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Chapter 3 - Cells and Tissues Cell Anatomy. Cells and Tissues. Carry out all chemical activities needed to sustain life Cells - the building blocks of all living things Tissues - groups of cells that are similar in structure and function. Anatomy of the Cell.
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Cells and Tissues Carry out all chemical activities needed to sustain life • Cells - the building blocks of all living things • Tissues - groups of cells that are similar in structure and function
Anatomy of the Cell • Cells not all the same, but share general structures • 3 main regions • Nucleus • Cytoplasm • Plasma membrane
The Nucleus • Control center • Contains (DNA) • 3 regions • Nuclear membrane • Nucleolus • Chromatin
Nuclear Envelope (Membrane) • Barrier of nucleus • Made of double phospholipid membrane • Pores allow for exchange of material with rest of the cell
Nucleolus • Nucleus contains 1 or more nucleoli • Make ribosomes • Ribosomes migrate to cytoplasm through nuclear pores
DNA – Chromatin & Chromosome Forms • Composed of DNA and protein • Chromatin - throughout nucleus in thread form • Chromosomes -condensed DNA forms before cell divides
Cytoplasm Material outside nucleus and inside plasma membrane 1. Cytosol • Fluid that suspends other elements 2. Organelles • Machinery of cell 3. Inclusions • Non-functioning units
1. Ribosomes • Made of protein and RNA (made in nucleolus) • Sites of protein synthesis • Found at two locations • Free in the cytoplasm and • Attached to rough endoplasmic reticulum
2. Endoplasmic reticulum (ER) • Fluid-filled tubules for carrying substances • Two types • Rough ER • Studded with ribosomes • Makes parts for membranes • Smooth ER • Makes & breaks cholesterol • Fat metabolism • Detoxifies drugs
3. Golgi apparatus • Modifies and packages proteins (3 types) • Secretory vesicles • Cell membrane components • Lysosomes
4. Lysosomes • Sacs of enzymes • digest nonusable materials 5. Peroxisomes • Sacs of oxidase enzymes • Detoxify harmful substances • Break down free radicals (highly reactive chemicals) • Replicate by pinching in half • Remember bubbling liver?
6. Mitochondria • “Powerhouses” of the cell • Change shape continuously • Uses O2 to break down food • Provides ATP for energy
7. Cytoskeleton • Protein structures • throughout the cytoplasm • Internal framework Three different types • Microfilaments • Intermediate filaments • Microtubules
8. Centrioles • Rod-shaped bodies made of microtubules • Make spindle fibers during cell division
Plasma Membrane • Barrier for cell contents • Double phospholipid layer • Hydrophilic heads • Hydrophobic tails • Other materials in membrane • Proteins • Cholesterol • Glycoproteins
Plasma Membrane Specializations • Microvilli • Finger-like projections • Increase surface area for absorption • Membrane junctions • Tight junctions - impermeable • Desmosomes - anchor • Gap junctions - communicate
Cellular Projections • Not found in all cells • Used for movement • Cilia move materials across the cell surface • Flagellum propels the cell