Cell Biology Basics

Fundamental Concepts of Biology

• The lowest level of organization of matter capable of performing life activities is a cell.
• The term 'cell' in biology was first used by Robert Hooke in 1665.

Cell Theory and Discoveries

• Theodor Schwann concluded that animals are composed of cells.
• Matthias Schleiden proposed that all organisms are made up of one or more cells.
• According to cell theory, the basic unit of structure for all organisms is the cell.
• Rudolf Virchow observed that "new cells could only arise from existing cells".

Cellular Functions and Organelles

• Protein synthesis occurs in the ribosomes of the cell.
• The endoplasmic reticulum (ER) is known as the 'roads' of the cell.
• The Rough ER obtains its rough appearance from ribosomes attached to its surface.
• The Ribosomes help in making proteins.
• The Golgi apparatus is responsible for packaging, modifying, and transporting materials within a cell.
• Smooth ER functions to synthesize lipids and detoxify drugs and poisons.
• Cytoplasm vacuoles store nutrients and maintain turgor pressure in plant cells.

Plant Cellular Components

• Plastids in plant cells perform various functions including photosynthesis and storage of products.
• Chromoplasts derive their yellow, orange, or red color from carotenoids.
• The amyloplast is known for temporarily storing starch in plants.
• Chlorophyll in chloroplasts plays a crucial role in capturing light energy for photosynthesis.
• The fluid-filled region enclosed by the two membranes of a chloroplast is called the stroma.

Organelles and Their Functions

• The main function of peroxisomes is to break down hydrogen peroxide and other harmful substances.
• Lysosomes are known as the 'clean-up crews' of the cell, digesting waste materials and cellular debris.
• Glyoxysomes are microbodies that help convert stored fats into carbohydrates during seed germination.
• Microfilaments are the cytoskeletal elements responsible for maintaining cell shape and enabling cell movement.
• Centrioles are primarily composed of microtubules and play a role in cell division.

Specialized Functions

• The smooth ER is crucial for lipid synthesis and detoxification processes.
• The plant cell wall functions primarily to provide rigidity and protection.
• The site of photosynthesis in green plants and algae is the chloroplast.
• The main component of the cell wall is cellulose.
• The peroxisome is involved in the metabolism of hydrogen peroxide.
• The endoplasmic reticulum functions in the synthesis, folding, modification, and transport of proteins and lipids.
• The main genome in a cell is located within the nucleus.