3.1.4 Proteins 3.1.4.1 General Properties Of Proteins

Question 1

3 examples of proteins that are vital compounds of all living organisms

Answer 1

Enzymes
Antibodies
Hormones

Question 2

3 functions of proteins in the body e.g

Answer 2

Holding body together
Controlling body chemistry (metabolism)
Fighting off disease (immune response)

Question 3

What element do organic molecules contain

Answer 3

Carbon

Question 4

What type of molecules are proteins

What 4 elements do they always contain

Answer 4

Large, complex molecules

Carbon, hydrogen, oxygen, nitrogen

Question 5

What’s nitrogen in proteins for

Answer 5

Growth

Question 6

What do mostly primary + secondary proteins sometimes contain

Answer 6

Sulphur

Question 7

What are the monomers that make up proteins

Answer 7

Amino acids

Question 8

What do amino acids mostly all end in

E.g

Answer 8

‘-ine’

Proline, valine

Question 9

2 words that link with nitrogen

Answer 9

Amino
Amine
Amide

Question 10

2 parts of an amino acid that always stay the same

Answer 10

Amino group

Acid group

Question 11

What’s the formula of the amino group

Answer 11

NH2

Question 12

What’s the formula of the acid group

Answer 12

COOH

Question 13

What part of an amino acid is always different

Answer 13

The R group

Question 14

How many different amino acids are there and so different r groups

E.g

Answer 14

20

E.g glycine, alanine

Question 15

Where is sulphur found if it’s present in an amino acid

Answer 15

The R group

Question 16

What’s the test for proteins

Answer 16

The Biuret Test

Question 17

What do you not need for the test for proteins

Answer 17

Heat

Question 18

What’s the method for the biuret test

Answer 18

Dissolve test substance in water (crush it if it’s a seed or really solid food)
Add biuret reagent

Question 19

What’s the biuret reagent consist of

Answer 19

Copper sulfate + sodium hydroxide mixture

Question 20

What shows protein is present at the end of the biuret test

Answer 20

Change in colour from blue to lilac/purple

Question 21

What dl enzymes do in the body

Answer 21

The controlling

Question 22

How are enzymes made

E.g

Answer 22

By adding ‘-ase’ to the substrate

E.g
Lactase breaks down lactose

Question 23

2 types of enzymes

Answer 23

Intracellular (working inside cells)
Extra cellular (working outside cells) - fungi

Question 24

How do amino acids join
What bonds are formed between them
Whats released

Answer 24

By condensation reactions
Releasing water
Forming peptide bonds

Question 25

How many amino acids In a dipeptide

Answer 25

2

Question 26

How many amino acids In a tripeptide

Answer 26

3

Question 27

How many amino acids In a polypeptide

Answer 27

Many

Question 28

Whats protein made from (not amino acids) E.g

Answer 28

1/more polypeptides (polymers) E.g haemoglobin molecule made from 4 polypeptides (2 alpha + 2 beta polypeptide chains)

Question 29

What has the backbone N-C-C-N-C-C

Answer 29

Dipeptide

Question 30

How many levels of structure do proteins have

Answer 30

4

Question 31

What's the first structure called | What is it

Answer 31

Primary structure | The sequence of amino acids (order in which they are joined)

Question 32

3 words describing the primary structure

Answer 32

Long, fibrous strands

Question 33

What type of proteins are primary and secondary structure

Answer 33

Structural

Question 34

What's the 2nd level of proteins structure | What's the amino acid chain like now

Answer 34

Secondary structure | Folded and coiled

Question 35

What's the secondary structure held in place by

Answer 35

Hydrogen bonds

Question 36

2 most common secondary structure proteins

Answer 36

Alpha helix-spiral shape | Beta sheet - pleated like folded paper e.g silk from worms

Question 37

What's the 3rd level of protein structure called | What's it like

Answer 37

Tertiary structure | Overall shape of amino acid chain (globular) e.g whole polypeptide

Question 38

How does the tertiary structure become globular

Answer 38

When in water e.g cytoplasm , a wide variety of forces combine to twist, fold and bend the polypeptide into its most stable shape

Question 39

What are there many areas of in the tertiary structure

Answer 39

Secondary structure

Question 40

What type of proteins are the 3rd and 4th structural level

Answer 40

Functional

Question 41

What's the 4th structural protein level called When does it occur E.g

Answer 41

Quaternary structure When the protein has more than 1 polypeptide chain E.g haemoglobin has 4

Question 42

What structure does a protein made up of just 1 polypeptide chain not have

Answer 42

Quaternary

Question 43

What component do quaternary proteins often have E.g

Answer 43

A non-protein component which is sometimes an ion E.g the haem in haemoglobin

Question 44

What group is the haem in haemoglobin know as

Answer 44

Prosthetic group

Question 45

What are the 2 main groups protein structure can be split into

Answer 45

Globular | Fibrous

Question 46

What type of protein is globular

Answer 46

Functional - tertiary

Question 47

What type of protein is fibrous

Answer 47

Structural - secondary

Question 48

2 facts about globular proteins

Answer 48

Generally rounded in shape | Tend to have a chemical function

Question 49

4 examples of chemical functions globular proteins may have What are these all

Answer 49

``` Enzymes Hormones e.g insulin Haemoglobin Antibodies Membrane proteins ``` All shape-specific

Question 50

2 facts about fibrous proteins

Answer 50

Usually long,thin molecules | Generally have a structural function

Question 51

What are fibrous proteins the fabric of

Answer 51

The body

Question 52

3 examples of fibrous proteins and their uses

Answer 52

Collagen - strength to tissues Keratin - strength to skin, hair, nails Actin + myosin - muscles contract

Question 53

What 2 relatively weak forces is the shape of globular proteins maintained by

Answer 53

Hydrogen bonds | Ionic bonds

Question 54

Where do the hydrogen bonds and ionic bonds in globular proteins come from

Answer 54

The acidic and amine groups

Question 55

What forces to big, tough fibrous proteins rely more on

Answer 55

Strong disulfide bridges