Biology Biological Molecules (Proteins)

Front 1

What elements can proteins contain?

Back 1

Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur

Front 2

What are the functions of proteins?

Back 2

1. Structural proteins (e.g. collagen in ligaments, keratin in nails)

2. Enzymes

3. Some hormones (e.g. adrenaline, insulin)

Front 3

What are proteins?

Back 3

Polymers of similar monomers called amino acids

Front 4

What is the structure of an amino acid?

Back 4

Front 5

What reaction creates a dipeptide?

Back 5

Condensation reaction forming peptide bond

Front 6

What is the definition of hydrophonic?

Back 6

Insoluble

Front 7

What is the definition of hydrophillic?

Back 7

Soluble

Front 8

What is the primary structure of a protein?

Back 8

The sequence of amino acids in the polypeptide

Front 9

What is the secondary structure of protein?

Back 9

The alpha helix or beta pleated sheet formed by weak hydrogen bonds

Front 10

What is the tertiary structure of a protein?

Back 10

When the secondary structure folds on itself again as a result of bonding between the variable groups of amino acids

Front 11

What is a hydrogen bond?

Back 11

Bonding between slightly negative Oxygen and slightly positive Hydrogen in variable groups

Front 12

What are ionic bonds?

Back 12

Bonding between positively and negatively charged variable groups

Front 13

What are disulphide bonds?

Back 13

Strong covalent bonds between Sulfur containing variable groups

Front 14

What is a hydrophobic interaction?

Back 14

Hydrophobic elements clustering away from water

Front 15

What is the structure of globular proteins?

Back 15

1. Tertiary structure like a tangled knot

2. Soluble

3. Involved in reactions (e.g. hormones)

Hint 15

1. Tertiary structure?

2. Soluble or insoluble?

3. What are they used for?

Front 16

What are fibrous proteins?

Back 16

1. 3D shapes fibres like a rope

2. Insoluble

3. Involved in structural roles (e.g. keratin, collagen)

Hint 16

1. Shape?

2. Soluble or insoluble?

3. What is it involved in?

Front 17

What is the quaternary structure of protein?

Back 17

Bonding of proteins in the tertiary structure or non-protein groups to make functional proteins (e.g. haemoglobin is 4 polypeptides and 4 non-protein groups)

Front 18

What is the test for proteins?

Back 18

1. Add Biuret and heat

2. Purple is a positive result

Front 19

What are enzymes?

Back 19

Globular proteins which are biological catalysts which have a specific complementary active site to the substrate

Front 20

How are enzymes denatures?

Back 20

1. pH

2. Temperature

Increases the kinetic energy breaking the hydrogen and ionic bonds in the tertiary structure

Hint 20

2 factors and how they affect the structure

Front 21

What do enzymes do in a reaction?

Back 21

Lower the activation energy

Front 22

What is the lock and key method?

Back 22

Active site is complementary to the substrate like a key bonding to form a enzyme-substrate complex

Front 23

What are limitations of the lock and key method?

Back 23

Assumes enzymes are rigid in shape but proteins can change in response to the enviroment (pH/temperature) or the binding of various substances

Front 24

What is the induced fit model?

Back 24

Active site is not precisely complementary but changes shape to bond to form a enzyme-substrate complex. The changed active site places a strain on the bonds in the enzyme lowering the activation energy

Front 25

What shape are competitive inhibitors and why?

Back 25

Shaped similar to the substrate to be complementary to the activesite and, therefore, bind blocking enzyme-substrate complexes from forming

Front 26

Will a reaction stop with competitive inhibitors?

Back 26

No as the proteins are not denatured

Hint 26

Front 27

How do non-competitive inhibitors work?

Back 27

Bind to the enzyme at the inhibitors bonding site (not the active site) changing the tertiary structure, therefore, changing the active site stopping enzyme-substrate complexes

Front 28

Will the reaction stop with non-competitive inhibitors?

Back 28

Yes as the tertiary structure is changed so the enzyme is denatured

Hint 28

Front 29

How will adding more substrate effect inhibitors?

Back 29

1. Competitive inhibitors will increase the reaction rate

2. Non-competitive inhibitors nothing will happen as enzymes are denatured

Front 30

How can temperature denature enzymes?

Back 30

As the temperature increases the kinetic energy increases so there are more enzyme-substrate complexes. As the temperature increases above optimum the kinetic energy begins breaking hydrogen and ionic bonds changing the tertiary structure and denaturing enzymes.

Hint 30

How does kinetic energy effect enzymes?

Front 31

How can pH denature enzymes?

Back 31

Interfere with hydrogen and ionic bonds in the tertiary structure changing the shape of the active site

Front 32

What limits the rate of reaction if the amount of substrate is increased?

Back 32

An increase in substrate will increase the amount of enzyme-substrate complexes until the active site of all enzymes are fully saturated (occupied)

Front 33

How does the concentration of enzymes effect the rate of reaction?

Back 33

As the concentration of enzymes increases the rate of reaction increases