Biomolecules; Proteins

Question 1

Amino acid

Answer 1

Sub unit of proteins joined together by peptide bonds. Amino acid sequence of a protein determines its conformation

Question 2

Primary Structure

Answer 2

the linear sequence of amino acids joined by peptide bonds. A single polypeptide. The sequence of amino acids determines the final conformation of the protein.
Simple beads on a string form

Question 3

Function group

Answer 3

Amino group (NH3)-CH- Carboxyl group

Question 4

Polar amino acids

Answer 4

Asparagine, Glutamine, Tyrosine, Serine, Threonine contain a carboxyl group.

Question 5

Non polar amino acids

Answer 5

Glycine, Alanine, Valine, Leucine, Isoleucine, Tryptophan, Proline, Cysteine, Methionine, Phenylalanine

Question 6

Electrically charged amino acids

Answer 6

Aspartic acid, Glutamic acid, Arginine, Lysine, Histidine

Question 7

Secondary Structure

Answer 7

how the linear sequence folds in on itself results from hydrogen bonding between amino acids

Question 8

Alpha Helix

Answer 8

Uniform helical coil sheet
Structure is maintained by the hydrogen bond between backbone of the amino and the following turns of the coil
Oxygen part is of carboxyl group of one amino acid the hydrogen is part of the amino group of the fourth amino acid down the chain.
3.6 AA in each complete turn of the helix
Basic structural unit of some fibrous proteins that makeup wool, hair, skin and nails
Elasticity due to helical shape and hydrogen bonding

Question 9

Beta sheet

Answer 9

zigzag where the beta pleats are formed through hydrogen bonding with a polypeptide folded back on itself
Half of the R group projects above the sheet and the other half project below it
Strong and flexible but not elastic good for support
Fibroin the protein in silk

Question 10

Tertiary Structure

Answer 10

The individual amino acids of the polypeptide join to each other by bonds between their R groups. These R groups also have different chemical bonding - there are R groups that form covalent bonds, some that form ionic bonds, and still others that form hydrogen bonds and disulphide bonds.

Question 11

Quaternary Structure

Answer 11

This level only occurs when there is more than one polypeptide in a protein.The individual polypeptides in the quaternary structures are joined to each other by bonds between the R- groups, just like the tertiary level.
Structure More than 1 Polypeptide/ Subunit
Made of different polypeptide units

Question 12

Molecular Chaperones

Answer 12

Proteins assisted in folding by the molecular chaperones

Hsp60 Hsp70 Hsp90 are the three main class (Heat Shock

Question 13

Hsp70

Answer 13

recognizes exposed, unfolded regions of new protein chains - especially hydrophobic regions it binds to these regions and protects them until productive folding reactions occur

Question 14

Hsp60

Answer 14

acts on fully synthesized proteins isolates the protein and provides better condition for folding through binding of ATP.

Question 15

What determines the biological role of protein

Answer 15

Entire protein structure
Different region of a single protein can have different function
Many proteins are modular 2 or more globular regions - domains connected by less compact regions of polypeptide chain
In turn each domain can have different functions e,g. one domain could act as an enzyme while the other docks the membrane

Question 16

Enzyme

Answer 16

Speed up chemical reactions because they are a biological catalyst
All chemical reactions in living organisms require an enzyme to work
Building molecules- synthesise enzyme
Breaking down molecule - digestive enzymes
Each enzymes needs to be specific therefore has a corresponding name
E.g sucrose- sucrase lipids - lipase
Not changed by reaction
Reusable
Very little needed for the reaction

Question 17

Classes of proteins

Answer 17

Enzyme, structural proteins, storage proteins, transport proteins, regulatory proteins, motile proteins, protective proteins

Question 18

Enzyme

Answer 18

catalyse specific chemical reactions

Question 19

Structural proteins

Answer 19

strengthen and protect cells and tissues e.g. collagen

Question 20

Storage proteins

Answer 20

store nutrients e.g. ovalbumin

Question 21

Transport proteins

Answer 21

move substances between cells and across cell membranes e.g. haemoglobin

Question 22

Regulatory proteins

Answer 22

Control the activities of proteins, genes, cells and tissues e.g. protein kinases

Question 23

Motile proteins

Answer 23

Generate movement in cells and tissues e.g. myosin; movement of intracellular structures

Question 24

Protective proteins

Answer 24

efend against foreign invaders e.g. antibodies bind to specific foreign proteins