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Transcript
Early scientists who observed cells made detailed sketches of what they saw. Early scientists who observed cells made detailed sketches of what they saw. CORK Early scientists who observed cells made detailed sketches of what they saw. CORK These early sketches revealed an important relationship between art and biology, the most visual of the sciences Microscopes provide windows to the world of the cell • The light microscope (LM) enables us to see the overall shape and structure of a cell Eyepiece Ocular lens Objective lens Specimen Condenser lens Light source Light microscopes •Magnify cells, living and preserved, up to 1,000 times Light microscopes •Magnify cells, living and preserved, up to 1,000 times The electron microscope •Allows greater magnification and reveals cellular details Different types of light microscopes •Use different techniques to enhance contrast and selectively highlight cellular components Different types of light microscopes 220! 1,000! •Use different techniques to enhance contrast and selectively highlight cellular components Figure 4.1E Figure 4.1F Most cells are microscopic and vary in size and shape 10 m 100 mm (10 cm) Human height Length of some nerve and muscle cells Unaided eye 1m Chicken egg 10 mm (1 cm) 1 mm Frog egg 1 µm 100 nm Most plant and animal cells Nucleus Most bacteria Mitochondrion Mycoplasmas (smallest bacteria) Viruses Electron microscope 10 µm Light microscope 100 µm Ribosome 10 nm 1 nm Figure 4.2A 0.1 nm Proteins Lipids Small molecules Atoms A small cell has a greater ratio of surface area to volume than a large cell of the same shape. 10 µm 30 µm 30 µm Surface area of one large cube = 5,400 µm2 10 µm Total surface area of 27 small cubes = 16,200 µm2 There are two kinds of cells Prokaryotic and Eukaryotic. Prokaryotic cells •Are small relatively simple cells Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have and outer membrane (Gram-negative) Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) •Have pili or fimbrae (adhesins) Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) •Have pili or fimbrae (adhesins) •May have a circular plasmid Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) •Have pili or fimbrae (adhesins) •May have a circular plasmid •Are haploid with no nuclear membrane Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) •Have pili or fimbrae (adhesins) •May have a circular plasmid •Are haploid with no nuclear membrane •Have inclusion bodies Prokaryotic cells •Are small relatively simple cells •Do not have membrane bound organelles •Two main classes: Gram-positive and Gram-negative •May have a capsule •May have a rigid cell wall •May have an outer membrane (Gram-negative) •May have a periplasmic space (Gram-negative) •May have a flagellum (motility) •Have pili or fimbrae (adhesins) •May have a circular plasmid •Are haploid with no nuclear membrane •Have inclusion bodies •Have different ribosomes Eukaryotic cells are partitioned into functional compartments. Membranes form the boundaries of many eukaryotic cells. membranes These membranes form compartments in the interior of the cell and enable a variety of metabolic activities membranes One such compartment is the nucleus. –A true nucleus distinguishes a Eukaryotic cell from a Prokaryotic cell. Nucleus A typical animal cell contains a variety of membranous organelles. Smooth endoplasmic reticulum Rough endoplasmic reticulum Nucleus Flagellum Not in most plant cells Lysosome Ribosomes Centriole Golgi apparatus Peroxisome Microtubule Cytoskeleton Plasma membrane Intermediate filament Mitochondrion Microfilament A typical plant cell has some structures that an animal cell lacks such as: •chloroplasts •a rigid cell wall Nucleus Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum Golgi apparatus Not in animal cells Central vacuole Chloroplast Cell wall Mitochondrion Peroxisome Plasma membrane Microtubule Intermediate filament Microfilament Cytoskeleton The nucleus •The nucleus is the cell’s genetic control center Nucleus The nucleus •The nucleus is the cell’s genetic control center •It is separated from the cytoplasm by the nuclear membrane Nucleus Two membranes of nuclear envelope The nucleus •The nucleus is the cell’s genetic control center •It is separated from the cytoplasm by the nuclear membrane •It contains the cell’s DNA and ultimately directs the activities of the cell. Nucleus Two membranes of nuclear envelope Many cell organelles