BIOCHEM 2 - PROTEIN FUNCTION

Question 1

Most abundant protein in animals

Answer 1

collagen

Question 2

SOLUBILITY OF COLLAGEN IN WATER

Answer 2

Water-insoluble fibers

Question 3

Location of collagen in the cell

Answer 3

extracellular

Question 4

Has great tensile strength (due to aldol crosslinks)

Answer 4

collagen

Question 5

contributes to great tensile strength of collagen

Answer 5

aldol crosslinks

Question 6

major role of collagen

Answer 6

stress-bearing component of connective tissues

Question 7

location of collagen in body

Answer 7

Cartilage, bones, tendons, ligaments & skin

Question 8

Primary Structure of collagen

Answer 8

• (-X–Y–G-)-
  
  • X–Pro/Hyp; Y–any aa
  • each chain is about 800 aa residues long

Question 9

Secondary Structure of collagen

Answer 9

• Left-handed α-helix
  
  • 3.3 aa/turn
  • Pitch: 10 Å

Question 10

Tertiary structure

Answer 10

• 3 chains are parallel & wind each other in a right-handed manner to form a triple-helical structure
  
  • H-bond involving Hyp and Hyl residues
  • intramolecular and intermolecular aldol covalent crosslinks

Question 11

Structural proteins

Found predominantly in walls of arteries, lungs, intestines and skins

Answer 11

elastin

Question 12

“slide & stretch” over one another to maintain structural integrity and provide recoil

Answer 12

Elastin

Question 13

MW of elastin

Answer 13

MW = 72 kDa;

Question 14

hydrophobicity of elastin

Answer 14

highly hydrophobic

Question 15

Connective tissue protein; has elastic properties

Answer 15

elastin

Question 16

Consists predominantly of nonpolar aa residues, 1/3 G, 1/3 V + A, rich in P

Answer 16

elastin

Question 17

protein having Random coil conformation

Answer 17

elastin

Question 18

protein having Intramolecular and intermolecular desmosine crosslinks

Answer 18

elastin

Question 19

is formed from threeallysyl side chainsplus one unalteredlysl side chain from the same or neighbouringpolypeptide.

Answer 19

Adesmosinecross-link

Question 20

responsible for the rubber properties of elastin

Answer 20

Adesmosinecross-link

Question 21

Hemeproteins; conjugated proteins

Answer 21

myoglobin

hemoglobin

Question 22

Responsible to the red color of the blood
Prosthetic group (non-protein part)
Porphyrin ring
Centrally bound Fe+2

Answer 22

heme

Question 23

Monomer

Contains a heme

Answer 23

myoglobin

Question 24

primary structure of myoglobin

Answer 24

1 Structure: 153 aa

Question 25

secondary structure of myoglobin

Answer 25

2 Structure: Helical

Question 26

tertiary structure of myoglobin

Answer 26

3 Structure: Globular

Question 27

Found in skeletal and cardiac muscle

Answer 27

myoglobin

Question 28

Folded globin chain forms a crevice which encloses a heme group

Answer 28

myoglobin

Question 29

Heme group of myoglobin is inside the protein since it’s

Answer 29

hydrophobic

Question 30

Roughly spherical molecule found in red blood cells

Answer 30

hemoglobin

Question 31

Transport O2 from lungs to every tissue in the body

Answer 31

hemoglobin

Question 32

Each globin chain of hemoglobin binds a heme group through the______ of a ____________

Answer 32

imidazole ring of a distal histidine residue

Question 33

Globin of hemoglobin binds the heme at the (site)

Answer 33

5th site – “distal histidine site”

