Form and Function- Proteins

Question 1

What are proteins?

Answer 1

Proteins are complex macromolecules composed of one or more chains of amino acids.

Question 2

What roles do proteins play in biological processes?

Answer 2

Proteins play essential roles in structural support, catalysis, and signalling pathways.

Question 3

What is the general structure of an amino acid?

Answer 3

An amino acid has a central carbon (alpha carbon) bonded to a carboxyl group (–COOH), an amino group (–NH2), a hydrogen atom (–H), and a unique organic side chain (R-group).

Question 4

How do amino acids join together?

Answer 4

Amino acids join through a condensation reaction to form a peptide bond, releasing a water molecule.

Question 5

What is an N-terminal and C-terminal in a dipeptide?

Answer 5

The N-terminal is the free amino group not involved in the peptide bond, while the C-terminal is the unbound carboxyl group.

Question 6

What are essential amino acids?

Answer 6

Essential amino acids are those that the body cannot produce and must be obtained from food.

Question 7

What are non-essential amino acids?

Answer 7

Non-essential amino acids can be produced by the body from other amino acids or by the breakdown of proteins.

Question 8

Can vegan diets provide essential amino acids?

Answer 8

Yes, vegan diets can provide all essential amino acids through plant-based protein sources like beans, lentils, nuts, seeds, and tofu.

Question 9

What is the genetic code?

Answer 9

The genetic code specifies how information in DNA is translated into the sequence of amino acids in proteins.

Question 10

What are codons?

Answer 10

Codons are groups of three nucleotides that specify the type of amino acid or stop signal required.

Question 11

What is a polypeptide?

Answer 11

A polypeptide is a chain of amino acids linked together by peptide bonds.

Question 12

What is the primary structure of a protein?

Answer 12

The primary structure refers to the specific sequence of amino acids in a polypeptide chain.

Question 13

What is the secondary structure of proteins?

Answer 13

The secondary structure refers to local folding patterns like alpha helices and beta-pleated sheets.

Question 14

What stabilizes the tertiary structure of proteins?

Answer 14

The tertiary structure is stabilized by interactions between R-groups, including hydrogen bonds, ionic bonds, disulfide bonds, and hydrophobic interactions.

Question 15

What is denaturation?

Answer 15

Denaturation is the alteration of a protein’s structure, causing it to lose function, usually permanently.

Question 16

What factors can cause denaturation?

Answer 16

pH and temperature are critical factors that can cause denaturation of proteins.

Question 17

What are hydrophobic and hydrophilic R-groups?

Answer 17

Hydrophobic R-groups are non-polar and repel water, while hydrophilic R-groups are polar or charged and attract water.

Question 18

What is the quaternary structure of proteins?

Answer 18

The quaternary structure refers to the arrangement of multiple polypeptide chains in a protein.

Question 19

What are examples of polypeptides?

Answer 19

Examples include lysozyme, alpha-neurotoxins, glucagon, and myoglobin.

Question 20

What are integral proteins?

Answer 20

Integral proteins have regions with hydrophobic amino acids, helping them to embed in membranes.

Question 21

What is an example of an integral membrane protein?

Answer 21

Rhodopsin is an example of an integral membrane protein that has hydrophobic regions.

Question 22

What determines the function of a protein?

Answer 22

The function of a protein arises from its unique structure.

Question 23

What are the different levels of protein structure?

Answer 23

Proteins can have primary, secondary, tertiary, and sometimes quaternary structures.

Question 24

What is quaternary structure?

Answer 24

The quaternary structure refers to the arrangement and interaction of two or more polypeptide chains to form a functional protein.

Question 25

What is an example of a protein with quaternary structure?

Answer 25

Haemoglobin consists of four polypeptide chains: two ɑ-chains and two β-chains.

Question 26

What is haemoglobin considered?

Answer 26

Haemoglobin is considered a conjugated protein as it is associated with a non-protein component called haem.

Question 27

What is the role of haem in haemoglobin?

Answer 27

Haem is responsible for binding to oxygen in the lungs and facilitates the transport of oxygen throughout the body.

Question 28

How are the four subunits of haemoglobin held together?

Answer 28

The subunits of haemoglobin are held together by non-covalent bonds.

Question 29

What are non-conjugated proteins?

Answer 29

Non-conjugated proteins consist only of polypeptide subunits.

Question 30

What are examples of non-conjugated proteins?

Answer 30

Collagen and insulin are examples of non-conjugated proteins.

Question 31

What are conjugated proteins?

Answer 31

Conjugated proteins have non-protein components such as metal ions or carbohydrates in addition to polypeptide subunits.

Question 32

How do non-protein components affect protein function?

Answer 32

Non-protein components can increase a protein’s diversity and functionality.

Question 33

What is the structure of globular proteins?

Answer 33

Globular proteins are usually spherical in shape with irregular folds and are soluble in water.

Question 34

What is an example of a globular protein?

Answer 34

Insulin is an example of a globular protein that consists of two polypeptide chains.

Question 35

What is the function of insulin?

Answer 35

Insulin regulates the amount of glucose in the blood.

Question 36

What is the structure of fibrous proteins?

Answer 36

Fibrous proteins have a long, narrow shape and are usually composed of repeating structures designed for strength and stability.

Question 37

What is an example of a fibrous protein?

Answer 37

Collagen is an example of a fibrous protein that forms the main component of connective tissue.

Question 38

What is the structure of collagen?

Answer 38

Collagen is made up of three polypeptide chains twisted together in a triple helix structure.

Question 39

What amino acids are abundant in collagen?

Answer 39

Collagen is rich in glycine, proline, and hydroxyproline residues.