Chapter 5- Biological Macromolecules and Lipids (Done)

Question 1

Order of abundance of macromolecules in our body

Answer 1

water > protein > lipids > nucleic acid > carbohydrate

Question 2

4 premises of macromolecules

Answer 2

1) Polymeric chain of limited kinds (< 100) of monomers
2) Formed by covalent bond through dehydration/condensation
3) Giant size
4) Immense diversity

Question 3

Anabolic reaction

Answer 3

Build up from small to big molecules
(dehydration/condensation)
-endothermic

Question 4

Catabolic reaction

Answer 4

Break down from big to small molecules

hydrolysis
- exothermic

Question 5

Carbohydrate empirical formula

Answer 5

CnH2nOn or CnHn(OH)n

Question 6

Role of carbohydrates

Answer 6

1) energy source (glycogen in animals, starch in plants)
2) molecular recognition in immune system
3) structural role (cellulose in plant cell wall, chitin in exoskeleton)

Question 7

Aldehyde sugar

Answer 7

Aldose

• can form ring structure more easily due to COH at the end
• number of carbons and ring structure align (e.g. 6-carbon sugar glucose is a hexagon shape)

Question 8

Ketone sugar

Answer 8

Ketose

-number of carbons and ring structure do not align (e.g. 6-carbon sugar fructose is a pentagon shape)

Question 9

α-glucose

Answer 9

H (top), OH (bottom) on 1st carbon

-role: energy polysaccharides (glycogen, starch)

Question 10

β-glucose

Answer 10

OH (top), H (bottom) on 1st carbon

-role: structural polysaccharides (cellulose, chitin)

Question 11

Maltose

Answer 11

α-glucose (1-4) glucose

Question 12

Sucrose

Answer 12

α-glucose (1-2) β-fructose

Question 13

Lactose

Answer 13

β-galactose (1-4) glucose

Question 14

1-6 glycosidic bond

Answer 14

branched structure

Question 15

1-4 glycosidic bond

Answer 15

linear structure

Question 16

Starch

Answer 16

• energy storing carbohydrate in plants
• α-glucose monomers
  1) amylose: 1-4 glycosidic bonds
  2) amylopectin: 1-4 and 1-6 glycosidic bonds
• both form amyloplast - organelle that stores starch
• hydrophobic - don’t affect osmolarity

Question 17

Amylose

Answer 17

• type of starch
• α-glucose monomers - energy storing carbohydrates in plants
• 1-4 glycosidic bonds
• 500-20,000 α-glucose monomers
• form amyloplast - organelle that stores starch
• hydrophobic - don’t affect osmolarity

Question 18

Amylopectin

Answer 18

• type of starch
• α-glucose monomers
• energy storing carbohydrates in plants
• 1-4 and 1-6 glycosidic bonds (1-4 > 1-6)
• form amyloplast - organelle that stores starch
• hydrophobic - don’t affect osmolarity

Question 19

Glycogen

Answer 19

• α-glucose monomers
• energy storing carbohydrates in animals
• forms 4kcal of energy per gram
• 1-4 and 1-6 glycosidic bonds (1-6 > 1-4)
• stored in liver, muscle, brain
• hydrophobic - don’t affect osmolarity

Question 20

Cellulose

Answer 20

• β-glucose monomers
• structural carbohydrates in plant cell wall
• 1-4 bonds
• cross linked by H-bond
• make microfibrils

Question 21

Chitin

Answer 21

• β-glucose monomers combined with nitrogen-containing appendages
• structural carbohydrates in exoskeletons (arthropods, cell wall of fungi)
• 1-4 bonds
• cross linked by H-bond
• make microfibrils
• strong and flexible - used in surgical threads
• digested ONLY by bacteria

Question 22

3 types of lipids

Answer 22

1) Neutral fat (triacylglycerols)
2) Phospholipids
3) Steroids

Question 23

Triacylglycerols

Answer 23

also called neutral fat (neutral pH)

