Ch. 4 Structure & Function of the Cell

1. Ch. 4 Structure & Function of the Cell • What is the smallest unit in an organism that is able to carry out all the processes of life? • Cells • What would an organism be called if it has only one cell? • Unicellular • An organism with more than one cell is called this? • Multicellular

2. Cell Theory • 1. All living organisms are composed of cells. • 2. All cells come from existing cells. • 3. These cells are the organism’s basic units of structure and function.

3. Cell Discoveries • Robert Hooke- a British scientist who discovered cells in a slice of cork with a microscope in 1665. The cells were dead. • This was the first reported discovery of cells. • Anton van Leeuwenhoek- was the first to observe living cells almost ten years after Hooke’s discovery of dead cells.

4. Schleiden- expanded on cell observation by discovering that all plants have cells in 1838. First to see plant cells. • Schwann- discovered all animals have cells a year later.

5. Cell Structure • All of a cell’s food, oxygen, and other material enter through its surface and the wastes exit through the surface also. • The shape and size of a cell varies greatly, even among the same organism. • Pg. 70 • What is the large structure in most cells, that is usually near the center? • Nucleus • Eukaryote- organisms with a nucleus. • Prokaryote- organism without a nucleus.

6. Cell Organelles • An organelle is a cell component that performs a specific function in the cell. • 1. Cell Membrane- separates the cell from other cells. It allows substance in and out of the cell. • 2. Cytoplasma- saltwater fluid that protects the cell. • 3. Nucleus- directs the activity of the cell.

7. 4. Nuclear envelope- is a membrane that surrounds the nucleus. Lets things in and out of the nucleus. • 5. Nucleoplasm- a protein substance that makes up most of the nucleus. • 6. Chromatin- are fine strands that contain DNA and proteins.

8. 7. Chromosomes- made up of chromatin, which coils up when the cell divides. • How many chromosomes are in the cell? • 46 • 8. Nucleolus- controls protein synthesis.

9. Parts outside the nucleus • 9. Endoplasmic reticulum- a membrane system used to store proteins. 2 Types 1. Smooth E.R.- few if any ribosomes 2. Rough E.R.- covered with ribosomes 10. Ribosomes- site of protein synthesis. 11. Golgi apparatus- is where protein packing & processing takes place.

10. 12. Mitochondria- is the site of respiration. This is where energy is released within the cell. • This is where ATP is formed. • ATP provides chemical energy to produce chemical reactions in the cell. • Where would you find ATP in your body? • 13. Lysosomes-digestive enzymes that break down broken cells and diseases. • 14. Cytoskeleton- a complex unit of proteins in the cytosol for support and movement of organelles with the cell.

11. Microfilaments are thin threads of the cytoskeleton that aid in cell movement and contractions. • Microtubules are larger strands in the cytoskeleton that extend out from the nucleus to the cell membrane. These microtubules come together to form spindle fibers during mitosis to move chromosomes • Cilia- short hair like extensions that line the outside surface of a cell. • Flagella- is a longer hair like extension, with a whip like appearance.

12. Plant Cells • Differences Between Plant & Animal Cells • 1. Cell Wall- helps support and protect the plant cell. Cellulose is found here. • 2. Plastids- store pigments and food in the cell. • Chloroplasts- makes chlorophyll • Chromoplasts- makes colorful pigments • Leucoplasts- stores starches, proteins, and lipids

13. 3 things that plant cells have that animal cells may not. • 1. Cell wall • 2. Plastids • 3. Vacuole – some animal cells may not have this.

14. Cell Organization • CELLS  TISSUES ORGANS  ORGAN SYSTEMS  ORGANISMS • ORGANISMS  POPULATIONS  COMMUNITIES  ECOSYSTEMS  BIOSHPERE