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68 Cards in this Set
- Front
- Back
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plasma membrane
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encloses cell contents, mediates exchanges with the extracellular environment and plays a role in cellular communication |
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What has a semi-permeable membrane that allows the attachment to other cells or structures, and serves as a point of communication and recognition among cells?
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plasma membrane
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membrane proteins
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proteins that reside in the plasma membrane, either spanning its entire distance (integral membrane proteins) or just attached to the inner or outer surface (peripheral membrane proteins) |
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marker molecules
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usually glycoproteins on outside surface of cells as identification (membrane protein)
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attachment proteins
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used to attach cells to each other (cadherins) also can be used to attach cells to other molecules (membrane protein)
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transport proteins
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integral membrane proteins that allow movement across the membrane of hydrophobic or large molecules
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receptors
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exposed portion on the extracellular surface that binds to and recognizes extracellular molecules. The binding of a specific molecule causes a cascade of intracellular reactions.
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enzymes
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membrane proteins that catalyze reactions close to the inner or outer surface of the membrane |
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cytoplasm
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all the stuff inside the plasma membrane, but outside the nucleus, the site of most cellular activities
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cytosol
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the fluid portion of the cytoplasm containing the cytoskeleton, cytoplasmic inclusions and dissolved or suspended molecules, especially ions or proteins.
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cytoplasmic inclusions
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groups of molecules produced inside, or taken inside the cell. ex: lipid droplets, glycogen granules, hemoglobin and pigments (like melanin)
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cytoskeleton
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supports the cell structure and organelle placement within the cell. Also responsible for change in cell shape and movement of organelles or molecules within a cell.
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microfilaments
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the smallest filaments that form bundles, sheets, or networks to support cellular shape. Highly organized actin filaments found in muscle cells are crucial to movement
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nucleus |
the control center of the cell, and it contains almost all of the cellular DNA. DNA is translated into mRNA which is transcribed into protein molecules.
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nucleolus |
a dense region inside the nucleus where rRNA is produced, which is used along with proteins to make ribosomes.
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ribosomes |
structures that are necessary to transcribe proteins from mRNA. |
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endoplasmic reticulum |
A series of membranes inside the cell continuous with the nuclear membrane, can be rough or smooth. |
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rough ER |
has ribosomes attached and is the site of production of proteins that will be integral membrane proteinsor extracellularly transported proteins |
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smooth ER |
manufactures lipids like phospholipids cholesterols, steroid hormones and carbs |
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golgi apparatus |
referred to as the distribution center of the cell. consists of flattened membrane sacs. Concentrate, modify, and package for distribution proteins made by the rER |
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lysosomes |
membrane bound vesicle formed in the golgi apparatus containing hydrolytic enzymes. Digest vesicles brought into the cell containing nucleic acids, proteins, sugars and lipids. The cells digestive system |
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peroxisomes |
the membrane bound vesicles that contain enzymes to break down fatty acid and amino acids. |
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mitochondria |
provide energy for the cell by being the major site of ATP production. The citric acid cycle, and the electron transport chain both take place here. Mitochondrial DNA instruct some proteins for metabolic reactions |
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centrioles |
small, barrel shaped organelles oriented at right angles to each other. these are necessary for cell division |
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Cells |
the structural units of all living things |
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extracellular materials |
substances contributing to body mass that are found outside the cells |
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intracellular |
inside the cell
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interstitial fluids |
the fluid in tissues that bathes all of our cells and has major and endless roles to play. |
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cellular secretions |
include substances that aid in digestion and some that act as lubricants |
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glycolipids |
lipids with attached sugar groups found only in outer plasma surface. 5% of total membrane lipids |
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cholesterol |
20% of membrane lipids. has a polar region (its hydroxyl group) and a nonpolar region (its fused ring system). It wedges its platelike hydrocarbon rings between the phospholipid tails, which stabilize the membrane while decreasing the mobility of the phospholipids and fluidity of the membrane |
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integral proteins |
