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79 Cards in this Set
- Front
- Back
What is a light microscope?
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optical instrument with lenses that refract visible light to magnify images and project them into a viewer's eye or onto photographic film.
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What is magnification?
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increase in the apparent size of an object
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What is a micrograph?
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photo taken through a microscope
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What is cell theory?
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theory that all living cells are composed of cells and that all cells come from other cells.
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What is an electron microscope?
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- microscope that uses magnets to focus on electron beam through, , or onto the surface of, a specimen.
- achieves a hundredfold greater resolution than a light microscope. |
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What is scanning electron microscope?
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microscope that uses an electron beam to study the fine details of cell surfaces or other specimens.
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What is a transmission electron microscope?
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microscope that uses an electron beam to study the internal structure of thinly sectioned specimens.
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light microscope
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What type of microscope would be used to study the change in shape of a living human white blood cell?
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scanning electron microscope
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What type of microscope would be used to study the finest details of surface texture of a human hair?
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transmission electron microscope
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What type of microscope would be used to study the detailed structure of an organelle in a liver cell?
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What is a plasma membrane?
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- membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules into and out of the cell.
- consists of a phospholipid bilayer with embedded proteins. |
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What are prokaryotic cells?
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- cell lacking a membrane enclosed nucleus and other membrane enclosed organelles.
- in domains; bacteria and archaea |
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What is eukaryotic cells?
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- cell has membrane enclosed nucleus and other membrane enclosed organelles
- composes all organisms except bacteria and archaea |
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What are chromosomes?
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- threadlike, gene carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis
- main gene carrying structure of a prokaryotic cell - consists of a very long piece of chromatin, combo of DNA and protein |
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What are ribosomes?
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- cell structure consisting of RNA and protein organized into 2 subunits and functioning as the site of protein synthesis in the cytoplasm
- in eukaryotic cells, they are constructed in the nucleolus. |
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What is a cytoplasm?
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- contents of a eukaryotic cell between the plasma membrane and the nucleus.
- consists of a semifluid medium and organelles - refers to the interior of a prokaryotic cell |
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What are the basic features of all cells?
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- bounded by a plasma membrane
- all have 1 or more chromosomes carrying genes mad up of DNA - contain ribosomes - interior called cytoplasms |
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What is a nucleoid?
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dense region of DNA in a prokaryotic cell.
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What is a flagella?
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- long cellular appendage specialized for locomotion
- the ones in prokaryote and eukaryotes differ in both structure and function = like cilia, eukaryotic flagella have a 9+2 arrangement of microtubules, covered by the cell's plasma membrane |
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What 3 features are common to prokaryotic and eukaryotic cells?
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- plasma membrane
- chormosomes - ribosomes |
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- prokaryotic cells are smaller
= don't have nucleus that house their DNA = no membrane enclosed organelle = smaller, somewhat different ribosomes |
What 3 features differ between prokaryotic and eukaryotic cells?
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What is an organelle?
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membrane-enclosed structure with a specialized function within a cell
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- nucleus and ribosome carry out genetic control of the cell
- those involved in the manufacture, distribution, and breakdown of molecules include; the endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, and peroxisomes. - mitochondria in all cells and chloroplasts in plant cells function in energy processing - structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall |
What are the 4 basic functional groups organelles and other structure of Eukaryotic cells?
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What is cellular metabolism?
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all the chemical activities of a cell
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What is nucleus?
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- atom's central core, containg protons and neutrons
- genetic control center of a eukaryotic cell |
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What is a chromatin?
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- combination of DNA and proteins that constitutes eukaryotic chromosomes
- often used to refer to the diffuse, very extended form taken by chromosomes when a cell isn't dividing. |
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What is a nuclear envelope?
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- double membrane that encloses the nucleus, perforated with pores that regulate traffic with the cytoplasm
- separate phopholipid bilayers with associated proteins |
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What is a nucleolus?
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structure within the nuclues where ribosomal RNA is made and assembled with proteins imported from the cytoplasm to make ribosomal subunits.
