Cell Structure and Function

Cell Structure and Function

Overview of Cell Structure

  • A cell is the smallest structural and functional unit of an organism.
  • Cells can be divided into two main types: prokaryotic (non-nucleated) and eukaryotic (nucleated)

Fundamentals of Prokaryotic Cells

  • Prokaryotic cells are smaller and simpler compared to eukaryotic cells.
  • They lack a nucleus and most other organelles.
  • They do have ribosomes, but these are smaller and less complex than the ones in eukaryotic cells.
  • Prokaryotic cells also have a flagellum for movement and a cell wall for protection.

Understanding Eukaryotic Cells

  • Eukaryotic cells are found in a wide range of organisms, from fungi to plants and animals.
  • This cell type is larger and has a more complex structure, with a variety of organelles.
  • Central to these organelles is the nucleus, which contains the cell’s DNA.
  • Other key organelles include mitochondria, ribosomes, the endoplasmic reticulum, lysosomes, and the Golgi apparatus.

Role of Cell Organelles

  • Cell organelles play vital roles in maintaining the function of the cell.
  • Each organelle has a distinct role; for example, ribosomes are involved in protein synthesis, mitochondria produce ATP for energy, while the ER and Golgi apparatus are involved in protein processing and packaging.

Cell Membrane Structure and Function

  • The cell membrane is composed of a phospholipid bilayer with embedded and associated proteins.
  • It controls what enters and leaves the cell, protecting the cell from its environment and controlling the movement of substances in and out of the cell.

The Central Role of Mitochondria

  • Mitochondria are vital organelles and are often referred to as the powerhouses of the cell.
  • They play a critical role in generating ATP, the energy currency of the cell, through a process known as cellular respiration.

The Functions of the Nucleus

  • The nucleus is the control centre of the cell, containing the genetic material (DNA) and controlling the cell’s growth and reproduction by controlling gene expression.

Understanding the Role of Ribosomes

  • Ribosomes are structures made of protein and RNA in the cytoplasm which are the sites of protein synthesis.

Endoplasmic Reticulum and Golgi Apparatus Functions

  • The endoplasmic reticulum (ER) and Golgi apparatus are involved in protein synthesis and modification.
  • The ER synthesises proteins before they are processed and modified in the Golgi apparatus, to then be transported to their destinations.