DNA Structure and Replication

• Main functions of DNA includes replication and gene expression (protein synthesis).

DNA Structure

• Nucleic acids include DNA and RNA.
• Macromolecules are polymers made of monomers or building blocks.
• Nucleotides serve as the monomer of DNA.
• Nucleotides consist of three parts: a phosphate group, a deoxyribose sugar, and a nitrogenous base.
• DNA contains four nitrogenous bases: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
• Phosphate-sugar backbone makes up the sides of the DNA ladder.
• Nitrogenous bases make up the rungs of the DNA ladder.
• RNA has Uracil (U) instead of Thymine (T), is single-stranded, and contains a ribose sugar.
• Base pairing of nitrogenous bases occur as follows: T pairs with A, and C pairs with G; U replaces T in RNA.
• Purines/Pyrimidines are linked by hydrogen bonds, T-A have 2 hydrogen bonds, and C-G have 3 hydrogen bonds.
• The DNA molecule is anti-parallel.
• New DNA nucleotides are only added to the 3'side of a DNA molecule.

DNA Replication

• Helicase, DNA polymerase, Ligase, RNA primers, and Okazaki fragments are involved in DNA Replication

From Gene to Protein

• The nucleus contains DNA, which consists of chromosomes; these chromosomes contain genes in specific positions.
• Humans have 23 pairs of chromosomes.
• Nucleus controls all cell activities.
• A gene encompasses the code to make a protein.

Proteins

• Amino acids serve as the building blocks/monomers.
• Humans require 20 amino acids; 9 are essential, and 11 are non-essential
• Proteins are made up of many amino acids in a specific sequence.
• Amino acids are joined together by peptide bonds to form a polypeptide chain.
• The specific sequence of amino acids determines the protein and its function
• Proteins consist of specific shapes determined by amino acid sequence.
• The shape of the finished protein determines its function.
• Proteins have 4 possible levels of folding: primary, secondary, tertiary, and quaternary.
• DNA has two main functions: reproduction (replication) and to contain the information to control all cell activities (making a protein).
• Protein synthesis involves two main processes: Transcription and Translation.

Transcription

• Messenger RNA (mRNA) carries the code of DNA.
• A codon is a sequence thats part of the genetic code
• Messenger RNA (mRNA) is synthesized using the template strand of DNA and RNA polymerase.
• Initiation (start) codons, mRNA polymerase, and termination (stop codons) powerpoint; mRNA is processed and spliced before it leaves the nucleus powerpoint.

Translation

• The code contained in mRNA translates into a specific sequence of amino acids.
• Messenger RNA (mRNA), codon, ribosome, initiation of polypeptide synthesis; transfer RNA (tRNA); anti-codon, base pairing are all responsible for translation.
• There are also the addition Amino acid, peptide bonds, elongation of the polypeptide chain; and termination
• Use the diagram on page 243 to study translation

Gene or Point Mutation

• Nucleotide substitution has 3 possible effects: silent, missense or nonsense mutation.
• Nucleotide insertion/deletion can lead to frame shift mutation.

Explore DNA's structure, including nucleotides, nitrogenous bases, and the sugar-phosphate backbone. Understand base pairing rules (A-T, C-G) and the significance of the 3' end for DNA replication. Learn about the differences between DNA and RNA, focusing on the unique components of each.