lecture8.pptx - Lecture#8\u2026\u2026\u2026 Angiosperms Form Function \u2022 contain all the usual eukaryotic \u201csuspects\u201d \u2013 mitochondria Golgi(dictysomes ER

lecture8.pptx - Lecture#8u2026u2026u2026 Angiosperms...

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Lecture #8……… Angiosperms: Form & Function
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Plant cells contain all the usual eukaryotic suspects mitochondria, Golgi (dictysomes), ER, vacuoles etc…. double phospholipid plasma membrane with embedded proteins and carbohydrates BUT they also possess a cell wall cytoplasm and the organelles are sometimes referred to as the protoplasm or the protoplast (single plant cell) nucleus is similar to the animal cell nucleus
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Plant cells unlike animal cells – plant cells are capable of storing large quantities of many substances some substances are stored within the cytoplasm tannins, phenols, silica calcium oxalate crystals
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Plant Vacuoles other materials are stored within vacuoles primary central vacuole – water and salts and wastes increasing the size of this vacuole can rapidly expand the size of the cell without the need to make more protoplasm in seed plants – this vacuole becomes a storage depot for starches required for embryonic growth spherosomes or lipid bodies - lipid
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Plastids plant cells also possess specialized structures known as plastids plastids = group of dynamic organelles that are able to perform many functions made of an inner membrane and an outer membrane with a stroma in between many similarities to a mitochondria several types within a plant cell
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1. Chloroplasts form from immature pro-plastids once the cell is exposed to light contain the photosynthetic pigment chlorophyll and all the accessory proteins and complexes required for photosynthesis inner membrane is elaborately folded into membrane sheets called thylakoid membranes (large surface area for photosynthetic machinery) in certain areas the thylakoid membranes is folded into vesicle- like bags stacked together – grana (transport of H+ ions required in photosynthesis)
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Other Plastids 2. amyloplasts – in plants tissues that can’t photosynthesize roots, bark and wood cells accumulate sugar and store it as starch 3. chromoplasts – e.g. in tomatoes and yellow squash bright red, yellow and orange lipids accumulated here 4. leucoplasts – large and unpigmented plastids no chlorophyll or lipid pigments involved in the synthesis of fats and phospholipids potato amyloplasts tomato chromoplasts
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The Cell Wall all cells of the plant have cell walls (except the sperm) an active, dynamic organelle with many metabolic functions contains large amounts of cellulose in the form of cellulose microfibrils = 10 to 25 nm wide made by rosette protein complexes
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The Cell Wall all cells have a thin primary cell wall made of cellulose also contains pectin = a complex polysaccharide that allows for plant growth pectin also forms the middle lamina found between two plant cells middle lamina – “cement”-like layer of pectin found between two plant cells
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The Cell Wall in cells that require strength – there is a thicker secondary wall that is
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