Cell Structure and Diversity Study Notes

Overview of Cell Structure and Diversity

  • Cells are the fundamental units of all living organisms.
  • Two main types of organisms: unicellular (single cell) and multicellular (many cells).

Eukaryotic vs. Prokaryotic Cells

  • Eukaryotic cells have a nucleus and membrane-bound organelles (e.g., animals, plants, fungi).
  • Prokaryotic cells lack a nucleus and membrane-bound organelles (e.g., bacteria, Archaea).

Animal and Plant Cell Structure

Animal Cells:

  • Composed of a nucleus, cytoplasm, and cell membrane.
  • Cytoplasm consists of the cytosol (liquid) and organelles.

Plant Cells:

  • Contain nucleus, cytoplasm, cell membrane, cell wall, chloroplasts, and large vacuoles.

Differences Between Animal and Plant Cells

  • Animal cells lack a cell wall and chloroplasts, while plant cells have both.
  • Plant cells have large, permanent vacuoles; animal cells have small, transient vacuoles.

Electron Microscopy

  • Used for high-resolution imaging (up to 1 million times magnification).
  • Types: Transmission (TEM) for internal structures and Scanning (SEM) for surface details.

Cell Membrane Structure and Function

  • Composed of a lipid bilayer with embedded proteins.
  • Semi-permeable, allowing selective movement of substances.

Nucleus and Chromatin

  • Control center housing DNA, which is organized into chromosomes.
  • Contains nucleolus, responsible for RNA production.

Mitochondria

  • Powerhouses of the cell, involved in energy production (ATP synthesis).
  • Structure includes outer membrane and folded inner membrane (cristae).

Ribosomes

  • Sites of protein synthesis made of ribosomal RNA and proteins; non-membrane-bound.

Endoplasmic Reticulum (ER)

  • Membranous organelle involved in protein and lipid synthesis.
  • Rough ER has ribosomes; Smooth ER does not.

Golgi Apparatus

  • Modifies, sorts, and packages proteins and lipids for transport.

Plant Cell Unique Structures

  • Cell wall made of cellulose, providing support and shape.
  • Chloroplasts, sites of photosynthesis, contain chlorophyll.
  • Large vacuole for storage and maintaining turgor pressure.

Stem Cell Diversity and Function

  • Stem cells can differentiate into various cell types; include pluripotent (all cells) and multipotent (limited types).
  • Potential applications in medicine for diseases like diabetes, Parkinson’s, etc.

Ethical Considerations in Stem Cell Research

  • Ethical questions surrounding the rights of embryos, medical research implications, and equitable access to treatments.