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35 Cards in this Set
- Front
- Back
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• Light Microscopes
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visible light
o Magnification- ratio of an object’s image size to its real size o Resolution→ measure of the clarity of the image |
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• Electron Microscope (two kinds)
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can see organelles- uses electrons instead of light
o Scanning electron microscope- shows the surface of a specimen o Transmission electron microscope- shows the inside of a specimen o Electron microscopes kill the specimen while light microscopes don’t |
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• ALL CELLS have what?
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plasma membrane
cytosol (cytoplasm) chromosomes ribosomes |
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• PROKARYOTIC
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Bacteria or Archaea
o DNA is in a designated region (nucleoid) and its not membrane bound o No membrane bound organelles o Smaller than eukaryotics→ bigger ratio of surface area to volume o Circular chromosome of DNA |
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• EUKARYOTIC
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• Protists, fungi, animals, plants
o Nuclear envelope covers the nucleus and the DNA o Membrane bound organelles o Bigger than prokaryotic cells o Linear chromosome of DNA |
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surface area to volume ratio
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o You want a big surface area and small volume to make an efficient cell
o When cells get too big they don’t have enough surface area to support their large volume- that’s why they splits o This is why cells are small o You want a high surface area to volume ratio so the cell can efficiently exchange enough materials to support itself |
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Parts of a prokaryotic cell
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• Pili→ used for movement, sticking to things, and bacterial conjugation
• Nucleoid→ region where the cell’s DNA is located (not membrane enclosed) • Ribosomes • Plasma membrane→ encloses the cytoplasm • Cell wall→ rigid structure outside of plasma membrane • Capsule→ jelly like outer coating on some prokaryotes • Flagella→ used for movement on some prokaryotes • Bacterial chromosome plasmids--> small circle of DNA with 3-5 genes in it- separate from bacterial DNA - used in plasmid conjugation |
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Parts of an Animal cell
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• Endoplasmic Reticulum (ER)→ network of membranous sacs and tubes- used for transportation
o Rough ER→ has ribosomes attached to it o Smooth ER→ no ribosomes attached to it • Flagellum→ used for movement on some eukaryotes- made of microtubules • Centrosome→ region where the cell’s microtubules are initiated- contains a pair of centrioles (function unknown) • Cytoskeleton→ like the bone structure of the cell- used for structure, shape, movement- made of proteins o Microfilaments- solid o Intermediate filaments o Microtubules- hollow o Microvilli→ increases the cell’s surface area • Peroxisome→ organelle with different metabolic functions→ produces hydrogen peroxide • Mitochondria→ cellular respiration, generates ATP, generates energy • Lysosome→ digestive organelle where macromolecules are broken down • Golgi apparatus→ modifies sorts and secretes cell products • Ribosomes→ make proteins- not membrane bound • Plasma membrane→ encloses the cell • Nucleus o Nuclear envelope→ double membrane enclosing the nucleus- has pores where RNA comes out of- connected to the ER o Nucleolus→ not membrane bound- involved in producing ribosomes o Chromatin→ material consisting of DNA and proteins- visible as individual chromosomes during mitosis • Parts of animal cell that aren’t in plant cells→ Lysosomes, centrioles, flagella |
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Parts of Plant cell
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• Nucleus
o Nuclear envelope o Nucleolus o Chromatin • Centrosome→ where the microtubules originate- no centrioles in plant cells • Golgi apparatus • Mitochondria • Peroxisome • Plasma Membrane • Cell wall→ outer layer that maintains cell shape and protects cell from damage- made of cellulose • Plasmodesmata→ channels through the cell wall that connect the cell to the cytoplasms of adjacent cells • Chloroplast→ where photosynthesis happens • Cytoskeleton o Microfilaments- solid o Microtubules- hollow o Intermediate filaments • Central vacuole→ huge organelle- used for storage, breakdown of waste products, breakdown of macromolecules- bigger vacuoles make plant cells grow • Ribosomes • ER (rough and smooth) • Parts of plant cell that aren’t in animal cells→ chloroplasts, vacuole, cell wall, plasmodesmata |