are connected through the endomembrane system that manufactures and distributes cell products Smooth endoplasmic reticulum Rough endoplasmic reticulum Nucleus Ribosomes Golgi apparatus Smooth endoplasmic reticulum has a variety of functions: •Synthesizes lipids •Processes toxins and drugs in liver cells •Stores and releases calcium ions in muscle cells Smooth ER Rough ER Nuclear envelope TEM 45,000! Smooth ER Ribosomes Rough ER Rough endoplasmic reticulum: •Manufactures membranes •Makes proteins Smooth ER Rough ER Nuclear envelope TEM 45,000! Smooth ER Ribosomes Rough ER Rough endoplasmic reticulum: •Ribosomes on the surface of the rough ER produce proteins that are secreted, inserted into membranes, or transported to other organelles Transport vesicle buds off 4 Ribosome Secretory (glyco-) protein inside transport vesicle 3 Sugar chain 1 2 Glycoprotein Polypeptide Rough ER The Golgi apparatus: • finishes, sorts, and ships cell products Golgi apparatus Golgi apparatus Transport vesicle from ER New vesicle forming “Shipping” side of Golgi apparatus Transport vesicle from the Golgi TEM 130,000! “Receiving” side of Golgi apparatus Lysosomes • are digestive compartments within a cell Rough ER Transport vesicle (containing inactive hydrolytic enzymes) Plasma membrane Golgi apparatus Lysosome engulfing damaged organelle Engulfment of particle “Food” Lysosomes Food vacuole Digestion Lysosomes • are digestive compartments within a cell • destroy bacteria that have been ingested Rough ER Transport vesicle (containing inactive hydrolytic enzymes) Plasma membrane “Food” Golgi apparatus Lysosome engulfing damaged organelle Engulfment of particle Lysosomes Food vacuole Digestion Lysosomes • are digestive compartments within a cell • destroy bacteria that have been ingested • Recycle damaged organelles Rough ER Transport vesicle (containing inactive hydrolytic enzymes) Plasma membrane Golgi apparatus Lysosome engulfing damaged organelle Engulfment of particle “Food” Lysosomes Food vacuole Digestion Lysosomes • • • • are digestive compartments within a cell destroy bacteria that have been ingested Recycle damaged organelles Abnormal lysozymes cause fatal diseases Rough ER Transport vesicle (containing inactive hydrolytic enzymes) Plasma membrane “Food” Golgi apparatus Lysosome engulfing damaged organelle Engulfment of particle Lysosomes Food vacuole Digestion Cystinosis Vacuoles function in the general maintenance of the cell: • Plant cells contain a large central vacuole with lysosomal and storage functions • Protists have contractile vacuoles that pump out excess water Contractile vacuoles LM 650! Nucleus A review of the endomembrane system Rough ER Transport vesicle from ER to Golgi Transport vesicle from Golgi to plasma membrane Plasma membrane Nucleus Vacuole Lysosome Smooth ER Nuclear envelope Golgi apparatus Chloroplasts: • convert solar energy to chemical energy • found in plants and some protists • Convert solar energy to chemical energy in sugars Chloroplast Stroma TEM 9,750! Inner and outer membranes Granum Intermembrane space Mitochondria: • harvest chemical energy from food: • carry out cellular respiration • uses the chemical energy in food to make ATP for cellular work • Mitochondrial disease Mitochondrion Outer membrane Inner membrane Cristae Matrix TEM 44,880! Intermembrane space The cytoskeleton: • • • • helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Tubulin subunit Actin subunit Fibrous subunits 7 nm Microfilament 25 nm 10 nm Intermediate filament Microtubule The cytoskeleton: • • • • • helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Tubulin subunit Actin subunit Fibrous subunits 7 nm Microfilament 25 nm 10 nm Intermediate filament Microtubule The cytoskeleton: • • • • • • helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Microtubules give the cell rigidity, provide anchors for organelles, act as tracks for organelle movement, divide the chromosomes, and power cilia and flagella Tubulin subunit Actin subunit Fibrous subunits Microfilament 25 nm 10 nm 7 nm Intermediate filament Microtubule The cytoskeleton: helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Microtubules give the cell rigidity, provide anchors for organelles, act as tracks for organelle movement, divide the chromosomes, and power cilia and flagella Figure 4.17A LM 600! Colorized SEM 4,100! • • • • • • Figure 4.17B Cell surfaces: • protect, support, and join cells • interact via their surfaces Plasma membrane Plant cells • Are supported