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- to house and copy DNA and pass it on to daughter cells in cell division
- build ribosomal subunits - transcribe DNA instructions into RNA and therby control the cell's function What is the main function of the nucleus? |
What is the main function of the nucleus?
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ribosomes syntehsize proteins according to the isntructions carried by messenger RNA from the DNA in the nucleus.
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What roles do ribosomes play in carrying out the gentic instructions of a cell?
ribosomes syntehsize proteins according to the isntructions carried by messenger RNA from the DNA in the nucleus. |
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What is the endomembrane system?
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network of membranes inside and around a eukaryotic cell, relating either through direct physical contact or by the transfer of membranous vesicles
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What is a vesicle?
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sac made of membrane in the cytoplasm of a eukaryotic cell.
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What is an endoplasmic reticulum?
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extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded and ribosome-free regions
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What is smooth endoplasmic reticulum?
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portion of the endoplasmic reticulum that lacks ribosomes
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WHat is rough endoplasmic reticulum?
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portion of the endoplasmic reticulum with ribosomesattached that make membrane proteins and secretory proteins
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What is a glycoprotein?
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protion with 1 or more short chains of sugars attached to it
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What is a transport vesicle?
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- small membranous sac in eukaryotic cells cytoplasm carrying molecules produced by the cells
- vesicle buds from the endoplasmic reticulum or golgi and eventually fuses with another organelle or plasma membraen releasing its contents |
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- it porduces a huge variety of molecuels, including phospholipids for cell membranes, steroid hormones, and proteins (synthesized by bound proteins) for membranes, other organelles, and secretion by the cell.
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Why is the endoplasmic reticulum called a biosynthetic factory?
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- golgi receives transport vesicles that bud from the ER and that contain proteins synthesized by ribosomes attached to the ER.
- Golgi finishes processing the proteins and then dispatches transport vesicles that secrete proteins to the outside of the cell |
What is the relationship of the golgi apparatus to the ER in a protein secreting cell?
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What is a lysosome?
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- digestive organelle in eukaryotic cells
- contains hydolytic enzymes that digest engulfed food or damaged organelles. |
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it breaks down damaged organelles and recycles their molecules.
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How is a lysosome like a recycling center?
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What is a vacuoles?
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membrane-enclosed sac that is part of the endomembrane system of a eukaryotic cell and has diverse function
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What is a central vacuole?
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in a plant cell, a large membranous sac with divrse roles in growth and the storage of chemicals and waste.
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yes, it forms by pinching in from the plasma membrane, which is part of the endomembrane system
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Is a food vacuole part of the endomembrane system?
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What are peroxisomes?
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organelle containing enzymes that transfer hydrogen atoms from various substances to oxygen, producing and then degrading hydrogen peroxide.
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transport vesicles move membranes and substances they enclose between components of the endomembrane system.
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How do transport vesicels help tie together the endomembrane system?
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What is mitochondria?
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- an organelle in eukaryotic cells where cellular respiration occurs
- enclosed by 2 membranes, it's where most of the cell's ATP is made. |
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What is a mitochondrial matrix?
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compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle.
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What is cristae?
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an infolding of the innermitochondrial membrane.
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What is cellular respiration?
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process that converts the chemical energy of sugars and other food molecules ot the chemical energy of ATP.
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What are chloroplasts?
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organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water
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What is stroma?
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- dense fluid within the chlorplast that surrounds the thykaloid membrane and is involved in synthesis of organic molecules from carbon dioxide and water.
- sugars are made in here by enzymes of the Calvin cycle. |
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What are thylakoids?
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- flattened membranous sac inside a chloroplast
- contain chlorophyll and the molecular complexes of the light reaction of photosynthesis. - stack of them is called a granum |
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What is granum?
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- stack of membrane-bounded thylakoids in a chloroplast
- site where light energy is trapped by chlorophyll and converted to chemical energy during the light reaction of photosynthesis. |
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thylakoid membranes are most extensive providing a large area of membranes that contains chlorophyll for photosynthesis.
