1. Cell & Subcellular Organelles - BASIC STRUCTURE OF THE CELL

Summary

Dr. Suresh's lecture delves into the intricacies of cells and subcellular organelles, highlighting the differences between prokaryotic and eukaryotic cells. He emphasizes the cell's role as the fundamental unit of life, detailing the structure and function of eukaryotic cells, which include a plasma membrane, various organelles, and a nucleus. The lecture also covers techniques like ultracentrifugation for isolating these organelles based on their molecular weight, providing a comprehensive understanding of cellular biology.

Takeaways

• 🔬 Cells are the basic unit of life, with prokaryotes and eukaryotes being the two main types, differing in structure and complexity.
• 🌿 Prokaryotic cells, such as bacteria, lack a well-defined nucleus and have a simpler structure compared to eukaryotic cells.
• 🧬 Eukaryotic cells, found in organisms like humans and animals, are enclosed by a membrane and contain various subcellular organelles.
• 🔍 The cell's structure is crucial for understanding the chemical reactions that occur within living systems.
• 📚 Studying cell composition is essential for biochemistry as it helps in understanding the biological activities and functions of cells.
• 🏡 The nucleus, ribosomes, endoplasmic reticulum, and mitochondria are key subcellular organelles in eukaryotic cells, each with specific functions.
• 🔄 Prokaryotic cells are smaller (1 to 10 micrometers) and have a cell wall instead of a cell membrane, while eukaryotic cells are larger (10 to 100 micrometers).
• 🌐 The presence or absence of a cell membrane, cytoplasm, and subcellular organelles distinguishes prokaryotic from eukaryotic cells.
• 🧪 Ultracentrifugation is a technique used to separate subcellular organelles based on their molecular weight and sedimentation rate.
• 📊 Markers such as DNA, catalase, and lactate dehydrogenase are used to identify and confirm the isolation of specific subcellular organelles.

Q & A

What is the fundamental role of cells in life?

Cells are the basic unit of life and are responsible for all biological activities. They are the structural and functional units through which chemical reactions necessary for life occur.

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a well-defined nucleus and have a simpler structure, while eukaryotic cells have a nucleus enclosed by a membrane and contain various subcellular organelles.

What are the key features of a typical eukaryotic cell?

A typical eukaryotic cell includes a plasma membrane, microtubules, centrioles, nucleolus, golgi complex, endoplasmic reticulum, lysosomes, cytoplasm, mitochondria, free ribosomes, nucleus, chromatin, nuclear pore, nuclear envelope, and ribosomes.

Why is it important to study the chemical reactions happening in living cells?

Studying the chemical reactions in living cells is important because these reactions are essential for understanding the biological processes and functions of the cell.

What is the size difference between prokaryotic and eukaryotic cells?

Prokaryotic cells are typically 1 to 10 micrometers in size, while eukaryotic cells are larger, ranging from 10 to 100 micrometers.

How do prokaryotic cells differ structurally from eukaryotic cells in terms of cell wall and cell membrane?

Prokaryotic cells have a cell wall instead of a cell membrane, whereas eukaryotic cells have a well-defined cell membrane.

What technique is used to separate subcellular organelles in eukaryotic cells?

Ultracentrifugation is used to separate subcellular organelles based on their molecular weight by applying centrifugal force.

How does the presence of subcellular organelles differ between prokaryotic and eukaryotic cells?

Prokaryotic cells do not have membrane-bound organelles, whereas eukaryotic cells contain various subcellular organelles such as the nucleus, mitochondria, and endoplasmic reticulum.

What is the role of the nucleus in eukaryotic cells?

The nucleus in eukaryotic cells serves as the control center, containing the cell's genetic material and regulating gene expression.

How can one identify if a particular subcellular organelle has been isolated during the ultracentrifugation process?

One can identify isolated subcellular organelles by identifying specific marker substances or enzymes unique to each organelle, such as DNA for the nucleus or catalase for lysosomes.