Life science

• Biology is the natural science that involves the study of life and living organisms
• Without biology, it would be difficult to understand the anatomy of humans, animals, and other creatures
• Life sciences


  The study of biology, including the study of organisms like plants, animals, microorganisms, and human beings
• Living things


  • Have self-sustaining processes
  • Can eat, grow, respire, reproduce, obtain and use energy for metabolic processes
  • Include visible organisms and invisible things like viruses and bacteria
• Organisms


  All living things on Earth, including those that move, respire, are sensitive, grow, reproduce, release waste, and consume food
• Cells


  The building blocks of life, the smallest unit of life, with the potential to sustain life
• Types of cells


  • Prokaryotic cells (found in bacteria and archaea, no nucleus or organelles)
  • Eukaryotic cells (found in advanced organisms like animals, plants, and fungi, have a nucleus and organelles)
• Genes


  The basic physical and functional unit of heredity, made up of DNA, containing information required to keep an organism alive
• Evolution


  The change and development of living things over millions of years, explained by the theory of evolution by natural selection
• Eukaryotic cells


  Cells found in more advanced organisms like animals, plants, and fungi. These cells have a nucleus which contains DNA and has organelles.
• Gene


  The basic physical and functional unit of heredity. It is made up of DNA and varies in size. It contains all the information required to keep the organism alive. The information from these genes is passed from the parent to the offspring when the organisms reproduce.
• Evolution


  The change and the way in which living things change and develop over millions of years. The theory of evolution by natural selection has given the best explanation for the huge diversity of species on the planet Earth. For over 4 billion years the natural selection is considered to be carving life.
• Evolution is considered to be the cornerstone of modern biology. It has driven the development of life with the help of genetic mutations.
• Biology is a broad field of study and the study of evolution, ecology and genetics are much broader.
• Longest and largest bone in the human body

  • Femur
• Number of Chromosomes in the human gene

  • 46
• Cell


  The fundamental and structural unit of all living organisms
• Cells are the 'Building Blocks of Life' or the 'Basic units of Life'
• Organisms

  • Unicellular
  • Multicellular
• Functions performed by cells

  • Digestion
  • Respiration
  • Reproduction
• Cells


  • Give rise to tissue
  • Multiple tissues make up an organ
  • Many organs create an organ system
  • Several organ systems functioning together make up the organism
• No knowledge of cells

  More than 330 years ago
• The discovery of the microscope made it possible to observe and study cells in detail
• Robert Hooke


  Coined the term 'cell' after observing dead cells through his microscope
• Anton van Leeuwenhoek


  First observed live cells
• Robert Brown


  Discovered the 'nucleus'
• Matthias Schleiden stated that cells are the building blocks of all plants

  1838
• Theodor Schwann stated that cells are the fundamental units of animals

  1839
• Cell Theory


  Cells are the basic units of all living organisms
• Cell Theory failed to explain how new cells arise
• Rudolf Virchow stated 'Omnis cellula e cellula' which means that new cells come from already existing cells


  1855
• Three important points of the modified cell theory

  • The cell is the basic functional and structural unit of all living organisms
  • All living organisms are made up of cells
  • All cells arise from pre-existing cells
• The female egg (Ovum) is the largest cell in the human body
• The smallest cell is the sperm
• Who first saw and described a live cell?

  • Anton von Leeuwenhoek
• Cell


  The basic functional and structural unit of all living organisms
• All living organisms are made up of cells
• All cells arise from pre-existing cells
• The body units in charge of reproduction are also cells
• Ovum (female egg)

  The largest cell in the human body