Living Environment Flashcards

Which statement correctly describes the relationship between DNA, genes, and chromosomes?

Answer: Chromosomes contain DNA, which is organized into genes

Chromosomes are structures made of DNA that is organized into functional units called genes, each coding for a specific protein.

A plant grown in a dark room will grow toward a small hole of light. This behavior is caused by the unequal distribution of:

Answer: Auxin

Auxin is a plant hormone that accumulates on the shaded side of a stem, causing those cells to elongate more and bend the plant toward light.

During which phase of the cell cycle does DNA replication occur?

Answer: S phase (synthesis)

DNA replication occurs during the S (synthesis) phase of interphase, before the cell begins mitosis.

A student notices that plants near a factory producing nitrogen compounds grow much taller than plants farther away. This best illustrates:

Answer: The effect of abiotic factors on organisms

Nitrogen availability is an abiotic (non-living) environmental factor that affects plant growth and development.

Which best explains why surface proteins on human cells are important to the immune system?

Answer: They allow the immune system to distinguish self from non-self cells

Cell surface proteins act as markers (antigens) that allow immune cells to identify the body's own cells versus foreign pathogens.

In an energy pyramid, which level contains the greatest amount of stored energy?

Answer: Producers

Producers (plants) form the base of the energy pyramid and contain the most energy; each successive level loses about 90% of energy.

A child inherits blood type AB from their parents. Which statement about this trait is correct?

Answer: Both A and B alleles are expressed equally (codominance)

Blood type AB results from codominance, where both the A and B alleles are fully expressed simultaneously in the phenotype.