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AP Bio Ch 6 Vocab
Vocabulary on cell structure and organelles
68
Biology
Undergraduate 1
09/19/2010

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Term
Organelle
Definition
Subcellular units, little organs too small to be seen with a light microscope
Term
Prokaryote
Definition
DNA is concentrated, but not in a true nucleus. They are smaller than Eukaryotic cells and do not have the membrane bound organelles
Term
Eukaryote
Definition
Has a true, membrane bound nucleus and organelles. Larger than Prokaryotes
Term
Plasma Memebrane
Definition
A selective barrier which allows passage of oxygen, nutrients and wastes.
Term
Chemical exchange and surface area
Definition
Cells require a surface area sufficient to allow for the transport of materials necessary for cell metabolism. Larger organisms have MORE cells, not larger ones.
Term
Internal cell membranes
Definition
Participate in cell metabolism, enzymes are built into these membranes. Each type has unique proteins in a phospholipid bilayer
Term
Nucleus
Definition
Contains the genetic material enclosed in a bilayer membrane.
Term
Nuclear Envelope
Definition
The bilayer membrane which surrounds the nucleus and separates its contents from the cytoplasm. Has pores for passage of materials out of the nucleus.
Term
Pore complex
Definition
An intricate protein structure at the nuclear pores which regulates the passage of large macromolecules and particles into and out of the nucleus.
Term
Nuclear Lamina
Definition
A netlike array of protein filaments which lines the interior side of the nuclear envelope fo structural support
Term
Nuclear Matrix
Definition
A framework of protein fibers throughout the nucleus to maintain nuclear shape and possibly function in organizing genetic material.
Term
Chromatin
Definition
A complex of proteins and DNA. Thin and threadlike until it begins to coil prior to cell division.
Term
Chromosomes
Definition
Made up of chromatin. Form prior to cell division. Humans have 46 in somatic cells and 23 in their haploid sex cells.
Term
Nucleolus
Definition
A mass of densely packed granules and fibers. Synthesizes ribosomal RNA which joins proteins from the cytoplasm to form the large and small subunits of the ribosomes
Term
Ribosomes
Definition
rRNA and proteins make up this 2 part organelle which carry out protein synthesis. Can be bound to ER or loose in the cytosol.
Term
Bound ribosomes
Definition
Generally make proteins for membrane insertion, packging within organelles or for export from the cell.
Term
Free Ribosomes
Definition
Make proteins which function in the cytosol
Term
Endomembrane System
Definition
Synthesizes proteins then transports them into membranes and organelles or out of the cell, metabolism and movement of lipids and detoxification of toxins. Includes the nuclear envelope, ER, Golgi, Lysosomes, Vacuole and Plasma membrane.
Term
Vesicles
Definition
Sacs made of membrane, carry out a variety of functions, used in transporting materials separate from the cytosol.
Term
Endoplasmic Reticulum
Definition
Accounts for more than half the total membrane in most Eukaryotic cells. A network of tubules and sacs called cisternae. Interior is called the lumen or cisternal space. Continuous with the nuclear envelope. Two distinct, but connected kinds, smooth and rough.
Term
Smooth ER
Definition
No ribosomes attached. Synthesis of lipids (oils, phospholipids, steroids), Detxifies drugs by adding a hydroxyl group, responsible for drug tolerance. Stores Calcium ions important in muscle contractions.
Term
Rough ER
Definition
Has Ribosomes attached which create the polypeptide chain or primary protein structure. As the chain is made it enters the ER lumen where it folds into its native shape. Most are glycoproteins which have associated carbohydrates attached by the ER. these are transported in vesicles. Also, makes membranes for the cell.
Term
Transport Vesicles
Definition
Vesicles which transport materials from one part of the cell to another.
