Chapter 10 The cell is the basic unit of life. Using a Microscope - Worksheet (diagram and functions of a microscope) - Lab (p. 394-395) What you are viewing under a microscope (P.393) - Magnified image (larger) - Inverted image (upside down) - Reversed image (backwards) What are living things made of? Early idea: all living things are made of air, fire and water Now: all living things are made of cells (cell theory) Cell: the basic, functional unit of life Characteristics of Living Things/Cells (P. 391 Table 10.1) All living things... 1.Grow 2.Move 3.Respond to stimuli 4.Reproduce Growth A result of the cells in your body increasing in number New cells will grow to replace old cells that die. Examples Movement A change in position, shape or location (locomotion) Respond to Stimuli Stimulus: anything that causes an organism to react. Maybe external or internal Reproduction Producing more of the same kind (offspring)
Parts of a Compound Light Microscope Part Function Eyepiece Used for viewing and contains a lens that magnifies Barrel (Tube) Holds the eyepiece and objective lenses at proper distance from each other Arm Supports the eyepiece and used for carrying Coarse Adjustment Knob Brings an object into focus at low or medium power Fine Adjustment Knob Brings an object into focus at high power Objective Lenses Magnify the image (3 or 4 lenses) Revolving Nosepiece Stage (May have clips) Iris Diaphragm Light Source/Lamp Base Holds the three objective lenses Supports the slide Controls the amount of light reaching the specimen Supplies the light needed to view the slide Supports the entire microscope
The Cell Theory states: The cell is the basic unit of life. All living things are made of one or more cells. All cells come from other living cells. Seven Cell Organelles... Cell membrane: Surrounds and protects the contents of the cell Controls the movement of materials in and out of the cell Cell wall: Found only in plant cells Tough, rigid structure that give plant cells their box-like shape Made mostly of cellulose Chloroplast: Green structures that contain chlorophyll Capture the sun s energy for photosynthesis Found only in plant cells Cytoplasm: Jell-like fluid that in which the organelles float Helps to move materials like food to different parts of the cell Nucleus: Large round structure often visible Contains the chromosomes The control centre of the cell Vacuole: Balloon-like spaces in the cytoplasm Stores materials that cannot be used right away (smaller and more numerous in animal cells) Mitochondrion: (plural: Mitochondria) Oval, bean-like structures Produces energy by breaking down food particles
Plant vs. Animal Cells Vacuole Cytoplasm PLANT CELL ANIMAL CELL Organelle Plant Cell Animal Cell Cell Wall Cell Membrane Brick Shape Round Shape Chloroplast Cytoplasm Nucleus Vacuole large and less small and more Mitochondria What are three main differences between plant and animal cells? 1. Plant cells have chloroplasts 2. Plant cells have cell walls which give them a rectangular, regular shape 3. Plant cells have fewer and larger vacuoles
Dividing Cells Necessary for growth and reproduction Will replace cells that are dead or in need of repair How does this happen? Mitosis Growth and Reproduction depend on cell division Mitosis is the process by which cells divide to produce more identical cells. -Example of cell division for growth: skin cells divide to produce more skin cells to heal a cut or injury. -Example of cell division for reproduction: a bacteria cell divides to become two cells Mitosis occurs in body cells and Meiosis occurs in sex cells (egg and sperm) Videos http://www.sci.sdsu.edu/multimedia/mitosis/mitosis.gif http://www.youtube.com/watch?v=m73i1zk8ea0 http://www.youtube.com/watch?v=zewddr9ho-4 Energy for Cells Cells need energy for all life processes. Energy is stored in food called glucose (a type of sugar) To release energy, cells must carry out cellular respiration, the energy is converted to another form of energy. Takes place in the mitochondrion. Most energy is released as heat. Oxygen is necessary for cellular respiration. Carbon dioxide and water vapour are waste gases produced. These are removed from the cell.