Lecture Notes: Fundamental Unit of Life

Introduction

• Warm welcome to students; emphasis on engagement.
• Clarification that today's session is a one-shot lecture focusing on important concepts.

Akash National Talent Hunt Exam (ANTHE)

• Overview of ANTHE:
  • Opportunity to visit NASA.
  • Cash awards and scholarships available.
  • Online and offline exam formats.
• Importance of participating in the exam.

Telegram Group

• Announcement of chapter revisions and PDF resources available on the group.
• Availability of mock tests and doubt sessions.
• Subscription benefits for early subscribers to access mini learning programs.

Focus on Cells

Discovery of Cells

• Robert Hooke: Coined the term "cell" in 1665, observed dead cells.
• Leuwenhook: Observed the first living cell using improved microscopes.

Types of Cells

• Unicellular Organisms: Single-celled (e.g., amoeba).
• Multicellular Organisms: Composed of multiple cells, each performing specific functions.

Cell Membrane

• Protective outer covering of the cell.
• Functions as a selectively permeable barrier for molecular transportation.

Protoplasm

• Refers to the living content of the cell, including nucleus and cytoplasm.
• Structure consists of lipids and proteins.

Types of Transport

1. Active Transport: Requires energy, moves from low to high concentration.
2. Passive Transport: No energy required; includes osmosis and diffusion.
   • Osmosis: Movement of water across a semi-permeable membrane.
   • Diffusion: Movement of solute and solvent from high to low concentration.

Tonicity of Solutions

• Hypertonic Solution: Higher solute concentration; cells shrink.
• Hypotonic Solution: Lower solute concentration; cells swell.
• Isotonic Solution: Equal concentration; no net movement.

Cell Nucleus

• Master of the Cell: Contains genetic material.
• Nuclear Membrane: Double membrane with nuclear pores for material exchange.
• Nucleolus: Site for ribosome synthesis.
• Nucleoplasm: Fluid containing chromosomes.

Chromosomes and DNA

• Chromosomes are condensed forms of DNA, visible during cell division.
• DNA wraps around proteins to form chromatin.
• Genes are segments of DNA responsible for traits.

Types of Cells: Prokaryotic and Eukaryotic

• Prokaryotic Cells: No nucleus; genetic material freely suspended (nucleoid).
• Eukaryotic Cells: Nucleus contains genetic material.

Organelles in Cells

• Mitochondria: Powerhouse of the cell; ATP production.
• Endoplasmic Reticulum (ER):
  • Smooth ER: Lipid synthesis.
  • Rough ER: Protein synthesis.
• Golgi Apparatus: Modifies and packages proteins and lipids.
• Lysosomes: Contain digestive enzymes to break down waste; known as "suicide bags."

Plant vs. Animal Cells

• Plant cells have a cell wall and large vacuoles; animal cells do not.
• Chloroplasts: Site of photosynthesis; contain chlorophyll.
• Plastids: Different types include chloroplasts, chromoplasts (color), and leucoplasts (storage).

Cell Division

• Mitosis: Equational division; identical daughter cells.
• Meiosis: Reductional division; half the number of chromosomes in daughter cells.

Summary and Conclusion

• Review of key concepts discussed.
• Encouragement to subscribe for further learning resources and sessions.
• Reminder for students to engage with the material and participate in future sessions.