Term
Golgi Complex
Definition
Products from the ER are modified and stored before being sent to other parts of the cell or out of the cell. Made up of flattened, membranous sacs, called cisternae. Stacks have polarity a cis and a trans face. Cis receives from the ER by way of transport vesicles. The Trans face pinches off and forms a vesicle for transport. the ER ptoducts are modified while in the Golgi lumen such as adding carbohydrates to glycoproteins. It also makes certain macromolecules. the membranes of the cisterae have unique proteins for the varying functions they perform.
Term
How does the Golgi Complex make sure the product in its vesicles get to the right place?
Definition
They tag the vesicle with things like phosphate groups and other membrane proteins.
Term
Lysosome
Definition
A membranous sac with hydrolytic enzymes used to digest old organelles autophagy) and macromolecules. The enzymes here are functional at a different pH than that of the cytosol to prevent problems should one break open. Phagocytosis occurs here when the lysosome engulfs nutrients for digestion or, as in the case with white blood cells, virus or bacteria cells.
Term
Autophagy
Definition
When Lysosomes digest old organelles or other cellular organic material.
Term
Food Vacuoles
Definition
Formed by phagocytosis. The engulfing of food particles by a lysosome.
Term
Contractile Vacuoles
Definition
Common in freshwater protists which move by pumping excess water out of the cell.
Term
Central vacuole
Definition
In plant cells, enclosed by a membrane called the Tonoplast. Formed by collecting smaller vacuoles derived from the ER and Golgi. It serves as storage for organic compounds and inorganic ions. Can also be for waste disposal. Allow the cell to get larger by gaining fluid .
Term
Mitochondria
Definition
Converts energy to a form the cell can use. Sites of cellular respiration and metabolic processes which create ATP with the help of oxygen. Membrane enclosed but NOT part of the endomembrane system. Has its own DNA. Internal membrane has folds to increase surface area called cristae.
Term
Cristae
Definition
The interior membrane of mitochondria. They increase the surface area where the metabolic activities of the organelle happen. Encloses the mitochondrial matrix.
Term
Mitochondrial MAtrix
Definition
Enclosed by the cristae or internal mitochondrial membrane. It contains the mitochondrial DNA, enzymes and ribosomes.
Term
Chloroplasts
Definition
Only in plants and algae. Perform photosynthesis which converts sunlight energy into chemical energy. Membrane bound. interior structures include plastids, thylakoids, granum and stroma.
Term
Plastids
Definition
Amyloplasts, the colorless plastids in starches like roots and tubers (potatoes), chromoplasts such as flowers that contain pigemtns seen in petals and chloroplasts which contain chlorophyll.
Term
Thylakoids
Definition
Flattened, interconnected sacs. The site of the light dependent reactions of photosynthesis
Term
Granum
Definition
A stack of thylakoids.
Term
Stroma
Definition
The fluid outside the thylakoids which contains the chloroplasts DNA, enzymes and ribosomes.
Term
Peroxisomes
Definition
A single membrane bound metabolic compartment. They have enzymes which transfer a H from a substrate to oxygen. This produces hydrogen peroxide. Some break down fatty acids for transport to the mitochondria. In the liver they detoxify alcohol. While the hydrogen peroxide, H2O2 is itself toxic, the organelle can convert it into water. They do not bud from the endomembrane system but grow due to proteins made in the cytosol, lipids made in the ER and in the peroxisome itself.
Term
Cytoskeleton
Definition
Made up of microtubules, microfilaments and intermediate filaments. For cellular structure, support, motility and regulation. It provides anchorage for organelles, it is always changing. Important in cilia and flagella for motility. Important in muscle cells and in forming a "monorail" system for neurotransmitters.
Term
Motor Proteins
Definition
Work with the cytoskeleton to facilitate movement of the cell or in cilia and/or flagella.
Term
Microtubules
Definition
Found in the cytoplasm of all eukaryotic cells. Hollow rods or tubes made from the globular protein tubulin. They shape and support the cell. They also guide secretory vesicles from the Golgi to the plasma membrane. Also imprtant in cell division. In many cells they grow out of an area called the centrosome.
Term
Centrosome
Definition
Where, in the cell, the microtubles may grow out of.
