Cell structure and function

Cell Biology

• Cell biology is also known as cytology
• Dr. Katja Vogt is a researcher in cell biology
• She is affiliated with the School of Medicine at University of Central Lancashire

Cell Structure and Function

• Key Learning Objectives:
  • Describe the components of the cell
  • Explain the structure and function of major cell organelles
  • Discuss the cell cytoskeleton
  • Highlight the importance of cellular trafficking

The Eukaryotic Cell

• The eukaryotic cell has many components:
  • Cell membrane
  • Nucleus
  • Ribosome
  • Endoplasmic reticulum (ER)
  • Golgi apparatus
  • Centriole
  • Mitochondria

Ribosomes

• Ribosomes are comprised of two subunits:
  • Large (60S)
  • Small (40S)
• Include ribosomal RNA (rRNA) to stabilise ribosomal structure
• Produced and assembled in the nucleolus
• Function: protein synthesis

Golgi Apparatus

• The Golgi apparatus is responsible for:
  • Polysaccharide synthesis
  • Modifying secretory products
  • Sorting secretory products
  • Packaging secretory products
  • Concentrating and storing secretory products

Endoplasmic Reticulum (ER)

• The ER is responsible for synthesising, packing, and processing various molecules
• There are two forms of ER:
  • Rough ER (RER)
  • Smooth ER (SER)

Rough ER (RER)

• The RER is responsible for:
  • Protein synthesis sequestered from the cytoplasm
  • Secretory proteins
  • Integral membrane proteins
  • Lysosomal enzymes
• Function: Core glycosylation

Smooth ER (SER)

• The SER is responsible for:
  • Lipid metabolism
  • Steroid hormone synthesis
  • Gluconeogenesis
  • Detoxification

Vesicles

• Vesicles are compartments carrying various substances within the cell

• Three types of vesicles:

  • Granules
  • Lysosomes
  • Peroxisomes

Granules

• Granules are vesicles destined for exocytosis
• Abundant in specialised secretory cells

Lysosomes

• Lysosomes have a pH of 5
• Contain hydrolytic enzymes
• Function: Degradation of material

Peroxisomes

• Peroxisomes participate in hydrogen peroxide metabolism
• Assist in fatty acid oxidation

Mitochondria

• Mitochondria are known as the power-house of the cell
• Function: Synthesise their own DNA and some proteins
• Mitochondria grow and reproduce
• Can move rapidly and change shape

Mitochondria - Structure

• Mitochondria have a prokaryote relic
• Contain their own DNA (mtDNA), which is maternally inherited
• Has two membranes:
  • Outer membrane - permeable to molecules
  • Inner membrane - folded into cristae