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• Nuclear envelope
nuclear lamina nuclear matrix |
o Encloses the nucleus
o Double membrane (lipid bilayer) o Has pores for MRNA and other stuff to go in and out of o Nuclear lamina→ array of protein filaments that maintain the nucleus’ shape o Nuclear matrix→ framework of fibers throughout the nucleus’ interior that maintains shape |
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• Chromosomes
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o Chromosomes are made out of chromatin (protein with DNA wrapped around it)
o Humans have 46 chromosomes o Human sex cells have 23 chromosomes hold DNA |
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• Nucleolus
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o Makes ribosomal RNA (rRNA- which makes ribosomes when combined with proteins)
o Sometimes there are two or more nucleoli inside the nucleus |
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Ribosomes
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• Ribosomes→ made of rRNA and protein
• Carry out protein synthesis • Not membrane enclosed • Free ribosomes→ float around in the cytoplasm- make proteins that function in the cytosol • Bound ribosomes→ attached to the rough ER or nuclear envelope- make proteins that have a specific destination or need to be sent outside of the cell • Bound and free ribosomes can switch places- cell adjusts number of bound and free ribosomes according to need |
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Endomembrane system
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nuclear envelope, ER, Golgi, lysosomes, vacuoles, plasma membrane
network of membranes used for transportation, protein synthesis, metabolism/movement of lipids, detoxification of poisons |
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• Vesicles
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sacs made of membrane that travel between membranes to help connect them
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• ER
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o ER accounts for more than half of the total membrane in eukaryotic cells
o Made of network of tubules and sacs called cisternae o ER lumen/cisternal space (internal compartment of the ER) • ER membrane separates ER lumen/cisternal space from the cytoplasm o Nuclear envelope is connected to ER membrane and ER lumen o Rough ER and Smooth ER |
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• Functions of Smooth ER
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o Helps with lipid synthesis, carb metabolism, detoxification of poisons
o Enzymes in smooth ER synthesize lipids like oils, phospholipids, and steroids- makes sex hormones o Adds hydroxyl groups to toxins so they can be easily flushed through the body- liver cells have lots of smooth ER o Stores calcium ions • Muscle cells have smooth ER that pump calcium ions from the cytosol into the ER lumen- when the muscle cell gets stimulated by a nerve cell it moves the calcium ions back across the ER membrane into the cytosol which trigger contraction of the muscle cell • In other cells calcium ion movement can trigger other responses |
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• Functions of rough ER
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o Makes secretory proteins and membranes
o Bound ribosomes make proteins that have a specific destination- uses the ER to transport the proteins o Glycoproteins→ proteins that have carbs covalently bonded to them- most secretory proteins made in the rough ER are glycoproteins • Secretory proteins leave the ER in vesicles that grow and bud off of the transitional ER • Transport vesicles→ vesicles in transit from one part of the cell to another o ER makes more membrane and expands • Grows in place by adding membrane proteins and phospholipids to its own membrane • ER makes its own membrane phospholipids • Makes membranes (ex: makes lysosome membranes) |
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• Golgi Apparatus
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o Modifies packages and ships proteins for transport
o Made of cisternae (flattened membrane sacs) o Two poles of the Golgi- cis and trans • Cis→ closer to the ER • Transport vesicles enter the golgi through the cis side • Trans→ closer to cell membrane • Packaged proteins exit the golgi through the trans side o Proteins are modified as they move from the cis to the trans side o Golgi also makes polysaccharides o Cisternal maturation model→ theory that the cisternae of the Golgi actually progress from the cis to the trans side o Golgi adds molecular “identification tags” like phosphate groups which tell the packaged proteins where to go o Vesicles that come off of the Golgi also have “molecular identification tags” that tell them where to put the protein |
