1.5 Proteins

Question 1

How do proteins generally form, starting from amino acids? There are 3 steps after AA sequence

Answer 1

Amino acid to dipeptide to polypeptide to protein

Question 2

What is a protein?

Answer 2

• molecule consisting of polypeptides (polymers of amino acids) folded into a 3D shape

Question 3

Which elements are proteins comprised of? (2 pts)

Answer 3

• CHNOPS

- but sulfur is found potentially in the side chain (R group)

Question 4

What determines the function of a protein?

Answer 4

• shape

Question 5

What are amino acids? (2)

Answer 5

• molecules that have an amino group and a carboxyl group

- 20 different amino acids

Question 6

What is the general structure of a protein? Refer to page 61 if needed for examples of others

Answer 6

• amino group (NH2) bonded to Centrail carbon
• central carbon bonded to H, R group, Amino group, and carboxyl (COOH) group
• butterfly molecule

Question 7

How are amino acids unique from each other?

Answer 7

• they all have a unique side chain (R-group)

- based on side chains physical and chemical properties

Question 8

How can side chains be groups as?

Answer 8

• Polar (hydrophilic)
• non polar (hydrophobic
• charge or ionic (hydrophilic)

Question 9

What determines shape AND function of a protein?

Answer 9

• Side chain interaction

Question 10

What are peptide bonds?

Answer 10

• bonds between amino acids

Question 11

How is a peptide bond formed between two amino acids?

Answer 11

• the carboxyl group of one AA must be positioned next to the amino group of another

Question 12

How are polypeptides unique from each other? (3)

Answer 12

• unique sequence of AA and directionality
• each end is chemically unique as one end is a free amino group (N-terminus) and the other is a free carboxyl group (C-terminus)

Question 13

What determines the 3D Shape of protein and how?

Answer 13

• sequence of amino acids

- a polypeptide twists and folds due to R group interaction to form a protein

Question 14

In terms of anabolic and catabolic, what is dehydration synthesis and hydrolysis?

Answer 14

• dehydration synthesis is anabolic

- hydrolysis is catabolic

Question 15

How do proteins function as antibodies?

Answer 15

• helps protect the body from disease

Question 16

How do proteins function as an enzyme?

Answer 16

• carry out chemical reactions or assist in creating new molecules (or break molecules)

Question 17

How do proteins function as a messenger?

Answer 17

• transmits signals (ie. hormones)

- ex. Insulin, proteins end in -in

Question 18

How do proteins function as structural components?

Answer 18

• provide structure and support

Question 19

How do proteins function for transport and storage?

Answer 19

• bind to and carry small atoms (like hemoglobin) and molecules through the body

Question 20

What is the primary level of protein structure? (3)

Answer 20

• linear change of AA
• determined via genes
• dictates secondary and tertiary forms

Question 21

What is the secondary level of protein structure?

Answer 21

• coils and folds due to hydrogen bonding within polypeptide backbones

Question 22

• what is the tertiary structure of proteins? (3)

Answer 22

• 3D folding due to interactions between the side chains of the AAs
• reinforced by hydrophobic interactions and disulfide bridges of the side chains
• the covalent bond formed

Question 23

What is the quaternary structure of a protein? (2)

Answer 23

• association of two or more polypeptides

- found only in some proteins

Question 24

What do all levels of proteins determine?

Answer 24

• FUNCTION!!! remember that shape determines function