• 1 glycerol + 3 fatty acids
• bonded by 3 ester bonds

Role:

1) efficient storage of excess energy (9kcal per gram)
2) thermal insulator (subcutaneous layer, stored as adipose cells)

Question 24

Lipids

Answer 24

hydrophobic

insoluble in water

Question 25

Fatty acid

Answer 25

- carboxyl group at the end (acidic properties) 1) saturated F.A - no double bond - linear - high density (solid) 2) unsaturated F.A - more than 1 double bond - has kinks (bending) - low density (plant and fish liquid oil)

Question 26

Hydrogenation

Answer 26

Breaking double bonds into single bonds (stirring oil makes butter) -converts tasteless liquid oils into tasty solid fat -also leads to trans double bond fat (unhealthy), causing atherosclerosis (lipid deposits in blood vessel)

Question 27

Phospholipid

Answer 27

1 glycerol + 2 fatty acids + 1 phosphate group (PO4 2-) (2 ester bonds) -amphipathic (both hydrophobic and -philic) ' Role: -form phospholipid bilayer (plasma membrane)

Question 28

Steroids

Answer 28

- no glycerol, fatty acid or ester bonds - four fused rings: 3 hexagonal ring + 1 pentagonal ring - precursor = cholesterol 1) sex hormones: progesterone, testosterone, estradiol 2) corticoid hormones: mineralocorticoid and glucocorticoid 3) vitamin D: absorption of Ca2+ in small intestine

Question 29

Cholesterol

Answer 29

- acts as fluidity buffer in membrane - metabolized in liver and transported through blood - HDL (more protein, healthy) and LDL (less protein, unhealthy) - precursor of other steroids

Question 30

Function of proteins

Answer 30

1) enzymes 2) structure to cells and tissues e. g. keratin, elastin, collagen 3) energy storage e. g. casein, albumin 4) immune protein - antibody

Question 31

Draw amino acid structure

Answer 31

``` carboxyl group (acidic) amino group (basic) -amphoteric properties ```

Question 32

Globular vs. fibrous shape of proteins

Answer 32

1) Globular - water soluble - charged or hydrophilic amino acids e. g. enzyme, plasma protein 2) Fibrous - water insoluble - hydrophobic amino acids e. g. keratin, collagen

Question 33

4 hierarchical level of protein structure

Answer 33

1) Primary structure -linear sequence of amino acids -only changed by mutation 2) Secondary structure -stabilized by H-bonds -forms: α-helix (coiled) - H-bond between every 4th amino acid β-pleated (folds) - H-bond between 2 antiparallel polypeptide backbone 3) Tertiary structure -chemical interaction between side chains ionic, hydrogen, covalent bonds (S-S crosslinks), hydrophobic interactions 4) Quaternary structure -more than 2 polypeptides -biological functional protein

Question 34

Nucleic acids

Answer 34

- phosphodiester bonds between phosphate group and pentose sugar on either side (5th C and 3rd C) - N-glycosidic bond between 1st C in sugar and nitrogenous base

Question 35

Pyrimidines

Answer 35

Cytosine, Thymine, Uracil single rings -one 6-membered ring

Question 36

Purines

Answer 36

Adenine, Guanine Double rings -one 6-membered ring and 5-membered ring

Question 37

A-T

Answer 37

2 hydrogen bonds

Question 38

Nucleoside

Answer 38

ribose sugar + base

Question 39

DNA double helix

Answer 39

- two strand of antiparallel DNA strands | - winds around as a right-handed coil

Question 40

G-C

Answer 40

3 hydrogen bonds

Question 41

Phosphate-phosphate bonding

Answer 41

phosphoanhydride bridge

Question 42

Sickle cell anemia

Answer 42

- caused by change in 6th amino acid of beta-1 subunit of hemoglobin (glutamate to valine) - reduces affinity and capacity for O2 transportation