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Preliminary Biology Notes of All Topics

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Year 11 Preliminary Biology

Full Syllabus Dot Point Notes

Patterns in Nature, the Local Ecosystem, Life on Earth & Evolution of the Australian Biota


Patterns in Nature

  1. Organisms are made up of cells that have similar structural characteristics

  1. Outline the historical development of the cell theory, in particular the contributions of Robert Hooke and Robert Brown
  • The cell theory:
  • All living things are composed of cells
  • The cell is the smallest unit of life
  • All living cells arise from pre-existing cells
  • Historical development:
  • 1485 - Leonardo da Vinci used glass lens to study small objects
  • 1626 - Francesco Redi conducted experiment which disproved spontaneous generation thus proving ‘all living cells arise from pre-existing cells’
  • 1665 – Robert Hooke observed cork cells using a compound microscope and described ‘little boxes or cells distinct from one another’
  • 1676 - Anton von Leeuwenhoek described unicellular organisms - bacteria - in pond water (animalcules)
  • 1831 - Robert Brown observed the nucleus in plant and animal cells
  • 1839 - Schleiden and Schwann formulated the cell theory that ‘cells are a small unit of life and ‘all living things are made up of cells’
  • 1858 - Virchow stated: ‘where a cell exists, there must have been a pre-existing cell, just as the animal only arises from an animals and the plant only from a plant.’
  • 1933 - Max Knoll and Ernst Ruska developed the transmission electron microscope
  • 1965 - Cambridge Instruments produced first scanning microscope
  1. Describe the evidence to support the cell theory
  • All living things are composed of cells: Leeuwenhoek discovered unicellular organisms
  • Cells are the smallest unit of life: Hooke discovered that the cork is made up of cells
  • All living cells arise from pre-existing cells: Virchow observed cells dividing, disproving spontaneous generation
  1. Discuss the significance of the technological advances to the development of the cell theory
  • Invention and further development of the microscope: Robert Hooke’s development of the compound microscope enabled him to see the basic structure of cells
  • Improvements were made to lenses- increased resolving power and allowed more detailed observations of the cell structure.
  • Robert Brown’s later development of a single lens microscope was used to identify the cell nucleus.
  • Ernst Ruska built the first electron microscope in 1933, which allowed a more detailed observation of all cell structures = organelles
  1. Identify cell organelles seen with current light and electron microscope

Light Microscope

Electron Microscope

Nucleus

Nucleus

Nucleolus

Nucleolus

Vacuoles

Vacuoles

Chloroplast

Chloroplast

Cell Wall

Cell Wall

Mitochondria

Mitochondria

Golgi Body

Cell Membrane

Endoplasmic Reticulum (smooth and rough)

Lysosomes (mostly animals, rare in plants)

Ribosomes

Peroxisomes

  1. Describe the relationship between the structure of cell organelles and their function

Organelle

Structure

Function

Mitochondria

Smooth outer membrane, highly folded inner membrane (structure called matrix, edges called cristae)

Site of respiration and creation of ATP for cell energy

Chloroplasts

Plastids containing pigments e.g. chlorophyll stored in internal membrane stacks

Site of photosynthesis in green plants

Golgi Body/Apparatus

Flattened membrane bound sacs

Store and secrete important biochemical e.g. proteins and lysosomes

Lysosomes

Membrane bound spheres or ovals with lipid bilayer

Contain digestive enzymes to digest unwanted material within the cell

Smooth and Rough Endoplasmic Reticulum (ER)

Membrane bound channels, where some are smooth (do not consist of ribosomes attached to the outside) and some rough (has ribosomes attached to it)

Rough ER collects polypeptides and amino acids from the cytosol and assembles proteins for transportation. Smooth ER manufactures lipids and sometimes continues it metabolism process

Ribosomes

Small spherical bodies either moving freely or connected to rough endoplasmic reticulum

Site of protein synthesis

Nucleus

Membrane bound sphere containing DNA, chromosomes and in some cases RNA

Control centre of cell

Cell Membrane

Flexible semi-permeable membrane – hydrophilic heads and hydrophobic tails consisting of proteins and lipids with a phospholipid bilayer

Selective transport of substances in and out of cell

Cell Wall

Rigid external coating around the cell membrane made of cellulose (plants) or other material e.g. Silica, chitin, etc.

Supports and strengthens cell

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