Life Sciences

• Cells


  The basic units of life
• 7 Characteristics of life

  • Movement
  • Respiration
  • Sensitivity
  • Nutrition
  • Excretion
  • Reproduction
  • Growth
• Biological organisation


  Atom -> Molecule -> Cell -> Tissue -> Organ -> Organ System -> Organism -> Population -> Community -> Ecosystem -> Biosphere
• Atom


  The smallest particle of matter
• Molecule


  A cluster of atoms
• Organelle


  Structure in a cell
• Cell


  Smallest unit of life
• Tissue


  A group of cells working together to perform the same function
• Organ


  A group of tissues working together to perform the same function
• Organ System


  A group of organs working together to perform a function as a whole
• Organism


  A living animal or plant
• Population


  A group of organisms of the same species in a certain area
• Species


  A group of organisms that have similar characteristics, that can interbreed and produce fertile offspring
• Community


  Different populations in a certain area interacting with each other
• Ecosystem


  An area where living organisms interact with each other as well as their non-living environment
• Biosphere


  The part of Earth and its atmosphere that can support life
• Cells are the basic units of life
• Cells


  • Structural and functional
  • All living organisms consist of 1 or more cells
• Cell characteristics


  • Most cells are microscopic: cannot be seen by the naked eye
  • Cells are measured in micrometers (μm)
  • Cells are differentiated - they have different shapes and sizes
  • Cells are specialized-they have different functions
• Organelle


  A subcellular structure that has one or more specific jobs to perform in the cell, much like an organ does in the body. Present in both plant and animal cells
• Cell membrane


  Thin living membrane that encloses the contents of the cells, is selectively permeable (controls entry and exit of cells), and acts as the security fence
• Cytoplasm


  Jelly-like substance made up of water, proteins and sugars, has many organelles with different functions, and is where many chemical reactions take place
• Nucleus


  Enclosed by nuclear membrane, contains nucleoplasm (the fluid inside), has a dense body called the nucleolus, controls the activities of the cell, and contains DNA (deoxyribonucleic acid) found in the chromatin network
• Mitochondrion


  Rod-shaped, powerhouse of the cell, performs cellular respiration - the breaking down of glucose to release energy (ATP)
• Plant cell structures


  • Cell wall (non-living, consists of cellulose, fully permeable, maintains shape, supports & strengthens the cell)
  • Chloroplast (contains chlorophyll, site of photosynthesis)
  • Large vacuole (maintains cell shape, stores water and nutrients)
  • Differences from animal cells: rigid/regular shape, presence of cell wall, larger vacuole, presence of chloroplasts
• Learning Activity


  • Turgor (pressure created when plant cells fill with water)
  • Chloroplast (cell organelle that contains chlorophyll)
  • DNA (deoxyribonucleic acid, the molecule that contains the genetic information of the cell)
  • Nucleoplasm (the liquid part of the nucleus)
  • Nucleolus (the dense area in the nucleus of a cell)
  • Cellulose fibres (the type of fibres that make up cell walls)
  • Mitochondria (the "power houses" of a cell)
  • Tonoplast (the membrane around a plant cell's vacuole)
  • Gene (the smallest unit of genetic material found in the nucleus of a cell)
  • Metabolism (the chemical reactions that take place in a cell)
  • Chromatin network (the structural and functional network that consists of chromosomes, found in the nucleus)
• The pressure created when the vacuoles in plant cells fill with water is called turgor
• Chloroplasts are the cell organelles that contain chlorophyll
• DNA (deoxyribonucleic acid) is the molecule that contains the genetic information of the cell
• The liquid part of the nucleus is called the nucleoplasm
• The dense area in the nucleus of a cell is called the nucleolus
• The type of fibres that make up cell walls are cellulose fibres
• Mitochondria are the "power houses" of a cell
• The membrane around a plant cell's vacuole is called the tonoplast
• The gene is the smallest unit of genetic material found in the nucleus of a cell
• Metabolism refers to the chemical reactions that take place in a cell
• The chromatin network consists of the structural and functional network of chromosomes found in the nucleus
• Compound light microscope


  Instrument used to view small objects, consists of lenses, mirrors, and other components that allow for magnification and illumination of the specimen
• Slide preparation


  Cover slip used to cover specimen, scalpel used to cut specimen, dropper used to place cover slip on specimen
• Body cavities


  Internal chambers that protect delicate organs and permit changes in the size and shape of organs without disrupting their functions