Cell Biology Notes and Concepts

Scientist Spotlight: David Goodsell

  • Profession: Associate Professor in the Department of Molecular Biology, Scripps Research Institute, La Jolla, California.
  • Known For: Watercolor paintings of living cells.
  • Background: Originally trained as a structural biologist.
  • Artistic Development: Developed a unique style of scientific drawing during graduate school.
  • Interest in Illustration: Gained interest in scientific illustration while writing molecular graphics programs for visualizing protein and DNA structures.
  • Skill Development: Further enhanced his skills in science and art during his postdoctoral years.

Understanding Cell Structure

Sketch Activity
  • Task: Sketch current mental picture of a cell.
  • Discussion Point: Compare drawings with group mates for similarities and differences, focusing on essential cellular concepts such as:
  • Ability to reproduce.
  • Use and transformation of energy and materials from the environment.

Cellular Components

Neutrophil (White Blood Cell) Overview
  • Components:
  • Mitochondria: Energy production.
  • Nucleus: Contains DNA.
  • Phagosome: Particle engulfment.
  • Specific Granules: Contain proteins like Lactoferrin, Lysozyme, and immune-related molecules.
  • Secretory Vesicles: Involved in secretion processes.
  • Functionality: Engaged in immune response and pathogen destruction.

Comparing Cell Types

Prokaryotic vs. Eukaryotic Cells
  • Differences:
  • Prokaryotic Cells: Lack a nucleus and membrane-bound organelles; generally smaller.
  • Eukaryotic Cells: Have a nucleus and various organelles; can be multicellular or single-celled.
  • Examples: Yeast (eukaryotic) vs. Bacteria (prokaryotic).
Tree of Life
  • Concept: Evolutionary history shows a common ancestor for all life forms.
  • Eukaryotic Evolution: Likely evolved once with diverse groups of organisms branching out from a single lineage.

Organelles and Their Functions

  1. Nucleus:
  • Contains DNA, regulates cellular activities.
  • Importance of nuclear pores in material exchange between nucleus and cytoplasm.
  1. Rough Endoplasmic Reticulum (RER):
  • Studded with ribosomes, involved in protein synthesis.
  • Functions as a continuation of the nuclear envelope.
  1. Golgi Apparatus:
  • Modifies, sorts, and packages proteins.
  • Associated with the RER for receiving newly synthesized proteins.
  1. Mitochondria:
  • Powerhouse of the cell, generates ATP through respiration.
  • Relationship with other organelles for energy demands.
  1. Chloroplasts (in plant cells):
  • Site of photosynthesis, converting light energy into chemical energy.
  • Importance of double membrane structure in functionality.
  1. Cytoplasm:
  • Jelly-like substance holding organelles, facilitating biochemical reactions.

Design Challenge Framework

Design Process
  1. Identify Problems: Define what needs to be solved regarding cell structure.
  2. Determine Success Criteria: What are essential qualities for a viable cell?
  3. Evaluate Solutions: Analyze proposed designs against established criteria.
  4. Choose Solution: Select the most effective design based on evaluation.
Building Blocks of Life
  • Key Requirements for Building Cells:
  • Essential Nutrients: Lipids, carbohydrates, amino acids, proteins required for cell integrity and function.
  • Chemical Properties: Understanding the role of atoms and compounds in cellular structure.

Elemental Composition of Biomolecules

  • Predominant Atoms: 98% of living organisms' mass comprised of:
  • Carbon (C)
  • Hydrogen (H)
  • Nitrogen (N)
  • Oxygen (O)
  • Phosphorus (P)
  • Sulfur (S)

Chemical Concepts in Biology

Electronegativity
  • Definition: Tendency of an atom to attract shared electrons in a chemical bond.
Bonds and Interactions
  1. Polar vs. Non-Polar Covalent Bonds:
  • Polar: Unequal sharing of electrons.
  • Non-Polar: Equal sharing of electrons.
  1. Hydrogen Bonds: Special case of attraction in polar molecules.
  2. Ionic Bonds: No sharing; complete transfer of electrons from one atom to another.