Biology today

(d) unbranched chain of glucose molecules linked by b, 1,

4 glycosidic bond.

9. Arachidonic acid gives rise to
   (a) terpenes (b) prostaglandins
   (c) gangliosides (d) cerebrosides.


10. A functional but non–protein amino acid is
    (a) ornithine (b) citrulline
    (c) diaminopimelic acid (d) all of these


11. Which of the following have carbohydrate as prosthetic
    group?
    (a) Glycoprotein (b) Chromoprotein
    (c) Lipoprotein (d) Nucleoprotein


12. Which factor is responsible for inhibition of enzymatic process
    during feed back?
    (a) Substrate (b) Enzymes
    (c) End product (d) Temperature


13. The major role of minor elements inside living organisms is
    to act as
    (a) co-factors of enzymes
    (b) building blocks of important amino acids
    (c) constituent of hormones
    (d) binder of cell structure.


14. Km value for enzyme is substrate concentration to produce
    (a) twice Vmax (b) half Vmax
    (c) Vmax (d) one fourth of Vmax.


15. Hexose and pentoses are the most common
    (a) monosaccharides (b) polysaccharides
    (c) disaccharides (d) oligosaccharides.


16. Sucrose is made up of
    (a) glucose - galactose (b) glucose - fructose
    (c) glucose - glucose (d) fructose - fructose.


17. Why do plants store their carbohydrate in the form of
    starch?
    (a) Starch is insoluble in water.
    (b) Starch is soluble in water.
    (c) Starch is polymer of glucose and fructose.
    (d) Starch is heteropolysaccharides.


18. Nucleic acids have multiple negative charges due to
    (a) sugars (b) phosphoryl groups
    (c) associated protein (d) purine and pyrimidines.


19. The spatial arrangement produced by the twisting and folding
    of the peptide chains in a protein is referred to as its
    (a) primary structure (b) secondary structure
    (c) tertiary structure (d) quaternary structure.


20. Substrate is
    (a) a reactant in an enzyme catalysed reaction
    (b) a reactant in any reaction
    (c) a reactant in a reaction accelerated by any catalyst
    (d) all of the above
    21. Which of the following statement is correct?
    (a) All enzymes are proteins.
    (b) Endoenzymes are enzymes present in digestive juice.
    (c) Gamma - aminobutyric acid (GABA) is an inhibitory
    neurotransmitter in brain and some other parts.
    (d) Xylose is a hexose sugar.
    22. Which of the following is a typical example of feed back
    inhibition?
    (a) Sulpha drugs and folic acid synthesiser bacteria
    (b) Allosteric inhibition of hexokinase by glucose
    6-phosphate
    (c) Reaction between succinic dehydrogenase and succinic
    acid
    (d) Cyanide and cytochrome reaction
    23. Identify the given structural formulae and select the correct
    option.

N

N

H

N

N

NH 2 O

HN

O

H

N

(^12)
1 2
(a) Adenine Uracil
(b) Guanine Thymine
(c) Adenine Guanine
(d) Cytosine Thymine

24. The correct order of chemical composition of living tissues/
    cells in term of percentage of the total cellular mass is
    (a) Nucleic acid > Proteins > H 2 O > Carbohydrates > Ions >
    Lipids
    (b) H 2 O > Proteins > Nucleic acid > Carbohydrates >
    Lipids > Ions
    (c) H 2 O > Proteins > Carbohydrates > Nucleic acid >
    Lipids > Ions
    (d) Lipids > Ions > Carbohydrates > H 2 O > Proteins >
    Nucleic acid


25. Match the items in column I with those in column II and
    choose the correct answer.
    Column I Column II
    (Biomolecules) (Examples)
    A. Carbohydrates (i) Glutelins
    B. Protein (ii) Cholesterol
    C. Nucleic acid (iii) Glycogen
    D. Lipid (iv) Adenylic acid
    (a) A-(iii); B-(i); C-(iv); D-(ii)
    (b) A-(ii); B-(iii); C-(iv); D-(i)
    (c) A-(iii); B-(iv); C-(i); D-(ii)
    (d) A-(iv); B-(i); C-(ii); D-(iii)