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91 Cards in this Set
- Front
- Back
What is an ORGANELLE?
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Subcellular structure find in the CYTOSOL of the the cell.
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What are components of CELL THEORY?
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all organisms are made up of cells; cell is the simplest form of matter that can live; cell structure is related to function; all cells are related by their descent from earlier celss
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What are the two types of ELECTRON MICROSCOPE?
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1. SCANNING ELECTRON MICROSCOPE (SEM) - used for the detailed study of the surface of a specimen.
2. TRANSMISSION ELECTRON MICROSCOPE (TEM) - used mainly for the study of the internal structure of the cell. |
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Light microscopes (LMs)
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visible light passes through a specimen and then through glasses lenses, which magnify the image
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What is CYTOLOGY?
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The study of a cell's structure
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Quality of image depends on 3 things
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magnification; resolution; contrast
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What is CELL FRACTIONATION?
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To take a cell apart and seperate the major organelles from one another. (Usually done with a centrifuge.)
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magnification
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ratio of an object's image size to its real size
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What are the basic features common to all cells?
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- All bounded by a membrane (called a PLASMA MEMBRANE)
- CYTOSOL (semifluid substance within the membrane) - All cells have CHROMOSOMES (carrying genes in the form of DNA) - RIBOSOMES - tiny organelles that make proteins according to instructions from the genes. |
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resolution
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the measure of the clarity of the image, or the minimum distance of two distinguishable points
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What is the major difference between PROKARYOTIC and EUROKARYOTIC cells?
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Chromosomes of a eukaryotic cell are located in a membrane-enclosed organelle called the NUCLEUS.
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contrast
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visible difference in parts of the sample
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Where is DNA found in a PROKARYOTIC cell?
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Concentrated in a region called the NUCLEOID (though it is not enclosed by a membrane.
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Limits of LMs
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cannot resolve dtail finer than about .2 micrometers, resolution is limited by shortest wavelength of light used to illuminate the specimen; can magnify to about 1000 times the specimen's size; use stains/dyes to enhance specimen
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What is the NUCLEAR LAMINA?
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A netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope.
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6 LM techniques
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Brightfield stained and unstained; phase contrast; differential-interference contrast; fluorescence; confocal
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Where are CHROMOSOMES found?
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In the nucleus.
- Chromosomes carry genetic information. - Chromosomes are made up of material called CHROMATIN (a complex of proteins and DNA). |
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brightfield unstained
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light passes through specimen; image has little contrast
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What is the NUCLEOLUS?
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A prominent structure within the non-dividing nucleus; where ribosomal RNA (rRNA) is synthesized from instructions in the DNA.
- Proteins imported from the cytoplasm are assembled |
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brightfield stained
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staining enhances contrast but staining means specimen is fixed/preserved/dead
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What is a RIBOSOME?
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The organelles that carry out protein synthesis; made of RNA and protein
- Free Ribosomes float free in the cytosol - Bound Ribosomes are attached to the outside of the Endoplasmic Reticulum. |
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phase contrast
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enhances contrast in unstained cells by amplifying variations in density within specimen; useful for examining living cells
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What is the difference between FREE and BOUND Ribosomes?
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Free - Most proteins made on free ribosomes function within the cytosol (eg. enzymes that catalyse the first steps of sugar breakdown.)
- Bound: generally make proteins that are desined either for insertion into membranes, for packaging within certain organelles such as lysosomes or for export from the cell (secretion). |
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differential-interference contrast
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like phase contrast, but making the image appear 3D
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What is the ENDOMEMBRANE SYSTEM and what does it do?
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Different membranes that make up the Eukaryotic cell; regulates protein traffic and performs metabolic functions in the cell
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fluorescence
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tags molecules with fluorescent dyes or antibodies; substances absorb ultraviolet radiation and emits visible light
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What components of a cell are included in the ENDOMEMBRANE SYSTEM?
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Nuclear envelope; endoplasmic reticulum; Golgi apparatus; lysosomes, various kinds of vacuoles and the plasma membrane.
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confocal
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uses lasers and special optic for 'optical sectioning' of fluorescently-stained specimens
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What is the ENDOPLASMIC RETICULUM?
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A network of sacs and tubes active in membrane synthesis and metabolic processes
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electron microscopes
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achieve a resolution of about .002 nm; two types; able to study organelles; stains kill specimen
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What are two types of the ENDOPLASMIC RETICULUM?
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SMOOTH ER: so named because it's outer surface lacks ribosomes
ROUGH ER: has ribosomes that stud the outer surface of the membrane. |
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Scanning electron microscopes (SEM)
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focus a beam of electrons onto the surface of a specimen, provides a 3D image; specimen usually coated with thin gold film
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What is the role of the SMOOTH ER?
