Biological Macromolecules.

1. The ingredients for life

2. Very large molecules commonly created by polymerization
of smaller subunits (monomers)
Monomers: individual constituent molecules of
macromolecules.

3. Carbohydrates
Proteins Conventional
Nucleic acids
Lipids

4. Macromolecules form supramolecular assemblies
(Ex. membrane) which in turn organize into
organelles, cells, tissues, organs & finally the whole
organisms.

5. “Hydrates of Carbon”
Polyhydroxyaldehyde/ketone or compounds which produce
them on hydrolysis
Held together by glycosidic bonds
Primarily composed of C, H and O.
Sugars are carbs that are soluble in water, & sweet to
taste
Empirical formula: CnH2nOn

6. Based on the number of subunits present:
Monosaccharides:
i. Aldoses based on functional group
ii. Ketoses
a) Triose, Tetrose, Pentose, etc. based on carbon atoms present.
Oligosaccharides:
• Disaccharide, trisaccharide, etc. based on monosaccharides
present.
Polysaccharides:
i. Homopolysaccharides Ex. glucans, fructosans, starch etc.
ii. Heteropolysaccharides Ex. Hyaluronic acid, etc.

7. It is a fast fuel for the body; 4 cal/g
Serve as precursors for fats, a.a. etc.
To store energy. Ex. Glycogen, etc.
 Structural component:
• Cellulose in plants
• Exoskeleton of some insects
• Cell wall of microorganisms
Cell growth, adhesion & fertilisaion

8. Organic substance relatively insoluble in water,
soluble in org. solvents, related to fatty acids &
utilized by the living cells.
Lipids are not polymers
Mostly small mol.
Heterogeneous group of compounds (fats, oils, steroids,
waxes,etc.)
Animal fat is solid, while that of plants is liquid.
 C, H, O, N, S, P (O is vey less)
2 types of monomers: fatty acids & long chain alcohols

9. A. Simple lipids: esters of fatty acids with alcohols
a) Fats & oils (triacylglycerols)
b) Waxes
B. Complex lipids: in addition have groups such as
phosphate, nitrogen base, carbs, prot., etc.
a) Phospholipids: Based on alcohol pr. further divided as:
i. Glycolipids: Ex. Lecithin, cephalin, etc.
ii. Sphingophospholipids: Ex. spingomyelin, etc.
b) Glycolipids: alcohol is sphingosine; Ex. cerebrosides,
gangliosides, etc.
c) Lipoprotein
d) Others: sulfolipids, aminolipids & lipopolysaccharides

10. C. Derived lipids: Ex: glycerol, f.a., steroid
hormones, fat soluble vitamins, etc.
D. Miscellaneous lipids: Ex. Carotenoids, terpenes,
squalene, hydrocarbons such as pentacosane, etc.

11. Triacylglycerols are concentrated fuel reserve of the body
Phospholipids & cholesterol are constituents of membrane
str. & membrane permeability
Serve as a source of fat soluble vitamins
Steroid hormones & prostaglandins are cellular metabolic
regulators.
Protect internal organs, serve as insulating materials, and
give shape & smooth appearance to the body.

12. Carboxylic acids with hydrocarbon side chain
Mostly occurs in esterified forms as major
constituents of lipids.
F.a. of animal origin are much simpler
Simplest form of lipids

13. Even and odd carbon fatty acids:
• Most natural f.a. are even i.e. 14C – 20C
• Reason: biosynthesis of f.a. mainly occurs with
sequential addition of 2C units.
• Most common: palmitic acid (16C) & stearic acid
(18C)
• Among odd chain, propionic acid (3C) & valeric acid
(5C) are well known.

14. Saturated and unsaturated f.a.
• Saturated f.a. do not contain double bonds, while
unsaturated f.a. contain one or more double bonds.
• f.a. with one double bond are monounsaturated,
while 2 or more are polyunsaturated f.a. (PUFA)

15. Greek: ‘proterion’ – holding first place
 Berzelius => utmost important to life (1830)
Mulder => high mol. wt. nitrogen rich org.
substance pr. in animals and plants
 monomer: amino acids; bond: peptide
They show N & C-terminal
Most abundant org. mol.
Constitute 50% cellular dry wt.
Fundamental basis of str. & function of life

16. 300 a.a. occur in nature, only 20 a.a. are std. & are
reapeatedly found in str. of prot.
This is due to universal nature of genetic code
(controlled by DNA)
Group of org. compounds containing 2 functional
groups:
i. Amino group – basic (NH2)
ii. Carboxyl group – acidic (COOH)

17. A.a. is α – a.a. when both carboxyl as well as amino group
is attached to same carbon.
R – side chain, which varies in all 20 a.a.
A.a. mostly exist in ionized form

18. If a carbon is attached to 4 diff. groups, it is
asymmetric & therefore exhibits optical isomerism
If NH2 is on right hand side it is dextro, if it is on
left hand side it is laevo

19. Prot. Are polymers of L - α – a.a.
1. Pri. Str.: linear seq of a.a.; backbone; polypeptide
2. Sec. str.: spatial arrangement of prot. By twisting of
polypeptide chain
i. α – helix
ii. β- pleated sheet
3. Tertiary str.: 3D str. of a functional prot.
4. Quaternary str.: 2 or more polypeptide chains

21. Functional classification:
1. Structural: keratin (hair) & collagen (bone)
2. Enzymes: Hexokinase, pepsin, etc.
3. Transport: hemoglobin, serum, albumin.
4. Hormonal: insulin, GH.
5. Contractile: actin, myosin.
6. Storage: ovalbumin, etc.
7. Genetic: nucleoproteins
8. Defense: snake venoms, Igs.
9. Receptor: hormones, viruses.

