Proteins Flashcards

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1
Q

What is an amino acid

A

The monomers from which proteins are made

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2
Q

In an amino acid what does the NH2 represent

A

The amine group

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3
Q

In an amino acid what does the COOH represent

A

A carboxyl group

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4
Q

In an amino acid what does the R represent

A

The side chain

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5
Q

What changes in an amino acid

A

The side group (R group )

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6
Q

What does the condensation between 2 amino acids produce

A

A peptide bond

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7
Q

A dipeptide formed by condensation what

A

Two amino acids

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8
Q

A polypeptide is formed by condensing what

A

Many amino acids

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9
Q

What does an enzyme do

A

Lowers the activation energy for the reaction it catalyses

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10
Q

What do the properties of enzymes relate to

A

Tertiary structure of its active site
It ability to combine with a complementary substrate to form an enzyme- substrate complex

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11
Q

What are all proteins monomer

A

Amino acids

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12
Q

How many different amino acids

A

20

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13
Q

2 groups in an amino acid ( general)

A

Amine group
Carboxylic acid group

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14
Q

What chnages in the structure of the amino acid

A

The R group

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15
Q

What are the 4 main elements in an amino acid

A

Nitrogen
Hydrogen
Carbon
Oxygen

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16
Q

What is the bond between 2 amino acids called

A

A peptide bond

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17
Q

What type of reaction is 2 amino acids joining together and why

A

Condensation reaction
Molecule of water is lost

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18
Q

What is the name for 2 amino acids bonded together

A

Dipeptide

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19
Q

Where does protein synthesis take place

A

Ribosome

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20
Q

What are 3 or more amnio acids joined together called

A

A polypeptide

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21
Q

Hydrophobic =
Hydrophilic =. (Hint charge)

A

Non-polar
Polar

22
Q

Difference between protein and polypeptide

A

Polypeptide has to fold into a complex 3D shape
Once folded and carrying out it’s function it is a protein

23
Q

Level 1 of protein structure + importance

A

Primary Structure
- specific order of amino acids in a polypeptide
Helps determine 3D shape of molecule - function

24
Q

How is the structure of a protein determined

A

By the DNA sequence of the gene which encodes for that polypeptide

25
Q

Level 2 protein structure
Groups in a polypeptide chain + charges

A

C=0 and N-H
C=0 —> -
N-H —> +
Charges attract to form hydrogen bonds
Causes twists and folds

26
Q

Level 2 protein structure

A

Is the overall 3D shape of protein
Areas of beta pleat sheet
Areas of alpha helix

27
Q

Level 4 protein structure

A

Subunit - multiple polypeptides
Only applies to proteins with 2 subunits
Prosthetic groups

28
Q

What is a subunit protein

A

Made up of multiple polypeptide chains

29
Q

What is the prosthetic group + what they do

A

Non- protein molecules forming part of the structure of a protein
Help protein carry out its role

30
Q

What are proteins with prosthetic groups called

A

Conjugated proteins

31
Q

What is an uncharged R group called

A

Non-polar amino acid

32
Q

Are non-polar amino acids attracted to water

A

No

33
Q

What is it called when a polar amino acids is not attracted to water

A

Hydrophobic

34
Q

Explain a hydrophobic interaction

A

Amino acids with hydrophobic R groups cluster together and exclude water molecules

35
Q

Where are hydrophobic and hydrophilic amino acids found

A

Hydrophobic in the centre of proteins away from water
Hydrophilic on the surface of proteins where they can interact with water molecules

36
Q

Where is an iconic bond found (proteins)

A

Between amino acids with charged R groups

37
Q

How are ionic bonds in proteins broken

A

By changed in PH

38
Q

What is a disulphide bond

A

When the Sulphur atoms between two cysteine molecules form a covalent bond

39
Q

What are the two types of secondary structure

A

Alpha helix’s
Beta pleated sheets

40
Q

What are the two groups of proteins

A

Globular
Fibrous

41
Q

Globular proteins are soluble/insoluble + why

A

Soluble
They have hydrophilic amino acids on their surface
( hydrophobic are in centre)

42
Q

Are Fibrous proteins soluble / insoluble + why

A

Insoluble
Hydrophobic R groups

43
Q

Which test is used for proteins

A

Biuret

44
Q

How to carry out biuret test

A

Add sodium hydroxide - to make alkaline
Add copper (ll) sulfate solution
Negative - blue
Positive - purple

45
Q

Amylase, protease and lipase do what to the thing they break chemical process

A

Hydrolyses

46
Q

Test for proteins

A

Add Biuret
Positive results purple

47
Q

Two ways in which all dipeptides are similar

A

Amine group
Carboxylic group

48
Q

One way in which dipeptides are different

A

Different R groups

49
Q

What bonds are present in Tertiary structure of amino acid

A

Hydrogen
Disulphide bridges ( only between cysteine)
Ionic

50
Q

Where is lactose attached to a polypeptide to form a glycoprotein

A

Golgi apparatus

51
Q

Level 3 protein structure

A

The interactions between the R groups
- hydrogen bonds (between R groups)
- disulphide bridges
- ionic bonds

52
Q

What interactions occur between non-polar R groups

A

Weak hydrophobic interactions (non polar = hydrophobic