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56 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 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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What is CYTOLOGY?
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The study of a cell's structure
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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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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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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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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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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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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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What is the NUCLEOLUS?
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A prominent structure within the non-dividing nucleus.
- Here a special type of RNA called ribosomal RNA (rRNA) is synthesized from instructions in the DNA. - Proteins imported from the cytoplasm are assembled with the rRNA into large nd small ribosomal subunits in the nucleolus. |
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What is a RIBOSOME?
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The organelles that carry out protein synthesis.
- Free Ribosomes float free in the cytosol - Bound Ribosomes are attached to the outside of the Endoplasmic Reticulum. |
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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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What is the ENDOMEMBRANE SYSTEM?
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Different membranes that make up the Eukaryotic cell.
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What components of a cell are included in the ENDOMEMBRANE SYSTEM?
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Nuclear envelope; edoplasmic reticulum; Golgi apparatus; lysosomes, various kinds of vacuoles and the plasma membrane.
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What is the ENDOPLASMIC RETICULUM?
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An extensive network of membranes that seperates the internal compartment of the ER, caled the ER lumen or cisternal space, from the cytosol.
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What composes 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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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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What is the role of the ROUGH ER?
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Protein secretion produced by ribsomes attached to the rough ER.
- Also the membrane factory for the cell |
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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 odified and stored and then sent to other destinations. - Especialy extensive in cells specialized for secretion. |
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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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What composes 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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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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What is the role of the ROUGH ER?
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Protein secretion produced by ribsomes attached to the rough ER.
- Also the membrane factory for the cell |
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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 odified and stored and then sent to other destinations. - Especialy extensive in cells specialized for secretion. |
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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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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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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.)
- lysomal enzymes work best in the acidic environment found in lysosomes. |
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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.
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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.
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What is a VACUOLE?
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Membrane sac that plays a role in intracellular disgestion and the release of cellular waste products.
- In the plant cell, the central vacuoleis usually the largest compartment. |
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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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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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What is a MITOCHONDRIA?
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- Sites of cellular respiration
- Sites of the metabolic process that generates ATP by extracting energy from sugar, fats and other fuels with the help of oxygen. |
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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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Are MITOCHONDRIA and CHLOROPLASTS part of the endomembrane system?
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In contrast to the organelles of the endomembrane system, these organelles have at least two membranes separating the innermost space from the cytosol.
- additionally, the contain DNA that prgorams the synthesis of the proteins made onthe organelle's own ribsomes |
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What is a PLASTID?
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e.g. The Chloroplast is a specializd member of a family of closely related plant organelles.
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What is a PEROXISOME?
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A specialized metabolic compartment bounded by a single membrane.
- they contain enyzmes that transfer H from various substrates to O, producing Hydrogen peroxide. |
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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 - Composed of microtubules microfilaments and intermediate filaments. - Can be disassembled and reassembled to change the shape of the cell |
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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 bot 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, each is composed of nine sets of triplet 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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Perferations found in the walls of plant cells through which cytosol passes to connect to the chemical environment of adjacent cells.
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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 are the staple ingredients of the plama membrane?
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- Lipids and proteins
- To a lesser extent, carbohydrates |
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What is the most abundant lipid in the plasma membrane?
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Phosopholipids
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What is AMPHIPATHIC?
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A phosopholipid is amphipatic in that it has both hydrophilic and hydrophobic regions.
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What is an INTEGRAL PROTEIN?
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A protein that pentrates th hydrophobic core of the lipid bilayer.
- Many can be transmembrane prtoein, which completely span the membane |
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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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