MA+Cells

Chapter 3 CELLS (1) What is a Cell? Cells are very small, only 100 micrometers, and each kind of cell has a different purpose. They all exchange substances with their environment.

(2) What does the cell theory state? The cell theory states that there is nothing smaller than cells, that all living things are made of cells, and that new cells come from old cells. (3) Why are cells so tiny? Cells are so small because they need a large surface area. (4) What are the three main parts of a eukaryotic cell? A nucleus, mitochondria, and plasma membrane. (5) Which of these also occur in prokaryotes (bacteria)? Which one does not occur? The plasma membrane is in both and the nucleus and mitochondria is only in Eukaryotes. (6) How might the nucleus, the endomembrane system, and two of the organelles in eukaryotic cells have arisen? These structures could have developed from the archea who lived in extreme conditions that may be too salty, too hot, or to acidic. (7) What is a tissue? A tissue is a group of cells of the same type do perform the same job. (8) What are the four major types of tissues found in the human body? Also describe each one. Connective tissue: binds and supports body parts Muscular Tissue: moves the body and its parts Nervous Tissue: Receives stimuli and conducts nerve impulses. Epithelial Tissue: covers body surfaces and lines body cavities.