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.
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