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Cell Structure and Function. Unit 2 H=Chap. 4. What is a cell? Give me 2 examples. Types of Cells. Animal. Bacterial. Plant. Discovery of the Cell (4-1). In 1665, the English scientist ROBERT HOOKE, used a microscope to examine a thin slice of cork.
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Cell Structure and Function Unit 2 H=Chap. 4
What is a cell? Give me 2 examples
Types of Cells Animal Bacterial Plant
Discovery of the Cell (4-1) • In 1665, the English scientist ROBERT HOOKE, used a microscope to examine a thin slice of cork. • He described it as consisting of “great many little boxes”. • It reminded him of the small rooms in which monks lived… CELLS!
Cell Theory All living things are composed of one or more cells • Cells are the basic units of structure and function in all living things. ALL cells come from preexisting cells.
Cell Diversity 1. SHAPE - Diversity of form reflects a diversity of function
Cell Diversity 2. SIZE – visible with unaided eye, microscopic, etc.
MOST CELLS ARE SMALL FOR 2 REASONS 1. A SMALL CELL HAS MORE SURFACE AREA THAN A LARGE CELL FOR A GIVEN VOLUME OF CYTOPLASM 2. THE CELL'S NUCLEUS (THE BRAIN) CAN ONLY CONTROL A CERTAIN AMOUNT OF LIVING, ACTIVE CYTOPLASM
Cell Diversity 3. INTERNAL ORGANIZATION: Organelles, Eukaryotes and prokaryotes
Parts of the Cell Animal Bacterial Plant
Parts of the Cell • EQ= What are membranes and what purpose do they serve? • Give an example of one.
1. THE PLASMA MEMBRANE (Present in ALL cell types) Functions: • Regulates what enters/leaves the cell • Separates internal environment from the external environment • Composed of a lipid bilayer (Fat) • Selectively-permeable membrane
2. THE CELL WALL • (Plant cells ONLY) • Surrounds the cell membrane • Helps to protect and support the cell Cell Wall Cell Membrane
3. THE CYTOPLASM • The fluid-filled area BETWEEN the NUCLEUS & the CELL MEMBRANE…fluid & organelles • “cyto” = cell “plasm” = fluid • Cytosol = cell fluid only
4. THE NUCLEUS(Eukaryotic cells) • Control center of the cell • Contains DNA • Double Layer Membrane called the NUCLEAR ENVELOPE • covered with many small pores • The NUCLEOLUS synthesizes (makes) ribosomes, which are important in making proteins for the cell
Chromatin: nuclear DNA (long fibers known as chromosomes) Nucleolus: Ribosome synthesis Nucleoplasm: Fluid of the nucleus Nuclear Envelope: Double membrane Nuclear Pore: Regulate flow of materials in and out of cell Figure 7.8 Pg. 177
A.k.a. = E.R. 5. ENDOPLASMIC RETICULUM • Extension of the nuclear membrane • regions with ribosomes = ROUGH ER (transport ribosomes) • regions w/o ribosomes = SMOOTH ER (lipid synthesis) Figure 7.8 Pg. 177
6. RIBOSOMES • Sites of protein synthesis • 2 sub-unit
7. GOLGI APPARATUS The function of the Golgi Apparatus is to sort, chemically alter, and package important molecules. (UPS guy!) Figure 7.9 Pg. 178
GOLGI APPARATUS Figure 4.9
8. MITOCHONDRIA • Powerhouse of the cell… (generates fuel for cell’s activities) • Sites of cellular respiration
9. CHLOROPLAST *powerhouse of the plant cell *Chlorophyl pigment gives plants their color *site for PHOTOSYNTHESIS
10. LYSOSOMES "Suicide Sac's" • Responsible for intracellular digestion. • Lysosomes are membranous sacs of acidic enzymes. (Rare in plant cells) Figure 4.10 A
11. PEROXISOMES • Detoxify harmful substances that enter the body.
12. VACUOLE • Stores extra material for the cell. • Nutrients, water, etc. • The “garage”
All CELLS HAVE DIFFERENT SHAPES AND ARE CAPABLE OF SOME TYPE OF MOVEMENT. 13. CYTOSKELETON • HELPS SUPPORT CELL STRUCTURE AND DRIVE CELL MOVEMENT.
CYTOSKELETON • Cilia – short hair-like extensions on the cell that aid in cell movement • Flagella – long hair-like extension on a cell that helps the cell propel