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• Lysosomes
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o Lysosomes→ sac of digestive enzymes used to digest and break down stuff
o Lysosomes are acidic so lysosome enzymes work best in acidic conditions o Rough ER makes hydrolytic enzymes and lysosome membrane o Phagocytosis→ eating something else • Lysosomes digest food vacuoles full of stuff like simple sugars • Macrophages (type of white blood cell) eat bacteria o Autophagy→ lysosomes break down damaged organelles • Lysosomes use their hydrolytic enzymes to break down damaged cell parts • Helps recycle the cell’s organic material |
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• Vacuoles
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o Plant and fungi cells have one or several vacuoles
o Break things down, store things o Food vacuoles→ formed by phagocytosis, hold food o Contractile vacuoles→ freshwater protists use these to pump excess water out of the cell o Central vacuole→ plant cells have a big central vacuole enclosed by a membrane called the tonoplast- derived from the ER and the golgi • Tonoplast is a selective membrane- controls what goes in and out • Holds reserves of organic compounds like proteins and inorganic compounds like K and Cl • Stores things that would be dangerous/poisonous if kept floating in the cytosol • Contains pigments that color the cell • Contains poisonous compounds that are poisonous to predators • Major contributor to cell growth |
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BOTH mitochondria and chloroplast
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• Membrane enclosed but they’re not part of the endomembrane system
• Both organelles have at least two membranes separating the innermost space from the cytosol o Their membrane proteins are made by free ribosomes in the cytsol and by their own ribosomes-- not the ER • Both organelles have their own DNA and their own ribosomes o Grow and reproduce within the cell |
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Mitochondria
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cellular respiration, makes ATP from sugars/fats/oxygen
o In both plant and animal cells o Found in nearly all eukaryotic cells including plants animals fungi protists o Motile and contractile cells have more mitochondria than others o They move around and reproduce on their own o Enclosed by two phospholipid bilayer membranes o Outer membrane is smooth, inner membrane has lots of folds (called cristae) o Cristae divides mitochondria into two compartments • Intermembrane space→ region between inner and outer membranes • Mitochondrial matrix→ enclosed by the inner membrane • Has enzymes and mitochondrial DNA and ribosomes • Enzymes catalyze cellular respiration • Cristae in the matrix increases surface area which enhances cellular respiration productivity (example of structure fitting function) Four layers... Matrix Cristae Inter membrane space Outer membrane |
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• Chloroplasts
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• Chloroplasts→ only in plants and algae- use the sun to make sugars from water and CO2
o Chloroplasts belong to the family of plant organelles called plastids • Amyloplasts→ colorless plastids that store starch→ in roots and tubers • Chromoplasts→ colorful plastids (chloroplasts are in this category) o Thylakoids→ flat membranous system inside a chloroplast o Granum→ stack of thylakoids o Stroma→ fluid outside the thylakoids • Contains chloroplast DNA and ribosomes and enzymes o Membranes separate chloroplast into three regions • Intermembrane space, stroma, thylakoid space o Reproduce, grow, and move on their own |
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• Peroxisomes
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o Bounded by a single membrane
o Metabolic function o Has enzymes that combine hydrogen from various substrates with oxygen (makes H2O2) o Some peroxisomes use oxygen to break fatty acids into smaller molecules that can be transported to mitochondria o Peroxisomes in liver detoxify alcohol and other toxins by making H2O2 o Peroxisome also has catalase in it so it can break down the H2O2 because that’s also poisonous o Glyoxysomes→ kind of peroxisome found in fat storing tissue of plant seeds→ has enzymes that convert fatty acids into sugar to use as energy for the seed o Not connected to the endomembrane system o Grow larger by taking proteins from the cytosol, lipids from the ER, and lipids from itself and building itself up o Can split in two to reproduce |
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• Cytoskeleton
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network of fibers that give the cell shape, structure, and method of transportation for molecules
Microtubules microfilaments intermediate fibers • Important in animal cells b/c they don’t have cell walls • Provides anchorage for enzymes and organelles • Changes shape all the time- disassembles and reassembles itself |
