cell biology ch 2

intracellular vs extracellular

duh inside and outside of cell separated by cell membrane

pinocytosis

"cell drinking" Smaller vesicles form and they contain molecules dissolved in liquid rather than particles.

phagocytosis

"cell eating", solid particles are ingested and phagocyte vesicles are formed. white blood cells and some other cell types phagocytize bacteria, cell debris, and foreign particles. IMPORTANT in eliminating harmful substances from the body THAT WHITE BLOOD IS THE PHAGOCYTE ABSORBING THE OLD RED BLOOD CELLS(which could also be pathogens) the cellular process of engulfing solid particles by the cell membrane to form an internal phagosome by phagocytes and protists. a phagosome is a vacuole formed around a particle absorbed by phagocytosis. The vacuole is formed by the fusion of the cell membrane around the particle. A phagosome is a cellular compartment in which pathogenic microorganisms can be killed and digested. Phagosomes fuse with lysosomes in their maturation process, forming phagolysosomes.

receptors linked to channel proteins

Some membrane bound receptors help form ligand gated ion channels...acetylcholine released from nerve cells is a chemical signal that combines with membrane bound receptors of skeletal muscle cells. the combination of acetylcholine molecules with the receptor sites opens NA+ channels in the plasma membrne and the NA+ diffuses into the skeletal muscle trigger events that cause cells to contract

endocytosis vs exocytosis

endo is uptake of material through the plasma membrane by the formation of a VESICLE...exocytosis is when a secretion accumulates within vesicles and these secretory vesicles move to the plasma membrane where they fuse with the plasma membrane and the vesicles contents are expelled from the cell...example of exo is secretion of digestive enzymes by the pancreas and the mucus by salivary glands.

integral protein vs peripheral protein

integral proteins are deep in lipid bilayer while peripheral is attached to inner or outer surfaces of lipid bilayer

isosmotic vs isotonic

osmotic refers to the concentration of the solutions and tonic refers to the tendency of cells to swell or shrink...both are comparable terms

vesicle

a membrane bound sac within the cytoplasm of a cell

gene

a sequence of nucleotides in a DNA molecule that specifies the structure of a protein or RNA molecule

lipids

phospolipids(form bilayer) and cholesterol(accounts for one third of lipids in plasma membrane. cholesterol limits the movement of phospholipids providing stability to plasma membrane)

selective permeable

plasma membrane allows only certain substances to pass through it...because of the permeability of the membrane and its ability to transport molecules seletively the cell is able to maintain homeostasis

receptor-mediated endocytosis

plasma membrane may contain specific receptor molecules that recognize certain substance and allow them to be transported into the cell by phagocytosis or pinocytosis...the receptor site only binds with certain molecules...This mechanism increases the rate at which the cells take up specific substances FIGURE THAT HAS BINDING SITES ON PLASMA MEMBRANE AND WHEN MOLECULES BIND IT GOES INWARD LIKE A SEMICIRCLE THEN A FULL CIRCLE INSIDE THE PLASMA MEMBRANE.

non diegetic (thank you jack johnson)

A non-diegetic insert is a film technique that combines a shot or a series of shots cut into a sequence, showing objects represented as being outside the space of the narrative. Put more simply, a non-diegetic insert is a scene that is outside the story world which is "inserted" into the story world.

chromatin

Chromatin- histone proteins and DNA- chromatin condenses into chromosomes during- interphase(S part of it to be even more specific)(around nucleolus) Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene expression and DNA replication. The primary protein components of chromatin are histones that compact the DNA. Chromatin is only found in eukaryotic cells: prokaryotic cells have a very different organization of their DNA which is referred to as a genophore (a chromosome without chromatin).

