Proteins Flashcards

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1
Q

What is the monomer for proteins?

A

Amino acids

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2
Q

What are the elements that make up proteins?

A

Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulphur

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3
Q

How many proteins are proteinogenic?

A

20

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4
Q

What are the difference parts of an amino acid?

A
  • An R-group
  • An amino group
  • A carboxyl group
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5
Q

What is the R-group?

A

It is a side chain added on to the amino acid

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6
Q

What is the bond between 2 amino acids?

A

It is a peptide bond with the C, O, N and H

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7
Q

What is the primary structure?

A

The sequence of amino acids are joined in a protein chain

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8
Q

What is the average chain of a primary structure?

A

100 amino acids

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9
Q

What are the bonds in the primary chains?

A

Peptide chains

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10
Q

What is the secondary structure?

A

It is the initial folding of singular polypeptide chains

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11
Q

What is the alpha helix structure?

A

The alpha helix is a secondary structure in a helix structure with 36 amino acids and 10 turns of the helix,
It has H bonds
Left hand is anticlockwise and right is clockwise

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12
Q

What are the bonds holding the secondary structures together?

A

Peptide bonds

Hydrogen bonds between the -NH groups and the -CO of another 4 places ahead the chain

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13
Q

What is the beta pleat structure?

A

Some fold slightly in a zig-zag structure, where the chains folds over in itself, forming a sheet like structure
It has H bonds

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14
Q

What is the tertiary structure?

A

This is when the coils and pleats start to fold, along with the areas of straight chains of amino acids.
It has a very specific shapes which are held together by bonds between close amino acids.

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15
Q

What is the tertiary structures shape?

A

Spherical

Supercoiled

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16
Q

What is the quaternary structure?

A

It is multiple polypeptide chains are arranged to make the complete protein molecule.

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17
Q

What holds a quaternary structure together?

A
Peptide bonds
Hydrogen bonds
Ionic bonds
Disulphide links
Hydrophilic and hydrophobic interactions
18
Q

What holds a tertiary structure together?

A
Peptide bonds
Hydrogen bonds
Ionic bonds
Disulphide links
Hydrophilic and hydrophobic interactions
19
Q

Where are the hydrogen bonds?

A

They are between an amino group and carboxyl group or between polar areas of the R- groups

20
Q

Where are the ionic bonds?

A

Form between the carboxyl and amino groups that are part of R-groups. These ionise into NH3+ and COO- groups. The positive and negative ions cause the ionic bonds

21
Q

Where are the disulphide links?

A

In between the R-groups of the amino acids cysteine contains sulphur, disulphide bridges are formed between the R-groups of 2 cysteine to make strong covalent bonds.

22
Q

Where are the hydrophilic and hydrophobic interactions and why do they happen?

A

They happen when the R-groups are hydrophilic or hydrophobic.
If the R-group is hydrophilic it will mean it will be near the water
If the R-group is hydrophobic it will mean it will be away from the water

23
Q

What are the features of globular proteins?

A

Compact
Roughly spherical
It is soluble

24
Q

How is a globular protein formed?

A

It is when the proteins fold so hydrophilic R-groups are away from the water and the hydrophobic R-groups are close to the water

25
Q

What is a globular proteins used for?

A

Used in chemical reactions
Immunity
Muscle contractions

26
Q

What is insulin?

A
  • It is a globular protein
  • It is a hormone that regulates glucose concentration in the blood
  • It has a secondary structure of helixes and is folded into a tertiary structure
  • It is water soluble
  • It has a specific shape for its function
27
Q

What is the structure of haemoglobin?

A
  • It is a globular protein
  • It has 4 subunits that are wrapped in a haem group.
  • Each haem group has an iron inside it
  • It has 2 alpha and 2 beta subunits
  • It is a conjugated protein
28
Q

What is myoglobin?

A

-It is a globular protein

29
Q

What is pepsin?

A
  • It is a globular protein
  • It is an enzyme to break down proteins in the stomach
  • It is a symmetrical tertiary structure
  • It has mostly acidic amino acids so it is stable in the stomachs acidic conditions
  • The tertiary structure is held together by hydrogen bonds and 2 disulphide bridges
30
Q

What is catalase?

A
  • It is a globular protein
  • It is in a quaternary protein shape
  • It as 4 haemprosthetic groups
  • It contains Iron in the prosthetic groups
  • It breaks down H2O2 which is a toxic byproduct of metabolism, so the catalase gets rid of it
31
Q

How is a fibrous protein formed?

A
  • It is a long insoluble chain because of the many hydrophobic R-groups in the primary structure
  • It has a limited range of amino acids with small R-groups
  • They make long strong molecules that aren’t folded into complex structures
  • It is strong, tough and fibrous
32
Q

What is a fibrous proteins used for?

A

It has mostly structural uses

33
Q

Where is collagen found?

A
  • Used in connective tissue
  • Found in skin, tendon and ligaments
  • Made up of 3 polypeptides wound in a long and strong rope-like structure
  • It is flexible
34
Q

What is keratin?

A
  • Found in hair, nails, skin
  • Large portion of sulphur-containing amino acids, so there are many disulphide bonds
  • The disulphide bonds make the material strong an inflexible
  • The more rigid the structure the more disulphide bonds there are
35
Q

where is elastin used

A

-In the walls of blood vessels and in the alveoli of the lungs
-It gives the vessels and alveoli flexibility to expand and retract
It is a quaternary protein mede from stretchy molecules and tropoelastin

36
Q

What is the structure of collagen?

A
  • peptide bonds , between amino acids / in polypeptide
  • every 3rd amino acids is , same / glycine
  • coil / twist / spiral / helix
  • left-handed (helix)
  • glycine / small R group , allows closeness / twisting (of polypeptide chains)
  • three polypeptide chains
  • hydrogen / H , bonds between (polypeptide) chains
  • no / few, hydrophilic (R) groups on outside (of molecule)
  • (adjacent molecules joined by) crosslinks
  • crosslinks / ends of molecules , being staggered
  • fibril
37
Q

What is the structure of haemoglobin?

A

-globular
-hydrophobic (R) groups on inside / hydrophilic
(R) groups on outside
-4 , chains / sub-units / polypeptides
-idea that subunits are (two) different types
-α / alpha , helix
idea that proportion of glycine similar to that, of other amino acids / in other proteins

38
Q

What does the iron do in a haemoglobin?

A

haem group reversibly binds with oxygen

39
Q

What is a chain of amino acids called?

A

Polypeptide chain

40
Q

How many oxygen atoms can 1 haemoglobin bind to?

A

4 oxygen atoms in each haemoglobin