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Flashcards in Chapter 3 Deck (71)
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1

cell

3 main parts: plasma membrane, cytoplasm, nucleus

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plasma membrane

forms the cell's flexible outer surface, separates internal environment from external environment; selective membrane

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cytoplasm

consists of all cellular contents between the plasma membrane and the nucleus

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cytosol

fluid portion of the cytoplasm, contains water, dissolved solutes and suspended particles

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organelles

characteristic shape and specific function i.e. cytoskeleton, ribosomes, ER

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nucleus

large organelle that houses most of a cell's DNA. Contains chromosomes and genes

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plasma membrane

flexible yet sturdy barrier that surrounds and contains the cytoplasm of a cell

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lipid bilayer

two back to back layers made up of three types of lipid molecules (phospholipids, cholesterol and glycolipids). Lipids are amphiapthic so the hydrophilic head and hydrophobic tail form the bilayer (heads to the outside)

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phospholipids

lipid that contains phosphorus

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cholesterol

steroid with an attached hydroxyl (OH) group which makes them weakly amphipathic.

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glycolipid

lipid with attached carbohydrate group

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integral protein

permenantly embedded in membrane

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transmembrane protein

span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid (sticks into the cell, through the membrane and outside the cell)

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peripheral protein

attached to the polar heads of the membrane lipids or to integral proteins at the inner or outer surface of the membrane

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glycoprotein

protein with carbohydrate group attached to the ends that protrude into the extracellular fluid

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functions of integral proteins

form ion channels, act as carriers, receptors, enzymes, linkers

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function of membrane glycoproteins and glycolipids

serve as cell identity markers

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ion channel

pores/holes that specific ions (i.e. potassium ions) can flow through to get into or out of the cell

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carrier

selectively move a polar substance or ion from one side of the membrane to the other (aka transporter)

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receptors

cellular recognition sites (recognizes and binds a specific type of molecule)

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enzyme

catalyze specific chemical reactions

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linker

anchors proteins in the plasma membrane of neighbouring cells to one another or to protein filaments inside and outside the cell.

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cell identity markers

enable a cell to recognize other cells of the same kind during tissue formation and recognize and respond to potentially dangerous foreign cells.

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concentration gradient

difference in the concentration of a chemical from one place to another

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membrane fluidity

most of the membrane lipids and many of the membrane proteins easily rotate and move sideways in their own half of the bilayer

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selective permeability

plasma membranes permit some substances to pass more readily than others

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electrochemical gradient

the combined influence of the concentration gradient and the electrical gradient on movement of a particular ion

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passive processes

substance moves down a concentration gradient/electrical gradient to cross the membrane using only its own kinetic energy

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active processes

cellular energy is used to drive the substance against the concentration gradient

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diffusion

passive process in which random mixing of particles in a solution occurs because of the particles' kinetic energy