22. Classification based on chemical nature &
solubility:
1. Simple: a.a.
2. Conjugated: a.a. + prosthetic group
3. Derived: degraded products

23. a) Globular proteins: spherical/oval; soluble in H2O &
other solvents and digestible.
i. Albumins: H2O & dil. salt sol. and coagulated
ii. Globulins: neutral & dil. salt sol.
iii. Glutelins: dil. acids & alkalis; mostly found in plants
iv. Prolamines: 70% alcohol
v. Histones: H2O & dil. acids; strongly basic
vi. Globins: not basic; NH4OH
vii. Protamines: NH4OH; strongly basic; in association with nucleic
acids Ex: sperm prot.
viii. Lectins: carb. binding prot.; interaction between cell & prot.

24. b) Fibrous proteins: fiber like prot., insoluble in water,
& resistant to digestion. Albuminoid or
scleroprotein (predominant)
i. Collagens:
• Conn. tissue prot. lacking tryptophan
• On boiling with H2O/dil. acid, yield gelatin (soluble & digestible)
ii. Elastin: elastic tissues (tendons & arteries)
iii. Keratin: pr. In exoskeletal str. (horns, hairs, etc.)

25. a) Nucleoproteins: nucleic acid; ex. nucleohistones
b) Glycoproteins: carb. (>4% of prot); ex. mucin(saliva)
c) Lipoproteins: lipids; ex. Serum lipoprot.
d) Phosphoproteins: phosphoric acid; ex. caesin
e) Chromoproteins: coloured; ex. haemoglobin
f) Metalloproteins: metal ions (Fe, Cu,etc.); ex.
Ceruloplasmin (Cu), etc.

26. a. Primary derived protein: first product of hydrolysis
i. Coagulated: denatured prot. (heat, acids, alkalies, etc.); ex.
coaguated albumin (egg white)
ii. Proteans: earliest product (enzymes, dil. acids,etc.); insoluble in
water; ex. fibrin
iii. Metaproteins: second stage products (slightly stronger acids &
alkalies); acid & alkali metaprot.
b. Secondary derived protein: progressive hydrolytic products of
hydrolysis
i. Proteoses
ii. Peptones
iii. Polypeptides
iv. Peptides

27. Nucleic acids are macromol. composed of many
monomers, called nucleotides.
Discovered by Johann Friedrich Meischer (1869)
Two types: DNA & RNA
DNA contains genetic material (Avery, Macleod &
MacCarty)

28. Composed of a nitrogen base, pentose sugar &
phosphate
Functions:
1. Str. components of some coenzymes of B – complex vit. (e.g. FAD,
NAD+)
2. Energy reactions of the cell
3. Control of metabolic reaction
Nucleoside: nitrogen + sugar
base

29.  Aromatic heterocyclic compounds
Purines are numbered anti-clock wise, while pyrimidines
are numbered clockwise
Purines: adenine (A) & guanine (G)
Pyrimidine: thymine (T), cytosine (C), Uracil (U)

30. Five carbon monosaccharides (pentose)
RNA => D-ribose
DNA => D-deoxyribose

31. Polymers of deoxyribosenucleotides
Monomeric units: dAMP, dGMP, etc.
Chargaff’s rule: molar equivalence between the
purines and pyrimidines in DNA
Watson and Crick model (1953) [B-DNA]
1. Right handed double helix
2. Width = 2nm
3. Each turn = 3.4nm, with 10 pairs, therefore distance
between each pair 0.34nm
4. Deoxyribose phosphate backbone (3’-5’ phosphodiester
bond); hydrophilic; N-bases are stacked inside & are
hydrophobic

32. Both the strands are complementary to
each other due to base pairing.
Two strands are held together by
hydrogen bonds. G-C bond is 50%
stronger than A-T
Genetic info resides on one of 2 strands,
which is known as sense or template
strand.
Major and minor groves are pr.

33. Variations of conformation of nucleotides
6 diff. forms: A, B, C, D, E, & Z. [B, A & Z are imp]
B-form => Watson & Crick; most predominant
under normal physiological conditions
A- form=> right handed helix; 11bp per turn;
tilting of bps by 20o away from central axis
Z- form => left handed helix; 12bps per turn;
strands move in a zig-zag fashion
Transition between helical forms significant in
regulating gene expression

35. Chemical basis of hereditary (genetic reserve)
Maintains identity of species
DNA controls every aspect of cellular function
DNA is organized into genes
Genes => fundamental units of genetic info
Central dogma

36. RNA is a polymer of ribonucleotides held together by
3’-5’ phosphodiester bridges.
Pentose sugar is ribose
RNA contains the pyrimidine uracil instead of thymine
It is usually a single stranded polynucleotide
Chargaff’s rule is not obeyed
Orcinol can stain RNA due to pr. of ribose
Alkali can hydrolyse RNA to 2’-3’ cyclic diesters. Due
to OH at 2’ position.

37. 1. Messenger RNA
2. Transfer RNA
3. Ribosomal RNA

38. Biochemistry by U. Satyanarayana & U.
Chakrapani
11th standard biology Maharashtra State board
Crash course (youtube channel)