Cells+WB

(1) What is a Cell? (2) What does the cell theory state? (3) Why are cells so tiny? 3.2 Evolutionary History of the Human Cell (4) What are the three main parts of a eukaryotic cell? (5) Which of these also occur in prokaryotes (bacteria)? Which one does not occur? (6) How might the nucleus, the endomembrane system, and two of the organelles in eukaryotic cells have arisen? Chapter 4 TISSUES (7) What is a tissue? (8) What are the four major types of tissues found in the human body? Also describe each one.

1. Cells are the the smallest parts of the human body which have properties of living organisms. 2. The cell theory states that all form of life come from cells. It also states that all cells come from pre-existing cells. 3. Cells are so tiny because they have a small surface area / volume ratio. 4. The three main parts of a eukaryotic cell are the nucleus, cytoplasm, and the plasma membrane. 5. Prokaryotes, or bacteria, contain a plasma membrane and a cytoplasm. They do not contain a nucleus. 6. Science suggests that the nucleus, endomembrane system, and two of the organelles could have evolved from the archea, who live around deep sea vents, in extreme environments. 7. A tissue is a large cluster of cells, which hold the human body together. 8. Connective tissue holds the body and limbs together. Nervous tissue conducts stimuli, and connects to the central nervous system. Muscular tissue is responsible for movements in the human body through expansion and contraction. Epithelial tissue provides a "casing" for the body, and protects various organs and bones.