by rigid cell walls made largely of cellulose • Connect by plasmodesmata, which are connecting channels Walls of two adjacent plant cells Vacuole Plasmodesmata Layers of one plant cell wall Cytoplasm Plasma membrane Animal cells are embedded in an extracellular matrix • Which binds cells together in tissues • Tight junctions can bind cells together into leak-proof sheets • Anchoring junctions link animal cells into strong tissues • Gap junctions allow substances to flow from cell to cell Tight junctions Anchoring junction Gap junctions Extracellular matrix Space between cells Plasma membranes of adjacent cells A typical animal cell contains a variety of membranous organelles. Smooth endoplasmic reticulum Rough endoplasmic reticulum Nucleus Flagellum Not in most plant cells Lysosome Centriole Peroxisome Microtubule Cytoskeleton Intermediate filament Microfilament Ribosomes Golgi apparatus Plasma membrane Mitochondrion A typical plant cell has some structures that an animal cell lacks such as: •chloroplasts •a rigid cell wall Nucleus Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum Golgi apparatus Central vacuole Not in animal cells Chloroplast Microtubule Intermediate filament Cytoskeleton Microfilament Cell wall Mitochondrion Peroxisome Plasma membrane Review Eukaryotic organelles comprise four functional categories • • • • Manufacturing Breakdown Energy processing Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing – Nucleus » DNA and RNA synthesis, assembly of ribosomes – Ribosomes » Protein synthesis – Rough ER » Synthesis of membrane proteins, secretory proteins, hydrolytic enzymes, formation of transport vesicles – Smooth ER » Lipid synthesis, carbohydrate metabolism, detoxification, and calcium ion storage – Golgi » Macromolecule modification, temporary storage, transport, and lysosome formation • Breakdown • Energy processing • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing • Breakdown – Lysosomes » Digestion / recycling – Vacuoles » Digestion / recycling, storage of chemicals, and water balance • Energy processing • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing • Breakdown • Energy processing – Chloroplasts » Conversion of light energy to chemical energy (sugars) – Mitochondria » Conversion of chemical energy of sugars, fats, proteins to the universal energy source, ATP • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • • • • Manufacturing Breakdown Energy processing Support, movement, and communication between cells – Plasma membrane and associated proteins » Cell barrier, communication, transport – Cell wall » Cell shape, protection, connection to other cells – Cytoskeleton » Cell shape, anchorage and movement of organelles, cell movement, signaling, transport of molecules – Extracellular matrix » Connection of cells, regulation of cell function – Cell junctions » Communication, connection of cells Review Eukaryotic organelles comprise four functional categories • • • • Manufacturing Breakdown Energy processing Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing – Nucleus » DNA and RNA synthesis, assembly of ribosomes – Ribosomes » Protein synthesis – Rough ER » Synthesis of membrane proteins, secretory proteins, hydrolytic enzymes, formation of transport vesicles – Smooth ER » Lipid synthesis, carbohydrate metabolism, detoxification, and calcium ion storage – Golgi » Macromolecule modification, temporary storage, transport, and lysosome formation • Breakdown • Energy processing • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing • Breakdown – Lysosomes » Digestion / recycling – Vacuoles » Digestion / recycling, storage of chemicals, and water balance • Energy processing • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing • Breakdown • Energy processing – Chloroplasts » Conversion of light energy to chemical energy (sugars) – Mitochondria » Conversion of chemical energy of sugars, fats, proteins to the universal energy source, ATP • Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories • Manufacturing • Breakdown • Energy processing • Support, movement, and communication between cells – Plasma membrane and associated proteins » Cell barrier, communication, transport – Cell wall » Cell shape, protection, connection to other cells – Cytoskeleton » Cell shape, anchorage and movement of organelles, cell movement, signaling, transport of molecules – Extracellular matrix » Connection of cells, regulation of cell function – Cell junctions » Communication, connection of cells
