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Flashcards in Chapter 3 Deck (71):
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

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diffusion rate

influenced by : steepness of concentration gradient, temperature, mass of diffusing substance, surface area and diffusion distance

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facilitated diffusion

an integral membrane protein assists a specific substance across the membrane - either a membrane channel or carrier

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diffusion through ion channels

a solute moves down its concentration gradient across the lipid bilayer through a membrane channel

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osmosis

diffusion where there is a net movement of a solvent through a selectively permeable membrane

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aquaporins

integral membrane proteins that function as water channels

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osmotic pressure

force exerted by the solution with the impermeable solute

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tonicity

measure of the solutions ability to change the volume of cells by altering their water content

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isotonic solution

any solution in which a cell maintains its normal shape and volume

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hypotonic solution

a solution that has a lower concentration of solutes than the cytosol inside the cell

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hemolysis

hypotonic solution causes the RBC to swell and eventually burst

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lysis

the rupture of other types of cells due to placement in a hypotonic solution

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hypertonic solution

higher concentration of solutes than the cytosol of the cell

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crenation

shrinkage of cells because water molecules move out of the cells faster than they enter due to a hypertonic solution

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active transport

movement of solutes against the concentration gradient requiring energy

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primary active transport

energy derived from hydrolysis of ATP changes the shape of a carrier protein which pumps a substance across a plasma membrane against the concentration gradient

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pump

carrier proteins that mediate primary active transport

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Na+/K+ pump or Na+/K+ ATPase

expels sodium ions from cells and brings potassium ions in

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secondary active transport

the energy stored in Na+ or H+ concentration gradient is used to drive substances across the membrane against their own concentration gradient

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vesicular transport

transport in small spherical sacs

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cytoskeleton

network of protein filaments that extends throughout the cytosol

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centrosome

located near the nucleus; consists of two components: a pair of centrioles and pericentrolar cylindrical structures

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Cilia

numerous short, hairlike projections that extend from the surface of the cell

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flagella

short hairlike projections that extend from the surface of a cell; longer than cilia

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ribosomes

sites of protein synthesis

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endoplasmic reticulum

network of membranes in the form of flattened sacs or tubules

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rough ER

continuous with the nuclear membrane and usually is folded into a series of flattened sac. Studded with ribosomes; is the site of protein synthesis

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Smooth ER

extends from rough ER to form a network of membrane tubules- no ribosomes on the surface. Synthesizes fatty acids

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Golgi Complex

Modifies, sorts, packages and transports proteins received from the rough ER
- Forms secretory vesicles that discharge processed proteins via exocytosis into extracellular fluid

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Lysosome

membrane enclosed vesicles that form from the Golgi Complex
- digest substances via endocytosis
-carry out the digestion of worn out organelles
- implement autolysis (digestion of an entire cell)
-accomplish extracellular digestion

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Peroxisome

smaller version of a lysosome

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Proteasome

tiny barrel shaped structures consisting of four stacked rings of proteins around a central core
- carry out destruction of unneeded, damaged or faulty proteins

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mitochondia

powerhouse of the cell - generate most ATP through aerobic respiration

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nucleus

- control cellular structure
- directs cellular activities
- produces ribosomes in nuceoli

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nuclear envelope

double membrane that separates the nucleus from cytoplasm (lipid bilayers)

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nuclear pores

openings in the nuclear envelope that control the movement of substances between the nucleus and cytoplasm

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nucleolus

spherical bodies in the nucleus that produce ribosomes

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gene

hereditary units

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chromosome

long molecule of DNA coiled with several proteins

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chromatin

the complex of DNA, proteins and RNA

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transcription

the genetic info represented by the sequence of base triplets in DNA serves as a template for copying the information into a complementary sequence of codons

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translation

the nucleotide sequence in an mRNA molecule specifies the amino acid sequence of a protein