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Which membrane in a chloroplast appears to be the most extensive, and why?
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What is an endosymbiont theory?
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- theory that mitochondria and chloroplasts originated as prokaryotic cells engulfed by an ancestral eukaryotic cell.
= engulfed cell and its host cell then evolve into a single organism |
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1st endosymbiotic event would have given rise to eukaryotic cells containing mitochondria. At least 1 of them may have then taken up a photosynthetic prokaryote, giving rise to eukaryotic cells that contain chloroplasts in addition to mitochondria.`
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All eukaryotes have mitochondria, but not all eukaryotes have chloroplast. Why might this be?
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What is a cytoskeleton?
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- network of protein fibers in the cytoplasm of a eukaryotic cell.
- includes; microfilaments, intermediate filaments, and microtubules |
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What are microfilaments?
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- thinnest of the 3 kinds of protein fibers making up the cytoskeleton of a eukaryotic cell.
- solid, helical compound of the globular protein actin. |
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What are intermediate filaments?
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- intermediate-sized protein fiber that is 1 of the 3 main kinds of fibers making up the cytoskeleton of eukaryotic cells.
- ropelike, made of fibrous proteins. |
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What are microtubules?
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- thickest of the 3 main kinds of fibers making up the cytoskeleton of a eukaryotic cell
- hollow tube made of globular proteins called tubulins. - found in cilia and flagella |
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intermediate filaments.
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What component of the cytoskeleton is most important in holding the nucleus in place within the cells.
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microtubules
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Which component of the cytoskeleton is most important in guiding transport vesicles from the golgi to the plasma membrane?
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microfilaments
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Which component of the cytoskeleton is most important in containing muscle cells?
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What are cilia?
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- short celluar appendage specialized for locomotion
- formed from a core of 9 outer doublet microtubules and 2 single microtubules (9+2) pattern covered by the cell's plasma membrane. |
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- both have the (9+2) pattern of microtubules and mechanism for bending.
- different = cilia are shorter, more numerous, and beat in a coordinated oar like patern = longer flagella, which are limited to 1 or a few per cell , undulate like a whip. |
Compare and contrast cilia and flagella.
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both have the same arrangement of microtubules doublets with attached dynein motor proteins that cause them to bend.
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Why does a lack of dynein proteins affect the action of both cilia and flagella?
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What is an extracellular matrix?
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- mesh work surrounding animal cells
- consists of glycoproteins and polysaccharides |
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What are integrins?
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transmembrane protein that interconnects the extracellular matrix and the cytoskeleton.
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anchoring junction
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A muscle tear injury would probably involve the rupture of which type of cell juntion?
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What are tight junctions?
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plasma membranes of neighboring cells are tightly pressed against each other and knit together by proteins.
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What are anchoring junctions?
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- function like rivets, fastening cells together into strong sheets
- common to tissues subject to stretching of mechanical stress EX: skin and heart muscles |
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What are gap junctions?
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- aka communicating junctions
- channels that allow small molecules to flow through protein lined pores between cells. |
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What is a cell wall?
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- protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists.
- protects the cells and helps maintain its shape. |
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What is plasmodesmata?
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an open chennel in a plant cell wall through whcih strands of cytoplasms connect from adjacent cells.
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a gap junction
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What animal cell junction is analogous to a plasmodesma?
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- mitochondria supply energy in the form of ATP
- smooth ER helps regulate contraction by the uptake and release of calcium ions - microfilaments function in the actual contractile apparatus |
How do mitochondria, smoother ER, and the cystoskeleton contribute to the contraction of a muscle cell?
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The ultrastructure of a chloroplast is best studied using what?
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transmission electron microscope
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rough ER > golgi > transport vesicle > plasma membrane
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A type of cell called a lymphocyte makes proteins that are exported from the cell. What is the path of a protein from the site where its polypeptides are made to its exports?
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