DNA Structure and Function Quiz

DNA Structure and Function

• DNA is the hereditary material found in chromosomes.
• Watson and Crick discovered DNA's double helix structure using X-ray diffraction data.
• DNA is composed of long strands of nucleotides.
• Each nucleotide consists of a sugar, phosphate, and a nitrogenous base.
• The phosphate and sugar molecules form the DNA backbone.
• Nitrogenous bases are attached to the sugar.

Nitrogenous Bases

• Nitrogenous bases are categorized into purines and pyrimidines.
• Purines are adenine and guanine.
• Pyrimidines are cytosine and thymine.
• Base pairing is specific: adenine pairs with thymine, and cytosine pairs with guanine.
• Hydrogen bonds hold base pairs together.

DNA Replication

• During DNA replication, the DNA helix unwinds.
• Enzymes break hydrogen bonds between the base pairs.
• Nucleotides are assembled to form a complementary strand for each template strand.
• DNA polymerase facilitates the matching of nucleotides to their complements.
• Two identical DNA molecules result from the process.

DNA and Protein Synthesis

• DNA controls all cellular activities.
• Protein synthesis occurs on ribosomes.
• DNA's instructions for protein synthesis are carried by RNA.
• RNA contains uracil instead of thymine, which is in DNA.
• There are three main types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
• mRNA carries the DNA instructions to ribosomes.
• tRNA brings amino acids to ribosomes.
• rRNA forms the structure of ribosomes.