2.1_DNA_structure_and_Function__1_

Group Presentations Requirements

  • Individual Submission (Due Feb 13):

    • Names of the five students in the group.

    • Group Topic.

    • Three references from primary literature related to the topic.

    • Three preferred presentation dates from the group.

Overview of Group Presentations

  • Learning Objective:

    • Utilize information from various sources to construct and communicate knowledge.

  • Task:

    • Gather information on a current biological topic from research articles, texts, web, and other sources.

    • Analyze and synthesize the information for a class presentation.

Oral Presentation Grading Criteria

  • Total Points: 75

    • Content (25 pts):

      • Substantive summary of important recent results (past 5 years) from scientific literature.

    • Appearance & Effectiveness of Slides (20 pts):

      • Slides should be organized, readable, and contain a balance of text and figures.

    • Presentation (30 pts):

      • All members participate in the presentation.

      • Team displays mastery of content and can answer questions.

      • 10 minute presentation with 5 minutes for questions.

DNA Structure and Function

  • Base Pairing:

    • T-A (Thymine-Adenine)

    • C-G (Cytosine-Guanine)

Understanding DNA

  • Function:

    • Acts as a recipe for biological information.

Key Discoveries (1952-1953)

  • Watson & Crick:

    • Published the structure of DNA - double helix in February 1953.

  • Nobel Prize (1962):

    • Awarded to Watson, Crick, and Wilkins for their discoveries.

Rosalind Franklin

  • Contribution:

    • Created Photo 51 in 1952, providing crucial evidence for DNA structure.

DNA Structure

  • Components:

    • Nucleotides (sugar, phosphate group, nitrogenous bases).

    • Double helix structure with complementary strands.

Packaging of DNA

  • Hierarchy:

    • DNA double helix (2nm) ➔ Nucleosome ➔ 30 nm fiber ➔ Higher-order chromatin ➔ Chromosome (700nm).

Central Dogma of Biology

  • Information Flow:

    • DNA ➔ mRNA ➔ Proteins.

  • Key Processes:

    • Transcription: DNA to mRNA.

    • Translation: mRNA to Protein.

The Genetic Code

  • Definition:

    • Rules translating DNA base sequences into amino acid sequences.

  • Triplet Code:

    • Proposed by George Gamow as a 3-letter code encoding 20 amino acids.

Codon Table

  • Explanation:

    • Codons consist of 3 nucleotides, each coding for a specific amino acid.

    • Example: UUU ➔ Phenylalanine, CUU ➔ Leucine.

Genes and Genetic Variation

  • Definition of Genes:

    • Units of heredity located on chromosomal DNA, coding for proteins.

    • Encode phenotype, with only 1.5% of DNA coding for proteins.

  • Mutations:

    • Changes in nucleotide sequences, affecting protein function.

Examples of Genetic Variation

  • Single Base Substitution:

    • Sickle cell anemia resulting from a mutation in hemoglobin gene.

In-Class Question

  • Purines:

    • Which nitrogenous bases are classified as purines?

    • Options: A. Uracil, B. Guanine, C. Thymine, D. Cytosine, E. All of these.

Final Tasks

  • Homework Assignment:

    • Create a mind map of the lecture content with at least 10 nodes using a mind mapping tool.