CELLS

The Cell Overview
Early Contributions
Robert Hooke - The first person to see cells, he was looking at cork and noted that he saw "a great many boxes. (1665)
Anton van Leeuwenhock - Observed living cells in pond water, which he called "animalcules" (1673)
Theodore Schwann - zoologist who observed that the tissues of animals had cells (1839)
Mattias Schleiden - botonist, observed that the tissues of plants contained cells ( 1845)
Rudolf Virchow - also reported that every living thing is made of up vital units, known as cells. He also predicted that cells come from other cells. (1850 )

The Cell Theory
1. Every living organism is made of one or more cellss.
2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions.
3. All cells arise from pre-existing cells.

*Why is the Cell Theory called a Theory and not a Fact?
Cell Features

Ribosomes - make protein for use by the organism
Cytoplasm - jelly-like goo on the inside of the cell
DNA - genetic material
Cytoskeleton - the internal framework of the cell
Cell membrane - outer boundary of the cell, some stuff can cross the cell membrane.

Types of Cells
Prokaryotic Cells
Prokaryotes are very simple cells, probably first to inhabit the earth.
Prokaryotic cells do not contain a membrane bound nucleus.
Bacteria are prokaryotes.
DNA of bacteria is circular.
The word "prokaryote" means "before the nucleus"

Other features found in some bacteria:

Flagella - used for movement
Pilus - small hairlike structures used for attaching to other cells
Capsule - tough outer layer that protects bacteria, often associated with harmful bacteria
Eukaryotic Cells
Eukaryotic cells are more advanced cells.
These cells are found in plants, animals, and protists (small unicellular "animalcules").


The eukaryotic cell is composed of 4 main parts:
cell membrane - outer boundary of the cell
cytoplasm - jelly-like fluid interior of the cell
nucleus - the "control center" of the cell, contains the cell's DNA (chromosomes)
organelles - "little organs" that carry out cell functions

ORGANELLES WITH DNA
* The Mitochondria and Chloroplasts have their own DNA
* ENDOSYMBIOSIS THEORY - eukaryotic cells evolved from the engulfing of bacteria cells, thus creating additional cell parts

CELL MEMBRANE
* Function: to regulate what comes into the cell and what goes out
* Composed of a double layer of phospholipids and proteins

Cell projects

Cell Project
Purpose: The purpose of this projectis to make a 3D model of a cell in order to better understand the parts and workings of a cell.
Using household items make a three-dimensional model of a plant or animal cell that meets the criteria listed below. (Sample items: cereal, balloons, gummi worms, mints, fruit slices, dried fruit, matches, gum balls, peanuts, rope licorice, jelly beans, sesame seeds, other candies, toothpicks. Craft packages also may work: clay, beads, pipecleaners..etc)

Choose what type of cell you will build, a typical plant or animal cell. Include this label somewhere on your model.
Create a KEY or label in some way each part on your model and its function.
Cell Project Rubric

Category Scoring Criteria Excellent
(3 pts) Satisfactory
(2 pts) Needs Work
(1 pt)

Craftsmanship Model cell is creative and shows effort
The model is 3 dimensional
Model stays together, is not too messy or cumbersome to move around

Cell Parts Type of cell and student name are found on both the key and the model
Key, legend, or labeling easy to use to identify the parts on your model
Accurate description of the function of each cell part is provided
Appropriate material is used (item looks like the cell part)
Shape corresponds to the type of cell: plant or animal

Written word Grammar, spelling
Score Total Points