The plasma membrane : the outer boundary of the living part of the cell. Function: (i) selective permeability- to ... â
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The Plasma Membrane • The plasma membrane or cell membrane is the outer boundary of the living part of the cell. • Function: (i) selective permeability, i.e. it allows certain molecules to pass through, while preventing others from entering or leaving the cell ; (ii) to receive signals from the outside environment. MMKS 12/2017
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The plasma membrane : the outer boundary of the living part of the cell.
Function: (i) selective permeability- to allows certain molecules to pass through (preventing others from entering or leaving the cell). MMKS 12/2017
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(ii) to receive signals from the outside environment. MMKS 12/2017
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Cytoplasm • The cytoplasm is composed of several types of organelles and a fluid matrix, the cytosol in which the organelles are distributed. • The cytosol is an aqueous solution of salts, sugars, amino acids, fatty acids. nucleotides and other materials. • Cytosol = Bio solvent
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CYTOPLASM – composed of several types of organelles and a fluid matrix. - the cytosol in which the organelles are distributed
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The cytosol is a crowded solution of many different types of molecules that fills much of the volume of cells.
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Organelles
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Mitochondrion (plural = mitochondria) • “Powerhouse” of the cell • Generate cellular energy (ATP) • More active cells like muscle cells have MORE mitochondria • Both plants & animal cells have mitochondria • Site of CELLULAR RESPIRATION (burning glucose)
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MITOCHONDRIA Surrounded by a DOUBLE membrane
Has its own DNA Folded inner membrane called CRISTAE (increases surface area for more chemical Reactions) Interior called MATRIX MMKS 12/2017
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Organelles
• Mitochondria • Gk, mitos = thread, chondrios = granule ) • They are the powerhouses of the cell and maternal inheritance organelles. • It appears as short rods or filamentous or sausage shaped bodies.
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Interesting Fact --• Mitochondria Come from cytoplasm in the EGG cell during fertilization Therefore … • You inherit your mitochondria from your mother! MMKS 12/2017
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• Mitochondria have a double membrane around them. • The outer membrane is fairly smooth.
• The inner membrane is highly folded to form structures called cristae.
• The cristae greatly increase the inner membrane's surface area.
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• Both respiratory electron transport chain and ATP synthetase are located in inner membrane.
• Enzymes connected to the cristae control the chemical reactions that form ATP.
• Function - Production of energy during cellular respiration.
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What do mitochondria do? “Power plant” of the cell
Burns glucose to release energy (ATP)
Stores energy as ATP MMKS 12/2017
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1950s by Romanian-American cell biologist George Emil Palade, The term "ribosome" was proposed by scientist Richard B. Roberts in the end of 1950s:
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Ribosomes • Made of PROTEINS and rRNA • “Protein factories” for cell • Join amino acids to make proteins • Process called protein synthesis
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Ribosomes Can be attached to Rough ER OR
Be free (unattached) in the cytoplasm MMKS 12/2017
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Ribosomes • are not membrane bound. • They are very tiny granules and packets of RNA, nucleoproteins and enzymes. • They are found both in prokaryotes and eukaryotes. • They are very abundant in embryonic cells.
• Functions - to synthesize proteins, including enzymes.
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• Each ribosome comprises two parts, • a large subunit and a small subunit. • These subunits are synthesized in nucleolus. • Multiple ribosomes on a single mRNA strand form a polyribosome or polysome.
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Golgi Apparatus (named for Camillo Golgi in 1898) • It is a stack of membrane-bound vesicles. It is likely an outgrowth of the ER system. • It associates with the ER, involved with packaging of materials for transport in the cells.
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Golgi Bodies Look like a stack of pancakes
Modify, sort, & package molecules from ER for storage OR transport out of cell MMKS 12/2017
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Golgi
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Golgi Animation
Materials are transported from Rough ER to Golgi to the cellMMKS membrane by VESICLES24 12/2017
• The Golgi apparatus occupies a central portion in the secretory pathway,
• receiving newly synthesized proteins and lipids from the ER and directing them to either the cell membrane or the vacuoles (tonoplast).
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• During mitosis, Golgi stacks provide the membrane and cell wall molecules needed for cell plate formation in plant cells. • The new Golgi stacks arise by fission. • Functions : Production of cellular secretion.
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centrosome
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Centrosomes Gk. centrum = center and soma = body) • It may occasionally be present in some cells of lower plants. • It lies near the exterior surface of the nucleus. • It is non- membranous mass of two rod-like centrioles.
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• Each centriole contains 9 triplet microtubules that
radiate from the center like the spokes of a wheel. • The 2 centrioles lie at right angles to each other.
• They are duplicated when the cell undergoes cell division.