Question 34

Tetramer: α2β2 | Each subunit contains one heme

Answer 34

hemoglobin

Question 35

each subunit of hemoglobin contains how many heme

Answer 35

1 | total of 4 heme

Question 36

how many heme does hemoglobin have

Answer 36

4

Question 37

primary structure of hgb

Answer 37

``` α = 141 aa β = 146 aa ```

Question 38

secondary structure of hgb

Answer 38

helical

Question 39

tertiary structure of hgb

Answer 39

globular

Question 40

quaternary structure of hgb

Answer 40

4 folded chain in tetrahedral arrangement

Question 41

O2 and CO2 have different binding sites

Answer 41

Oxyhemoglobin Carbaminohemoglobin Carboxyhemoglobin Methemoglobin

Question 42

Decrease in pH causes | 2

Answer 42

release of O2 and converts oxyhemoglobin to deoxyhemoglobin.

Question 43

Genetically altered hemoglobin

Answer 43

sickle cell anemia

Question 44

in sickle cell anemia which aa is defective

Answer 44

6th aa of β subunit | Glu Val

Question 45

Regulatory proteins | Endocrine hormones

Answer 45

INSULIN & GLUCAGON

Question 46

responsible for carbohydrate homeostasis

Answer 46

INSULIN & GLUCAGON

Question 47

Produced from β-cells of Islets of Langerhans

Answer 47

INSULIN

Question 48

regulatory protein with 2 polypeptide chain | (51 aa residues)

Answer 48

INSULIN

Question 49

protein having | Intermolecular and intramolecular disulfide linkage

Answer 49

INSULIN

Question 50

Hypoglycemic hormone

Answer 50

INSULIN

Question 51

linkages found in insulin

Answer 51

Intermolecular and intramolecular disulfide linkage

Question 52

Produced from α-cells of Islets of Langerhans

Answer 52

glucagon

Question 53

Single polypeptide chain | (29 aa residues)

Answer 53

glucagon

Question 54

Involved in increasing the blood levels of glucose

Answer 54

glucagon

Question 55

how many aa residues are in a single polypeptide chain of glucagon

Answer 55

29 AA residues

Question 56

how many aa residues are in insulin

Answer 56

51 AA residues

Question 57

DISEASES RELATED TO INSULIN

Answer 57

Hypoglycemia Hyperglycemia Diabetes mellitus

Question 58

Defense proteins | Also known as antibodies

Answer 58

immunoglobulins

Question 59

secrete antibodies

Answer 59

B lymphocyte:

Question 60

is a protein that is produced by the body in response to an “invading” (foreign) substance.

Answer 60

An antibody

Question 61

- are produced as part of the body’s immune response to protect itself.

Answer 61

An antibody

Question 62

is the substance that the body is trying to “fight off” (eliminate or reduce) by mounting an immune response

Answer 62

antigen

Question 63

Y-shaped molecule | Tetramer

Answer 63

immunoglobulins

Question 64

linkages found in immunoglobulins

Answer 64

Interchain and Intrachain disulfide linkages

Question 65

chains of immunoglobulins

Answer 65

Light Chain | Heavy Chain

Question 66

regions of immunoglobulins

Answer 66

Constant Region | Variable Region

Question 67

Antibody that is commonly found in human secretions like tears, mucous and saliva

Answer 67

IgA

Question 68

Cell attached antibody which function is still under study

Answer 68

IgD

Question 69

Antibody responsible for allergic reactions

Answer 69

IgE

Question 70

Most dominant antibody in humans. This antibody is responsible for secondary immune response

Answer 70

IgG

Question 71

The antibody which serves as protection for primary infections

Answer 71

IgM

Question 72

DISEASES related to immunoglobulins

Answer 72

Autoimmune Diseases Inherited Immunodeficiency HIV

Question 73

In what oxidation state must the iron atom be for the heme to bind oxygen

Answer 73

Fe (II), +2

Question 74

Which type of hemoglobin binds more tightly to oxygen, fetal or adult?

Answer 74

Fetal

Question 75

is hemoglobin an allosteric enzyme

Answer 75

yes

Question 76

the affinity of fetal hemoglobin for oxygen is higher than

Answer 76

that of maternal hemoglobin