DNA and RNA

Deoxyribonucleic acid is found within the nucleus...nuclear dna and associated proteins are organized into discrete units called chromosomes(proteins called histones- which are important for the structural organization of DNA. MOST of the cells life the chromosomes are dispersed throughout the nucleus as delicate filaments referred to as chromatin which during cell division disperes becomes densely coiled forming compact chromosomes. RNA= ribonucleic acid, because the DNA is a large molecule and can not leave the nucleus it has an intermediate, RNA, which can leave the nucleus through nuclear pores DNA determines the structure of messenger RNA(mRNA), ribosomal RNA(rRNA, and transfer RNA(tRNA).

active transport

IMPORTANT because it can move substances from higher concentration to lower concentration or against their concentration gradient ...atp powered pumps combine with substances and move them across the plasma membrane, atp is used(intracellular ATP and 3 Na+ ions attache to the (ex Na+-K+ pump)... then the ATP breaks down to ADP and a phosphate(release of energy) causing a shape change. Na+ leaves and 2 K+ bind to the Na+-K+ pump causing the phosphate to detach and another shape change and K+ is released inside the cell

cytoplasma

The cytoplasm has three major elements; the cytosol, organelles and inclusions...cytosol is the liquid portion that is not within the membrane bound organelles. The cytoplasm also contains the protein filaments that make up the cytoskeleton, as well as soluble proteins and small structures such as ribosomes,

enzyme

SOME membrane proteins function as enzymes which catalyze chemical reactions on inner or outer surface of the plasma membrane....some enzymes on the surface of cells in the small intestine break the peptide bonds of dipeptides to form two single amino acids.

mediated transport 3 characteristics

Specificity- each transport protein binds to and transports only a single type of molecule or ion Competition- is the result of similar molecules binding to the transport protein, closely related substances may bind to the same site. Two things affect what substance moves across the plasma membrane at a greater rate. 1- the substance in the greater concentration 2- substance that binds to the binding site more readily Saturation- the rate of movement of molecules across the membrane is limited by the number of available transport proteins...When all binding sites are occupied the rate of movement remains constant even though the concentration of the substance increases further

receptors linked to G protein complexes

alter the activity of a G protein complex located on inside of cell. The G protein complex associates only if receptor that has a chemical signal bound to it...if so they become associated with each other and the alpha subunit seperates from the other sub units and the alpha stimulates a cell response in three ways-by means of intracellular chemical signals, by opening ion channels, by activation of enzymes associated with the plasma membrane

Membrane proteins

can function as marker molecules, attachment proteins, transport proteins, receptor proteins or enzymes

facilitated diffusion

carrier proteins combine with substances and move them across the plasma membrane, from lower to higher conentrations with the rate of transport being proportioanl to the concentration gradient until saturation- no atp used

Four functions of a cell

cell metabolism and energy use-Chemical reactions that occur within cells are referred to as metabolic reactions...the energy released from some metabolic reactions fuels cellular activties such as the synthesis of molecules and muscle contraction, during some metabolic reactions energy is released as heat which is essential for maintaining body temp synthesis of molecules-Different cells of the body synthesize various types of molecules, including proteins nucleic acids and lipids communication-chemical/electrical signals...nerve cells produce chemical signals by which they communicate with muscle cells, and muscles respond by contracting or relaxing reproduction and inheritance- most cells contain copy of all genetic info of the ind., cells called gametes trnsmit genetic info to the next generation

marker molecules

cell surface molecules that allow cells to identify other cells or molecules, they are mostly glycolipids or glycoproteins. ex immune systems ability to distinguish between self cells and foreign cells such as bacteria of donor cells.

phagocytosis/pinocytosis vs active transport

does not require energy and does not demonstrate the degree of specificity or saturation that occurs in active transport...also they involve the bulk movement of material into the cell

transport protein

channel proteins, carrier proteins and ATP powered pumps

glyococalyx

collection of glycolipids, glycoproteins, and carbohydrates on the outer surface of the plasma membrane

Hypercholesterolemia

common genetic disorder chatacterized by the reduction in or absence of low density lipoproteins LDL receptors on cell surfaces, which interefes with the receptor mediated endocyosis of LDL chol. inadequate chol uptake , chol synthesis is not regulated and too much chol is produced leading to atherosclerosis(plaque in arteries) leads to heart attacks or stroke

solution

consist of solutes dissolved in a solvent(water)

