Transcript CELLS
CELLS Cell Theory •All living things are composed of cells •Cells are the smallest functional part of a living organism •All cells come from other cells CELL TYPES •Cells are either: PROKARYOTIC or EUKARYOTIC Prokaryotic cells 1. No nucleus or membrane bound organelles •Nuclear region, contains one single DNA molecule arranged in a circular chromosome 2. Structure: • They have RIBOSOMES!! •Cell membrane • Cell wall (different than plants) • Some have capsules outside wall •Some have pilli or flagella Eukaryotic cells •Have NUCLEUS and membrane bound organelles •Plasma membrane •Cytoplasm - everything between plasma membrane and nucleus Organelle • A minute (small) membrane bound structure within a plant or animal cell that has a particular job or function. EUKARYOTIC CELLS Nucleus • • • • • • CONTROL CENTER for activities & reproduction DNA & chromosomes housed here. Has double membrane Pores (holes or openings) to get messages in and out Chromatin = DNA & Protein put together Nucleolus - site of ribosome production PLASMA MEMBRANE •Made of phospholipid and protein bilayer. •Cell boundary •Regulates entering & exiting of materials cytoskeleton phospholipid Channel protein Ribosomes • Site of Protein Synthesis Mitochondria • Site of cellular respiration. Energy production • Powerhouse. Numerous amounts in cells needing lots of energy where a lot of work is done (example: muscle cells) Chloroplasts • Site of photosynthesis where light energy is converted to chemical energy. • Contains the green pigment chlorophyll which captures light. • Found only in plants. VACUOLE • STORAGE for food and water • PLANT VACUOLES are larger than animal vacuoles Some protista cell vacuoles pump water out by contracting: FIND 2 Contractile vacuoles in this Paramecium? Cell Walls • Has Cellulose • Nonliving • Rigid • Outer boundary • Provides protection and shape Animal vs Plant Cell •Animal cells • Roundish •Plant cells • Rectangular •Large permanent central vacuole •Cellulose cell wall •Chloroplasts •(All other organelles are common to both) HOW DO THE CHROMOSOMES OF PROKARYOTIC CELLS DIFFER FROM THOSE OF EUKARYOTIC CELLS? •Except in the mitochondria and other organelles, eukaryotic chromosomes are linear whereas prokaryotic chromosomes are circular. •Eukaryotes typically have many chromosomes, whereas prokaryotes have only a single chromosome. •Eukaryotic chromosomal DNA in the nucleus is wound on nucleosome cores whereas prokaryotic DNA is “naked”—i.e., there are no nucleosomes or other proteins on which the DNA is wound. •Most eukaryotic cells are diploid, receiving a set of chromosomes from each parent. Thus their chromosomes occur in homologous pairs, each consisting of one chromosome from each parent bearing basically the same genes in the same order. Prokaryotes are haploid; their single circular chromosome is unpaired. Time to your wor CELL SPECIALIZATION • Different kinds of cells suited for a different activity. DIVISION OF LABOR •Different cells divide their labor. Each has a specific function and supports each other. Levels of Structure •1. Cell •2. Tissue •3. Organ •4. Organ system •5. Organism 5. Organism 4. Organ System 3. Organ 2. Tissue 1. Cells TISSUE • Group of cells that are alike in structure and activity in an organism. EXAMPLES: - muscles - motion - bones – support - nerves - coordination, perception and automatic body functions Can you name some other types of tissue? ORGAN •Several tissues working as a unit heart •animal brain cell stomach stem •plant trunk cell leaf CAN YOU LIST SOME MORE ANIMAL ORGANS? ORGAN SYSTEM Many organs involved in carrying out a function •digestive •nervous •skeletal •excretory •respiratory •endocrine •circulatory •muscular •reproductive •integumentary ORGANISM •Complete living thing Cell All 4 make up the Tissue organism Organ Organ system BYE BYE BYE!! BYE!!