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Bio 12 > Quiz 3 - Biochem (pro, enzy) > Flashcards

Quiz 3 - Biochem (pro, enzy) Flashcards

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Biology 101 flashcards
1
Q

What are some functions of proteins? (7)

A

-enzymes (DNA)
-structure
-carriers & transport
-cell communication (signals, receptors)
-defense
-movement
-storage

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2
Q

What is the structure of an amino acid?

A

-has a central asymmetric carbon
-attatched to 4 diff groups (exception of glycine ; R group is H)
-Amino group
-Carboxyl group
-Hydrogen
-R-group (varies for each acid)

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2
Q

What is the structure of proteins? (monomer)

A

= amino acids
-20 diff amino acids (9 are essential, and must come form diet)

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3
Q

What is the structure of proteins? (polymer)

A

= polypeptide
-one or more polypeptide chains folded n bonded together
-large and complex molecules
-complex 3d shape

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4
Q

How does the effect of diff R groups make a POLAR amino acid?

A
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5
Q

How does the effect of diff R groups make a NONPOLAR amino acid?

A
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6
Q

What does amino acids containing sulfur do?

A

-Forms disulfide bridges
-Covalent cross links between sulfhydryls
-Stabilizes 3-d structure

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7
Q

How do you build a protein?

A

-dehy syn, joins amino acids to form peptides
-covalent bond likes amino acids in a peptide is a PEPTIDE BOND

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8
Q

how do you form a polypeptide

A

-multiple peptide bonds result in a polypeptide

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8
Q

What are the names for the ends of polypeptide chains? (whats the end?)

A
  • N-Terminus = NH2 end
  • C-Terminus = COOH end
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9
Q

How do polypeptide chains grow?

A

Repeated sequence:
-N-C-C backbone
-can only grow in one direction

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9
Q

What is a proteins structure and function?

A
  • FUNCTION DEPENDS ON STRUCTURE
  • 3-D, twisted, folded.
    -4 lvls of protein structure
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10
Q

Explain the Primary structure of a protein (3)

A
  • Order of amino acids in chain
  • sequence determined by genes (DNA)
  • slight change can affect a lot; sickle cell anemia
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11
Q

Explain the Secondary structure of a protein (3)

A
  • LOCAL FOLDING
  • folding along short sections of polypep
  • interactions between adjacent amino acids; H-BONDS, weak bonds
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11
Q

What does Local Folding form?

A

a(alpha) helix –> one helix

OR

B(beta)–> pleated sheet
a protein can have both!

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12
Q

Explain the Tertiary structure of a protein (5)

A

-WHOLE MOLECULE FOLDING
-interactions between DISTANT amino acids
-HYDROPHOBIC int.
-HBONDS n IONIC
-DISULFIDE BRIDGES, S-H
anchors 3D shape

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13
Q

Explain the Quaternary structure of a protein (3)

A

-MORE THAN ONE POLYPEP CHAIN bonded together
-only some proteins have quaternary
-HYDROPHOBIC int.

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14
Q

What is the smallest and largest protein? How many possible amino acid seq are there?

A
  • Insulin (small)
  • Titin (large)
    For a polypeptide of “n” amino acids there are 20^n possible amino acid sequences
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14
Q

What does it mean to “denature” a protein?

A
  • To UNFOLD it
  • Conditions that disrupt H-bonds, ionic, & disulfide bridges
  • Ex; temp, pH, salinity
  • ALTERS 2nd n 3rd structure; 3D shape
15
Q

What happens when you denature a protein

A

It destroys its functionality.
-Some can return to their functional shape, many cannot.

15
Q

How can we visualize a protein

A

-x-ray crystallography
-extrapolating from amino acid sequence

16
Q

What are the two reactions for Metabolism

A

ANABOLIC
- FORM bonds between molecules
- eg. dehy syn

CATABOLIC
-BREAK bonds between mols
-eg. hydrolisis

**both require ENZYMES to work

17
Q

What chemical reactions RELEASE energy?

