chapter 2: the structure of viruses and cells
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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 - PowerPoint PPT PresentationTRANSCRIPT
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
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
Viral DiseasesDisease Affected Body Part VaccineAIDS Immune system no
Chicken Pox Skin yes
Common Cold Respiratory System no
Influenza (flu) Respiratory System yes
HPV Cervix (female) yes
Herpes Skin no
Pneumonia Respiratory System yes
Smallpox Skin yes
HIV/AIDS
HIV = human immunodeficiency virusAIDS = 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
X axis = Temperature (celsius)
Y axis = Viruses (millions)
36.9 1.0
37.2 1.0
37.5 0.5
37.8 0.25
38.3 0.10
38.9 0.05
Things to put in your line graph1. Title: The Impact of Temperature on the Number of Viruses2. Label the x and y axis (x is temperature (C); y is number of
viruses (millions) ).3. Intervals for y, each line is 0.05, but just label 0.1, 0.2, etc.
(skip two boxes, one line break)4. Break on x axis5. Use whole numbers on x axis, start at 36 and skip 5 boxes
b/w each number.6. 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.
1. What happens to the number of viruses as the temperature increases?
2. Why do we get a fever when a virus is attacking our body?
3. 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
1. All organisms are made up of one or more cells.
2. Cells are the basic units of structure and function in all organisms.
3. 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
Prokaryotic vs. Eukaryotic CellsProkaryotic (No) Eukaryotic (You = true)No Membrane Bound Nucleus Has a true membrane bound
nucleusBacterial Cells Animal and Plant Cells
Simple one-celled organisms Complex (one to multi-celled)
The Animal CellOrganelle (structures inside cytoplasm) Function
Nucleus Directs the activities of the cell, and contains DNA.
Cell Membrane Semi-permeable outer Boundary, materials in and out
Cytoplasm Gel-like material where organelles are
Mitochondria Food is broken down and energy is released. Gives power to the cell.
Golgi Body Packages and moves proteins to the outside of the cell
Ribosomes Make Proteins
Endoplasmic Reticulum Moves materials around the cell
Lysosomes Digests waste and breaks down food
Vacuole Stores water and waste
Chromatin Genetic information inside the nucleus
Nuclear Membrane Outer covering of nucleus
Nucleolus Located inside the nucleus where RNA is produced
Diagram of Animal Cell
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.
Plant Cell
Organelle Function
Nucleus CEO, brains of the cell
Cell Membrane Allows materials in and out of cell
Cell Wall Extra Protection for the plant, rigid
Vacuole Stores Waste and Water, very large
Chloroplast Makes Energy for the cell, photosynthesis
Ribosomes Make Proteins
Endoplasmic Reticulum Super highway, move materials around cell
Mitochondria Mighty Mitochondria, powerhouse
Cytoplasm Gel-like material for organelles
Chromatin Genetic information
Nuclear Membrane Outer boundary for nucleus
Diagram of Plant Cell