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38 Cards in this Set
- Front
- Back
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monomers join by ...
to form ..... |
dehydration synthesis / condensation rxn
-make water as product to form polymers |
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carbohydrates:
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-cell structures and energy sources
- consist of C, H and O w/ formuala (CH2O)n -monosaccharides: simple sugars with 3-7 carbons; are the building blocks for dissacharides --ex: glucose: hexose -disacharides: when 2 monosachs are joined by dehydration synthesis -disachs can be broken by hydrolysis: hydrolysis: adding water |
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oligosaccharides:
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-consists of 2-20 monosachs
-polysachs consist of tens to hundreds of monosachs joined throuh dehydration synthesis -starch, glycogn, dextran and cellulose are polymers of GLUCOSE that are covalently bonded differently - chitin is closely related to cellulose |
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lipids:
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-primary component of cell memberates
-consist of C, H and O -are nonpolar and insoluble in water (but dissolve in nonpolar solvents ) -simple lipids >fatty acids >triglycerides: saturated and unsaturated ( cis vs trans) |
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triglyceride (simple lipids)
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are simple lipids; contain glycerol and a gropu of compounds known as fatty acids
-glycerol : 3 carbon atoms that have OH groups -fatty acid: long hydrocarbon chains , ending in carboxyl (-COOH) glyceride: 1 fatty acid diglyceride: 2 fatty acids triglyceride: glycerol and THREE fatty acids , in teh rxn 3 water molecules are formd through dehydration to form an Ester linkage with glycerol to the fatty acids fatty acid is SATURATED: NO double bonds; become solid more easily bc are straight and able to pack togeher more closely UNSATURATED: have DOUBLE BONDS; have kinks so allow the mmb to be more fluid -cis fatty acid: when H are on teh same side of the double bond -trans fatty acid: H are on opposite sides |
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complex lipids : phospholipids
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contain elements as P, N and S in addition to the C, H and O found in simple lipids
phospholipids : made of glycerol, two fatty acids and in place of a third fatty acid a phosphate group is bonded to one of the organic groups -build the mmb -have polar and nonpolar regions -when placed in water: polar towards water molecules and form H bonds ; consist of phosphate group and blycerol ; while NONPOLAR: fatty acids |
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Liposome:
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bilayers of both hydrophobic and hydrophylic
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micelle
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all hydrophobic fatty acids in teh middle
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bilayer sheet
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2 layers
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nucleotides
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pentose
phosphate group nitrogen base -purines: Adenine and Guanine -pyrimidines: Cytosine and Thymine |
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nucleoside
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pentose
nitrogen base |
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DNA
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*double starnaded : stores genetic info
*alternating sugar and phosphate group from teh backbone of the double helix : the rungs are formed by the nitrogen containing bases *complementary pairing of Nitrogen containing bases occurs between A-T and G-C GC conten: increase in high temp so DNA doesnt degrade |
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RNA differs from DNA in 3 major ways
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RNa : the second principla kind of a nucleic acid
1. RNa is single stranded that is flexible so can acquire a structure and a function 2. ribose ( the 5 carbon sugar) has an OH at the 2' carbon 3. substitutes Uracil for Thymine there are RNA molecules that dont encode a protein product but have other functions within the cell. one is ribozymes- RNA molecules that have cell catalytic activity bc they can acquire a structure STRUCTURE ALWAYS LEADS TO FUNCTION ( proteins) |
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the Genetic code is degenerate
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genetic code is degenerate bc have 64 diff codon combination, each codon is 3 nucleotides :
out of 64: 3 code for a stop codon : which terminates translation the other 61 represent one of the 20 amino acids - this is why its degenerate bc diff codons can code for the same aa -there are differences: ex proline: can have 4 diff codons but for tyrosine have 2 codons and or MET only one codon: START codon degeneracy is derived from the wobble the third nucleotide the first2 the cononical nucleotided: they dont change,if thy change then the codon changes but for ex proline , the third nucleotide can be any of the four and the aa is sitll the same |
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Proteins:
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* are essential in cell structure and function
