O GoConqr está de visual novo! Conte para nós o que você achou.

Registre-se grátis

Flashcards

Proteins

Usuário eliminado O usuário eliminou as informações de disciplina Inglês 35 flashcards

Flashcards do conjunto (35)

  1. 1What are some roles of proteins?structural
    catalysts (enzymes)
    carrier (haemoglobin)
    protective (antibodies)
    signalling (receptors)
  2. 2What is the function of a protein determined by?external chemistry and shape
    ^determined by amino acid composition
    diff AA have diff chemical and structural properties
  3. 3What are the levels of protein structure?primary - sequence of AA
    secondary- 2D fold
    tertiary- 3D fold
    quaternary - interaction of subunits
  4. 4What are two key features of the primary structure of a protein?N-terminus
    -amino terminus (H3N+)
    C-terminus
    -carboxyl terminus (COO-)
  5. 5How many different R groups are there? Why are they important?20
    result in a variety of chemical properties:
    hydrophobic/hydrophilic
    polar/non-polar
    structural
  6. 6Which amino acids have nonpolar, aliphatic side groups?glycine, Gly G
    alanine, Ala A
    valine, Val V
    leucine, Leu L
    methionine, Met M
    isoleucine, Ile I
  7. 7Which amino acids have aromatic side groups?Phenylalanine, Phe F
    Tyrosine, Tyr Y
    Tryptophan, Trp W
  8. 8Which amino acids have positively charged side groups?Lysine, Lys K
    Histidine, His H
    Asparagine, Asn N
  9. 9Which amino acids have negatively charged side groups?Glutamate, Glu E
    Aspartate, Asp D
  10. 10Which amino acids have polar, uncharged side groups?Serine, Ser S
    Threonine, Thr T
    Cysteine, Cys C
    Proline, Pro P
    Aspartate, Asp D
    Glutamine, Glu Q
  11. 11What is the peptide bond?bond that holds adjacent AA together
    structural implications:
    planar, H bonding
  12. 12What differentiates a protein from a peptide?chains from 50+ are classed as proteins
  13. 13Why is there such a huge variation in proteins?50-2500 AA in a typical protein
    20 possible AA per positon
    so huge variation
  14. 14What is the secondary structure of a protein determined by? What are the two main types?the interactions between the peptide bonds via hydrogen bonding
    two main types: a-helix and B-sheet
  15. 15Explain the a-helix secondary structure3.6 residues per 360degturn
    stabilised by H bonding between peptide bonds - results in 0.54nm pitch
    R groups point downwards
  16. 16Explain the b-sheet secondary structureforms a flat sheet surface with strands of protein alongside
    stabilised by H bonds between amide links
    strands can be parallel or anti-parallel
    b-sheets can be stacked to form 3D structure
  17. 17What is the tertiary structure?the 3D fold of the protein which brings together secondary structure in 3D space
  18. 18What is the quaternary structure?a fold of 3D folded
    not all proteins have quaternary structure
    can be homo or hetero
    e.g. haemoglobin (4 subunits)
  19. 19Explain the structure of collagenstrong 3D structure
    triple helix with a large number of prolines in a Pro-Pro-Gly
    staggering of the three chains helps H-bonding btw chains
  20. 20What is the result of post translational modification of amino acid side chains?covalent strand crosslinks
    includes di-sulphide bonds between cysteine and lysine
  21. 21What is the nomenculture of proteins based on?3D shape
    globular
    -majority of proteins
    -overall globular shape, with a mix of 2nd structures
    fibrous
    -extensive packaging of 2nd structure
    -often dominated by one type of 2nd structure
    -form structural proteins e.g. collagen, keratin
  22. 22Proteins can be made up of domains. What are protein domains?discrete regions of 3D structure
  23. 23What are proteins produced by?ribosomes
    (translation of RNA to proteins)
  24. 24What is the hydrophobic effect?the observed tendency of nonpolar substances to aggregate in aqueous solution and exclude water molecules
    in proteins this means you get a hydrophobic centre
    the exceptions to this is membrane proteins
  25. 25What are molecular chaperons?a diverse group of proteins that assist with the folding and in some cases unfolding of proteins but are not involved in the usual biological functions for these proteins
  26. 26When do levels of chaperones increase?when the cell is subjected to stress e.g. heat shock
  27. 27How do chaperones help with folding?some bind to hydrophobic residues and prevent hydrophobic effect driven folding e.g. HSP70
    some act to protect the folding protein from the cytoplasm e.g GroEL
    chaperones often use ATP to provide energy to the folding process
  28. 28What are some causes of protein folding diseases?inherited mutation
    environmental stress
    mechanism
    -loss of function
    -toxic gain of function
    -dominant negative
  29. 29What are some diseases associated with protein folding?neurodegeneration
    -Alzheimer's
    -Parkinson's
    metabolic disorders
    -monogenic obesity
    cancer
  30. 30What are the four types of post translational modification of proteins?addition of other functional groups
    -acetate, phosphate, lipids
    addition of other proteins/peptides
    -Ubiquitination
    changing the chemical nature of AA
    -Deamination
    structural changes
    -Di-sulphide, cleavage
  31. 31Explain how protein phosphorylation worksaddition of covalently bonded phosphate group by protein kinases
    usually Ser, Thr, Tyr
    alters structural conformations of a protein causing it to become activated, deactivated or changes its function
    (dephosphorylation done by phosphatase)
  32. 32Explain the importance of the formation of di-sulphide bonds - a post translational modificationcovalent links between cysteine residues
    stabilises 3D structure
    require specific environment to form
    (often found extracellularly)
  33. 33Explain the importance of cleavagebreaks down proteins into smaller peptides and amino acids so can be absorbed and used by an organism
    e.g.
    preproinsulin --> proinsulin --> insulin
  34. 34Explain the process of Ubiquitinationfree Ubiquitin = Ub
    Ub activated by E1 which uses ATP to form complex with Ub
    E1-Ub transferred to E2
    E2 joins to E3 - allows polymerization of 1 or more Ub molecules on target proteins
    mono-Ubation= regulatory processes e.g. endocytosis, DNA repair, transcriptional regulation
    multi-Ubation - labels substrate for degradation by the proteasome
  35. 35What is deamination?unavoidable chemical reaction in physiological conditions
    but can be reduced by removing reactive species from the cytosol
    results in structural changes - therefore, protein damage

Informações

Descrição
O usuário eliminou as informações de disciplina FlashCards sobre Proteins, criado por Usuário eliminado em 08-09-2018.
Criado por
Usuário eliminado · set 2018
Atualizado
8 set 2018
Visualizações
9
Histórico
  • Criado por Ifeoma Ezepue · 13 nov 2015
  • Copiado por amaim maryam · 8 set 2018
Avaliação

Fale Conosco

Sobre o que é sua mensagem?

O que você acha do novo visual?

Você gostou?