AP UNIT 1 REVIEW

In vascular plants, water flows from root to leaf via specialized cells called xylem. Xylem cells are hollow cells stacked together like a straw. Which statement describes how water is pulled up through the xylem to the leaves of the plant?

• As water exits the leaf, hydrogen bonding between water molecules pulls more water up from below

• As water exits the leaf, signals are sent to the roots to pump more water up to the leaves through the xylem by adhesion.

• Evaporation from the leaf decreases the hydrogen bonds that form between the water molecules in the xylem, which helps the water molecules to be pulled up the xylem.

• Evaporation of water from the leaf increases the hydrogen bonds that form between water molecules in the air, providing the energy for transport.

Phosphorous (P) is an important nutrient for plant growth. Figure 1 shows Arabidopsis thaliana plants grown under phosphorus‐sufficient (left) and phosphorus‐starved (right) conditions for six weeks. 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 proteins and lipids, limiting growth.

• The phosphorus-starved plant was unable to synthesize both the required proteins and carbohydrates, limiting growth.

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

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

A polypeptide is polymer of amino acids held together by peptide bonds. The process of dehydration synthesis creates these peptide bonds, as shown in Figure 1. As shown in Figure 1, an amino acid must have which of the following properties in order to be incorporated into a polypeptide?

• The ability to remain stable in the presence of water molecules

• An R-group

  R-group that is compatible with the R-group

  R-group of the last amino acid incorporated

• A central carbon atom that reacts with a nitrogen atom to form the peptide bond

• The ability to form a covalent bond with both its NH

  2

  NH2 group and its COOH

  COOH group

Tags

NGSS.HS-LS1-1

Which of the following describes a key difference among the 20 amino acids that are used to make proteins?

• Only some amino acids have an R-group

  R-group

• Only some amino acids have a carboxyl group (COOH)

  (COOH).

• Some amino acids are hydrophobic.

• Some amino acids contain the element phosphorus.

Which of the following statements is correct about the molecule shown in Figure 1 ?

• It is RNA

  RNA because of the relative direction of the two strands.

• It is RNA

  RNA because of the number of different nucleotides found in the molecule.

• It is DNA

  DNA because of the nature of the hydrogen bonds between guanine and cytosine.

• It is DNA

  DNA because of the nucleotides present.

Tags

NGSS.HS-LS1-1

Which of the following best describes a structural similarity between the two molecules shown in Figure 1 that is relevant to their function?

• Both molecules are composed of the same four nucleotides, which allows each molecule to be produced from the same pool of available nucleotides.

• Both molecules are composed of the same type of five-carbon sugar, which allows each molecule to act as a building block for the production of polysaccharides.

• Both molecules contain nucleotides that form base pairs with other nucleotides, which allows each molecule to act as a template in the synthesis of other nucleic acid molecules.

• Both molecules contain nitrogenous bases and phosphate groups, which allows each molecule to be used as a monomer in the synthesis of proteins and lipids.

Tags

NGSS.HS-LS1-1

Figure 1 represents a segment of DNA

DNA. Radiation can damage the nucleotides in a DNA

DNA molecule. To repair some types of damage, a single nucleotide can be removed from a DNA

DNA molecule and replaced with an undamaged nucleotide. Which of the four labeled bonds in Figure 1 could be broken to remove and replace the cytosine nucleotide without affecting the biological information coded in the DNA

DNA molecule?

• Bond X only

• Bond W only

• Bonds Y and Z at the same time

• Bonds W and Z at the same time

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-2

As shown in the diagram, when environmental temperatures drop below freezing, a layer of ice typically forms on the surface of bodies of freshwater such as lakes and rivers.

Which of the following best describes how the structure of ice benefits the organisms that live in the water below?

• The water molecules in ice are closer together than those in liquid water, so the ice prevents the passage of air to the water, maintaining a constant gas mixture in the water.

• The water molecules in ice are closer together than those in liquid water, so the ice forms a barrier that protects the organisms in the water from the freezing air temperatures.

• The water molecules in ice are farther apart than those in liquid water, so the ice floats, maintaining the warmer, denser water at the lake bottom.

• The water molecules in ice are farther apart than those in liquid water, so the ice floats, preventing the escape of gases from the liquid water.

Tags

NGSS.MS-LS2-3

NGSS.MS-LS2-4

Organic chemistry is a science based on the study of

• functional groups.
• vital forces interacting with matter.
• carbon compounds.
• inorganic compounds.

Tags

NGSS.HS-LS1-6

What is the molecule illustrated in the figure below?

• a trans polyunsaturated triacylglyceride
• a steroid similar to cholesterol
• a saturated fatty acid
• an unsaturated fatty acid

Tags

NGSS.HS-LS1-6