DNA STRUCTURE AND FUNCTION EXAM

A strand of DNA consists of thousands of smaller repeating units known as

• amino acids
• nucleotides
• polysaccarides
• lipids

In molecules of DNA, which nitrogenous base bonds with adenine?

• adenine
• uracil
• guanine
• thymine

Which nitrogenous base is normally present in DNA but absent from RNA?

• adenine
• cytosine
• thymine
• guanine

Within which organelle does process 1 occur?

• ribosome
• nucleus
• centriole
• lysosome

Messenger RNA molecules are formed as a result of process __ and _________ are needed for process 2.

• 1 and lysosomes
• 2 and lysosomes
• 1 and ribosomes
• 2 and ribosomes

DNA molecules serve as a template for the synthesis of molecules of

• amino acids
• mRNA
• carbohydrates
• lipids

What is an example of a molecule produced by this type of molecule?

• glucose
• glycogen
• a fatty acid
• a protein

How many codons are located on the mRNA molecule in the diagram?

• 1
• 6
• 3
• 9

Cosmic rays, X-rays, ultraviolet rays, and radiation from radioactive substances may function as

• pollinating agents
• plant auxins
• mutagenic agents
• animal pigments

Gene mutations occur in plant and animal cell nuclei when

• the hydrogen bases separate during replication
• the base sequence in DNA is changed
• ribose is substituted for deoxyribose in RNA
• cytosine in DNA is replaced by phosphorus in RNA