Cells: The Building Blocks of Living Things

CHARACTERISTICS OF LIVING THINGS:

Living things are often referred to as organisms. Before a thing can be classified as an organism, it must show all of the characteristics of living things.

1. Living things are composed of cells.

2. Living things reproduce, grow, and repair themselves.

3. Living things require energy.

4. Living things respond to the environment.

5. Living things have a life span.

6. Living things produce wastes.

CELL THEORY:

•All living things are composed of cells

•All cells come from pre-existing cells

PLANT & ANIMAL CELLS

Animal Cell Structures:

1. The Nucleus: the control center and directs all of the cell’s activities

2. Chromosomes: found inside the nucleus which contain genetic information (DNA)

3. Cell Membrane: acts like a gatekeeper, controlling the flow of materials into and out of the cell

4. Cytoplasm: watery fluid which keeps the cells structure solid; also transportation

5. The Vacuole: used to store water and nutrients, such as sugar and minerals

PLANT CELL STRUCTURES

- Contain the same features as animal cells, but they also have some special structures not found in animal cells.

- 1. The Vacuoles: filled with nutrients just like in animal cells, but takes up a much larger part of the cytoplasm. WHY?

- 2. The Cell Wall: protects and supports the plant cell. Animal cells do not have cell walls

- 3. Chloroplasts: contain molecules of green chemicals called chlorophyll…which allows the plant to make food. WHAT IS THIS PROCESS CALLED?

Photosynthesis: process by which plants produce their own food

Structures for Movement:1. The Flagellum: whiplike tail that helps some cells to move, they are not found on all cells

2. Cilia: tiny hairs that work together to move a cell, they are not found on all cells

Technological Advances of the Microscope:

• A. Single-Lens Microscope: invented by Anton Van Leeuwenhoek in the 1600’s that can magnify objects by 10X its size.

• B. Compound Light Microscope: limited to about 2 000X magnification (like the ones we use at school)… used light to pass through the specimen.

• C. Transmission Electron Microscope: capable of 2 000 000X magnification…instead of light it used beams of electrons to pass through the specimen.

• D. Scanning Electron Microscope: uses electrons that are reflected off a specimen…allows for three dimensional images to be created.

• Questions:

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