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Flashcards

Carbohydrates

Lydia McCarrick biochemistry univeristy English 52 cards

Carbohydrates

Cards in this deck (52)

  1. 1Fishcer projection and what does it show?- used to show 3D projections of molecules
    -vertical point back
    -horizontal point forwards
  2. 2Chemical structure of alcohol, ketone aldehyde and glycerol1) carbon chain with alcohol group on the end
    2) carbonyl carbon in middle of carbon chain
    3) carbonyl carbon at end of chain
    4) gycerol is 3c carbon with 3 oh groups attached down one side
  3. 3Structure of glyercolaldehyde and two forms-dextro= penultimate carbon points to the right
    Laevo= penultimate carbon points to the left    Structure of glyercolaldehyde and two forms
  4. 4What is a chiral/assymetric carbon?- it is a chiral centre
    - 4 different chemical groups attached
    - present in glyceraldehyde- allows for stereoisometry
  5. 5D/L glyceraldehydes- different compounds that are MIRROR IMAGES of each other
    - they are enantimors/stereoisomers
    -They rotate polarised light clockwise or anticlockwise
    -handled differently by enzymes as enzymes are stereospecific
    - D sugars= most common form
  6. 6Types of monosaccharide sugars: 1) glyceraldehyde 2) glucose 3) ribose1) triose, aldose sugar (has an aldehyde group)
    2) hexose aldose sugar
    3) pentose aldose sugar
  7. 7What are the 14 different version of hexose sugars in nature ?L and d forms of all the 7 hexose sugars
    1) glucose
    2) galactose
    3) gulose
    4) mannose
    5) allose
    6) altrose
    7)idose
  8. 8What is the acronym of the 7 hexose sugars?all altruists gladly make glue in gallon tanks
  9. 9Define epimer mannose and galactose are epimers of which other sugarEPIMER: only differ in one position
    glucose
  10. 10How are glucose, mannose and galactose similar ?all aldose monosaccharides , their aldehyde groups tend to react with their own hydroxyl groups and cyclise
    ( when cyclise they become pyranose sugars)
    - c1 and c 5 react together i.e. carbonyl carbon and penultimate carbon
  11. 11What kind of ring does a cycliced d- glucose molecule form?hemi- acetal, pyranose, heterocylic ring
    (alpha-d-glucose or aplha d- glucopyranose)
  12. 12What is the definition of a hemi-acetal ring? definition of pyranose ring?-compound derived from ketone/aldehyde respectively
    - 5 membered ring with 4 c and 10 forming ring
  13. 13What % of three forms of anomeric forms of glucose are present at equilibrium?alpha= 36%
    beta= 64%
    open chain= <0.1%
    all these are interchangeable with each other
  14. 14definition of anomeric?a special type of epimer, one of two stereoisomers of a cylic saccharide that differs only in the configuration at the hemi-acetyl (anomeric) carbon i.e. in glucose -oh position
  15. 15What two different 3D structures can glucose adopt? which is most common? and why can't it be planar?1) boat or chair
    2) chair
    3) 6 membered pyranose ring can't be planar because of tetrahedral geometry of saturated carbons
  16. 16define heterocyclic ringcompound that has 1 or more atoms other than c in it's ring structure
  17. 17cyclisation of ribose: 1) which carbons react 2) what are two products 3) what form are two products1) c1 and penultimate carbon
    2) d-ribose, and 2 deoxyribose
    3) furanose ring (5 membered ring 4c 1 oxygen )
  18. 18define 1) pyranose ring 2) furanose ring1) p= 6 membered ring 5 c 1 0
    2) f= 5 membered ring 4c 10
  19. 193 most common aldose sugarsglucose, mannose and galactose
  20. 20WHat are ketoses sugars?contain keto group i.e. carbonyl carbon in middle of molecule e.g. (dihydroxy acetone triose or d-ribulose, fructose,)
  21. 21what are the most important monosaccharides?glucose, galactose, mannose fructose,
  22. 22what are modified monosaccharides important in?glycoproteins (alpha-d-glucosamine, alpha-d-galactosamine)
    - phosphate groups and aa added to monosaccharides to modify them
  23. 23which monosccharides carry phosphate groups?glucose,1, phosphate
    glucose,6,phosphate
  24. 24What is inositol and what are inositol phosphates important in?analogue of a monosaccharide, inositol phosphates are important in cell signalling and reproductive hormones
  25. 25give three examples of ketoses sugarsd-ribulose, di-hyroxyacetone, fructose
  26. 26what type of bond forms between monosccharides? what reaction cause the bond formation?1) glycoscidic
    2) condensation
  27. 27what are the monomers and what is the bond linkages in lactose? what enzyme breaks it down?1) glucose and galactose
    2) beta 1-4 glycoscidic bond
    3) lactase or beta,-galactosidase
  28. 28what type of enzyme is b-galactosidase? how is it used with x-gal?1) it is an inducible enzyme i.e. turned on by presence of lactose in medium
