What is Biochemitry?Why importance?

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Introduction to Biochemistry
What is Biochemitry?Why importance? How to study
Biochemistry? Demands in this lesson
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Biochemistry is to study the molecular basis of
life. Why is it important and excited ?
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1. the chemical or molecular basis of some
central processes in biology are understood. 2.
common molecular patterns and principles in
diverse expressions of life. 3. biochemistry
impact on medicine. 4. the development of
biochemistry has enabled investigators to resolve
the most challenging and fundamental problems in
biology and medicine.
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1. Active in class 2. Memory on the basic
knowledge 3. Answer to the teachers question
bravely and freely. 4. Not left too much after
class 5. No need to preview, but review in time.
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Chapter I . Structure and function of
proteins Introduction to protein structure and
function 1. Enzymatic catalysis. 2. Transport
and storage 3. Coordinated motion 4. Mechanical
support. 5. Immune protection. 6.Generation and
transmission of nerve impulses. 7.Control of
growth and differentiation.
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Chapter I . Structure and function of
proteins (Part I) Main contents Amino
acids Peptides and polypeptides Determination of
amino acid composition of proteins Determination
of amino acid sequence of proteins
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Chapter I . Structure and function of
proteins 1. Amino Acids----The basic unit of
proteins, and Polypeptide
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• Amino acids
• The structure of amino acids and their
  properties
• (a)Amino acids have both acid and base
  properties
• (zwitterion).

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(b)Aromatic amino acids absorb light in the
near-ultraviolet (c)All amino acids except
glycine show asymmetry (d)Coloured by
ninhydrin
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• Common structure formula of L-amino acids

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• Classification of amino acids
• 1. Apolar, hydrophobic R chain
• 2. polar neutral (uncharged)
• 3. Acidic amino acid
• 4. Basic amino acid.

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Amino acids have both acid and base
properties 1. Introduction to Henderson-Hasselbac
h equation (Conception of pH scale and water
dissocation, acids dissociation)
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2. A simple amino acids with a nonionizable R
group gives a complex titration curve with two
inflection points. 3. More complex amino acids
with an ionizable R group show even more complex
titration curves.
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Aromatic amino acids absorb light in the
near-ultraviolet phenylalanine, tyrosine, and
typtophan
Quiz What importiance for this property of
amino acids? What can you do applying
this property?
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All amino acids except glycine show
asymmetry Chirality or handedness (take your
hand as example) Stereoisomeric pair D
dextrorotatory L levorotatory All amino
acids constructing proteins are L form. Some
D-amino acids in bacterial cell walls and
certain antibiotics.
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• 2. Peptides an polypeptides
• peptide bond partial double-bond character
• not rotated freely
• Amide plane and amide unit
• polypeptides chain
• Conception of polypeptides or oligopeptides
• other bond in proteins or polypeptides

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Peptides Short polypeptides chains, up to length
of about 20 amino acids, are called
peptides However if they are fragments of whole
polypeptide chains, we call it oligopeptides.
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3. Determination of amino acid composition of
proteins(step?) A. Break down the polypeptide
chain into AAs. B. Separate the free AAs. C.
Measure the quantities of each amino acids.
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Free amino acids are coloured by
ninhydrin (Reaction)
R-C-COOH 2
O
NH2
OH
C
H
C
OH
O
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Free amino acids are coloured by ninhydrin
(Production)


O
O
C
C
N
C

C
C
O
O
H
Ninhydrin coloured by red
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Structure and function of proteins Part II .The
Three-Dimensional Structure of Proteins Contain (
1)Primary structure (2)secondary structure
?-helix ?-pleated sheet
?-blend(turn) random coil one special
structure motif (eg.Zinc finger)
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(3) Tertiary structure special structure
domain (4) Quaternary structure subunit
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(5) Bonds in the protein structure (6)
Relationship of structure
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Domain
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Globular proteins
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Section 4 the physic and chemical character of
protein and isolation and purification of protein
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4. Determination of amino acids sequence of
proteins (steps?) (1) purification of
protein (2)cleavage of all disulfide
bonds (3)determination of the terminal amino acid
residues (4)specific cleavage of polypeptide
chain into small fragments in at least two
different cleavage methods.
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(5) Independent separation and sequence
determination of peptides produced by the
different cleavage methods. (6) Reassembly of
the individual peptides with appropriate overlaps
to determine the overall sequence.
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????? ?????
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1. ?????????????( )
A ??? B ??? C ??? D ??? E ???
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2. ????????????( )
A -NCCNNCCNNCCN- B -CHNOCHNOCHNO- C
-CONHCHCONHC- D -CNOHCNOHCNOH- E -CNHOCNHOCNHO-
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3. ?????????????????
A ????C-N?????N-C??? B ???C-N????????? C
????????N?C????? ???????? D
???C-N??????? E ????C-N?????????? ????
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4. ???????????????( )
A ???? B ???? C ???? D ???? E ????
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5. ?????????????????
A ????????????? B ????????????? C
?3.6?????????? D ?????????????????? E
?????????????????????

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6. ?????????????????
A ???????????? B ??????????? C ???????????? D
???????????? E ???????????????????
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7. ???????280nm ?????????( )
A ????-OH B ?????-SH C ??????? D ??????? E
???????
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8. ????????????????????
A ??? B ??? C ??? D ??? E ????
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9. ????????( )
A ?????? B ????? C ???? D ????? E ??????
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10. ????????pH6.0?,??????????,?????????????( )
A Val(pI5.96) B Asp(pI2.77) C Lys(pI9.74) D
Arg(pI10.76) E Tyr(pI5.66)
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11. Glycine, pK-COOH 2.34, pK-NH2 9.60, its
pI is ( )
A 11.94 B 7.26 C 5.97 D 3.63 E 2.34
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12. The unit composition of protein is ( )
A L-?-amino acids B D-?-amino acids C
L-?-amino acids D D-?-amino acids E
L,D-?-amino acids
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13. The main chemical bond which maintain
quaternary structure of protein is ( )
A hydrogen bond B salt bond C hydrophobic
bond D disulfide bond E van der waals force
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14. In which solution, does serum albumin,pI 4.7,
positively charge?
A pH4.0 B pH5.0 C pH6.0 D pH7.0 E pH8.0
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15. ??????????????( )
A ???????????? B ???? C ??????? D ???? E ????

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16. ???????????????????
A ?????????? B ?????????? C ???????????????? D
???????????? E R?????????????