L1 aa and prot

Question 1

LO1: ID main euk organelles and their func

Answer 1

• Cytoplasm- metab carbs, aa, nt. fatty acid synth.
• Lysosome- cellular dig.
• Golgi- Prot export. detox reacs.
• Mito- ATP synth.
• RER- mem synth. prot export. detox. prot synth. lipid and steroid synth.
• Nuc- Rna proc and ribos assemb. DNA synth and repair. RNA synth.
• PM- transp ions and small molecs.
• ribosome- prot synth.

Question 2

LO2: Discuss bonds imp for macromolec struc and interac.

Answer 2

weak non covalent elecstatic interacs

• H bond eg pep bond
• ionic interacs
• hydrophobic interacs
• van der walls

Question 3

LO3: expl diffs btw phob and phillic molecs in water.

Answer 3

• phob are non polar, do not form H bonds with water. Cluster together in water.
• phillic are polar, form H bonds with water.

Question 4

LO4: expl concept of ph, pk and buffers.

Answer 4

• pH= -log[H+].

- pK= likelihood of dissoc to rel H+. low= donates. pos R grps high pK so acc H. pH less than pH=protonated.

Question 5

LO5: gen struc off aa.

Answer 5

NH2-CHR-COOH

Question 6

LO6: classif aa acc to sc props. how aa charge is aff by pH.

Answer 6

• aromatic- phenylalanine, tyrosine, tryptophan
• polar uncharged- serine, threonine, cysteine, asparagine, glutamine.
• nonpolar aliphatic- glycine, alanine, proline, valine, leucine, isoleucine, methionine.
• neg- aspartate, glutamate.
• pos- lysine, ariginine, histidine.
• pI=pH where no overall charge. pI>7 is basic protein with mostly basic aa’s. pH>pI=deprotonated.

Question 7

LO7: how peptide is formed and key features.

Answer 7

COO- + NH3+ —–> H2O + O=C-N-H condensation reac

• All atoms of bond in same plane.
• No rotation about bond due to doub bond chars.
• Carbonyl O and amide H in trans conform.

Question 8

LO8: how aa can infl pI of prot.

Answer 8

• acidic prots cont lot neg aa’s and have low pI.

- basic cont lot pos aa’s and high pI.