2.1 3 Cells

2.1 3 Cells - Cells: The Living Units Units Overview...

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Unformatted text preview: Cells: The Living Units Units Overview Overview • History – 1665 - Robert Hooke 1665 • Observed and described cells in cork – 1670s - Anton van Leeuwenhoek 1670s • Cell theory – Every organism is composed of one or more cells – Cell is smallest unit having properties of life – All cells arise from pre existing cells • Size Size Overview Overview – Varies – bacteria to bird egg • Shape – Varies Varies – Examples- be able to identify different types of cells by looking at slide Examples- be • • • Nervous Epithelial- Ex. squamous, simple columnar, transitional squamous, EpithelialMuscle- 3, skeletal- long thin, smooth, cardiac Muscle- skeletal- Viewing specimens – microscopy • Light microscope • Electron microscope – Transmission electron microscope • Looking through the specimen Looking • Resolution is greater – Scanning electron microscope Scanning • • Looks at surface dimensions See the external details See Plasma Membrane Structure • Lipid bilayer – Phospholipid head – hydrophillic – Fatty acid tails – hydrophobic Fatty • Cholesterol • Glycocalyx Plasma Membrane Structure Plasma • Peripheral Peripheral Proteins Proteins • Integral • Functions – Transport • Channel proteins – Open always – Gated » Ligand regulated gates -channel that opens in response to a molecule » Voltage regulated gates - “muscles and nervous system” open and close in response to changes in charge response » Mechanical regulated gates - open and close based on change a change in shape of a cell. • Carriers – moves stuff from one side of the membrane to the other side of Carriers the membrane the Plasma Membrane Structure Plasma Proteins Proteins • Functions – Enzymatic activity – Receptors – Intercellular joining – Cell – cell recognition Cell – Attachment to cytoskeleton and extracellular Attachment matrix matrix Plasma Membrane Specializations Plasma • Microvilli- extension of plasma membrane, “little fingers” , in intestines and kidneys. Microvilli• Membrane junctions – Tight junctions – Desmosomes – Gap junctions Plasma Membrane Functions Plasma • Outer defining limit of cell – Regions • Intracellular • Extracellular – interstitial fluid • Selectively permeable – Regulates movement into and out of cell • Interactions with other cells Passive Membrane transport • Diffusion – Affected by • • • • Concentration gradient Size of particle Temperature Solubility Solubility Passive Membrane transport • Simple • Facilitated – Uses carrier proteins • Carriers • Channels Carriers Carriers • Characteristics – Specificity – Competition – Saturation • Types – Uniport- carries one molecule at a time – Synport- carry 2 or more molucules at a time – Antiport – in opposite directions Passive Membrane transport osmosis osmosis • Diffusion of water across a semi-permeable Diffusion membrane membrane • Affected by solute/solvent concentrations – – – Solute – substance dissolved Solvent – solution that does dissolving Types • • • Isotonic Hypotonic Hypertonic Hypertonic Passive Membrane transport filtration filtration • The movement of a substance through a The membrane from an area of higher higher pressure to an area of lower pressure pressure lower • Caused by fluid or hydrostatic pressure • Examples – Kidney nephron – Circulation Circulation Active membrane processes – Active transport Active • • • • Requires carrier proteins Uses energy from ATP Against concentration gradient Types – Primary active transport • Utilizes ATP directly – Secondary active transport • Utilizes energy stored in ionic gradients Active membrane processes – Vesicular transport Vesicular • Large particles, macromolecules and Large fluids fluids • Exocytosis • Endocytosis Endocytosis – Types • • • Phagocytosis- cell eating Pinocytosis- cell drinking Receptor mediated endocytosis Cytoplasm Cytoplasm • Cytosol- liquid part of cell – Mostly water – Contains soluble components – Inclusions- part of cell that doesn’t have any Inclusionsmembrane around outside of them membrane • Organelles Nucleus Nucleus • Structure – Nuclear membrane – pores- made of proteins made Nuclear – Nucleolus – Chromatin - DNA – Nucleoplasm • Functions – Separates DNA from rest of cytoplasm – Place for DNA to be copied Endoplasmic Reticulum Endoplasmic • Network of tubules or channels extending from Network nuclear envelope to cell membrane nuclear • Two types – Rough – protein production • Ribosomes on surface – Smooth – steroid production Ribosomes Ribosomes • Structure – Large and small subunits Large – Composed of proteins and ribosomal RNA – Located attached to ER or floating free in Located cytoplasm cytoplasm • Function – Production of proteins Golgi Apparatus • Structure- “pita bread” Structure- “pita • Function – Modify, concentrate and package proteins Modify, and lipids and • Materials arrive and leave in vesicles – Vesicle – membranous sac that moves Vesicle through cytoplasm through Lysosomes Lysosomes • Contain digestive enzymes • Functions – Digest particles from endocytosis – Digest worn out organelles- autophagy autophagy Digest – Breakdown non useful tissue- autolysis autolysis Breakdown – Breakdown bone to release calcium osteoclast Peroxisomes Peroxisomes • Membrane bound, self replicating Membrane organelle organelle • Functions – Detoxify harmful substances – Neutralize free radicals – Enzymes • Oxidases • Catalases Catalases Mitochondria Mitochondria • Structure • Function – location of cellular respiration Cytoskeleton • Structure • Functions – Overall shape to the cell to Overall – Distribution of cellular organelles Distribution – Cell motility *muscle *muscle Cell – Attached to desmosomes – Internal structural support Centrioles Centrioles • Located near nucleus • Functions – Produce spindle fibers – Bases of cilia and flagella Cellular extensions Cellular • Cilia – Propels substances across the cell surface • Flagellum – Propels cell itself ...
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