Proteins (Structure)

Question 1

What are the monomeric units of proteins?

Answer 1

Amino acids

Question 2

Where do we get amino acids from?

Answer 2

Our diet

Question 3

What elements do all proteins contain?

Answer 3

Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur

Question 4

Outline the journey an amino acid takes from food to protein in a cell

HINT: FRED EATS APPLES TO POWER UP

Answer 4

F - Food is ingested.
E - Enzymes break down proteins in the stomach and small intestine.
A - Amino acids are absorbed into the blood.
T - Amino acids travel through tissue fluid to cells.
P - Proteins are synthesized on ribosomes.

Question 5

How many common amino acids are there?

Answer 5

20

Question 6

How many amino acids are classified as non-essential, and why?

Answer 6

5 - body can synthesise them from other amino acids.

Question 7

How many amino acids are classified as essential, and why?

Answer 7

9 - Needed by infants and growing children for growth.

Question 8

Give 4 functions of proteins

Answer 8

enzymes
hormones
antibodies
structural proteins

Question 9

What do the interactions of differing R-groups determine?

Answer 9

The folding of the protein

Question 10

What type of reaction occurs to form a protein from 2 amino acids?

Answer 10

Condensation

Question 11

What type of bond is formed from the synthesis of a protein?

Answer 11

Peptide

Question 12

What is produced in the condensation reaction between two amino acids?

Answer 12

Water and dipeptide

Question 13

What is the general formula of an amino acid?

Answer 13

R-CH(NH2)-COOH

Question 14

What determines the differences between amino acids?

Answer 14

The differences between amino acids are determined by their R groups, also known as variable groups.

Question 15

Between which parts of the amino acid molecules does the condensation reaction between two amino acids occur?

Answer 15

The carboxyl group of one amino acid and the amine group of another amino acid

Question 16

How are amino acids joined together?

Answer 16

Amino acids join when the amine group of one reacts with the carboxylic acid group of another, forming a peptide bond and releasing water.

Question 17

What is a chain of amino acids called?

Answer 17

A polypeptide

Question 18

What are peptides? How do they make up proteins?

Answer 18

Peptides are polymers that are made-up of amino acid molecules which are the monomers.

Proteins consist of one or more polypeptides that are arranged as complex macromolecules, and they have a specific biological function.

Question 19

What is the end of a polypeptide with an amino group called?

Answer 19

The N-terminus

Question 20

What is the end of the polypeptide with a carboxyl group called?

Answer 20

The C-terminus

Question 21

What is produced when two amino acids join together?

Answer 21

A dipeptide and a molecule of water are produced.

Question 22

What is formed when many amino acids are joined by peptide bonds?

Answer 22

A polypeptide is formed.

Question 23

What enzyme catalyses the formation of peptide bonds, and when? Where is found?

Answer 23

Peptidyl transferase, an enzyme found in ribosomes, catalyses the formation of peptide bonds during protein synthesis.

Question 24

How do R groups influence protein structure?

Answer 24

The R groups interact with each other, forming various bonds that cause the polypeptide chain to fold into complex, specific structures.

Question 25

Why is the specific shape of a protein important?

Answer 25

The unique shape of a protein is crucial for its specific functions in living organisms.

Question 26

How does the sequence of amino acids affect a protein’s structure?

Answer 26

Different sequences of amino acids lead to different folding patterns and protein shapes, which are vital for diverse protein functions.

Question 27

What defines the primary structure of a protein?

Answer 27

The primary structure is the sequence of amino acids in a polypeptide chain, determined by the DNA sequence.

Question 28

What bonds are found in the primary structure of protein?

Answer 28

Peptide bonds are the only bonds involved in the primary structure.

Question 29

What shape is the primary structure of a protein?

Answer 29

Linear

Question 30

What forms the secondary structure of a protein?

Answer 30

The folding of the primary structure

Question 31

What bonds are involved in the secondary structure of proteins?

Answer 31

The secondary structure is held together by hydrogen bonds between the oxygen, hydrogen, and nitrogen atoms of the amino acids.

Question 32

What are the two common shapes formed in the secondary structure of proteins?

Answer 32

The two common shapes are the alpha helix (a coiled shape) and the beta-pleated sheet (a zigzag or folded shape).

Question 33

In the secondary structure, what do hydrogen bonds form between?

Answer 33

Partially positive H and partially negative O

Question 34

What defines the tertiary structure of a protein? What is it formed by? What is the folding influenced by?

Answer 34

The tertiary structure is the final 3D shape of a protein, formed by the folding of the polypeptide chain (secondary structure). This folding is influenced by interactions between R groups.

Question 35

What are the 4 types of bond formed at the tertiary level of structure?

Answer 35

Hydrophobic and hydrophilic interactions Hydrogen bonds Ionic bonds Disulfide bonds

Question 36

What do hydrophobic and hydrophilic interactions form between?

Answer 36

Polar and non-polar R-groups

Question 37

What do hydrogen bonds form between?

Answer 37

Partially positive H and partially negative O (weak bonds between polar R groups)

Question 38

What do ionic bonds form between?

Answer 38

Positively and negatively charged ions (stronger bonds between oppositely charged R groups)

Question 39

What do disulfide bridges form between?

Answer 39

Sulphur atoms contained within R-groups

Question 40

Which amino acid contains sulphur?

Answer 40

Cysteine

Question 41

What defines the quaternary structure of a protein? HINT: Queen Polly Interacts Gracefully

Answer 41

Q - Quaternary Structure: This is the highest level of protein structure, formed by multiple subunits. P - Polypeptide Subunits: The structure forms when two or more polypeptide subunits interact. I - Identical or Different: These subunits can be either identical or different. G - Groups (Prosthetic): The structure can include prosthetic groups (non-protein components that assist in protein function).

Question 42

What type of bonds holds together the quaternary structure?

Answer 42

ionic hydrogen disulfide hydrophobic and hydrophilic interactions

Question 43

What are examples of proteins with quaternary structure?

Answer 43

Examples include: enzymes (which often consist of identical subunits) insulin (which has two different subunits) haemoglobin (which has four subunits, made up of two sets of two identical subunits).

Question 44

How does the hydrophilic or hydrophobic nature of R groups affect protein folding?

Answer 44

Hydrophilic R groups are on the outside of the protein, interacting with water, while hydrophobic R groups are shielded inside the protein, away from the water in the cytoplasm.

Question 45

What is a prosthetic group?

Answer 45

a non-protein component of a conjugated protein

Question 46

What are simple proteins?

Answer 46

Proteins without a prosthetic group