Life Science (116-4) - 2 of 3

Which visual model best illustrates the complex feeding relationships among multiple species in an ecosystem?

• Food chain

• Food chain

• Food web

• Energy cycle

Which of the following best represents the flow of energy from one organism to another in an ecosystem?

• Food web

• Food chain

• Carbon cycle

• Energy pyramid

In an ecosystem, which model shows how energy decreases as it moves through trophic levels?

• Biogeochemical cycle

• Food chain

• Energy pyramid

• Food web

What is the primary function of DNA in living organisms?

• To provide structural support to cells

• To store genetic information for building and maintaining organisms

• To transport nutrients within the cell

• To produce energy for cellular processes

What is DNA primarily composed of?

• A single strand of amino acids wrapped around a lipid molecule

• A double strand of nucleotides wrapped around a histone protein

• A chain of carbohydrates forming a helical structure

• A single strand of nucleotides forming a circular loop

Which of the following correctly describes the components of a nucleotide in DNA?

• A phosphate group, a ribose sugar, and one of four nitrogenous bases (adenine, uracil, cytosine, or guanine)

• A phosphate group, a deoxyribose sugar, and one of four nitrogenous bases (thymine, adenine, cytosine, or guanine)

• A phosphate group, a glucose molecule, and one of four nitrogenous bases (adenine, thymine, cytosine, or guanine)

• A phosphate group, a deoxyribose sugar, and one of four nitrogenous bases (uracil, adenine, cytosine, or guanine)

What does Chargaff's first rule state about the composition of DNA?

• The amount of adenine equals the amount of guanine, and the amount of thymine equals the amount of cytosine.

• The amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.

• The amount of adenine equals the amount of cytosine, and the amount of guanine equals the amount of thymine.

• The amount of adenine equals the amount of uracil, and the amount of guanine equals the amount of cytosine.

Which nitrogenous bases pair together according to Chargaff's rule?

• Adenine pairs with guanine, and cytosine pairs with thymine.

• Adenine pairs with thymine, and guanine pairs with cytosine.

• Adenine pairs with cytosine, and guanine pairs with thymine.

• Adenine pairs with uracil, and guanine pairs with cytosine.

Why was Chargaff's rule important for understanding the structure of DNA?

• It explained how DNA replicates itself.

• It revealed the equal proportions of base pairs, which helped Watson and Crick deduce the double helix structure.

• It showed that DNA is composed of amino acids.

• It proved that DNA is single-stranded.

If one strand of DNA is 3’ ATT CCG GCA TAT 5’, what is the sequence of its complementary strand?

• 5’ TAA GGC CGT ATA 3’

• 5’ TTA GGC CGA TAT 3’

• 5’ TAA CCG GCT ATA 3’

• 5’ TAA GGC GCT ATA 3’