Building Blocks
This is a primary function of lipids in living organisms
A. Storing genetic information
B. Providing immediate energy for the cell
C. Forming the main structure of the cell membrane D. Speeding up chemical reactions as biological catalysts
C (Forming the main structure of the cell membrane)
Enzymes are specialized proteins that act as catalysts. How do enzymes speed up the rate of a biochemical reaction?
A. By increasing the temperature of the cell
B. By lowering the reaction's activation energy
C. By changing the pH of the surrounding environment
D. By providing additional energy to the reactants
B (By lowering the reaction's activation energy)
Ice tends to be less dense than liquid water. How does this characteristic help sustain life on Earth? A. Floating ice causes erosion that creates new habitats. B. Floating ice speeds up the freezing of the water below it. C. Floating ice prevents the water underneath from freezing, allowing organisms to survive. D. Floating ice keeps the water colder than the atmosphere to prevent evaporation.
C (Floating ice prevents the water underneath from freezing, allowing organisms to survive.)
Biogeochemical cycles, such as the carbon and water cycles, are driven primarily by energy from: A. Large aquatic animals. B. Within the Earth and from the Sun. C. The chemical breakdown of macromolecules. D. The rotation of the Moon around the Earth.
B (Within the Earth and from the Sun.)
A researcher is studying a molecule that consists of a sugar, a phosphate group, and a nitrogenous base. Which macromolecule is being studied?
A. Lipid B. Protein C. Nucleic acid D. Carbohydrate
C (Nucleic acid)
Proteins are composed of smaller subunits. Which of the following identifies the basic molecular structure of a protein?
A. Nucleotides
B. Amino acids
C. Monosaccharides
D. Fatty acids and glycerol
B - amino acids
The enzyme pepsin functions in the stomach at a pH of 2. Which of the following most likely happens to pepsin as it enters the small intestine, where the pH is between 7 and 9?
A. It becomes inactive.
B. Its activity increases.
C. It begins to replicate.
D. Its shape changes to engulf larger proteins.
A (It becomes inactive.)
Many cities in Florida bordering the ocean have a narrow range of temperatures throughout the year. Which property of water is responsible for this temperature moderation?
A. Versatility as a solvent
B. High specific heat of water
C. Expansion of water upon freezing
D. High surface tension caused by cohesion
B (High specific heat of water)
In the carbon cycle, which process allows plants to take in carbon dioxide from the atmosphere and convert it into energy-rich organic compounds?
A. Respiration B. Transpiration C. Photosynthesis D. Decomposition
C (Photosynthesis
Which type of microscope would be best to use to look at the legs of live ants?
A.Scanning B. Transmission electron C. Dissecting D. Light
C (Dissecting)
Carbohydrates like glucose and starch serve a vital role in life processes. What is the primary function of these macromolecules?
A. To provide and store energy
B. To catalyze biochemical reactions
C. To transmit hereditary information
D. To provide insulation and protection
A (To provide and store energy)
Which of the following environmental factors can directly affect the activity level of an enzyme?
A. Light intensity
B. Distance from the Sun
C. The amount of available oxygen
D. Temperature and pH concentration
D (Temperature and pH concentration)
Water is essential for plant life. Which property of water enables it to move from the roots to the leaves of high-altitude trees? A. Water expands as it freezes. B. Water is an excellent solvent. C. Water exhibits cohesive behavior and capillary action D. Water is able to moderate temperatures.
C (Water exhibits cohesive behavior and capillary action.)
How is carbon released back into the atmosphere as part of the biogeochemical cycle?
A. Through plant transpiration B. Through the process of cellular respiration C. Through the expansion of water upon freezing D. Through the action of enzymes during photosynthesis
B (Through the process of cellular respiration)
Why is the expansion of water upon freezing considered a unique property that supports life?
A. It allows plants to perform transpiration. B. It ensures that lakes do not freeze solid from the bottom up. C. It allows water to dissolve more solutes than any other liquid. D. It increases the amount of available oxygen in the atmosphere.
B (It ensures that lakes do not freeze solid from the bottom up.)
Which category of biological macromolecule includes DNA and RNA, which are responsible for storing and transmitting genetic information?
A. Lipids B. Proteins C. Nucleic acids D. Carbohydrates
C (Nucleic acids)
Why is the shape of an enzyme considered critical to its function?
A. The shape allows it to store energy in the form of ATP.
B. The shape allows it to bind specifically to a certain substrate.
C. The shape determines if the enzyme is a carbohydrate or a lipid.
D. The shape allows the enzyme to move easily through the cell wall.
B (The shape allows it to bind specifically to a certain substrate.)
Water is often called the "universal solvent." Which statement best explains why this property is essential for living organisms?
A. It allows water to float when it freezes.
B. It allows water to form bonds with carbon dioxide. C. It allows water to dissolve and transport nutrients within cells.
D. It prevents water from changing temperature when exposed to sunlight.
C (It allows water to dissolve and transport nutrients within cells.)
The Earth system contains fixed amounts of each stable chemical element. Where are these elements stored as they move through cycles?
A. Only in the atmosphere B. Only in living organisms C. Only in the solid earth and oceans D. In reservoirs including the solid earth, oceans, atmosphere, and living organisms
D (In reservoirs including the solid earth, oceans, atmosphere, and living organisms)
In the carbon cycle, how do photosynthesis and cellular respiration interact? A. Both processes release oxygen into the atmosphere. B. Both processes store solar energy in the form of glucose. C. The products of one process are used as the reactants for the other. D. Respiration provides the light energy needed for photosynthesis to occur.
C (The products of one process are used as the reactants for the other.)
A student is summarizing the four major categories of biological macromolecules. Which statement best describes a commonality among all of them? A. They all contain the element nitrogen. B. They are all carbon-based organic compounds. C. They all function primarily to store genetic data. D. They all consist of identical repeating glucose units.
B (They are all carbon-based organic compounds)
Based on the role of enzymes as catalysts, which of the following statements is true?
A. Enzymes are consumed and destroyed during a reaction.
B. Enzymes are used to provide the main source of glucose for a cell.
C. Enzymes allow reactions to occur more quickly at lower temperatures.
D. Enzymes are responsible for storing the genetic code in the nucleus.
C (Enzymes allow reactions to occur more quickly at lower temperatures.)
The special properties of water, such as cohesion and temperature moderation, are primarily due to which of the following?
A. High pH levels B. Covalent bonding C. Hydrogen bonding D. Rapid particle motion
C (Hydrogen bonding)
Which statement best describes the movement of matter through biogeochemical cycles?
A. Matter is created by the Sun and destroyed by consumers.
B. Matter is lost to space and must be replaced by photosynthesis.
C. Matter is continuously cycled and transformed between biotic and abiotic factors.
D. Matter moves in a one-way path from the atmosphere to the earth without returning.
C (Matter is continuously cycled and transformed between biotic and abiotic factors.)
Which of the following best describes the Law of Conservation of Mass as it applies to living systems? A. Mass increases as organisms grow. B. Mass is destroyed during cellular respiration. C. The total mass of matter remains constant as it cycles through an ecosystem. D. Mass is only conserved in producers but not in consumers or decomposers.
C (The total mass of matter remains constant as it cycles through an ecosystem.)