A

EXERGONIC
- digesting polymers
- hydrolisis reac (catabolic)

17
Q

What chemical reactions require the INPUT of energy?

A

ENDERGONIC
- Building polymers
-Dehy syn (anabolic) reac

18
Q

What is the difference between exergonic and endergonic reactions?

A

Exergonic : energy released, digestion (–delta G)

Endergonic : energy invested, synthesis (++delta G)

19
Q

What is delta G?

A

Change in free energy, ability to do work

20
Q

What is energy’s role in enzymes?

A

-Organisms require energy to live
-Comes from COUPLING exergonic + endergonic.

explanation: digestion produces products + energy
syn reactants r two things + energy to create one protein.

20
Q

What drives reactions?

A

Covalent bonds are so stable; therefore reactions don’t just happen spontaneously

21
Q

What is Activation energy?

A
  • The initial input of energy requires to break down large mol
    -must absorb energy to break bonds
22
Q

How do you reduce activation energy?

A
  • CATALYSTS
  • reduce the amt of Ea needed to start a reaction (flattens hill)
23
Q

So.. what are catalysts?

A
  • Reduces activation energy
  • ENZYMES are biological catalysts
  • enzymes lower activation energy without affecting deltaG
24
Q

Give 5 points on explaining enzymes

A
  • For proteins (& RNA)
  • Facilitate chemical reactions
  • Required for most bio reac
  • Highly specific (thousands of diff enzymes in cells)
  • Control reactions of life
24
Q

What is a substrate?

A
  • Reactant which binds to and enzyme
    (the bonded together mol)
25
Q

What is a Enzyme-Substrate complex?

A

Temporary molecule formed when enzyme bonds with substrate

26
Q

What is the Active site?

A

Enzyme’s catalytic site; substrate fits into active site

27
Q

What are the products?

A

the end result of a reaction

28
Q

What are the three properties of enzymes?

A
  • REACTION SPECIFIC; only works w/ specific substrate; HBONDS , IONIC BONDS
  • Not consumed in reaction; enzymes unaffected
  • Affected by Cellular Conditions; any condition that affects protein structure affects enzyme function; eg temp pH salinity
29
Q

How are enzymes named?

A

named for reaction they catalyze

Sucrase -> sucrose
Proteases -> proteins
Lipases -> Lipids
DNA polymerase -> builds DNA
Pepsin -> breaks down proteins

29
Q

What are the two types of models for enzymes?

A
  • Lock and Key; substrate fits into 3D structure of active site, Hbonds
  • Induced fit model; more accurate, substrate binding cause enzyme to change shape leading to tighter fit
    .. Conformational change
30
Q

How does this whole enzyme process work?

A

SYNTHESIS
- active site orients substrates in correct position for reaction

DIGESTION
- active site binds substrate and puts stress on bonds that must be broken

31
Q

What factors affect enzyme function?

A

-Enzyme concentration
-Substrate concentration
-Temperature
-pH
-Salinity
-Activators
-Inhibitors

32
Q

Explain how enzyme concen affects enzyme function (reac rate); and whats the limiting factors?

A

as enzyme inc, so does R.R
-LF: substrate, not all enzyme mols can find substrate

33
Q

Explain how substrate concen affects enzyme function (reac rate); and whats the limiting factors?

A

as sub inc, so does R.R
-LF: all enzymes already have active site engaged, SATURATED

34
Q

how does temperature affect enzyme function?

A

-Optimum Temp
-Heat: disrupts bonds
-Cold: mol move slower

35
Q

how does pH affect enzyme function?

A

-Changes in pH; adds or remove H+
-Has optimal pH

36
Q

How does salinity affect enzyme function?

A

-adds or removes cations n anions
-disrupts bonds
-enzymes intolerant of extreme salinity

Bio 12 (5 decks)

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