Rebecca Davenport Wednesday 10 35 1 15 9 25 16 Ch 6 Blueprint 1 Tour of the Cell a Cell basic unit of life i Two types of cells 1 Prokaryotic Archea bacteria a No nucleus b DNA in nucleoid c No membrane bound organelles d Cytoplasm bound by the plasma membrane e NO ER 2 Eukaryotic Eukarya a Generally much larger and more complex b DNA in nucleus bounded by the nuclear envelope c Membrane bound organelles a Organelles perform specific functions within the cell and are BOUND by a membrane b Each has its own environment function and composition 3 Common to botha Plasma membrane semifluid substance called cytosol chromosomes ribosomes 4 Difference between Prokaryotes and Eukaryotic cellsa True nucleus and membrane bound organelles 5 Plasma membrane Selective barrier that allows passage of gases nutrients and waste to service the volume of every cell a General structure of a biological membrane is a double layer of phospholipids and proteins all organelles have this layer b Phospholipid bilayer1 Asymmetrical 2 Outside carbohydrates 3 Bottom Inside layer proteins 4 Circle parts heads of phospholipids amphipathic or water loving 5 Tail center of layer is hydrophobic 6 How do things cross this membrane a Transmembrane Proteins c d Metabolic requirements set upper limit on cell size 1 Surface area to volume ratio is critical 6 Cytosol a semifluid substance a Cytoplasm compartment within the plasma membrane and its contents b Cytosol jelly like fluid of the cell c Subcellular components organelles ribosomes large proteins etc d Nucleus is NOT considered to be part of the cytoplasm in eukaryotes e Floating in the cytosol free ribosomes go where they re needed 7 8 Endomembrane system collection of membranes within and surrounding a eukaryotic cell related via direct contact or transfer of membranous vesicles a Components a Plasma membrane b Nuclear envelope c Endoplasmic reticulum d Golgi apparatus e Lysosomes f Vacuoles 9 Nucleus info central a Nucleus contains most of the cell s genes and is usually the largest organelle b Nuclear envelope encloses the nucleus in a double membrane a Each membrane composed of phospholipid bilayer c Nuclear pores regulate the entry and exit of molecules from the nucleus d Nuclear lamina Structural support maintains the shape of the nucleus which is composed of protein e Chromosomes discrete units that DNA is organized into a Chromatin smaller fibers that chromosomes are made of b Chromatin Histone Proteins DNA molecule c Chromatin condenses into visible chromosomes when cell prepares to divide f Nucleolus dark staining structure s in the nucleus a Place where ribosomes synthesized b Ribosomes made of rRNA and protein 1 Present in every living thing 2 Assembled in nucleolus 3 Carry out protein synthesis in two locations a Floating in the cytosol free ribosomes b Attached to the outside of the ER or the nuclear envelope bound ribosomes 10 Endoplasmic Reticuluma Area of intense biosynthesis to make things required for living b ER membrane is continuous with nuclear envelope c Two types of ER a Rough ER1 studded with bound ribosomes make proteins 2 Bound ribosomes are like a home security system determines what enters and leaves 3 Proteins made by ribosomes enter ER lumen modifications made exit via vesicles 4 Membrane factory b Smooth ER1 lacks ribosomes 2 Lipid synthesis 3 Drug detoxification 4 Calcium storage c Both types of ER synthesize phospholipids 11 Golgi Apparatus shipping and receiving center a Consists of flattened membranous sacs called cisternae a Cis and trans face b Functions warehouse of shipping receiving sorting and manufacturing 12 Lysosomes digestive compartments a A membranous sac of hydrolytic enzymes that can digest macromolecules a pH of lysosome very acidic b phagocytosis and autophagy 13 Vacuoles large vesicles derived from endoplasmic reticulum and golgi apparatus a Function Vary a Food Vacuole b Contractile Vacuole c Central vacuole 14 Peroxisomes oxidation a specialized metabolic compartments single membrane b Produce H2O2 and convert it to water c Perform reactions with many different functions a Detoxify alcohol b Break fatty acids into smaller molecules for use by mitochondrion 15 Energy processing organelles a Mitochondria the sites of cellular respiration metabolic process that uses oxygen to generate ATP ENERGY via respiration a Call the powerhouse of the cell b In nearly all eukaryotic cells 1 Including plants c Have smooth outer membrane and inner membrane folded into cristae the folds aka Cristae increase the surface area which increases energy production d Two compartments 1 Intermembrane space 2 Mitochondrial matrix e b Chloroplasts found in plants and algae are the sites of photosynthesis a Light is convert to chemical energy ATP which is used to make sugar and other macromolecule b Chloroplasts are one type of plastid c Chloroplasts contain the green pigment chlorophyll as well as enzymes and other molecules that function in photosynthesis d Chloroplasts are found in leaves and other green organs of plants and in algae e Chloroplast structure includes 1 Thylakoid membranous sacs the green disc a Granum stack of thylakoids you maximize energy production by stacking the thylakoids 2 Stroma the internal fluid f c Endosymbiotic theory a Mitochondria and chloroplasts have similarities with bacteria 1 Enveloped by a double membrane 2 Contain free ribosomes and circular DNA molecules 3 Grow and reproduce somewhat independently in cells 16 Extracellular components and connections a Most cells synthesize and secrete materials that are external to the plasma membrane b These extracellular structures include a Cell walls of plants1 The cell wall is an extracellular structure that distinguishes plants any many other organisms from animal cells a Animal cells DO NOT have cell walls 2 Function a Protection b Structural support and shape 3 Plant cell walls are made of mainly cellulose fibers embedded in other polysaccharides and protein b The extracellular matrix ECM of animal cells1 Animal cells lack cell walls but are covered by an elaborate extracellular matrix ECM a Glycoproteins such as collagen embedding in web of proteoglycans b Proteoglycans core protein carbohydrate chains covalently attached c Fibronectin attaches ECM to integrins 2 ECM proteins bind to receptor proteins in the plasma membrane called integrins 3 Functions in support movement adhesion regulation c Intercellular junctions neighboring cells within an organism
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