Chapter 2 Life Science

This week you will be discovering all of the amazing complexities of the cell. All cells on Earth have derived from one single cell about 3.5 billion years ago! Throughout this time our cells have built incredible machines and even incorporated other organisms into their genomes to preform the complex functions we see today.

Below you will find vocabulary, quotes, and notes for each section of Chapter 2 in Glencoe's Life Structure and function. Please read these before class. Assessments for this chapter include a "create-a-cell" project, quizzes, and a final test at the end. It should take about two weeks to learn this chapter so there's a lot of information.
Introduction to cells.

Chapter 2 Section 1
Cells are the building blocks of our bodies.
Organisms are made up of 1 to many cells.
These microscopic amazing micro machines are the key to life’s function.

Vocabulary:
Cell Membrane:
Cytoplasm:
Cell Wall:
Organelle:
Nucleus:
Chloroplast:
Mitochondrion:
Ribosome:
Endoplasmic reticulum:
Golgi body:
Tissue:
Organ:
Cell Theory:
virus:
Host cell:

Notes Chap 2 section 2
Viewing cells, Microscopy
Imagine that you are living in a world where there are no microscopes. How would you explain the world around you? Would you even know about cells? Would you know about anything microscopic? How could we explain how disease works? What is disease anyway?
Not very long ago:
In the1500’s the first microscope was made by a Dutch maker of reading glasses. He combined lenses and got a larger image than could be made by one lens.

In the mid 1600’s Antoine van Leeuwenhoek made a microscope and looked at pond water. He reported seeing things that no one had ever imagined, he called them beasties. We can assume now that he was looking at protists. His microscope could magnify up to 270 times or 270X.
Imagine the unknown world that this discovery opened up. It was like discovering a new continent with all new species of life never known before.

Explore page 50 in the text,
Bright field microscopes (1 dimentional)
Leeuwenhoek microscope (1 dimentional)
fluorescence microscope, transmission electron microscope, scanning electron microscope, phase-contrast microscope.

A simple microscope has 1 lens; an example would be a magnifying glass.

A compound microscope has multiple lenses and is much more powerful.

How do you get the total magnification power of a compound microscope?
Multiply the power of each lens in the scope.
Example- 10X lens piece, 43X objective lens. Multiply together. (10*43=430X power)
Do some examples

How do we see really small things? I mean REALLY small like atoms and parts of cells.
We use an electron microscope. These scopes don’t use lenses. They use a magnetic field in a vacuum to direct beams of electrons.

Different electron microscopes serve different purposes such as 1-D, 2-D, or 3-D.

Development of Cell Theory:
Cells weren’t discovered till the microscope was improved.
In 1665, Robert Hooke cut a thin slice of cork and examined it under a microscope. The cork seemed to be made up of little boxes, this reminded him of rooms in a monastery, these rooms were called cells. He therefore named the box-like structures cells.

Schleiden and Schwann claimed that plants and animals are made up of cells.

Virchow hypothesized that cells divide to form new cells.

Cell theory: (three parts)
1-All organisms are made up of cells
2-The cell is the basic unit of organization in all organisms.
3-All cells come from cells.

Notes: Viruses

Chapter 2 section 3.

What are Viruses?
What viruses do we know about from class and your personal lives?

A virus is a strand of hereditary material (DNA or RNA) surrounded by a protein coating.
No nucleus, no organelles, no cell membrane
Viruses come in a variety of shapes.
Not considered alive by definition.

Virus existence was proven when the electron microscope was invented. They are too small to be seen with a light microscope.

How do they multiply?
They don’t reproduce like most organisms, they make copies of themselves.
They need a host cell.
They can exist in the environment for years without a host and not die.
Once inside a host they can be active or latent. (inactive)

Review figure 15 virus replication. Draw on the board.

Active Viruses:
Causes the host cell to make new viruses and kills the host cell.

Latent Viruses:
A virus can enter a cell and incorporate itself into the host’s DNA. When the host cells duplicate the virus DNA is also duplicated. Under the right conditions, the virus can activate. HIV AIDS Herpes, cold sores

How are organisms affected?
Viruses can attack specific cells. Some may infect only one species. Some such as rabies can infect all animal species.

Viruses attach to cells like two puzzle pieces fit together. If they don’t fit perfectly than the virus cannot attach.

A virus that only attacks bacteria is called a bacteriophage.

Vaccines: A weakened strain of the virus can be injected into you so that your body can build up immunities to it. You body makes what are called interferons and antibodies, protein coats that protect your cells. If your body is immune to the virus then you won’t be affected if you are infected.

Edward Jenner developed the first vaccine in 1796 for smallpox.

What vaccines have you had? MMR, polio…etc.

In the near future, viruses may be used for helpful purposes. Since viruses incorporate their genes into your genome, we may be able to change defective genes in your body. The engineered virus would carry the new gene.

Antibiotics are used for bacterial infections and do absolutely nothing for viruses.