Cells

The Cell The cell is: the basic unit of life It is the simplest unit capable of: Independent existence

Cell Theory The cell is the smallest structural and functional living unit Organismal functions depend on individual and collective cell functions Biochemical activities of cells are dictated by their specific subcellular structures Continuity of life has a cellular basis

Cell Diversity Over 200 different types of human cells Types differ in size, shape, subcellular components, and functions

(a) Cells that connect body parts, form linings, or transport gases Erythrocytes Fibroblasts Epithelial cells (a) Cells that connect body parts, form linings, or transport gases Nerve cell Skeletal Muscle cell Smooth muscle cells (e) Cell that gathers information and control body functions (b) Cells that move organs and body parts Sperm Macrophage (f) Cell of reproduction Fat cell (c) Cell that stores nutrients (d) Cell that fights disease Figure 3.1

The Cell B. Life functions cells themselves are what is alive in organism 1. Reproduction 2. Growth/Development 3. Movement 4. Respiration 5. Digestion 6. Homeostasis 7. Respond/adapt 8. Excretion of wastes

The Cell Levels of organization atoms  molecules  cells  tissue  organs  organ systems Allows for division of Labor

The Cell There are 11 Organ Systems a. Skeletal f. Respiratory b. Muscular g. Excretory c. Skin (Integumentary) h. Endocrine d. Digestive i. Nervous e. Circulatory j. Reproductive k. Lymphatic

All the organs of the body were having a meeting, trying to decide who was the one in charge. "I should be in charge," said the brain, "Because I run all the body's systems, so without me nothing would happen.“ "I should be in charge," said the blood , "Because I circulate oxygen all over so without me you'd all waste away.“ "I should be in charge," said the stomach," Because I process food and give all of you energy.“ "I should be in charge," said the legs, "because I carry the body wherever it needs to go." 9

The Moral of the story? Even though the others do all the work…… "I should be in charge," said the eyes, "Because I allow the body to see where it goes." "I should be in charge," said the rectum, "Because I'm responsible for waste removal." All the other body parts laughed at the rectum And insulted him, so in a huff, he shut down tight. Within a few days, the brain had a terrible headache, the stomach was bloated, the legs got wobbly, the eyes got watery, and the blood Was toxic. They all decided that the rectum should be the boss. The Moral of the story?  Even though the others do all the work…… The asshole is usually in charge. 10

Types of Cells A. Prokaryotes 1.) Lack a true membrane- bound nucleus 2.) Single-celled a.) bacteria 3.) DNA located within cell

Types of Cells B. Eukaryotes 1. Has membrane-enclosed nucleus a. information center of the cell and contains DNA 2. Single-celled (unicellular) or many-celled (multicellular) 3. Has other membrane bound organelles 4. There are 2 types of Eukaryotic cells

Plant Cell

Animal Cell

Generalized Cell All cells have some common structures and functions Human cells have three basic parts: Plasma membrane flexible outer boundary Cytoplasm intracellular fluid containing organelles Nucleus control center

Cytoplasm Located between plasma membrane and nucleus Cytosol Water with solutes (protein, salts, sugars, etc.) Cytoplasmic organelles Metabolic machinery of cell Inclusions Granules of glycogen or pigments, lipid droplets, vacuoles, and crystals

Cytoplasmic Organelles Membranous Mitochondria Peroxisomes Lysosomes Endoplasmic reticulum Golgi apparatus Nonmembranous Cytoskeleton Centrioles Ribosomes

Mitochondria Double-membrane structure with shelflike cristae Provide most of cell’s ATP via aerobic cellular respiration Contain their own DNA and RNA

Outer mitochondrial membrane Ribosome Mitochondrial DNA Inner mitochondrial membrane (a) Cristae Matrix (c) Enzymes (b)

Ribosomes Granules containing protein and rRNA Site of protein synthesis Free ribosomes synthesize soluble proteins Membrane-bound ribosomes (on rough ER) synthesize proteins to be incorporated into membranes or exported from the cell

Endoplasmic Reticulum (ER) Interconnected tubes and parallel membranes enclosing cisternae Continuous with nuclear membrane Two varieties: Rough ER Smooth ER

Smooth ER Nuclear envelope Rough ER Ribosomes

Rough ER External surface studded with ribosomes Manufactures all secreted proteins Synthesizes membrane integral proteins and phospholipids

Smooth ER Tubules arranged in a looping network Enzyme (integral protein) functions: In the liver—lipid and cholesterol metabolism, breakdown of glycogen, and, along with kidneys, detoxification of drugs, pesticides, and carcinogens Synthesis of steroid-based hormones In intestinal cells—absorption, synthesis, and transport of fats In skeletal and cardiac muscle—storage and release of calcium

Golgi Apparatus Stacked and flattened membranous sacs Modifies, concentrates, and packages proteins and lipids Transport vessels from ER fuse with convex cis face of Golgi apparatus Proteins then pass through Golgi apparatus to trans face Secretory vesicles leave trans face of Golgi stack and move to designated parts of cell

destined for exocytosis Secretion by exocytosis Extracellular fluid Protein- containing vesicles pinch off rough ER and migrate to fuse with membranes of Golgi apparatus. 1 Rough ER ER membrane Phagosome Plasma mem- brane Proteins in cisterna Pathway C: Lysosome containing acid hydrolase enzymes Proteins are modified within the Golgi compartments. 2 Vesicle becomes lysosome Proteins are then packaged within different vesicle types, depending on their ultimate destination. 3 Secretory vesicle Golgi apparatus Pathway B: Vesicle membrane to be incorporated into plasma membrane Pathway A: Vesicle contents destined for exocytosis Secretion by exocytosis Extracellular fluid

Lysosomes Spherical membranous bags containing digestive enzymes (acid hydrolases) Digest ingested bacteria, viruses, and toxins Degrade nonfunctional organelles Break down and release glycogen Break down bone to release Ca2+ Destroy cells in injured or nonuseful tissue (autolysis)

Endomembrane System Overall function Produce, store, and export biological molecules Degrade potentially harmful substances

Nucleus Nuclear envelope Smooth ER Rough ER Vesicle Golgi apparatus Plasma membrane Transport vesicle Lysosome

Peroxisomes Membranous sacs containing powerful oxidases and catalases Detoxify harmful or toxic substances Neutralize dangerous free radicals (highly reactive chemicals with unpaired electrons)

Cytoskeleton Elaborate series of rods throughout cytosol Microtubules Microfilaments Intermediate filaments

Cell Website www.cellsalive.com/cells/3dcell.htm