Cell Biology Notes

History of the Cell

  • Dr. Robert Hooke (1665)
    • First discovered cells.
  • Matthias Schleiden and Theodor Schwann
    • Established Cell Theory in 1838.

The Cell Theory

  • All living things are made of cells.
  • Cells are the smallest unit of life.
  • All cells come from pre-existing cells.

Cell Functions

  • Structure & Support: Provides structure and support to the body of an organism.
  • Genetic Information: Cells contain DNA that carries genetic information passed on to daughter cells.
  • Energy Management: Manages fuel to provide the organism energy.
  • Waste Digestion: Digests unwanted materials.
  • Organismal Composition: Organisms can be made of very few or just one cell.

Structure and Function

  • Shape Determines Function: The shape of something helps it do its job; structure relates to function.
    • The structure of an object is directly related to the function it performs.

Examples of Structure-Function Relationship

  • Plant Cells: Plant cells are generally square.
    • They stack on top of each other like bricks, providing strength, allowing the plant to stand up straight.
  • Red Blood Cells: Red blood cells are round.
    • They need to roll through blood vessels easily. Their round shape prevents them from getting stuck.

Organelles of the Cell

  • Mitochondria
  • Nucleus
  • Lysosomes
  • Golgi

Nucleus

  • Storage of DNA (genetic material).
  • Controls the activity of all other organelles by facilitating cell growth, cell division, and protein synthesis.

Cell Membrane

  • Provides support and shape to the cell.
  • Regulates what is allowed to enter and exit through the cell.
  • Generates and distributes signals.

Cell Wall

  • Protects and maintains the shape of the cell.
  • Allows passage of some molecules into the cell but blocks others.

Ribosomes

  • Site of biological protein synthesis.
  • Assist in protein synthesis.

Mitochondria

  • Synthesis of energy from sugar in the form of ATP.
  • Equation: C6H{12}O6 + O2 \rightarrow CO2 + H2O + ATP

Chloroplast

  • Primary center for light-dependent/independent reactions.
  • Contains pigments called chlorophyll, which is vital for photosynthesis.

Photosynthesis

  • Plants produce sugar using energy from sunlight.
  • Chlorophyll inside the chloroplasts collects the light and gives a plant its green color.
  • Plants absorb water through the roots in the soil and carbon dioxide from the air.
  • Overall Equation: 6CO2 + 6H2O \rightarrow C6H{12}O6 + 6O2

Vacuole

  • Storage for nutrients and waste materials.
  • Protects the cell from toxicity.
  • Maintains homeostasis (balance).

Golgi Body / Apparatus

  • Modifies proteins & lipids.
  • Processes materials to be removed from the cell.
  • Makes & secretes mucus.
  • Packages products into vesicles for transport.

Endoplasmic Reticulum

  • Smooth ER:
    • Storage organelle, storage of lipids & steroids.
  • Rough ER:
    • Attached to the nuclear envelope, synthesis and packaging of proteins.

Cytoplasm

  • Area where most enzymatic reactions take place.
  • Protects organelles and genetic material.

Lysosome

  • Breakdown unwanted large macromolecules into smaller molecules.

Cilia/Flagella

  • Cilia and flagella are both involved in movement.
    • Cilia moves substances across its surface, while flagella moves itself as an entire cell from one point to another.

Organelle Location

  • Nucleus
  • Mitochondrion
  • Ribosomes
  • Lysosome
  • Golgi apparatus
  • Smooth endoplasmic reticulum
  • Rough endoplasmic reticulum
  • Cytoplasm
  • Cell membrane
  • Cell wall
  • Chloroplast
  • Vacuole
  • Centrioles
  • Microtubules
  • Secretory vesicle

Homework Check

  • Complete your cell analogy (last question on the organelle review worksheet). This will be checked for completion at the start of next class.