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Important to the synthesis of lipids, including oils, phospholipids and steroids.
- Enzymes help detoxify drugs and poisons, especially in the liver cells. - Stores calcium ions |
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Transmission electron microscope
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focus a beam of electron through a specimen; used to study internal structures of cells; profiles a thin specimen stained with heavy metals and enhance density
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What is the role of the ROUGH ER?
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Protein secretion produced by ribosomes and moved by transport vesicles
- Also the membrane factory for the cell |
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What is a GLYCOPROTEIN?
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A secretory proteins. (Have carbohydrates covalently bonded to them.)
- Found in the ER. |
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all cells (prok and euk) have...
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plasma membrane; cytosol; chromosomes; ribosomes
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all prokaryotic cells have...
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no nucleus; DNA in a unbound region called nucleoid; no membrane bound organelles, cytoplasm bound by plasma membrane; domains Bacteria and Archaea
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all eukaryotic cells have...
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DNA in a nucleus that is bounded a membrane called nuclear envelope; membrane bound organelles; cytoplasm in teh region b/w the plasma membrane and nucleus; domains Protists, Fungi, Animal and Plant; usually much larger than prok
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plasma membrane
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a selective barrier that allows sufficient passage of oxygen, nutrients and waste to service the volume of every cell; made of double layer of phospholipids
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What is the GOLGI APPARATUS?
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We can think of it as the center of manfacturing, warehousing, sorting and shipping.
- Products of the ER are modified and stored and then sent to other destinations. - Specialized for secretion. |
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The phospholipid tails and interior portions of membrane proteins are...; the phospholipid heads, exterior proteins/parts, and carbohydrate side chains are...; carb chains are only found on...
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Hydrophobic; hydrophilic and in contact with regions on either side of membrane; outer surface of plasma membrane
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lack a true nucleus, no membrane bound organelles, simpler in structure and smaller; bacteria and archaea
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Describe the path of a product from the ER to the Golgi appartus.
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Product protein:
- arrives on the CIS face (recieving end) - usual modified as it travels to the TRANS end (shipping side) - proteins are usually transported to the plasma membrane for secretion. |
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pili
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attachment structure son surface of some prok
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What is a LYSOSOME?
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A membranous sac of hydrolytic enzymes that an animal cell uses to digest all kinds of macromolecules. (Carry out intracellular digestion.) Food vacuole fuses with lysosome and enzymes digest food
- lysomal enzymes work best in the acidic environment found in lysosomes. |
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nucleoid
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region where the cell's DNA is located (not enclosed by a membrane
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What is PHAGOCYTOSIS?
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The process of whereby amoebas and other protists eat by engulfing smaller organisms or other food particles; forms food vacuoles
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ribosomes
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organelles that synthesize proteins
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What is AUTOPHAGY?
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The process by which lysosomes use their hydrolytic enzymes to reyclce the cell's own organic material such as another damaged organelle
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cell wall
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help shape and protect cell, made of cellulose, other sugars and protein, only in plants
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What is a VACUOLE?
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Membrane sac that aids in digestion of cell and the release of cellular waste products. They carry out hydrolysis and similar to lysosomes
-examples - food, contractile, and central |
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capsule
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jelly like outer coating of many prok
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What is a TONOPLAST?
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The membrane that encloses the large, central vacuole in a plant cell.
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flagella
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locomotion of organelles of some bacteria and animal cells
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How important is the VACUOLE to a plant cell?
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Extremely. Plant cells enlarge as their vacuoles absorb water, enabling the cell to become larger with a minimal investment in the new cytoplasm.
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centrosome
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region where the cell's microtubules are initiated; in an animal cell, contains a pair of centrioles
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What is a MITOCHONDRIA?
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- Sites of cellular respiration and metabolic process that generates ATP by extracting energy from sugar, fats and other fuels with oxygen. Power house of the cell
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cytoskeleton
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reinforces cells's shape functions in cell movement; components are made of protein; microfilaments, intermediate filaments and microtubules
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What are CHLOROPLASTS?
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Found only in plants and algae, are the sites of photosynthesis.
- contain the green pigment chlorophyll, along with enzymes and other molecules that function in the photosynthetic production of sugar. |
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microvilli
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projections that increase the cell's surface area
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Are MITOCHONDRIA and CHLOROPLASTS part of the endomembrane system?
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No, these organelles have at least two membranes separating the innermost space from the cytosol.
- they contain DNA that programs the synthesis of the proteins made on the organelle's own ribosomes, have a double membrane and have proteins made from free ribosomes |
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peroxisome
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organelles with specialized metabolic functions; produces hydrogen peroxide
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What is a PLASTID?