firmly inserted in the lipid bilayer. some protrude from only one membrane face, but most span the entire membrane and protrude on both sides. |
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peripheral proteins |
not imbedded in the lipid bilayer, attach loosely to integral proteins and are easily removed without disrupting the membrane |
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glycocalyx |
consists of glycoproteins and glycolipids to form a fuzzy, sticky, carbohydrate rich area at the cell surface |
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glycoprotein |
proteins that are in contact with the extracellular fluid with branching sugar groups |
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tight junctions |
impermeable junctions that form continuous seals around the cells. Prevent molecules from passing through the intercellular space. |
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desmosomes |
anchoring junctions that bind adjacent cells together, act like "velcro" and also help form an internal tension-reducing network of fibers. |
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gap junctions |
communicating junctions that allow ions and small molecules to pass and are particularly important for communication in heart and embryonic cells |
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selective permeability |
when the plasma membrane allows some substances to pass while excluding others |
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simple diffusion |
lipid soluble substances diffuse directly into through the lipid bilayer into the cell, using kinetic energy from the molecules to move along the concentration gradient |
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facilitated diffusion |
transported substances that either bind to protein carriers or move through protein channels |
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passive transport |
moves substances across the membrane without any energy input from the cell
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diffusion |
the tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration, or down along their concentration gradient |
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osmosis |
the diffusion of a solvent, such as water, through a selectively permeable membrane |
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osmolarity |
the total concentration of all solute particles in a solution |
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tonicity |
refers to the ability of a solution to change the shape or tone of cells by altering the cells internal water volume |
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isotonic solutions |
have the same concentration of nonpenetrating solutes as those found in cells. cells exposed to isotonic solutions retain their normal shape and exhibit no net loss or gain of water |
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hypertonic solutions |
have a higher concentration of nonpenetrating solutes than seen in the cell (strong saline solution) cells immersed in hypertonic solutions lose water and shrink or crenate |
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hypotonic solutions |
more dilute (contain a lower concentration of nonpentrating solutes than cells. Cells placed in a hypotonic solution plump up rapidly as water rushes into them. |
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3 molecules that can diffuse directly through the plasma membrane |
fats, oxygen, and carbon dioxide |
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active transport |
or solute pumping, depends on a carrier protein and energy. move against concentration gradients |
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primary active transport |
the energy to do work comes directly from the hydrolysis of ATP |
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secondary active transport |
transport is driven by energy stored in concentration gradients of ions created by active transport pumps |
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coupled systems |
move more than one substance at a time |
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vesicular transport |
transport of large particles and macromolecules into or out of a cell or between its compartments in membranous sacs called vesicles |
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endocytosis |
the vesicular transport of substances into the cell |
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what are the three types of endocytosis? |
phagocytosis, pinocytosis, receptor-mediated endocytosis |
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phagocytosis |
the cell engulfs a large particle by forming projecting pseudopods around it and enclosing it within a phagosome |
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pinocytosis |
fluid phase endocytosis. the cell gulps a drop of extracellular fluid containing solutes into tiny vesicles. no receptors are used |
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receptor-mediated endocytosis |
extracellular substances bind to specific receptor proteins, enabling the cell to ingest and concentrate specific substances in protein-coated vesicles. |
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exocytosis |
vesicular transport processes that eject substances from the cell interior into the extracellular fluid. the substance is enclosed in a membranous vesicle, which fuses with the plasma membrane and ruptures, releasing the substances to the exterior |
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vesicular trafficking |
vesicles pinch off from organelles and travel to other organelles to deliver their cargo |
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membrane potential |
transmembrane potential- voltage across the plasma membrane |
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ligand |
chemicals that bind specifically to plasma membrane receptors including: neurotransmitters, hormones, and paracrines |
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G-proteins |
protein that relays signals between extracellular first messengers and intracellular second messengers via an an effect enzyme |
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nuclear envelope |
a double membrane barrier separated by the fluid filled space that binds the nucleus |
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chromatin |
a fine, unevenly stained network of bumpy threads weaving through the nucleoplasm composed of 30% DNA, 60% globular proteins, and 10% RNA chains |
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chromosomes |
short, bar like bodies formed when a cell is preparing to divide, and chromatin threads coil and condense enormously. |
