Lecture Notes: Cell Structure and Function

Introduction

Humans start as a single cell
At birth, we have approximately 37.2 trillion cells (not counting bacteria/microbes)

Cytoplasm: Area where organelles are suspended
Mitochondrion:
- Site of cellular respiration
- Produces ATP (adenosine triphosphate), the energy currency of the cell
Lysosome:
- Site of cellular digestion (breakdown of carbohydrates, fats, proteins)
- Known as the 'suicide sac' of the cell
Golgi Bodies:
- Responsible for transportation, modification, and packaging of proteins and lipids
Endoplasmic Reticulum (ER):
- Network of pathways for material flow
- Types of ER:
  - Smooth ER: Lipid metabolism and detoxification of drugs
  - Rough ER: Contains ribosomes, responsible for protein synthesis
Cell Membrane (Plasma Membrane):
- Double-layered, differentially permeable
- Maintains cell equilibrium
Nucleus:
- Control center of the cell
- Contains chromosomes and genetic material

Cell Wall:
- Rigid outer protective layer
- Maintains shape of the plant cell
Large Central Vacuole:
- Responsible for intracellular digestion, space filling, and turgor control (pressure in the plant cell)
Plastids:
- Most known type: Chloroplast (site of photosynthesis)
- Other types: Chromoplasts (contain pigments)

Guard Cells:
- Form stomata for gas exchange
- Regulate opening and closing of stomata
Root Hair Cells:
- Increase absorption of minerals and water
Ciliated Cells (in windpipe):
- Remove dust particles from air inhaled
White Blood Cells (Leukocytes):
- Engulf and destroy infectious agents for immune defense