12 Questions
Who coined the term 'cell'?
Robert Hooke
What is the nucleus often referred to as in a cell?
The brain of the cell
What is the basic structural and functional unit of life?
Cell
According to cell theory, what are all living organisms made up of?
Cells
Who was the first to observe living cells under a microscope?
Anthony Von Leeuwenhoek
What is the role of the nucleus in a cell?
Controlling metabolic activities and enclosing genetic material
What is the concept of 'omnis cellula e cellula' introduced by Rudolf Virchow?
All cells arise from pre-existing cells.
What is the main difference between prokaryotic and eukaryotic cells in terms of nuclei?
Prokaryotic cells lack a well-defined nucleus, while eukaryotic cells have advanced nuclei.
What distinguishes prokaryotic cells in terms of membrane-bound organelles?
Prokaryotic cells lack membrane-bound organelles.
What is the function of the Golgi apparatus in plant cells?
The Golgi apparatus in plant cells is responsible for processing and packaging proteins.
Describe the composition of the plasma membrane based on the fluid mosaic model.
The plasma membrane is a lipid bilayer embedded with proteins.
What is the role of carrier proteins in the plasma membrane?
Carrier proteins have specific receptors and transport molecules in a 180-degree manner.
Study Notes
- A small positive thought in the morning can set the tone for the whole day, leading to a positive and energetic day.
- The concept of starting the day with a positive mindset is emphasized for a productive day.
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- The text introduces Ayush Agarwal welcoming viewers to study cell biology on Physics Wala platform.
- The chapter on cell biology in the class 11 curriculum is introduced as an important and familiar topic.
- The definition of a cell as the basic structural and functional unit of life is provided.
- All living organisms are composed of cells or are a product of cells.
- The distinction between unicellular and multicellular organisms is explained.
- Organisms composed of even one cell are considered living due to the presence of a cell.
- The term "cell" was coined by Robert Hooke, who observed compartment-like structures in cork under a microscope.
- Anthony Von Leeuwenhoek was the first to observe living cells in mud water under a microscope.
- The nucleus is referred to as the "brain" of the cell, responsible for controlling metabolic activities and enclosing genetic material.
- Cell theory states that the cell is the basic structural unit of life and that all living organisms are made up of cells.
- Cell theory also emphasizes that metabolic activities in living organisms are a result of cellular interactions.
- The concept of "omnis cellula e cellula" was introduced by Rudolf Virchow, stating that all cells arise from pre-existing cells.
- An overview of a cell includes diversity in shapes and sizes, with examples like mycoplasma and neurons.
- Prokaryotic cells lack a well-defined nucleus and have nucleoid or genophore, while eukaryotic cells have advanced nuclei.
- Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells show compartmentalization due to membrane-bound organelles.
- Prokaryotic cells have mesosomes, fimbriae, flagella, inclusion bodies, and ribosomes.
- Prokaryotic cells also have a cell wall made up of peptidoglycan, providing protection and maintaining cell shape.
- Eukaryotic cells have tubulin protein, providing cytoskeletal structure and aiding in locomotory structures.
- Eukaryotic cells show cyclosis, with cytoplasmic movement, and have 80S ribosomes in the cytoplasm.
- The presence of plasmids is a distinguishing feature of prokaryotic cells, absent in eukaryotic cells.
- Plant cells have a cell wall, large central vacuole, and plastids, while animal cells lack a cell wall, have small vacuoles, and centrosomes.
- The Golgi apparatus in plant cells is called dictyosomes, with non-interconnected cisternae, while animal cells have a standard Golgi body with interconnected cisternae.
- Both plant and animal cells share the common feature of the cell membrane, which is represented by the fluid mosaic model.- The fluid mosaic model describes the plasma membrane as a lipid bilayer embedded with proteins.
- Singer and Nicholson proposed the fluid mosaic model in 1972 while studying human RBCs.
- The plasma membrane is made up of lipid (40%), protein (52%), and some carbohydrate.
- The lipid bilayer consists of a hydrophilic head and a hydrophobic tail.
- Proteins in the plasma membrane can be extrinsic (attached on the surface) or intrinsic (embedded inside).
- Intrinsic proteins can be partially embedded or totally embedded, acting as tunnel proteins or carrier proteins.
- Tunnel proteins act as openings for hydrophilic substances to move across the membrane.
- Carrier proteins have specific receptors and transport molecules in a 180-degree manner.
- The plasma membrane's function is to allow selective movement of molecules in and out of the cell.
- The cell wall is a non-living, rigid layer that maintains cell shape and protects against bursting.
- The cell wall is made of different chemicals in different organisms like peptidoglycan, cellulose, hemicellulose, and chitin.
- Primary cell walls are thin and flexible, while secondary cell walls are thick and rigid.
- Middle lamella acts as a cementing substance to hold adjacent plant cells together.
- Tunnel proteins are intrinsic proteins acting as openings in the plasma membrane.
- Carrier proteins are solid intrinsic proteins that move molecules in a 180-degree manner.
- Bulk transportation of molecules occurs inside and outside the cell through proteins in the plasma membrane.
- Cell organelles like ER, Golgi bodies, lysosomes, and vacuoles form the endomembrane system, responsible for the transport and modification of cellular products.
- ER consists of cisterna, tubules, and vesicles and plays a role in protein synthesis and lipid synthesis.
- Golgi bodies modify and package proteins and lipids received from the ER for transportation.
- Lysosomes contain hydrolytic enzymes for digestion and exhibit polymorphism.
- Vacuoles store waste and excretory products temporarily, occupying a significant portion of plant cells.
- Mitochondria are the Powerhouses of the cell, producing energy through oxidative phosphorylation.
- Plastids like chloroplasts are responsible for photosynthesis, containing chlorophyll and other pigments for light absorption.
- Ribosomes are granular structures made up of rrna and proteins, responsible for protein synthesis.
- Ribosomes can be 70s or 80s, with two subunits each, joining during protein synthesis with the help of magnesium ions.- Cytoskeleton is exclusively found in eukaryotic cells and consists of filamentous protein structures that maintain cell shape, provide motility, and strength.
- There are three types of cytoskeleton in eukaryotes: microtubules, microfilaments, and intermediate filaments.
- Microtubules are made up of tubulin proteins, forming Alpha-Beta heterodimers, which then join to form protofilaments, and eventually 13 protofilaments form a hollow, unbranched microtubule structure.
- Microtubules help in maintaining cell shape, providing motility by forming cilia and flagella, and aiding in cell division by forming the centrosome organelle.
- Microfilaments are made of actin and myosin proteins, assisting in muscle contraction, relaxation, pseudopodia formation, and plasma membrane growth during cell division.
- Intermediate filaments are made of lamin proteins and are found in the nucleus to support and strengthen the nuclear membrane structure.
- Centrosomes are membrane-less organelles found in animal cells, consisting of two perpendicular centrioles made of microtubules arranged in a 9+0 pattern. They help in cell division.
- Basal bodies, derived from centrioles, are the origin points for cilia and flagella, which are made of microtubules arranged in a 9+0 pattern for motility.
- Cilia and flagella are membrane-bound structures made of tubulin protein with a 9+2 microtubular arrangement (9 doublets on the periphery and 2 in the center) within the axoneme, providing motility to eukaryotic cells.
Test your knowledge on cell biology basics including the definition of a cell, cell theory, cell structures, organelles, cytoskeleton, and cell membrane. Learn about prokaryotic and eukaryotic cells, plasma membrane composition, transport proteins, cell wall function, and more.
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