Cell Flashcards
Define Cell
Cell is the basic structural and functional unit of life.
Cell was first discovered by…
[ Who? When? How? and What cell? ]
- Robert Hooke
- 1665
- Self-made Microscope
- Cork Cell of Bark
Cell is a Latin word for…
[ Meaning in Latin ]
A Little room
Who first observed the living cell?
[ Who? When? How? and What cell? ]
- Leeuwenhoek
- 1674
- Improved Microscope
- Free living pond cells
Who discovered the Nucleus?
Robert Brown (1831) discovered the nucleus.
Who coined the term Protoplasm?
Purkinje (1839) coined the term protoplasm.
The Cell Theory
[ Authors and State the Theory ]
Schleiden and Schwann proposed the cell theory. They stated that,
- All plants and animals are composed of cells.
- Cell is the basic unit of life.
It was further expanded by Virchow by suggesting that all cells arise from pre-existing cells.
Cells have different shapes and size.
[ Why? ]
The shape and size of cells are related to the specific function they perform.
Cell Membrane
- Made of - Lipids and Proteins.
- Selectively Permeable Membrane.
- Outermost covering of the cell that separates the contents of cell from external environment.
- Regulates the entry and exit of materials in and out of cell.
- Prevents the entry of certain substances.
Diffusion
The net movement of particles from a region of higher concentration to a region of lower concentration.
Osmosis
The net movement of water from a region of higher concentration to a region of lower concentration
[OR]
from a region of lower solute concentration to a region of higher solute concentration through a selectively permeable membrane.
[ MUST - Selectively Permeable Membrane & SOLUTE CONCENTRATION ]
Hypotonic Solution
[ Hypo-potamus ]
- Outside solution has higher water concentration than inside the cell.
- Cell will swell.
Hypertonic Solution
- Outside solution has lower water concentration than inside the cell.
- Cell will shrink by water loss.
Isotonic Solution
[ Iso ]
- Medium has exactly the same water concentration as the cell.
- Cell will stay the same.
Examples of Osmosis
[ Any 2 from book ]
- Unicellular freshwater organisms and most plant cells gain water through osmosis.
- Absorption of water by plant root.
Endocytosis
- Flexibility of the cell membrane enables the cell to engulf food and other materials from external environment.
- Done in Amoeba
Cell Wall
- Plant cells.
- Rigid outer covering.
- Cellulose in plants - Structural strength.
- Help plants, fungi and bacteria to withstand very dilute (hypotonic) solutions without bursting.
- As cell swells, pressure is built-up against the cell wall. The wall exerts equal pressure against the swollen cell.
What is the plant cell wall made up of?
Cellulose
What is the fungal cell wall made up of?
Chitin
What is the bacterial cell wall made up of?
Peptidoglycan
Plasmolysis
HINT [ Plasmo - Plasma , Lysis - Breakdown ]
When a cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall.
Nucleus
[ Structure & Parts ]
- Nuclear Membrane
- Nuclear Pore
- Chromatin material ( pre division )
Nuclear Membrane
- Double layered covering of nucleus.
- Has pores which regulate movement of substances between the nucleus and the cytoplasm.
Chromatin Material or Chromosomes
- Rod shaped structures.
- Contains genetic information in the form of DNA.
- Chromosomes are in the form of entangled threads called chromatin before cell division.
Functional segment of DNA
Gene
Function of Nucleus
- Cellular Division.
- Regulates life processes of cell by directing chemical activities.
Genetic Material of Prokaryotes
[ Region called? ]
- Prokaryotes lack well-defined nuclear region.
- Nucleic acid is randomly scattered.
- This region is called Nucleoid.
Prokaryotes lack…
- Well defined nuclear region.
- Double membrane bound organelles
Chlorophyll of photosynthetic prokaryotes is associated with _ _ _ _ _ _ _.
Membranous vesicles
Prokaryotes - Eukaroytes
[ Differentiate Points ]
- Size
- Nuclear Region
- Chromosome Number
- Membrane-bound Organelles
Cytoplasm
- The fluid content inside the plasma membrane.
Name all cell organelles
[ Give one word to describe function ]
- Endoplasmic Reticulum - Internal transport system
- Golgi Apparatus - Secretory / Packing Centre
- Lysosomes - Suicidal bag
- Mitochondria - Power house
- Plastids - Color
- Vacuoles - Storage
- Ribosomes
Endoplasmic Reticulm
[ Internal Transport System ]
i. Structure
* Membrane-bound tubes or sheets
* Stacks of them
ii. RER
* Protein manufacture
* has ribosomes
iii. SER
* Lipid manufacture
* Liver cells ( vertebrated) - Drug detox
Proteins and Lipids synthesised are used as,
* Membrane bio genesis
* Enzyme / Hormone
Golgi Apparatus
[ Secretory and Packing Centre ]
i. Structure
* Membrane bound sacs arranged in stacks (cisterns)
* Hav connection with the ER.
ii. Function
* Storage, modification, packing of products
* Simple to Complex sugars
* Formation of Lysosomes
The enzymes of Lysosomes are from…
the Rough Endoplasmic Reticulm (RER).
Simple from complex substances
Lysosomes
Two membranes of Mitochondria
- Inner Membrane - Deeply folded to increase area of ATP generation.
- Outer Membrane - Porous
What is ATP?
- Adenosine triphosphate is the energy currency of the cell.
- The body uses energy stored in ATP to make chemical compounds and to do work.
Similarities of Mitochondria and Plastid.
- Both have their own DNA and ribosomes to make own proteins
Types of Plastids
[ State and write functions ]
- Chromoplast (coloured)
- Leucoplast (colourless or white) - storage of proteins, fats and starch.
Structure of Plastids
Numerous membrane layers embedded in a material called stroma.
