Keystone Review Module 1

Lungs and capillaries both have porous linings that allow certain substances to move into or out of the structures. Which function do these porous linings most likely serve in living organisms?

• heat release

• gas exchange

• carbohydrate absorption

• osmotic pressure regulation

Answer explanation

Oxygen and carbon dioxide molecules are transferred into and out of capillaries in the lungs.

Tags

NGSS.HS-LS2-3

What property of water is most responsible for plants being able to transport water from their roots to their leaves?

• the attraction between molecules

• a capacity to dissolve many substances

• the ability to form a low-density crystalline structure when frozen

• a capacity to absorb large amounts of energy as temperature increases

Answer explanation

Hydrogen bonds form between water molecules, and capillary action draws the water up the roots and stem to leaves.

The element carbon has multiple bonding patterns. Which bonding pattern cannot be formed by carbon?

• C-C

• C-C-C

• C=C=C

• C=C=C

Answer explanation

Carbon only has four valence electrons and the pattern shown would require six valence electrons.

Tags

NGSS.HS-LS1-6

Which process best describes the assembly of proteins from amino acids?

• Atoms are linked to form a compound.

• Monomers are linked to form a polymer.

• Atoms are added to a monomer until it becomes a polymer.

• Molecules are added to a compound until it becomes a monomer.

Answer explanation

Amino acids are monomers that link together to form complex protein polymers.

Which statement best compares a carbohydrate and a nucleic acid?

• The sequence of monomers in a carbohydrate stores genetic information and the bonds in a nucleic acid store energy.

• The bonds in a carbohydrate store energy, and the sequence of nucleotides in nucleic acid stores genetic information.

• A carbohydrate has a unique structure to assist diffusion across a plasma membrane, and a nucleic acid has a unique structure to assist chemical reactions.

• A carbohydrate has a unique structure to assist chemical reactions, and a nucleic acid has a unique structure to assist diffusion across a plasma membrane.

Answer explanation

Energy is stored in the bonds of carbohydrates such as glucose. The genetic code of DNA is determined by the sequence of nucleic acid monomers called nucleotides.

Each cell in the human body contains thousands of different enzymes responsible for regulating reactions within the cell. Which statement explains why a single enzyme is unable to regulate a variety of reactions?

• The binding of a product and an enzyme is specific.

• The binding of a substrate and an enzyme is specific.

• The enzyme is consumed by the products of the reactions.

• The enzyme is consumed by the substrates of the reactions.

Answer explanation

The active site on an enzyme fits only a specific substrate.

Which statement best describes a direct role of ATP in a paramecium?

• ATP provides the energy to move cilia.

• ATP stores the genetic code for replication.

• ATP signals the presence of other nearby organisms.

• ATP senses changes in the surrounding aquatic environment.

Answer explanation

ATP is the primary molecule of energy transfer in a cell.

Tags

NGSS.MS-LS1-2

Which statement best describes a function of the proteins embedded in the plasma membrane of cells?

• They provide instructions for the processes in a cell.

• They selectively allow certain particles into and out of the cell.

• They attract charges in the cell's environment to give the cell a net charge.

• They store the energy required by the rest of the membrane to perform its functions.

Answer explanation

Channel proteins and protein pumps regulate the movement of materials, such as gases and nutrients, across the plasma membrane.

How does a mitochondrion facilitate the movement of some materials between cells?

• It supplies the energy needed for moving molecules through membranes.

• It manufactures the proteins needed to form channels in cell membranes.

• It supplies digestive substances that break large molecules into smaller units.

• It produces fibers that attach to molecules and move them through the cytoplasm.

Answer explanation

Mitochondria convert glucose to ATP, the primary molecule of energy transfer for cells.

Tags

NGSS.HS-LS1-7

Plants are dependent on water. In most plants, water is absorbed by the roots and then moves up the stem of the plant and into the leaves by capillary action. Which properties of water are most responsible for the capillary action in plants?

• adhesion and cohesion

• low density and adhesion

• polarity and high specific heat

• high specific heat and cohesion

Answer explanation

Capillary action is the result of hydrogen bonds forming between water molecules (cohesion--water sticking to water) and the water molecules being attracted to the molecules inside the stem (adhesion--water sticking to other things).