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a plant organelle; e.g. The Chloroplast is a specialized member, give green color. Amyloplasts are colorless plastids that store starch, chromoplasts give fruit the yellow and orange color
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What is the CYTOSKELETON?
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Network of fibers extending throughout the cytoplasm.
- Gives mechanical support to the cell and helps maintain its shape - Plays a major role in organizing the structures ad activities of the cell through motility and regulation - Composed of microtubules microfilaments and intermediate filaments. |
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Is the CYTOSKELETON more important in plant or animal cells?
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Animal cells b/c they lack walls.
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What is CELL MOTILITY?
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Encompasses both changes in cell location and more limited movements of parts of the cell.
- Requires the interaction of the cytoskeleton with proteins called MOTOR PROTEINS |
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What is the function of the MICROTUBULES?
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- Thickest component of the cytoskeleton
- They shape and support the cell - Serve as tracks along which organelles equipped with motor proteins can move - Responsible for the separation of chromosomes during cell division - Act as compression-resisting girders of the cytoskeleton - provide support to the motion of CILIA and FLAGELLA |
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What is the CENTROSOME?
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A region often locatd near the nucleus that is considered to be a "microtubule-organizing center"
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What are CENTRIOLES?
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Found in the centrosome of the animal cell, composed of microtubules arranged in a ring
- Before a cell divides, centrioles replicate |
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Do plant cells have CENTROSOMES/CENTRIOLES?
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- Both have centrosomes
- Plant cells do not have centrioles |
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What is a DYNEIN?
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Dynein arms are responsible for he bending movements of cilia and flagella.
- Motor protein - Performs a complex cycle of movements caused by changes in the conformation of the protein with ATP providing the energy for these changes. (Like a cat walking along along the branch of a tree.) |
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Provide info on a MICROFILAMENT.
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- also called ACTIN filaments
- appear to be present in all eukaryotic cells - role is to bear tension (pulling forces) between the microtubules - form a 3-D network inside the plasma membrane that helps support the cells shape - known for their role in cell molility |
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What is a PSEUDOPODIA?
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Assist in the movement of amoeba
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What is MYOSIN?
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Motor protein that help with the movement of microfilaments
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What are INTERMEDIATE FILAMENTS?
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- Also specialized for bearing tension
- Larger than microfilament but smaller than microtubules - more permanent fixtures in cells than microtubules or microfilaments - they assist with the anchoring of the nucleus |
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What is PLASMODESMATA?
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channels that perforate plant cell walls; thru this, water and small solutes can pass from cell to cell
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What is SELECTIVE PERMEABILITY?
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The plasma membrane allows some membranes to cross it more easily than others.
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What is a GLYCOLIPID?
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A carbohydrate that is covalently bonded to lipids (e.g. to phospholipids in the plasma membrane layer)
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What is CISTERNAL MATURATION MODEL?
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the cisternae of the Golgi actually progress forward from the cis (flat) to the trans(bubbled) face of the Golgi, carrying and modifying their protein cargo as they move
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What do CONTRACTILE VACUOLES do in protists?
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in protists, they pump excess water out of cell , thereby maintaing the appropriate concentration of salt and other molecules
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What are roles of CONTRACTILE VACUOLES in plants?
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holds reserves of important organic compounds; plant cell's main repository of inorganic ions, as a K and Cl; contain pigments that color cell; help protect the plant against predators by containing compounds that are poisonous; can become very large
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What is the function of MOTOR PROTEINS?
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bring movement of cilia and flagella by propelling them; causes muscle cells to contract; aid vesicles in budding off and moving along Golgi body track; aid materials that move about inside cytoplasm
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What is INTERSTIAL FLUID?
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liquid b/w cells
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What is TIGHT JUNCTIONS?
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membranes of neighboring cells pressed together, preventing leakage of extracellular fluid
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Name the INTERCELLULAR JUNCTIONS
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plasmodesmata, tight junctions, desosomes, gap junctions
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What is GAP JUNCTIONS?
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(communicating junctions) provide cytoplasmic channels b/w adjacent cells
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What are ANCHORING (adherence) JUNCTIONS?
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(desosomes) fasten cells together into strong sheets
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What is the EXTRACELLULAR MATRIX (EMC)?
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animal cells lack walls but have this instead; made up of glycoproteins; function in support, adhesion, movement and regulation
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Examples of GLYCOPROTEINS
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collagen, proteoglycans, and fibronectin
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What are INTEGRINS?
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ECM proteins bind to receptor proteins in the plasma membrane
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