Proteins Flashcards

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1
Q

Draw and label a diagram of an amino acid

A

Must include:

  • amine group NH2
  • carboxyl group - COOH
  • variable R group
  • H
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2
Q

How many amino acids occur in life?

A

20

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3
Q

What elements do all proteins contain?

A

Carbon, hydrogen, oxygen, nitrogen

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4
Q

What are the 3 types of amino acids in life?

A

-5 non essential
Our body can make them from other amino acids
- 9 essential as they are only obtained by what we eat
- 6 conditionally essential
Only needed as children

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5
Q

Draw a labelled diagram demonstrating condensation and hydrolysis of peptide bonds

A
  • must show the water molecule removed

- use textbook to check

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6
Q

Draw a dipeptide and label the bond

A

Use book to check

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7
Q

Explain why there is a range of dipeptides and lots of variety in polypeptide chains

A

There are 20 amino acids
20x20 = 400 dipeptides

This quickly leads to a hugeee number of polypeptides

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8
Q

Define polypeptide

Define protein

A

Polypeptide - a polymer of amino acids

Protein - one or more polypeptide chains arranged as a macromolecule with a specific function

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9
Q

Define primary structure and describe how it is held together

A
  • this is the sequence of amino acids in the polypeptide chain
  • this is decided by DNA
  • it is put together on ribosomes
  • peptide bonds
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10
Q

Define secondary structure

  • what are the two types

- describe how it’s held in place

A
  • chain folds or coils of polypeptide chain = secondary
  • alpha helix or beta pleated sheets
  • hydrogen bonds form between NH and CO of non adjacent amino acids
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11
Q

Define tertiary structure

- describe how it is held in place

A
  • further folding caused by bonds and interactions between R groups
  • the secondary structure pulls R groups of amino acids closer
  • weak hydrophobic / Philic interactions
  • hydrogen bonds
  • ionic bonds - oppositely charged R groups
  • disulphide bridges - covalent and strong, but only between R groups containing sulphur
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12
Q

Explain quaternary structure

- describe how it is held in place

A
Associations between separate polypeptide chains 
- uses all types of bonding 
Hydrophobic / Philic interactions
Hydrogen bonds
Ionic
Disulphide bridges
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13
Q

Define globular protein

- properties

A
  • compact
  • water soluble
  • spherical
  • forms when hydrophilic R groups are on the outside of the protein, and hydrophobic are on the inside
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14
Q

Define fibrous proteins

A
  • long
  • insoluble
  • strong
  • 2D ish
  • high proportion of hydrophobic R groups
  • repetitive primary structure
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15
Q

Define prosthetic group

A

A non protein group that makes up the R group of an amino acid

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16
Q

Define conjugated protein

A
  • a globular protein that contains a prosthetic group
17
Q

Draw a table to show an example of

  • a conjugated protein
  • an enzyme
  • peptide hormone

For each describe structure and function

A

Conjugated protein

  • haemoglobin
  • globular
  • quaternary structure, 4 polypeptides
  • transports oxygen

Enzyme

  • catalase
  • globular
  • conjugated
  • breaks down H2O2

Peptide hormone:

  • insulin
  • globular
  • regulates blood glucose concentration
18
Q

3 examples of fibrous proteins

A

Keratin
Elastin
Collagen

19
Q

Compare structure properties and functions of 3 fibrous proteins

A

Keratin:

  • strong disulphide bridges
  • strong
  • inflexible
  • insoluble
  • present in hair, skin and nails

Elastin:

  • quaternary
  • stretchy
  • present in elastic fibres in blood vessels and alveoli

Collagen

  • 3 polypeptide wound together
  • strong, ropelike
  • flexible
  • connective tissue found in skin, tendons, ligaments