Introduction

INTRODUCTION

• Biology : The branch of science that deals with the study of living things.

• Branches of Biology
  • Botany : The branch of biology that deal with plant life
  • Zoology : Branch of biology dealing with animals .

• Plants : Primary producers of nature
• Flora : The plants of a particular region
• Fauna : The animals of a particular region
• The term Biology was coined by : Lamarck
• Father of Biology : Aristotle
• Father of Botany : Theophrastus
• Father of Zoology : Aristotle
• Father of modern biology : Charles Darwin
• Father of modern botany : Carl Linnaeus
• Father of molecular biology : Linus Pauling
• The term Species was coined by : John Ray
• The famous book of Aristotle : History of Animals
• The famous book of Theophrastu : Historia Plantum
• Father of Indian Botany : William Rosburgh
• The branch of biology which deals with the study of orgin of life : Abiogenesis
• The life originated from : Water
• The first successful experiment based on the orgin of life was done by : A.I Oparin(1932)

CELL

• Structural and Fundamental unit of life . All living organisms are made up of cells. The word cell is from the Latin word cellula.
• Cells are known as the building block of life .It was discovered and named by Robert Hooke (1665).
• The book ‘Micrographia’ was written by Robert Hooke.
• First to observe living cells such as bacteria, Protozoa and blood cells: Anton Van Leuwenhook.

Milestones in the history of cell biology

• Robert Brown : Discovered the centre of the cell and named it the nucleus(1831).
• M.T. Schleiden : Found out that the body of a plant is made up of cells(1838)
• Theodor Schwann : Found out that the body of an animal is made up of cells(1839)
• Rudolf Virchow : Observed dividing cells and inferred that new cells arise only from existing cells(1858).
• Study of cells : Cytology
• Study of tissue : Histology
• Cell Theory was formulated by M.J Schleiden and Theodor Schwann
• Scientist who modified cell theory : Rudolf Virchow
• The smallest cell : Mycoplasma(PPLO-Pleuro Pneumonia Like Organism)
• The largest cell : Unfertilized egg of ostrich
• The largest cell in human body : Ovum
• The smallest cell in human body : Sperm
• Longest cell in human body : Neuron(Nerve cell)
• The cell with longest lifespan in human body : Neuron
• The largest number of cell in human : RBC (Red Blood Cells)
• They are two types of cell:
  • Prokaryotic cell
  • Eukaryotic cell
• Prokaryotic cell : Cell without nucleus
• Eukaryotic cell : Cell with nucleus

Structure of the cell

• Cell wall : Outermost covering of the plant cell . It is made up of cellulose . It is a non living part of the cell.It is absent in animal cells.
• Cell membrane : Outermost covering of animal cell.
• Protoplasm
  • All the components of a cell internal to the cell membrane.
  • It is regarded as the Physical basic of life.
  • The fluid living content of cell that consist of cytoplasm & nucleoplasm

• Cytoplasm : The portion of protoplasm without the nucleus.
• Ribosome : Protein synthesis is done by Ribosomes
• Endoplasmic Reticulum(ER) : It is known as Skeletal system of the cell.
• Nucleus
  • Brain of the cell
  • All cellular activities are controlled by nucleus
  • It is only found in eukaryothic cells

• Chromosomes
  • Thread like units occurs in the cells during the time of cell division
  • It is madeup of DNA and proteins.
  • Chromosomes other than the sex chromosomes are called autosomes
  • Number of autosomes in human cell is 44 (22 pair) and number of sax chromosomes are 2

• Nucleic acids : The two different nucleic acids found in the cells of every living organism- DNA and RNA
• DNA : Deoxyribonucleic acid (found in nucleus and mitochondria)
• RNA : Ribonucleic acid(found in cytoplasm)
• The structure of DNA was 1st deduced by Waston and Crick
• Golgi bodies :
  • It is known as traffic police of the cell.
  • It is the secretory organelle of the cell.

• Mitochondria
  • The power house of the cell.
  • It converts oxygen and nutrients in to energy.
  • In mitochondria, the energy is stored in the form of ATP.
  • ATP – Adenosine Triphosphate.
  • ATP synthesis is takes places in Mitochondria.
  • The universal biological energy currency of the cell:ATP.
• Lysosomes :
  • Lysosomes are sac like structure bounded by a single membrane , known as suicidal bags
• The enzyme which is present in the lysosome is Hydrolytic enzyme.
• It is the digestive system of the cell

• Vacuoles :
  • It is a fluid filled sac within a cell.
  • In plant cells the vacuoles are large in size.
  • Animal cells either do not have a vacuole or they have very small vacuoles.
• Plastids :
  • Flat ,circular organelles found in plant cells
  • Plastids are absent in animal cells.

Three types of plastids

1. Chloroplasts : The green plastid found only in photosynthesis plant cells. It is known as the Kitchen of the cell.
2. Leucoplasts : These are the white or colourless plastids
3. Chromoplasts : These are coloured plastids which gives various colures to the flowers and
   leaves of plants.

Exambles of chromoplasts
Cur cumin : Yellow color of the turmeric.
Lycopine : Red color of the Tomato.
Carotene : Orange color of Carrot.

CELL DIVISION

• The process by which a parent cell divides into two or more daughter cells. Two types of cell division
• Mitosis : The cell division that takes place in plant and animal cells for the growth.
• Meiosis : The cell division that occurs in reproductive cells.
• Karyokinesis: Division of nucleus during cell division.
• Cytokinesis : Division of cytoplasm.