DNA Structure and Function Quiz

Study Notes

DNA is a double-stranded polymer of nucleotides.
Nucleotides are composed of a sugar (deoxyribose), a base (adenine, thymine, cytosine, guanine), and a phosphate group.
The backbone of DNA is formed by alternating sugar and phosphate units.
The "rungs" of the DNA ladder are formed by complementary base pairs: adenine bonds with thymine, and guanine bonds with cytosine.
DNA is typically found in the nucleus of a cell.
DNA forms the genes on chromosomes.
DNA replicates before cell division to ensure identical genetic information.
DNA provides instructions for the formation of every protein in the body.
DNA determines the type of organism and directs growth and development.

Nucleic acids include DNA and RNA.
Nucleic acids are large molecules in the body, composed of C, O, H, N, and phosphorus.
Each nucleic acid contains a sugar, phosphate group, and bases.
DNA bases: adenine, guanine, cytosine, thymine.
RNA bases: adenine, guanine, cytosine, uracil.
Nucleic acids contribute to nucleotide structure.

RNA is a single-stranded polymer of nucleotides.
RNA nucleotides are composed of a sugar (ribose), a base (adenine, uracil, cytosine, guanine), and a phosphate group.
RNA is mainly located outside the nucleus.
Different types of RNA exist: messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA).
RNA serves as a decoder and messenger for DNA information.

DNA serves as a blueprint for protein synthesis.
Proteins are made of polypeptide chains of amino acids.
The sequence of four nucleotide bases (A, G, C, T) in DNA specifies a particular amino acid.
Amino acids have distinct properties that separate them.
Different amino acid sequences create various proteins with diverse structures and functions.
Transcription: DNA information is transferred to mRNA.
mRNA detaches and leaves the nucleus, carrying the genetic code.
Translation: mRNA information is used to assemble amino acids in the correct order.
mRNA reaches the cytoplasm, binds to ribosomes, and tRNA transfers specific amino acids.
Each tRNA brings a specific amino acid to the ribosome.

DNA replication involves breaking weak hydrogen bonds between bases.
This separates single DNA strands.
Each separated strand serves as a template for a complementary molecule.
Unpaired bases attract matching free nucleotides.
DNA polymerase is the key enzyme in replication.
DNA polymerase moves along the template strand and adds correct new strands, ensuring complementary base pairing.

Mutations are inherited alterations of the genetic material.
Mutations can cause disease but may also be subtle.
Base-pair substitution: one base pair is replaced by another.
Frameshift mutation: involves inserting or deleting one or more base pairs.
Mutagens are agents that increase mutation frequency (e.g., chemicals, radiation).
Mutations can cause variations in amino acid sequences, thus altering protein structure and function.