Chapter 4Some of the basicsSlide 3Slide 4---Nucleoid is a dense region of DNA in a prokaryotic cellEukaryotes are much more complex The inside of the eukaryotic cell is compartmentalized into organellesSlide 7Some of the cellular organellesThe nucleus is the compartment that contains the cell’s genetic librarySlide 10---Nuclear envelope is a double membrane which encloses the nucleus of a eukaryotic cell---Nucleolus is a spherical shaped region in the nucleus where eukaryotic ribosomes are assembled.Slide 13---Chromatin is a complex of DNA and histone proteins, which make up chromosomes in eukaryotic cells.---Chromosomes are long threadlike associations of genes, composed of chromatin and found in the nucleus of eukaryotic cells.Ribosomes build the cell’s proteinsSlide 17-Ribosomes contain rRNA (ribosomal RNA) and many proteinsSlide 19What would happen if a cell stopped making properly functioning RNA?Many cell organelles are connected through the endomembrane systemEndomembrane system -components include: -Nuclear envelope -Endoplasmic reticulum -Golgi complex (apparatus) -Lysosomes -Vacuoles---Vesicles are membrane-enclosed sacs that are pinched off portions of membranes. Vesicles are formed at one site and move to a membrane at another site.>>>>>The endoplasmic reticulum manufactures membranes and performs other vital biosynthetic functionsSlide 25-Smooth ER (because there are no bound ribosomes attached)-Rough ER (because of the presence of bound ribosomes)The pathway of a secretory protein:Slide 29One type of vesicle which “leaves” from the Golgi complex is the lysosomeFunctions of lysosomes:>>>>>Mitochondria and chloroplasts are the main energy transformers of cellsHow are chloroplasts and mitochondria similar to prokaryotic cells?Slide 34Features: -Size 2.0-5.0 μm -Number per cell varies with metabolic activity -Can move and change shape -Space inside the inner membrane is called the stroma.---Mitochondria are organelles which use energy extracted from organic macromolecules (food) to produce ATP. Called cellular respiration.Features: -Size 1-10μm -Number per cell varies with metabolic activity -Can move and change shapeIf a cell had a nucleoid, it most likely would be a(n) ___________.Chapter 4Cell Structure and FunctionSome of the basics•The cell is the smallest living unit.•Genetic material in cells is deoxyribonucleic acid (DNA)Where is the DNA stored?PROKARYOTES EUKARYOTESNo nucleus or nuclear envelopeNucleus with a nuclear envelopeGenetic material in a “nucleoid region”Genetic material within the nucleusNo organelles or internal membranesContains cytosol with membrane-bound organellesFig. 4-19a---Nucleoid is a dense region of DNA in a prokaryotic cell---Cytoplasm is the entire region inside the cell membrane and outside the nucleus in cells that have a nucleus (i.e., most eukaryotic cells).Eukaryotes are much more complexThe inside of the eukaryotic cell is compartmentalized into organelles---Organelles are one of several compartments suspended in the cytoplasm of eukaryotic cells.Fig. 4.3Some of the cellular organelles1. Nucleus2. Endoplasmic reticulum3. Golgi complex4. Vesicles5. Mitochondrion6. Chloroplasts (in plants)The nucleus is the compartment that contains the cell’s genetic library ---Nucleus is a (usually) membrane-bound cellular organelle in eukaryotic cells. The nucleus contains most of the genes that control the cell.Fig. 4.3---Nuclear envelope is a double membrane which encloses the nucleus of a eukaryotic cellNuclear pore bilayer facing cytoplasmNuclear envelopebilayer facing nucleoplasm---Nucleolus is a spherical shaped region in the nucleus where eukaryotic ribosomes are assembled.-Sites of ribosome productionFig. 4.8a---Chromatin is a complex of DNA and histone proteins, which make up chromosomes in eukaryotic cells.---Chromosomes are long threadlike associations of genes, composed of chromatin and found in the nucleus of eukaryotic cells.Each species has a specific number of chromosomes (46 for humans)Ribosomes build the cell’s proteins---Ribosomes are cytoplasmic complexes which are the sites of protein synthesis.Fig. 4.10-Ribosomes contain rRNA (ribosomal RNA) and many proteins•Made up of two subunits•In prokaryotes the ribosomes are free in the cytoplasm•In eukaryotes the ribosomes are either free, or attached to a membrane (usually the membrane of the endoplasmic reticulum)ribosomesvesiclesFig. 4.11aWhat would happen if a cell stopped making properly functioning RNA?•Nothing. The cell would function properly.•The cell would not be able to translate the information in protein into DNA.•The cell would not be able to translate the information in DNA into protein.•The cell would not be able to translate the information in DNA into lipids.Many cell organelles are connected through the endomembrane systemFig. 4.14Endomembrane system-components include:-Nuclear envelope -Endoplasmic reticulum-Golgi complex (apparatus)-Lysosomes-VacuolesAll of the components are related either directly through physical contact or indirectly through vesicles.---Vesicles are membrane-enclosed sacs that are pinched off portions ofmembranes. Vesicles are formed at one site and move to a membrane at another site.>>>>>The endoplasmic reticulum manufactures membranes and performs other vital biosynthetic functions---Endoplasmic reticulum (ER) is an extensive membranous network of tubules and sacs -Largest part of the cell’s membrane system-Found in two forms smooth ER and rough ER.Fig. 4.11-Smooth ER (because there are no bound ribosomes attached)Functions:Synthesis of lipids (especially phospholipids and steroids)-Rough ER (because of the presence of bound ribosomes)Functions1. Manufacture of membranes2. Synthesis of secretory proteinsThe pathway of a secretory protein:1. Protein synthesized by a bound ribosome2. The newly synthesized protein moves through the ER membrane into the ER3. A vesicle carrying the protein is pinched off the ER and travels to the Golgi complex.>>>>>The Golgi complex (apparatus) finishes, sorts and ships many cell products.Fig. 4.12One type of vesicle which “leaves” from the Golgi complex is the lysosome ---Lysosomes are membrane-bound organelles which are digestive compartments that digest all major classes of macromolecules.Functions of lysosomes:1. Intracellular digestion---Food vacuoles are formed by phagocytosis of a food particle. Lysosomes fuse with these food vacuoles to digest the food. 2.
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