DNA Structure and Function

Organelle Identification

  • Control Center of the Cell:

    • Nucleus

Relationship Between DNA, Traits, and Chromosomes

  • Chromosomes:

    • Located within cells, containing DNA.

  • DNA:

    • Within DNA, traits are encoded through genes.

    • Example: Genes determine eye color.

Visual Identification

  • Be able to identify the following in a picture:

    • Cell

    • Nucleus

    • Chromosome

    • DNA

    • Gene

Sequencing from Smallest to Largest

  • Sequence the following items from smallest to largest:

    1. Atom (1)

    2. Nucleotide (2)

    3. Gene (3)

    4. DNA double helix (4)

    5. Chromosome (5)

    6. Nucleus (6)

    7. Cell (7)

Contributions of Scientists to DNA Structure

  • Chargaff:

    • Discovered that the quantity of adenine equals the quantity of thymine in DNA.

  • Franklin & Wilkins:

    • Conducted studies on DNA structure using X-ray scattering methods.

  • Watson & Crick:

    • Integrated X-ray data and bonding theory to deduce the structure of DNA.

Shape of DNA

  • Structure:

    • DNA is represented as a double helix.

DNA Backbone Identification

  • Sugar-Phosphate Backbone:

    • Composed of deoxyribose sugar.

Bonds in DNA

  • Nitrogen Base Bonds:

    • Hydrogen bonds connect the nitrogen bases together.

  • Backbone Bonds:

    • Covalent bonds secure the backbone components.

Monomers of DNA

  • Building Blocks:

    • A: Adenine

    • T: Thymine

    • C: Cytosine

    • G: Guanine

DNA Nucleotide Structure

  • Parts of a DNA Nucleotide:

    • Sugar

    • Phosphate

    • Nitrogenous base

Nitrogen Base Pairing

  • Base Pairing:

    • Adenine pairs with Thymine

    • Cytosine pairs with Guanine

Chargaff's Rule Applications

  • Example Calculation using Chargaff's Rule:

    • If 20% of adenine (A) is present in a DNA sample:

    • Thymine (T) = 20% (since A = T)

    • Combined A and T = 40%

    • Remaining = 100% - 40% = 60%

    • Cytosine (C) = 30%

    • Guanine (G) = 30%

Sequence of Nitrogen Bases

  • Importance of Order:

    • The specific sequence of nitrogen bases determines the sequence of amino acids in proteins.

Purpose of DNA

  • Blueprint Function:

    • DNA serves as a blueprint for transmitting genetic information.

    • It provides mechanisms that support cell reproduction, growth, and development.

  • Role in Body/Cells:

    • Stores essential genetic information for the regulation and normal functioning, development, and reproduction of cells.