Term
Centrioles
Definition
Within the centrosome of animal cells. They replicate prior to cell division.
Term
Tubulin
Definition
A dimer made up of alpha and beta polypeptide subunits. The microtubule grown in length by adding these dimers.
Term
Flagella
Definition
In Eukaryotes, specialized arrangements of microtubules such as on sperm cells. Also in some unicellular organisms for motility.
Term
Cilia
Definition
Like flagella. Locomotor appendages made of microtubules. In lung tissue and as locomotion in some single cell organisms.
Term
Basal Body
Definition
Anchors the cilia or flagella to a cell. identical in strucutre to a centriole In fact, the basal body of sperm cells is thought to become the centriole of the fertilized cell.
Term
Dynein
Definition
Polypeptide arm responsible for the back and forth motion of the cilia and flagella.
Term
Actin
Definition
A globular protein. The sub-units in microfilaments.
Term
Microfilaments
Definition
Made up of a twisted double chain of actin sub-units. Form a three dimensional network which function in the cytoskeleton to bear tension or pulling forces. Important in the contractile function of muscle cells.
Term
Myosin
Definition
Thicker protein filaments in muscle cells. Motor proteins which "walk" along the actin fibers in muscle cells.
Term
Psuedopodia
Definition
In amoeba movement, cellular extensions created by microfilaments.
Term
Intermediate filaments
Definition
More permanent than microtubules and microfilaments. Intermediate in diameter. Made of keratin proteins. Important in fixing the position of certain organelles.
Term
Cell Wall
Definition
In plants for protection, support and prevention of excessive water uptake. Usually made up of a primary wall, middle lamella and secondary wall. Much thicker than plasma membrane. Made of cellulose.
Term
Primary Cell Wall
Definition
Secreted first by young plant cells. Thinner and more flexible than a mature cells wall.
Term
Middle Lamella
Definition
Between primary walls of adjacent cells. A thin layer, rich in sticky polysaccharides called pectins. Glues adjacent cells together.
Term
Pectins
Definition
The sticky polysaccharides which glue adjacent plant cells together.
Term
Secondary Cell Wall
Definition
Between the plasma membrane and the primary cell wall. Deposited in several layers. For structure and support. Wood is an example. Has channels for communication.
Term
Extracellular Matrix (ECM)
Definition
In animal cells, made of glycoproteins secreted by the cells. Most abundant is collagen. Also has a network woven from proteoglycans. Some cells have fibronectins and integrins also. ECM is thought to regulate several kinds of cellular behavior.
Term
Collagen
Definition
The most abundant protein in the human body. Part of the extracellular matrix. Made up of glycoproteins. Forms strong fibers outside the cell membrane.
Term
Proteoglycans
Definition
Like collagen, made of glycoproteins. A small core protein with many, covalently bonded, carbohydrate chains. Forms large complexes when hundreds are attached to a single long polysaccharide molecule.
Term
Fibronectin
Definition
Also glycoproteins. Bind to cell surface reseptor proteins which are built into the plasma membrane.
Term
Integrins
Definition
Cell surface receptor proteins which are built into the plasma membrane. Transmit changes between the ECM and the cytoskeleton.
Term
Plasmodesmata
Definition
Channels in the cell walls of plants. Connects the chemical environments of adjacent cells. Allow passage of cytosol and small molecules between cells. Sometimes even small proteins and RNA are flowing between cells.
Term
Tight Junctions
Definition
In animal cells. the membranes of adjacent cells are pressed very tightly together, forms continuous seal around cells to prevent leakage of extracellular fluid. Ex: epithelial (skin) cells
Term
Desmosomes
Definition
Also called anchoring cells, function like rivets, fastening adjacent cells together in strong sheets. Held in place by intermediate filaments made of keratin protein.
Term
Gap Junctions
Definition
In animal cells. Also called communicating junctions. Provide cytoplasmic channels from one cell to another, adjacent, cell.Special membrane proteins with a pore thru which can pass ions, sugars, amino acids and other small molecules. Necessary for communication between cells in tissue.
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