* enzymes are proteins that speed chemical rxns * transporter proteins move chemicals across mmbs * flagella are meade of proteins *some bacterial toxins are proteins proteins can serve as scaffolds can pretty much do anything. they are your bricks and motar of the cell while your genome is your blue print |
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proteins consist of subunits called amino acids
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aa are building blocks fro proteins
aa contain one carboxyl (-COOH), one amino group attached to same alpha carbon witha side group (R group) which is the aa's distinguishible feature. -the side group can be a H atom, unbranched or branched chain of atoms or a ring structure |
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AMINO ACIDS can exist in either of 2 stereoisomers: D or L
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these confirugratio are mirror images that are 3D shapes : amino group is the thumb
D: right handed L: left handed aa found in protein are always in L isomers : except for glycine which does not have steroismers bc its the simples aa D aa occur in nature occasionally: in certain bacterial cell walls and antibiotics |
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peptide bonds between aa are formed by
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dehydration synthesis
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primary structure protein
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polypeptide strand
aa sequence chain first aa is what will be exposed, the N terminus the last aa will also be exposed , the C terminus so the carboxyl group of the first aa will form a peptide bond with the N terminus of the second aa alterattions of the primary wcan have profound metabolic effects. -ex: a single incorrect aa in a blood protein can produce the deformed hemoglobin molecule of sickle cell disease one reason for folding is that some parts of the a protein are attracted to water and other parts are repelled by it |
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secondary structure of protein
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is the localized , repetitious twisting or folding of a polypeptide chain .
- secondary shape results from H bonds joinng the atoms of the peptide bonds at diff locations along the polypeptide chain 2 types: 1) clockwise helices 2)Beta sheets ( form from parallel portions of the chains ) |
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tertiary structure:
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the overall 3D structure of a polypeptide chain
involves several interactions btwn various aa SIDE GROUPS in the polypeptide chain -ex: aa with nonpolar (hydrophobic) side groups usually interact at the core of the protein out of contact with water . the hydrophobic interation helps contribute to tertiary stsructure -H bonds btwn SIDE GROUPS and ionic onds btween oppositely charged SIDE GROUPS also contribute to tertiary structure -disulfide bridges btwin aa cystein : ex of covalent bond ; cysteine contain SH groups |
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Quaternary structure protein
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cluster of 2 or more individual POLYPEPTIDE chains or subunits that operate as a SINGLE functional unit
the bonds that hold it together are the same as those that maintain tertiary overall structure maybe globular or fibrous |
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proteins are post-translationally modified by conjugation with organic molecules
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1. glycoproteins: conatina sugars
2. nucleoproteins: contain nucleic acids 3. lipoproteins: conatin lipids 4. phosphoproteins: conatin phosphaste groups |
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Proky vs euky cells
what they share |
plasma mmb, cytoplasm (ribosomes), genome ( bud diff in the way it's regulated)
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proky characteristics
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1. their DNa is not enclosed w/in a mmb and is usually a singular circulatory arranged chromosome (some bacteria have 2 chrom and some have linear chromosome)
2. their DNa is not wrapped in histones, use Hu proteins instead 3. they lac mmb enclosed organneles 4. their cell walls almost always contain polysaccharide peptidoglycan 5. usually divide by binary fission : during this process the DNa is copied and the cell splits into 2 cells |
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euky characteristics
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1. Dna is found in nucleus which is separated from teh cytoplasm by a nuclear mmb ; and DNA is found in MULTIPLE chromosomes
2. DNA is wrapped around histones and with nonhistones 3. have mmb enclosed organelles : mitochondria, ER, golgi, lysosomes and sometimes chloroplast 4. their cell walls are chemically simple 5. cell division involves mitosis : chromosome replication and identical set is distributed into each of 2 nuclei |
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proky basic shapes and naming
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1. bacillus ( rod-shaped) ; In chain are called STREPTOBACILLI; oval and look ike cocci called COCCOBACILLI
2. coccus (spherical) ; chainlike are called STREPTOCOCCI; in chunks are called STAPHYLOCOCCI 3. spiral -spirillum: helical shape like a corkscrew and have fairly rigid bodies -vibrio -spirochete; are helical and flexible; move by axial filamens which resemble flagella but are contained w/in a flexible external sheath. scientific name: Bacillus (italics) ; normal typing is describing the shape |