nucleus

contains nuclear envelope nuclear pore(the nuclear envelope has pores on it) nucleolus(composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA (rRNA) is transcribed and assembled within the nucleolus.Malfunction of nucleoli can be the cause for several human diseases.) and nucleoplasm(The nucleoplasm is a highly viscous liquid that surrounds the chromosomes and nucleoli. Many substances such as nucleotides (necessary for purposes such as the replication of DNA) and enzymes (which direct activities that take place in the nucleus) are dissolved in the nucleoplasm.) chromatin(the readily stainable substance of a cell nucleus, consisting of DNA, RNA, and various proteins, that forms chromosomes during cell division. ) The nucleus is the control center of the cell(DNA within the nucleus regulates protein (eg enzyme) synthesis and therefore the chemical reactions of the cell)

crenation vs lysis

crenation is shrinking of cell while lysis is rupturing of cell

cystic fibrosis

defective channel protein fails to reach the plasma membrane from its site of production inside the cell. channel protein does not function normally or channel protein fails to bind ATP. the affected cells produce think viscous secretions which have a profound affect on the lung's ability to breathe or pancreas ability to digest.

osmosis

diffusion of water across a selectively permeable membrane(water diffuses through the lipid bilayer)

attachment protein

integral protein which allows cells to attach to other cells(called cadherins) or extracellular molecules(integrins) integrins function in pairs Cadherins (named for "calcium-dependent adhesion") are a class of type-1 transmembrane proteins. They play important roles in cell adhesion, ensuring that cells within tissues are bound together. They are dependent on calcium (Ca2+) ions to function, hence their name.

secondary active transport

ions are moved across the plasma membrane OUTSIDE the cell by active transport which establishes an ion concentration gradient, atp is created by this active transport and this energy is used to move a different ion or molecule INTO the cell...ex a Na+-K+ pump maintains a concentration of Na+ that is higher outside cell, Na+ ions move back into the cell through a transport protein BUT ALSO glucose molecules enter the cell at the same time as the sodium ion

channel proteins

leak ion channels or gated ion channels... ions or small moleculues of the right size charge and shape can pas through the channel, the charge in the hydrophilic part determines what ions pass through

viscosity

measure of how easily a liquid flows, thicker solutions have a greater viscosity

mediated transport...3 types of molecules it moves and the three types of transport proteins

molecules-large water soluble molecules or electrically charged molecules or ions( i guess that may be two kinda. carrier protein, channel protein and ATP powered pumps

carrier proteins

move molecules or ions from one side to the other

ATP powered pumps

movements are fueld by the breakdown of ATP (adenosine triphosphate. the breakdown of ATP to ADP (adenosine diphosphate) releases energy, changing the shape of the protein, which moves the ion or molecule across the membrane

receptor proteins

proteins or glycoproteins in plasma membrane that have an exposed receptor site which can attach to specific chemical signals, once the chemical signal binds to the receptor protein a G protein complex (alpha, beta and a gamma)attaches to the receptor protein, the GTP then breaks down into GDP the gamma and beta move away but the alpha moves even farther away from gamma(rides solo) and this alpha triggers a response(vague) ex a cell releases a chemical signal that diffuses to another cell and binds to its receptor which triggers a response

diffusion

random movement of molecules results in net movement from areas of higher to lower concentration

red blood cells and mRNA

red blood cells expel nuclei before it enters blood therefore can accomplish protein synthesis only as long as the mRNA produced before the nucleus degenerates remains functional. Red blood cells only live 120 days while cells with nuclei such as nerve skeletal and muscle cells survive sometimes a whole lifetime.

plasma membrane

the cell membrane we talk about in class(phospholipid bilayer and cholesterol...also proteins are embedded in the surface or lipid bilayer) interacts with external environment...head of phopholipid bilayer is polar and the tails are non polar

osmotic pressure

the force required to prevent water from moving by osmosis across a selectively permeable membrane

aquaporins

water channel proteins...they increase membrane permeability to water in some cell types such as kidney cells

hydrophilic and hydrophobic

water loving vs water fearing(in class hershey said they do not repel water just neutral to it)

cadherins and integrins(junctions?)

• These are both types of attachment sites in cells. • Integrins attach to extracellular proteins, such as basement membrane proteins. • Cadherins join cells to other cells. ◦ Tight junctions are found in the urinary bladder. Prevents any fluid from squeezing between the cells. ◦ Gap junctions are found in heart muscle cells. Allow ions to flow between cells and coordinates contraction of the heart muscle. The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.