ANS102

• Characteristics of living organisms
• Process by which a single cell divides into a complex animal body

  Represents an unbroken chain of reproductive cell division, all the way to original ancestors – 4 billion years ago
• Life


  Difficult to define but all living things share general properties
• Basic building blocks of life

  • Water
  • Carbon dioxide/ nitrogen rich organic molecules
• Macromolecules categorised into


  • Nucleic acids
  • Proteins
  • Carbohydrates
  • Lipids
• Proteins


  Formed from folded amino acid polymers, whose production is coded for by DNA. All organisms on Earth use the same DNA code. Proteins are used as structural building blocks (eg. collagen) or as catalytic enzymes.
• Complexity and hierarchical organisation in living systems

  • Macromolecules
  • Cells
  • Organisms
  • Populations
  • Species
• Reproduction


  Life cannot arise spontaneously but only from existing cellular life
• Reproduction through germ cells

  1. Germ cells (immortal cells which give rise to ova and sperm) there is an unbroken chain of cell division back through time to the first ancestral protocell

  2. At each level of the biological hierarchy living forms reproduce to generate others like themselves: genes replicate to produce new genes; cells divide to produce new cells; organisms reproduce, sexually or a-sexually, to produce offspring; populations fragment to produce new populations; species split over evolutionary time to produce new species.
• Possession of genetic program

  Nucleic acids encode the stricture of protein molecules which make up the structural and functional components of cells and bodies of living organisms
• Metabolism


  Living organisms maintain themselves by acquiring nutrients from their environments, and using this energy to power chemical reactions. Metabolic processes such as digestion of food, cellular energy production, and the synthesis of molecules and structures to build animal bodies take place at the level of chemical reactions within cells. Chemical reactions which break molecules into smaller parts to release energy are terms catabolic reactions, while reactions which build (synthesise) larger molecules are termed anabolic reactions.
• Development


  Characteristic changes that an organism undergoes from its origin to its final adult form. The processes and transitions which take place during the development of an animal vary between different animal groups. For example, some animals such as amphibians (e.g. frogs) and many invertebrates (e.g. butterflies) under metamorphosis during their development from a larval form to the adult form.
• Environmental interaction


  All organisms respond to environmental stimuli, a property called irritability.
• Movement


  Living systems and their parts show precise and controlled movements at many levels - from the movements of substances or organelles within cells, to the movements of organs or of large and complex external appendages.
• The history of life of Earth, demonstrates continuous change over time, from simple cellular beginnings to complex multicellular animals.
• Definition of 'animal'


  Multicellular; heterotrophic (energy from consumption of other organisms); capable of sexual reproduction; lack a rigid cell wall; are motile at some stage; and respond to external stimuli (usually)
• Carbohydrate


  Compounds made up of carbon, hydrogen, and oxygen atoms. They are one of the main types of nutrients and serve as a primary source of energy for living organisms. Carbohydrates can be divided into three main groups: sugars, starches, and fibres
• Amino acid


  Organic compounds that serve as the building blocks of proteins. They are composed of an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a side chain (also known as an R group) that varies among different amino acids. There are 20 standard amino acids that are commonly found in proteins.
• Nucleic acids


  Biopolymers, or large biomolecules, that are essential for the storage, expression, and transmission of genetic information in living organisms. They are composed of monomers called nucleotides, which consist of three components: Phosphate group, sugar molecule and nitrogenous base. DNA and RNA are examples.
• Proteins


  Large, complex molecules that are essential for the structure, function, and regulation of cells, tissues, and organs within living organisms. They are made up of long chains of amino acids, which are linked together by peptide bonds.
• Collagen


  Fibrous protein found in the extracellular matrix and connective tissues of animals, including mammals, birds, reptiles, and fish. It is the most abundant protein in the animal kingdom, comprising about one-third of the total protein content in mammals.
• Enzymes


  Specialized protein molecule that acts as a biological catalyst, facilitating and accelerating specific biochemical reactions within living organisms. Enzymes play crucial roles in various physiological processes, including metabolism, digestion, cellular signaling, and detoxification.
• Autotroph


  An organism that can produce its own organic compounds, such as sugars and other biomolecules, from inorganic sources of carbon and energy. Autotrophs are the primary producers in ecosystems because they are capable of synthesizing organic molecules from simple inorganic substances through processes like photosynthesis or chemosynthesis.
• Heterotroph


  An organism that cannot produce its own organic molecules from inorganic sources and, therefore, relies on consuming other organisms or organic matter for energy and nutrients
• Metabolism


  Refers to the complex set of biochemical processes that occur within living organisms to maintain life. It involves the conversion of nutrients into energy and the synthesis or breakdown of molecules necessary for cellular function, growth, and reproduction.
• Reproduction


  Biological process by which living organisms produce offspring, ensuring the continuation of their species. It is a fundamental characteristic of all living organisms and is essential for the survival and propagation of species.
• Movement


  Refers to the ability of animals to change their position or location in response to internal or external stimuli. Movement is a fundamental characteristic of animals and is essential for various biological functions, including feeding, escaping predators, mating, and finding suitable habitat
• All living organisms are composed of cells
• No life without cells
• Cells


  Basic structural and functional unit of life
• Cells are the fundamental unit of structure and function, and the lowest 'organisational unit' capable of 'life'. Cells can only originate through division of pre-existing parent cells.
• Characteristics of cells


  • Boundary, semi-permeable membrane and internal DNA
  • Cell membrane is formed of a lipid bilayer which has important properties for the passage or transmission of different molecules across the cells surface
  • Diffusion and osmosis are passive movements of solutes and solvents respectively across the cell membrane
  • Other molecules require active transport to be moved across the cell membrane
• Prokaryotic cells


  Earliest life were single celled organisms without internal cell organelles or the arrangement of genetic material into chromosomes
• Eukaryotic cells


  Have many internal membranes creating specialised compartments known as organelles, including a membrane-bound nucleus and internal 'machinery' such as mitochondria, endoplasmic reticulum, ribosomes, golgi bodies, and a supporting cytoskeleton.
• Animals


  Multicellular and have 'division of labour' among specialised cells, grouped to form tissues. Anatomically and/or functionally discrete clumps of tissue(s) form organs. Bodies do not consist only of cells but also extracellular matrix and fluid.
• Broad categories of tissues

  • Epithelial
  • Connective
  • Muscular
  • Nervous
• Connective tissue


  Consists of individual cells scattered within an extracellular matrix. Unlike cells of epithelial tissue, connective tissue cells are not directly attached to one another.

  
• Most common connective tissue cells

  • Fibroblasts
  • Adipocytes
  • Mast cells
  • Macrophages
  • Lymphocytes

  
• Connective tissue matrix


  Composed of ground substance and fibres. Ground substance; typically water stabilized by glycosaminoglycans, proteoglycans, and glycoproteins. In bone the ground substance includes mineralised calcium salts. In blood, the ground substance is fluid (plasma). Fibres: the principal fibre type is collagen which provides strength with flexibility; elastic fibres confer resiliency. The matrix is produced by fibroblasts (or related cell types -- chondroblasts in cartilage and osteoblasts in bone)
• Prokaryote


  • Lack a nucleus
  • Bacteria's
  • Genetic material in nucleoid
  • No membrane bound organelles
  • Smaller in size