2. Cells All living life forms are made of cells All cells have the same basic structure

3. Discovery of Cells Robert Hooke is known for using the microscope to look at pieces of a cork Those pieces reminded him of little boxes or what he called “cells”

4. Anton van Leeuwenhoek used a more powerful microscope to discover tiny animals in pond water He called them animacules We know now he saw single celled organisms

5. Cell Theory All living things are made up of one or more cells Cells are the basic units of structure and function in organisms All cells arise from existing cells

6. Which of the following led to the discovery of cells? A. Electricity B. Computers C. Microscopes D. Calculators 1.

7. Which of the following is part of the cell theory? A. All living things are made of one cell B. Cells are the basic units of structure and function in organisms C. Most cells arise from existing cells. D. Cells are nonliving units that make up organisms 2.

8. Looking at Cells A cell’s shape reflects the cell’s function Cell Shapes: Branched Flat Round Rectangular

9. There are at least 200 types of cells The human body is made up of 100 trillion cells

10. Cell Size All substances that enter or leave a cell must pass through the surface of the cell As a cell gets larger, it takes up more nutrients and releases more wastes

11. Cell size is limited by the cells surface area to volume ratio Cells with greater surface – to – volume ratio can exchange substances more efficiently

12. Cell features All cells have: A Cell Membrane Cytoplasm Ribosomes DNA

13. Cell Membrane The cell’s outer boundary Acts as a barrier between the cell and its environment

14. Cytoplasm Includes cytosol (fluid inside cell) and almost all the structures of a cell are suspended in the fluid Many ribosomes are found here

15. Ribosomes Cellular structure on which proteins are made

16. Prokaryotes vs Eukaryotes Prokaryote – single celled organism Eukaryote – Multicellular organism

17. Prokaryote Contain DNA Do not contain a nucleus Came before eukaryotes First appeared about 3.5 billion years ago

18. Eukaryotes Contain a nucleus that holds DNA Organelle – a structure that carries out specific activities inside the cell

19. The size to which cells can grow is limited by their A. Location B. Structure C. Function D. Surface area to volume ratio 3.

20. One difference between prokaryotes and eukaryotes is that prokaryotes do not have A. DNA B. A cell membrane C. Cytoplasm D. A nucleus 4.

21. Which cells have a cell membrane, cytoplasm, ribosomes, and DNA? A. Only animal cells B. Only prokaryotic cells C. Only eukaryotic cells D. All cells 5.

22. The genetic material that provides instructions for making proteins is A. DNA B. Cytosol C. Cytoplasm D. A ribosome 6.

23. A structure within a eukaryotic cell that carries out specific activities inside the cell is called a A. Organelle B. Cytoplasm C. Nucleus D. Membrane 7.

24. Which of the following statements about prokaryotes is correct? A. They have a nucleus B. Their evolution preceded that of eukaryotes C. The organelles in their cytoplasm are surrounded by membranes D. They are multicellular organisms 8.

25. Only eukaryotic cells have A. DNA B. Membrane – bound organelles C. Ribosomes D. Cytoplasm 9.