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Cytology Study of cells ~70 trillion = human body
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Cells Cells vary greatly in SIZE and STRUCTURE two main parts - NUCLEUS & CYTOPLASM, Enclosed in a CELL MEMBRANE (also called PLASMA MEMBRANE)
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Cell Membrane Extremely thin Outpouchings and infoldings Porous Selectively Permeable = controls what enters and leaves the cell, it allows some things to pass but not others
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Membrane Structure Lipids, proteins, carbs Phospholipid bilayer
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CYTOPLASM - area b/w the plasma membrane and nucleus. – metabolic reactions/activities take place. Filled with a clear fluid called CYTOSOL. Contains ORGANELLES
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Cytoskeleton- – protein rods/ tubules
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Microfilaments- tiny rods of the protein actin – Various cell movements Microtubules- long slender tubes of globular protein tubulin. – Maintain shape of cell – move organelles in cell
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Organelles Ribosome- – Protein/RNA – Structural support – Link amino acids together to form proteins
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Endoplasmic Reticulum- – Smooth ER- contains enzymes that synthesize lipids, absorb fats from digestive tract, break down drugs. – Rough ER- Contains Ribosome Site of Protein Synthesis Send to Golgi Apparatus
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Golgi Apparatus- – proteins arrive in vesicles from ER – Modifies proteins chemically – Send proteins in vesicles out of cell (vesicle trafficking)
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Vesicles- membranous sacs that vary in size/contents
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Mitochondria- 2 layers of membranes – Cristae- folded inner membrane – Matrix- fluid inside membranes – Captures/Transfers energy in the form of ATP
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Lysosome- – acts as garbage disposal – Break down proteins, carbs, nucleic acids – Destroy worn cell parts
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Peroxisomes- contain enzymes – Catalyze chemical reactions Synthesis of bile acids Breakdown of lipids Degradation of rare biochemicals Detoxification of alcohol
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Centrosome- two hollow cylinders (centrioles) – Made of microtubules – From spindle fibers to move chromosomes during mitosis
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Cilia/Flagella- motile extensions of certain cells
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Nucleus Spherical structure Contains DNA
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Nuclear Envelop- double layered membrane Nuclear pores- allow substances in and out Nucleoplasm- fluid inside Nucleolus- Site of ribosome production – Ribosomes move out nuclear pores Chromatin- DNA fibers – Form chromosomes in mitosis
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MEMBRANES phospholipid bilayer 2 Tails- Hydrophobic Head- Hydrophilic Controls movement of substances in and out of cell
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Peripheral proteins Integral proteins Function – Help communicate with other cells – Transport substances across membrane
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Subs move throughout membrane
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Passive Transport Diffusion- movement of particles from a concentrated area to a less concentrated area Equilibrium Diffusion Example
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Diffusion
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Passive Transport Osmosis - transport of water across membrane from a high concentration to a lower concentration – Hypertonic – Hypotonic – Isotonic
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Passive Transport Facilitated Diffusion - Transport proteins = pathway for molecules to pass through membrane
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Active Transport Uses Energy Moves against concentration gradient Some Carrier proteins act as pumps
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Sodium Potassium Pump – Na+ binds to carrier protein inside cell – Carrier protein splits Phosphate group from molecule of ATP and phosphate group binds ATP supplies energy needed to reshape protein – With new shape moves Na+ outside cell, and the shape is perfect to bind for K+ – Repeats
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Active Transport Exocytosis- vesicles exports product from cells Endocytosis- vesicle takes material into cell – Pinocytosis- transports of solutes or fluids – Phagocytosis-movement of large particles or whole cells
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Cell Life Cycle Mitosis = nuclear division followed by cytokinesis The steps of mitosis ensure that each new cell has the exact same number of chromosomes as the original
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Interphase – 90% of cells life – G1 – growth phase – S phase (synthesis) – genetic material replicates – G2 – synthesize structures
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Mitosis
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Prophase 1. chromosomes visible (chromatids) 2. centrioles migrate to the poles 3. nuclear membrane disappears 4. nucleolus disappears 5. spindle forms
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Metaphase chromosomes line up on the equator, spindle attaches
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Anaphase chromatids separate and move to opposite poles
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Telophase 1. chromosomes disappear chromatin 2. nuclear membrane reforms 3. nucleoli reappears 4. spindle disappears 5. centrioles duplicate
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Cytokinesis division of the cytoplasm to form 2 new daughter cells - organelles are divided - daughter cells are genetically identical
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Karyotype
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Homework Draw and label the phases of mitosis Label : Centromere, centrioles, spindle fibers, and sister chromatids
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