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Microtubules
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• Hollow, made of tubulin
• Thickets • Maintains cell shape (compression) • Moves cilia and flagella • Arranged in a ring with nine microtubules on the outside and two cross sections of microtubules in the inside (9+2 pattern)- shaped like a wagon wheel • Basal body→ anchors the cilia/flagella to the cell- looks like a centriole • Dynein→ motor protein that connects the microtubules in cilia/flagella- moves the cilia/flagella • Serve as tracks for intercellular transportation • Moves organelles • Moves chromosomes in cell division • Grow from the centrosome and centrioles |
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Microfilaments
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• Solid, made of actin
• Thinnest • Maintains cell shape (tension) • Changes cell shape • Muscle contraction • Cytoplasmic streaming- filaments contract and move cytoplasm around • Speeds up the distribution of materials within the cell • Cell motility (pseudopodia) aka cell “foot” • Actin filaments move cytoplasm around which moves the foot around • White blood cells and amoeba have pseudopodia • Cell division (makes the cleavage furrow) • Make up microvilli- microvilli increase the cell’s surface area- intestine cells • Important component of muscle cells • Myosin→ motor protein that connects microfilaments in muscle cells • Muscle cells contract when the actin and myosin filaments slide past each other |
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o Intermediate filaments
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• Made of proteins from the keratin family
• Middle in shape • Maintain cell shape (tension) • Anchors nucleus and organelles to the cytoskeleton • Forms nuclear lamina • Don’t disassemble and reassemble like filaments and tubules do- more permanent • Permanent component of a cell’s skeleton |
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importance of cytoskeleton in cell motility
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o Motor proteins→ interact with cytoskeleton to move the cell
• Move the cilia and flagella and muscle cells o Vesicles “walk” along the cytoskeleton “monorails”→ used for transportation o Cytoplasmic streaming→ Cytoskeleton contracts which moves the cytoplasm around→ another way to transport things in the cell |
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• Cell Wall
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o Only in plant cells and some prokaryotes, fungi, and protists
o Maintains cell shape, rigid, prevents excessive uptake of water o Makes the cell rigid which helps the plant resist gravity and fall over o Thicker than cell membranes o Made of Microfibrils made of cellulose |
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• Components of cell wall
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o Primary cell wall→ young plant cells grow this first- its thin and flexible
o Middle lamella→ between primary walls of adjacent cells (plant cells are connected to each other)- rich in pectins (a sugar)- holds cells together o Secondary cell wall→ between plasma membrane and primary wall • Wood has lots of secondary cell walls o Plasmodesmata (holes that connect plant cells together) |
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o Extracellular matrix
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mostly made of collagen which is a glycoprotein (protein covalently bonded to a carb)
o Collagen is the most abundant protein in the human body o ECM connects animal cells together o Proteoglycans→ form a network that holds the collagen fibers o Collagen and Fibronectin→ glycoproteins that attach cells to the ECM o Integrins→ anchor collagen and fibronectin ECM fibers to the cell- found in the cell’s plasma membrane- attaches cell to the ECM • Help the cell communicate with other cells |
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• Intercellular junctions
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points of direct physical contact in cells
IN ANIMALS • Tight Junctions • Membranes of neighboring cells are tightly pressed against each other • Forms seals around cells- prevents cell leakage • Desmosomes • Functions like rivets- lock cells together • Gap Junctions • Like plasmodesmata • Provide cytoplasmic channels from one cell to another • Helps with intercellular communication IN PLANTS o Plasmodesmata→ in plants • Channels in the cell wall that connect plant cells to each other • Cytosol passes through the plasmodesmata and connects neighboring cells |
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Where do bacteria carry out cellular respiration
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in the mesosome (inward folding of their plasma membranes)
increases the surface area and therefore metabolic productivity |
