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Life Science Ch. 2


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What is AIDS?
Aquired Immune Deficiency Syndrome- a fatal communicable disease caused by the HIV virus.
Cell Membrane
The structure that forms outer boundary of the cell that only allows certain materials to pass in and out.
Cell Theory
1.All organisms are made up of 1 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.
Cell Wall
A rigid structure outside the cell membrane that supports and protects the plant cell.
Organelles in plant cells in which light energy is changed into chemical energy in the form of sugar. Inside is chlorophyll, a green pygment that traps light energy.
The DNA in the nucleus that controls the cell.
Compound light microscope
A microscope that lets light pass through an object and then through 2 or more lenses. The power= eyepiece lens x objective lens.
Jelly-like fluid that contains the organelles of the cell.
Electron Microscope
A microscope that uses a magnetic field to bend beams of electrons.
Endoplasmic Reticulum (ER)
An organelle that is a folded membrane that moves materials around the cell.
Golgi Body
An organelle that is made of stacks of membrane-covered sacs that package and move proteins outside the cell.
Host Cell
The cell in which a virus reproduces.
The organelle that contains chemicals that digest wastes and worn-out cell parts as well as break down food. When a cell dies, they break it down. A membrane keeps it from breaking down a healthy cell.
Organelles where food molecules are broken down and energy is released to be stored in other molecules that can power cell reactions easily.
The largest organelle of a eukaryotic cell. It directs all the activities of the cell. It contains genetic blueprints for the operations of the cell. (DNA)
A structure made up of different types of tissues that work together to do a particular job.
The structures withing the cytoplasm of eukaryotic cells, each with its own specific job or jobs.
Organ System
A group of organs working together to do a certain job.
A small structure that makes proteins for the cell and is directed by the nucleus.
A group of similar cells which work together to do the same sort of work.
An inoculation that is made from damaged virus particles to prevent a certain disease.
A microscopic particle made of a DNA core surrounded by a protein coat. It infects host cells in order to reproduce.
What are viruses classified by?
Shape, kind of hereditary material they have, kind of organism they infect, method of reproduction
What are the 4 steps to an active virus invasion?
Attatch to the surface of the cell; Invade by injecting its DNA into the cell; copy and take control to force the cell to make new virus particles; release, the cell bursts and the virus particles go infect other cells.
Edward Jenner, an English doctor, developed a vaccine for smallpox in 1796 using what?
Cowpox. He put some on a local boy then introduced the deadlier smallpox repeatedly for 16 years, but the boy was immune to the disease.
What is the "warring" theory between the HIV virus and the body's immune system?
The HIV virus is adapted to mutate rapidly despite the pressures exerted by the host immune system so an infected person may take many years to develop AIDS.
What virus is being modified to be a potential AIDS vaccine?
The modified canarypox virus. It stops the production of HIV viruses by stimulating the immune system to manufacture antibodies against viruses that look like HIV but lack DNA.
In 1590, a Dutch maker of reading glasses, Zacharias Jassen, did what?
He put two magnifying glasses together in a tube, making the first crude compound microscope. Combining 2 lenses enlarged the image more than 1. Early CM weren't satisfactory, the image wasn't sharp or clear.
In the mid 1600s, Anton Van Leeuwenhoek, Dutch scientist, made a simple microscope with a tiny glass bead for a lens. He saw many new things in pond water. What was its power?
270x, 270 times larger than its actual size.
Convex lenses are used for what?
As magnifying lenses. They enlarge the image and bend the light toward your eye.
In a compound microscope, an eyepice lens usually has the power of 10x. That times the power of the objective lens equals the total magnification. What is the highest power some compounds can magnify to?
Up to 2000x
A stereo light microscope gives you a three-dimensional view of an object. It has an objective and an ocular for each eye. What are they used to look at?
Thick structures that light can't pass through, like whole insects or your fingertips.
A transmission electron microscope (TEM) can be used to study parts inside a cell, but it has to be sliced very thin and placed in a vacuum. A scanning electron microscope (SEM) lets you view and photograph living cells. Can you do this with a TEM?
No, because there is no air in a vacuum so only dead cells and tissues can be observed this way.
Cells weren't discovered until the microscope was improved. In 1665, who looked at a very thin slice of cork and named the little empty boxes "cells"?
Robert Hooke, an English scientist.
In 1838, Matthias Schleiden, a German scientist, used a microscope to study plant parts. He concluded what?
All plants were made of cells.
In 1839, Theodor Schwann, a German scientist, after observing many different animal cells, concluded all animals were made up of cells. What did the 2 conclude?
All living things are made of cells.
In 1854, a German doctor, Rudolph Virchow, hypothesized that cells divided to form new cells. During that time what did most people think?
That life came about spontaneously
The cell theory is one of the major theories in science. Based on the hypotheses and observations of many scientists, today it serves as the basis for scientist who study what?
The parts of cells, how cells are organized, and how cells and organisms reproduce and change through time.
What are the two basic types of cells?
Prokaryotic-nuclear material but no membrane (bacteria) and Eukaryotic- nucleus with membrane (animals and plants)

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