bio retake chap 1&2

Measurements show that the pH of a particular lake is 4.0 What is the hydrogen ion concentration of the lake?

10-4 M

Amylase is an enzyme that converts carbohydrate polymers into monomers. Glycogen synthase is one of the enzymes involved in converting carbohydrate monomers into polymers. Which of the following best explains the reactions of these enzymes?

Amylase aids in the addition of a water molecule to break covalent bonds whereas glycogen synthase aids in the removal of a water molecule to form covalent bonds.

Which of the following would most likely occur if cattle lost the ability to maintain a colony of microorganisms in their digestive tract?

Cattle would no longer be able to use cellulose as a primary source of glucose.

The amino acid in Figure 1 below is found in a region of a polypeptide that folds away from water. Which part of the amino acid most likely contributes to the hydrophobic behavior of this region of the polypeptide?

Methyl (CH3) group

A typical bag of fertilizer contains high levels of nitrogen, phosphorus, and potassium but trace amounts of magnesium and calcium. Which of the following best matches the fertilizer component with the molecule in which it will be incorporated by organisms in the area?

Nitrogen will be incorporated into nucleic acids.

The molecular structures of linoleic acid and palmitic acid, two naturally occurring substances, are shown in the figure. Based on the molecular structures shown in the figure, which molecule is likely to be solid at room temperature?

Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.

Mammals do not produce digestive enzyme B. However, sheep and cattle are two types of mammals that contain microorganisms in their digestive tract that produce enzyme B. Based on Figure 1, which of the following best compares the atomic structures of starch and cellulose?

Starch and cellulose are composed of repeating glucose monomers; however, in cellulose every other glucose monomer is rotated 180 degrees

Which of the following is the most likely reason for the difference in leaf growth?

The phosphorus-starved plant was unable to synthesize both the required nucleic acids and lipids, limiting growth.

The loss of water from a plant by transpiration cools the leaf. Movement of water in transpiration requires both adhesion to the conducting walls and wood fibers of the plant and cohesion of the molecules to each other. A scientist wanted to increase the rate of transpiration of a crop species to extend its range into warmer climates. The scientist substituted a nonpolar solution with an atomic mass similar to that of water for hydrating the plants. What do you expect the scientist's data will indicate from this experiment

Transpiration rates will fall to zero as nonpolar compounds do not have the properties necessary for adhesion and cohesion

Ultraviolet (UV ) radiation can damage by breaking weak bonds. Which of the following best explains how this occurs?

UV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs.

The diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. How is water able to move upward from the roots of a plant, through its xylem in the stem, and out to the leaves?

Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem.