 | Term | Definition |
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cell |
basic functional unit of all living things |
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plasma membrane (cell membrane) |
bounds the cell and encloses the nucleus and cytoplasm; separates internal metabolic events from the external environment and controls the movement of materials into and out of cell; double phospholipid membrane with polar hydrophilic heads forming outer faces/nonpolar hydrophobic tails pointing towards inside of membrane |
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cytoplasm |
consists of specialized bodies called organelles suspended in cytosol |
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cytosol |
fluid matrix that consists of water and dissolved substances such as proteins/nutrients |
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peripheral proteins |
proteins that attach loosely to inner/outer surface of membrane |
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integral proteins |
proteins that extend into the membrane; amphipathic like phospholipids |
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transmembrane proteins |
integral proteins that span across membrane, appearing at both surfaces |
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fluid mosaic model |
mosaic nature of scattered proteins within flexible matrix of phospholipid molecules in the cell membrane |
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phospholipid membrane |
selectively permeable; only small uncharged polar molecules and hydrophobic molecules freely pass across the membrane. large polar molecules and all ions are impermeable |
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channel proteins |
provide open passageways through membrane for certain hydrophilic substances such as polar and charged molecules |
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ion channels |
allow passage of ions across membranes. |
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gated channels |
ion channels in nerve/muscle open/close in response to specific chemical/electrical stimuli to allow specific ions |
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porins |
proteins that allow passage of certain ions and small polar molecules through membranes |
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aquaporins |
found in plasma membrane of certain cells that increase the passage rate of water molecules |
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carrier proteins |
bind to specific molecules, which are transferred across membrane after carrier protein undergoes change of shape. Passage of glucose into cell is by a carrier protein |
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transport proteins |
use energy (ATP) to transport materials across membranes. |
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active transport |
process done when energy is used to transport materials across membrane and the materials are said to be actively transported |
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Na+-K+ pump |
uses ATP to maintain higher concentration of Na ion and Potassium ion on opposite sides of the plasma membrane |
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recognition proteins |
give each cell type of unique identification' provides for distinction b/w self cells and foreign |
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glycoproteins |
recognition proteins are these because they have short polysaccharide chains attached |
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adhesion proteins |
attaches cells to neighboring cells or provide anchors for the internal filaments and tubules that give stability to the cell |
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receptor proteins |
provide binding sites for hormones or other trigger molecules and in response to hormone/trigger molecule, specific cell response is activated |
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cholesterol |
molecules distributed throughout phospholipid bilayer that provide some rigidity to the plasma membranes of animal cells |
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glycocalyx |
carb coat that covers outer face of the cell wall of some bacteria and outer face of plasma membrane of certain animal cells; consists of oligosaccharides attached to glycolipids and proteins; it may provide adhesion, a barrier to infection, or markers for cell recognition |
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glycolipids |
membrane phospholipids |
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glycoproteins |
proteins found in glycocalyx; they're of recognition proteins |
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organelles |
bodies within cytoplasm that serve to physically separate various metabolic reactions that occur within cells |
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nucleus |
contains DNA |
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nuclear envelope |
bounds nucleus; consisting of phospholipid bilayers similar to plasma membrane |
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chromatin |
threadlike matrix that when the cell divides condenses into rod-shaped bodies (chromosomes) |
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chromosomes |
rod-shaped bodies; rod shaped cell structures that direct the activities of a cell and passes on the traits of a cell to new cells <genetics> |
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nucleosomes |
bundles of DNA coiled up by the histones in chromosomes |
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nucleoli |
concentrations of DNA in process of manufacturing components of ribosomes |
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ribosome |
A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; Consists of rRNA and protein molecules, which make up two subunits. |
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endoplasmic reticulum |
consists of stacks of flattened sacs involved in production of materials;, system of passage ways for transporting substances through cytoplasm |
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rough ER |
ribosome present; creates glycoproteins by attaching polysaccharides groups to polypeptides as they're assembled by ribosomes |
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smooth ER |
w/o ribosomes, responsible for activities including synthesis of lipids/hormones. In liver, helps to break down toxins, drugs, toxins from cellular reactions |
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golgi apparatus |
group of flattened sacs that modify/package proteins/lipids into vesicles |
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vesicles |
small sacs that bud from outside of golgi body, migrate to/merge to plasma membrane, releasing content to outside of cells |
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lysosomes |
vesicles for golgi body that contain digestive enzymes; don't occur in plant cells;, garbage disposal of cell |
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peroxisomes |
break down various substances including hydrogen peroxide, fatty acids, and amino acids; |
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glyoxysomes |
peroxisomes in germinating seeds that break down stored fatty acids to generate energy for growth |
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mitochondria |
carries out aerobic respiration , in which energy (ATP) is obtained from carbs |
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chloroplasts |
carry out photosynthesis |
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microtubules, intermediate filaments, microfilaments |
3 protein fibers of decreasing diameter; involved in establishing shape/movement of cytoskeleton |
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cytoskeleton |
internal structure of the cytoplasm |
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microtubules |
made of protein tubulin/provide support/motility for cellular activities; found in spindle apparatus/flagella/cilia, all that project form plasma membrane to provide motility to cell |
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spindle apparatus |
guides movement of chromosomes during cell diivision |
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intermediate filaments |
provide support for maintaining shape of cell |
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microfilaments |
made of protein action/involved in cell motility; found in muscle cells/cells that move by changing shape |
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flagella, cilia |
structures that protrude form cell membrane/make wavelike movements; consist of microtubules arranged in nine pairs of microtubules in a circle surrounding a pair of microtubules |
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centrioles |
act as microtubule organizing centers located outside nuclear envelope that gives rise to the microtubules that make up spindle apparatus used during cell division; plants lack them |
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basal bodies |
act as microtubule organizing centers at the base of each flagellum and cilium and organize their development |
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vacuoles, vesicles |
fluid-filled membrane- bound bodies |
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transport vesicles |
move materials b/w organelles or b/w organelles and plasma membrane |
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food vacuoles |
temporary receptacles of nutrients; merge with lysosomes, whose digestive enzymes break down food |
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storage vacuoles |
in plants; store starch, pigments, and toxic substances |
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central vacuoles |
large bodies occupying most of interior of certain plant cells. when fully filled, they exert turgor, maintaining rigidity in cell; store nutrients/carry out functions otherwise assumed lysosomes in animal cells |
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turgor |
pressure on cell walls |
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contractile vacuoles |
specialized organelles in single-celled organisms that collect/pump excess water out of cell |
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cell walls |
found in plants, fungi, protists, and bacteria.develop outside plasma membrane/provide support for cell; consists mainly of cellulose. of fungi they're made of cellulose and chitin |
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cellulose |
polysaccharide made from beta glucose |
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chitin |
modified polysaccharide differing from cellulose in that one of the hydroxyl groups is replaced by group containing nitrogen |
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cell junctions |
serve to anchor cells to one another. provide passageway for cellular exchange |
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extracellular matrix |
in arer b/w adjacent cells; provides mechanical support/binds adjacent cells together |
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anchoring junctions |
protein attachments b/w adjacent animal cells |
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desmosome |
junction that consists of proteins that bind adjacent cells together, providing mechanical stability to tissues; also associated with protein filaments that extend into interior of cell/serve to hold cellular structures together |
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tight junctions |
tightly stitched seam b/w animal cells; encircles cell producing seal that prevents passage of materials b/w cells; characteristic of cells lining digestive tract where materials pass through cells to penetrate blood stream |
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communicating junctions |
passageways b/w cells that allow transfer of chemical/electrical signals ; two kinds occur |
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gap junctions |
narrow tunnels b/w animal cells that consist of proteins called connexins; allow communications b/w cells through exchange of materials/through transmission of electrical impulses; channel proteins of 2 adjacent cells that are closely aligned |
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connexins |
proteins that prevent the cytoplasms of each cell from mixing, but allow passage of ions and small molecules |
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plasmodesmata (plasmodesma) |
narrow channels b/w plant cells; tube of ER surrounded by cytoplasm/plasma membrane passes through channel |