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other shapes
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starshaped- stella
rectangular flat- Haloarcula |
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Proky are less complex :
7 major componets |
1. capsule : outside of wall
2. cell wall 3. plama mmb - no internal organelles 4. no internal organells 5. gneome inside cytoplasm with no envelope 6. inclusions / ribosomes 7. pilus/ fimbrae/ flagella |
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capsule
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made of glycocalyx that ais firmlly attached to the cell wall: glycocalyx is a substance that surrounds the cells composed of polysaccharide, polyeptide or both
capsule often protect pathogenic bacteria fromphagocytosis by the cells of the host capsoule makes them more resistant to antibiotics |
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slime
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also a component of glycocalys
helps cell with biofilm to attach to their target environmennt . through attachement, bacteria can grow on diverse surfaces |
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cell wall
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rsponsible for the shape of the cell
prevents bactrial cells from rupturing when teh water pressure inside the cell is greater than that outside the cell point of anchorage for flagella |
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composition and characteristics of bacterial cell wal
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composed of peptidoglycan : composed of repeating disaccharide attached by ppolypeptides to form a tattice that surrounds and protects teh entire cell : dissacharide composed of NAG and NAM- form the backbone
- adjacent rows are linked by POLYPEPTIDES ; consists of 4 aa attached to NAM in the backbone - aa occur in alternating patter of D and L forms -parallel tetrapeptide side chians may be directly bonded to e/o or linked by a peptide cross bridge consisting of a short chain of aa penicillin interferes witht he final linking of the peptidoglycan row by peptide cross bridges . as a result the cell wall is greatly weakened and the cell undergoes lysis destruciton caused by rupture of the plasma mmb and the loss of cytoplasm |
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gram (+) cell wall
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cell wall consists of many layers of peptidoglycan, formng a thick rigid structure
*additonally, contain teichoic acids which consist of an OH and phosphate * 2 classes of teichoic acids: lipoteichoic acid ( spans the peptidoglycan layer is linked to plasma mmb) ANA wall teichoic acid Olinked to peptidoglycan layter - bc of their negative phosphate group they may regulate the movement of cations into and out of the cell |
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gram (-)
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from a thin layer of peptidoglycan (one layer or very few layers)
*peptidoglycan is bonded to lipoproteins in outer mmb and is in teh periplasm (gel like fluid BTWN the outer mmb and teh palsma mmb * dont contain teichoic acids * bc have small amount of peptidoglycan they are more susceptible to mechanical breakage *the outer mmb of the gram negative cell consists of lipopolysaccharides (LPS) , Lipoproteins and phospholipids -its strong negative charge is an important factor in evading phagocytosis -outer mmb also provides a barrier to certain antibiotics ( ex penicilin ) , enzymes like lysosyme, detergents and certain dyes * however outer mmb does not proide barrier to all substances bc nutrients must pass : so nutrients go through porins |
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Lipopolysaccharides (LPS)
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of the outer mmb in gram (-): contains
1. Lipid A : is the lipid embedded in the top layer of the outer mmb , when gram (-) bacteria die, they release lipid A -endotoxin 2: core polysaccharide : attached to lipid A and contains unusual sugars: its role is structural to provide stability 3. O polysaccharide : extends outward from teh core polysaccharide and is composed of sugar molecules |
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cell walls and gram stain mech
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stain is based on differences in the structure of the cell walls fo (-) / (+)
crystal violet stains both gram + and - : bc dye enters the cytoplasm -when iodine (mordant) is applied it forms large cyrstals with the dye that are too large to escape through the cell wall -applicaiton of OH dehydrates the peptidoglycan of gram + making it more impermealbe to the crystal violet iodine * in gram - the OH dissolves the outer mmb and leaves small holes in thin peptidoglycan so cyrtal violet iodine can diffuse so looks colorless - segranin is added to distiguish the two apart since G(-) turns red |
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atypical cell walls
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*Mycoplasma: are the smallest bactria that can grow and reproduce outside living host cells
-have no cell walls -pass through fiter (were mistaken for viruses) -have sterols in plasma mmb ( lipids) *Arachae -wall-less -walls of pseudomurein (lack NAM and D- aa)- similar to pseudomurein -cant be gram stain but appear gram neg bc they do not contain peptidoglycan |
