Cell Structure and Function

• Learning is the only way to improve your life.
• Kindness results from true knowledge.
• Learning begins with respect.
• Opportunities increase with good behavior and decrease with bad behavior.
• Cells vary in size and structure depending on their function and compose every organ in the body.
• Cells are of two main types: prokaryotic and eukaryotic.
• Eukaryotic cells have two subtypes: plant and animal cells.
• Microscopes are needed to observe cells.
• Substances move within the cell through processes like diffusion and osmosis.
• Exocytosis is the process of removing substances from inside the cell to the external environment.

Processes Without Energy Consumption

• Diffusion involves the movement of molecules from an area of high concentration to an area of low concentration.
• Liquids or gases like O2 and CO2 exhibit diffusion.
• Osmosis involves the movement of solute or solvent molecules through a semipermeable membrane.
• Osmosis is the movement of water from an area with more water to an area with less water through a selectively permeable membrane.
• Osmosis is a physical and passive process, not requiring energy.
• Solute molecules move from low to high concentration areas and solvent molecules move from high to low concentration areas.

Explanation of Osmosis

• Solutions contain a solute and a solvent (water).
• Osmosis has three possibilities based on the type of solution.

Isotonic Solution

• The medium inside and outside the cell has the same water concentration; there is no net movement of water.

Hypotonic Solution

• The concentration of solutes is greater inside the cell than outside, resulting in water entering the cell (endomosis).
• Raisins swell when placed in water due to endomosis.

Hypertonic Solution

• The concentration of solutes is greater outside the cell than inside, resulting in water exiting the cell.
• Fruit pieces shrink in concentrated sugar solution as water exits them.
• In plant or animal cells in hypertonic solutions, water exits through exosmosis, causing cytoplasm contraction called plasmolysis.

Cell Organelles

• Cell organelles are specialized subunits within cells with specific functions.
• Except for the nucleus and chloroplast, other organelles are visible only with an electron microscope.

Plastids

• Plastids give color and are present only in plant cells.
• Plastids are important for photosynthesis.
• Mitochondria and plastids can replicate and produce their own proteins because they contain ribosomes and DNA.

Leucoplasts

• Leucoplasts are white or colorless plastids involved in the synthesis and storage of food like starch, oils, and proteins.

Mitochondrial Membrane

• The inner mitochondrial membrane is extensively folded into cristae.
• Cristae increase the surface area of the inner membrane by approximately five times compared to the outer membrane.
• Cristae membranes contain F1 particles, where energy production occurs.

National Centre for Cell Science (NCCS)

• NCCS is located in Pune at Savitribai Phule Pune University.
• NCCS conducts research in cytology.
• The National Animal Cell Repository is associated with NCCS.
• NCCS's main focus is research on cancer treatment.