    2) x-gal lactose derivative releases a bluw colour when beta galactosidase is expressed- attached to foreign gene and used to show where gene is being expressed
  29. 29what are the three most common monosaccharide sugars?glucose, fructpse, galactose,
  30. 30what are the three most common disaccharide sugars?lactose, sucrose, maltose
  31. 31sucroseMONOMERS: heterodimer of glucose/fructose
    LINKAGES: a-1,2-glycoscidic ( b-d-fructose turned upside down and back to front in disaccharide)
    Enzymes: sucrase/invertase
    USES: sucrose converted into ethanol for use in biofuels, use in form of high fructose corn syrup in foods,
  32. 32MaltoseMONOMERS: homodimer of alpha-d- glucose
    BOND: a-1,4, g bond
    ENYME: maltase
  33. 33LactoseMONOMERS: glucose and galactose
    ENZYME: lactase/ b-galactosidase
    bond: b-1-4- g.bond
  34. 34which are the reducing sugars and why are they reducing? In what case does sucrose become reducing?lactose and maltose because they have a free oh group on 5'c
    when it is broken down by invertase because the two monomers are reducing
  35. 35What does the oh group react with in benedict's reaget?The free oh group reacts with copper ions leading to characteristic color change
  36. 36what determines the susceptibility of carbohydrates to enzymatic attack?the stereo chemistry of the glycoscidic bonds i.e. beta bonds aren't normally broken down
  37. 37What are oligosccharides? Where are they found?intermediate length carbohydrates, aren't usually found in cells only as breakdown products of polysaccharides
  38. 38what are the main types of oligo/polysccharides?cellulose, starch, glycogen
  39. 39CELLULOSE WHAT PROVIDES STRGNTH?-linear homopolymer of glucose (b-1-4 bonds)
    - linear glycan chains line up side by side and are linked together by hydrogen bonds
    - individual fibers twist together to make cellulose microfibrils
    -high degree of h-bonds provides strength
    -exclusion of water make solubility very difficult
  40. 40What are the uses of cellulase in biotech?-can produce large quantities by fermentation technology
    -use to release foods or biofuels
    - use of de-repressed mutants found in fungi to produce large quantities of cellulase
  41. 41CELLULASEmade up three enzymes/genes that are difficult to transfer by recombinant technology
    1) endoglucanse- makes initial cut into cellulose
    2)exoglucanase- produces glucose dimer/celobiose
    3)cellobiase- breakse down cellobiose
  42. 42BIOMASSlarge crystalline cellulose surround by hemicellulose and lignin
  43. 43DEFINE 1) hemicellulose 2) lignin1) complex polymers of xylan and other polysccharides
    2) complex cross-linked polymers of phenolic compounds
  44. 44How can biomass be utilized?1) composting
    2) feeding to ruminants
    3) adding cellulase and releasing sugar for biofuels
    4) genetically engineering plants to contain their own cellulase
  45. 45CHITIN-structural polysaccharide
    -found in insects crustacean and fungi.
    MONOMER; n-acetylglucosamine
    (b-1,4 hompolymer)
  46. 46what two molecules make up plant starches? how are starches and glycogen different from cellulose?1) alpha-amylose and amylopectin
    2) they are designed to release energy quickly
  47. 47alpha amylose1) linear homo-polymer of alpha glucose with alpha 1,4 bonds
    2) linkages cause molecule to form alpha helix structure which is stabilised by h-bonds
    3) enzymes in saliva partially break it down into oligosaccharides but fully degraded in the SI by ALPHA GLUCOSIDASE
    4)
  48. 48amylopectin-alpha units form both alpha 1,4 and alpha 1,6 bonds
    beta-amylase attacks end of moelcule removing maltose units
    amylopectin is branched molecule
    in animals both beta/alpha amylose attacke amylopectin bt can't break aplha 1,6 bond
  49. 49What are limit dextrins:partially degraded branced oligosaccharides
  50. 50What are debranching enzymes?required lower in the gut to release maltose
  51. 51GLYCOGEN-glucose polymer
    -alpha-1,4/a-16 in starch but much greater branching (every 8-10 residues)
    -glycoegn froms cystolic particles
  52. 52Glycogen phoshorylase-uses ATP to break down glycogen into glucose-1-phosphate (NOT free glucose)
    ENZYME REPSONDS TO STIUMULUS:
    1) nervous system ( via ca2+ ion release)
    2) adrenaline (via phophorylation)
    enzyme regulatedby ca2+/AMP/adrenaline
    Actve enzyme has phosphate, amp or atp attached to it.

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univeristy biochemistry Flashcards on Carbohydrates , created by Lydia McCarrick on 16/05/2015.
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Lydia McCarrick
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