of thousands of smaller, repeating units called nucleotides. What function do nucleic acids serve besides storing genetic information?

• directing the synthesis of proteins

• providing structural support for organelles

• regulating homeostasis in cell membranes

• controlling chemical reactions in the cytoplasm

Which two groups of macromolecules are used as the primary source of energy for cellular functions?

• proteins and lipids

• lipids and carbohydrates

• nucleic acids and proteins

• carbohydrates and proteins

If a culture of liver cells were deprived of amino acids, which category of macromolecule would the liver cells not be able to construct properly?

• carbohydrates

• lipids

• nucleic acids

• proteins

Why does a layer of ice form on the surface of a pond during freezing weather?

•     Molecules of water in the solid phase are less dense than those in the liquid phase.

•       Molecules of water in the solid phase are more dense than those in the liquid phase.

•     Molecules of water in the liquid phase are less cohesive than those in the solid phase.

•     Molecules of water in the liquid phase are more cohesive than those in the solid phase.

Why is it essential to life that water has a high heat capacity?

• Water’s high heat capacity allows it to dissolve many other substances, making it a universal solvent.

• Water’s high heat capacity speeds up chemical reactions that require the addition of heat in order for the reaction to take place.

• Water’s high heat capacity allows the molecules to move very quickly, producing the heat that is required to keep cold-blooded animals warm.

• Water’s high heat capacity allows it to absorb a large amount of heat before increasing in temperature, allowing humans to maintain a steady body temperature.

All living things need to transport molecules from one place to another within the body in order to carry out necessary life functions. Water makes up approximately 60% of the human body. Which property of water best describes how it is able to transport these molecules from place to place and play such a vital role in life’s functions?

• The cohesive behavior of water molecules makes it easy to transport throughout the body.

• Water molecules are polar and have the ability to dissolve many organic compounds necessary for life.

• Water has a high specific heat which allows it to melt many of the substances that are necessary for life.

• The strong hydrogen bonds among the water molecules prevent the molecules from being broken apart as they are transported throughout the body

A group of students is trying to determine which detergent will best remove an oil stain. They stain five separate cloths with oil and then wash each of the cloths in a different detergent. They repeat each test two more times. Which step should be included in their investigative plan?

• Use a different type of oil for each test.

• Vary the size of the oil stain on each piece of cloth.

• Change the amount of detergent used during each trial.

• Place each oil stain on separate, but identical, pieces of cloth.

Several groups of researchers were conducting experiments to study how exercise affects cholesterol levels. One group had college students run two miles a day for six weeks. Another group had senior citizens participate in gentle water aerobics twice a week for a year. Cholesterol levels dropped slightly among the college students but dropped significantly among the senior citizens. Based on these results, what should the researchers plan to do next to validate the findings?

• Determine that exercise is more useful in lowering cholesterol levels in older people than in young adults.

• Conclude that moderate exercise is more beneficial at lowering cholesterol levels than intense exercise.

• Design more studies testing the effect of duration and intensity of exercise on cholesterol levels in different age groups.

• Repeat the experiment on college students using different groups of students until the results show a drop in cholesterol levels.

There are many enzymes found in the human body. What is the function of these enzymes?

• to provide the substrates for reactions to occur

• to adjust the temperature of the body to allow reactions to occur

• to lower the amount of energy needed for certain reactions to occur

• to increase the amount of energy available for certain reactions to occur