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Honors Biology Chapter 7 Section 2 Eukaryotic Cell Structure.
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Honors BiologyChapter 7 Section 2Eukaryotic Cell Structure SC B -2.2: Summarize the structures & functions of organelles found in a eukaryotic cell(including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, and cytoplasm
Cytoplasm Portion of the cell including everything inside cell membrane except nucleus Cytosol: liquid portion of cytoplasm
NUCLEUS • Contains DNA with its coded instructions for making proteins so is the “control center” • most prominent structure seen with light microscope • Parts: • Nucleolus • Nuclear Envelope • Nuclear Pores
NUCLEUS • Nucleolus • dense region in nucleus • produces subunits of ribosomes • Nuclear Envelope • dbl membrane surrounding nucleus • Outer layer contiguous with ER • Nuclear Pores • holes thru envelope • substances enter/leave nucleus thru these pores
DNA in NUCLEUS chromatin: DNA bound to proteins (called histones) Chromatin condenses into chromosomes when cell starts cell division
RIBOSOMES • assembly site for proteins • 2 subunits • Small • Large • made separately in nucleolus exit nucleus thru nuclear pores join when making proteins
RIBOSOMES Considering the function of ribosomes…. What types of cells do you think would have an abundance of ribosomes in them?
Endoplasmic Reticulum (ER) Internal membrane system 2 types: Smooth ER (SER) Rough ER (RER)
SER • make membranes for • cell membrane • other organs • detoxifies • drugs • alcohol • poisons
SER So… considering the functions of SER……what types of cells can you predict might have an abundance of SER?
RER “rough” because outer membrane is studded with ribosomes proteins made & released into RER where they are modified (sugar groups added making a glycoprotein) most of proteins made here are destined for export out of cell
RER What type of cell do you think would have lots of RER?
GOLGI APPARATUS stack of curved membranes usually found between ER and cell membrane Function: modify, sort, & package material received from ER storage in cell or export out of cell
GOLGI In what types of cells do you think there would be an abundance of Golgi bodies?
LYSOSOMES • membrane bound vesicle that has enzymes inside • Function: breakdown of macromolecules into smaller molecules which are then recycled in cytoplasm • Where do these macromolecules come from?
Lysosomes • Where do lysosomes get the macromolecules? • worn out organelles • engulfed bacteria or cell debris
VACUOLES membrane bounded storage facility Protists (one-celled organisms) put food particles in a food vacuole until need the nutrients plant cells have distinctive large central vacuole that stores water and some nutrients and helps plant maintain turgor when all cells have a filled central vacuole
MITOCHONDRIA • convert chemical energy in sugars ATP (high energy molecule that temporarily stores energy in form cells can use) = cellular respiration • dbl membrane • intermembrane space • cristae : folds of inner membrane • matrix: inside folds of cristae • has own DNA (maternal) & divides on own
CHLOROPLASTS • in plant cells • capture energy in sunlight chemical energy (photosynthesis) • dbl membrane • intermembrane space • inner membrane folds into thylakoid discs • stack of discs = granum • space around grana = stroma • contain chlorophyll • + DNA & divides on own
CYTOSKELETON • Function: • internal structure & support • movement of organelles & chromosomes • anchors organelles and cells Made of proteins 3 types: • microfilaments • intermediate filaments • microtubules
MICROFILAMENTS made of actin supports cell shape used by protist for movement http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter4/animation_-_cytoplasmic_streaming.html
Intermediate Filaments used to move organelles around cytoplasm
MICROTUBULES largest, strongest shaped like hollow straws with units that spontaneously come together or fall apart used to move organelles, chromosomes made in centrosomes
CELL ANALOGY • Eukaryotic cells are like a city: • each part has a job to be done • Nucleus : mayor • Mitochondria: power plant • Lysosomes: city dump and recycling center • SER: hospital • Golgi: UPS store • Cytoskeleton: roads & bridges • Cell Membrane: border patrol @ city limits