Cell Organelles: Golgi Bodies Quiz

Cell: Structure and Function

• Cell is the fundamental unit of life, self-replicating, and can be unicellular or multicellular.
• First cells were observed by Robert Hooke in 1665 from a slice of cork, with a diameter of 2-120µm.

Cell Theory

• Proposed by Matthias Schleiden and Theodor Schwann in 1839:
  • All living things are made up of cells.
  • Cells are the smallest working unit of all living things.
  • All cells come from pre-existing cells through cell division.

Protoplasm

• Composed of:
  • Water (70-80%)
  • Carbohydrates
  • Lipids
  • Proteins
  • Electrolytes (Sodium, Potassium, Magnesium, Calcium, Phosphate, Chloride, and Bicarbonate)

Cell Membrane

• Thin elastic outermost structure that envelops the cell.
• Consists of bilipid layer with embedded proteins: integral proteins and peripheral proteins.

Functions of Cell Membrane

• Protective: forms outermost boundary of the cell organelles.
• Digestive: takes in food and excretes waste products.
• Selective Permeability: allows non-polar molecules to dissolve and move rapidly across the membrane, while polar molecules have lower solubility.

Cytoplasm

• Thick, gel-like semitransparent fluid found in both plant and animal cells.
• Constituent parts: cytosol, cell organelles, and cytoplasmic inclusions.
• Bounded by the plasma membrane and contains many organelles in a eukaryotic cell.

Mitochondria

• First observed by Kolliker in 1850 as granular structures in the striated muscles.
• Called the 'powerhouse of the cell'.

Endoplasmic Reticulum

• Network of tubular and flat vesicular structures in the cytoplasm.
• Extensive network of closed, flattened membrane-bounded sacs called cisternae.
• Space inside the tubules is filled with Endoplasmic Matrix.

Types of Endoplasmic Reticulum

• Smooth Endoplasmic Reticulum: site of synthesis of lipid and steroid hormones.
• Rough Endoplasmic Reticulum: site of protein synthesis, processing, and packaging.

Golgi Bodies

• Collection of membrane-enclosed sacs composed of four or more stacked layers of thin, flat enclosed vessels.
• Consist of multiple discrete compartments.
• Functions:
  • Wrapping and packaging department of the cell.
  • Site of formation of lysosomes.
  • Adds certain carbohydrates to form glycoproteins.

Lysosome

• Irregular structures surrounded by the unit membrane.
• Acts as a form of digestive (lytic) system or the cell.
• Engulf worn out components of the cells in which they are located.
• When a cell dies, lysosomal enzymes cause autolysis of the remnant.

Peroxisome

• Lipid bilayer membrane surrounds which regulates what enters or exits the peroxisomes.
• Structure is similar to that of the lysosomes but with a different composition.
• Functions: H2O2 metabolism and detoxification.

Cytoskeleton

• System of fibers that maintains the structure of the cell and permits it to change shape and move.
• Made up primarily of:
  • Microtubules
  • Intermediate Filaments
  • Microfilaments

Cytoskeleton Components

• Microtubules: long hollow structures that determine the shape of the cell, role in the contraction of the spindle and movement of chromosomes and centrioles.
• Intermediate Filaments: flexible scaffolding or cell, help it resist external pressure.
• Microfilaments: long solid fibers responsible for the cell motion.

Nucleus

• Contains chromatin, RNAs, and nuclear proteins that move freely in aqueous solution.
• Has an internal structure that organizes the genetic material and localizes nuclear functions.
• Serves both as the repository of genetic information and as the cell's control center.

Test your knowledge on Golgi Bodies, which are mostly present in lipid forming cells like adipocytes and protein forming cells like pancreatic acinar cells. Learn about the structure and functions of Golgi Bodies in various types of cells.