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Chapter 2: The Structure of Viruses and Cells. VIRUSES. Virus - piece of hereditary material covered by protein that infects & reproduces ONLY inside a living cell The living cell is called a host cell. VACCINES. Vaccine- made from damaged virus particles that can ’ t cause disease anymore
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VIRUSES • Virus- piece of hereditary material covered by protein that infects & reproduces ONLY inside a living cell • The living cell is called a host cell
VACCINES Vaccine- made from damaged virus particles that can’t cause disease anymore Edward Jenner (1796) - Developed the first vaccine for smallpox
Latent vs. Active Viruses • Latent- appear to “hide” inside host cell for a certain period of time, until there is a stimulus • Herpes, mononucleosis, HIV, invading flu, cancer • Active- exhibiting symptoms for the disease • AIDS, flu with symptoms
HIV/AIDS HIV = human immunodeficiency virus AIDS = acquired immune deficiency syndrome HIV is the virus that causes the disease AIDS. HIV is spread through: sexual contact, sharing needles with an infected person, blood & body fluids, infected mother to unborn child
How does temperature affect viruses?Graphing Activity page 37
Things to put in your line graph • Title: The Impact of Temperature on the Number of Viruses • Label the x and y axis (x is temperature (C); y is number of viruses (millions) ). • Intervals for y, each line is 0.05, but just label 0.1, 0.2, etc. (skip two boxes, one line break) • Break on x axis • Use whole numbers on x axis, start at 36 and skip 5 boxes b/w each number. • Put your name in upper right hand corner, include t-chart, degrees C on points (dots), questions answered on back.
Answer the following questions on the back of your graph. • What happens to the number of viruses as the temperature increases? • Why do we get a fever when a virus is attacking our body? • What would happen if one had a virus in his/her body, but his/her immune system did not respond?
Cells • Cell:The smallest unit of life. The smallest unit of an organism that can perform all life functions. (grow, reproduce, attain energy and get rid of waste, adaptation)
Cell Theory • All organisms are made up of one or more cells. • Cells are the basic units of structure and function in all organisms. • All cells come from cells that already exist.
Discovering Cells • Robert Hooke first observed cells. (1665) He viewed a piece of cork under a microscope and saw small boxes that looked like cells in a monastery. You see this He drew this
Microscopes • Simple (1 lens) • Anton van Leeuwenhoek • Complex (2 lenses) • Zacharias Janssen Compound Light Microscope
Plant Cell • Plant cells have the same organelles as an animal cell except with the addition of two: • Cell Wall – Extra protection for the plant, rigid • Chloroplast – Makes energy for the cell, photosynthesis • Light energy is trapped in a green pigmented chemical (chlorophyll), and changed into chemical energy in the form of a sugar.