Question

1Plants can create new organs..................................................................

1. at seedling stage
2. at vegetative stage
3. at spring time
4. at summer time
5. all of the above

2.One of the compound below is NOT a primary product of photosynthesis....
A. Starch

B. Sucrose

C. Triose phosphate

D. Glucose

E. Phosphoglyceric acid (PGA)

3.Which chemical groups from a pair of amino acids must react to form a peptide bond?

A. the two R-groups or sidechains

B. the two carboxyls

C. the two alpha carbons
D. the amino group of one and the carboxyl of the other – think
E. the amino group of one and the alpha carbon of the other

4.Which of the following amino acids or amino acid derivatives is not made from Phenylalanine in human cells?

A. L-Tryptophan- I think
B. L-DOPA
C. Adrenaline (or epinephrine)

D. Dopamine
E. L-Tyrosine

5.The bacterial cell wall is sensitive to penicillin because penicillin.............................

1. hydrolyses the bond between NAG and NAM units in peptidoglycan.
2. is not attacked by enzymes in animal cells.
3. interacts with lipids in the bacterial cell wall.
4. binds to lipopolysaccharide in the bacterial cell wall.
5. binds to, and inactivates, a transpeptidase enzyme that catalyses the peptide crosslinks between NAG-NAM chains.

6.Protein synthesis requires which one of the following?

A. Peptide primer
B. Ribosomes
C. DNA polymerases

D. Restriction endonucleases

E. Peptidoglycan

7.What complex is a positive regulator of the Lac operon in E.coli?

A. Lac repressor
B. beta-galactosidase
C. CAP-cAMP

D. TFIID

E. tRNA

8.The endoplasmic reticulum...................................................................

A. is continuous with the outer nuclear envelope membrane.
B. can have ribosomes bound to it.
C. occurs in two forms, rough and smooth.

D. forms a membrane network throughout the cell.

E. all of the above

9.Which of the following statements about DNA synthesis in eukaryotes is correct?

1. Synthesis of linear chromosomes leads to telomere shortening in somatic cells.
2. Unwinding of DNA by helicases is facilitated by positive supercoils.
3. DNA synthesis is initiated at a single origin of replication.
4. The daughter strands are synthesised in a 3’-5’ direction.
5. Activation of an origin of replication generates a single replication fork.

   10.Which of the following statements is not true? Cellulose is

6. linear and has a high degree of hydrogen bonding
7. converted in nature to oligosaccharides and glucose by microbial cellulase enzymes
8. comprised of up to 15,000 b-1,4-linked D-glucose units
9. the main storage polysaccharide in plants
10. a structural polysaccharide

Answer 1

Question 3-

Answer-  (d) the amino group of one and the carboxyl group of other.

PEPTIDE BOND -

Question 4-

Answer - (A) L-tryptophan

All the other are made from phenylalanine in human cells.

Phenylalanine -

• it is a aromatic compound.
• It is an essential amino acids.
• Metabolism of phenylalanine occurs through tyrosine and related to many important biological compound.
• These compounds are epinephrine, Norepinephrine, dopamine, thyroid harmones and Melanin.

The below diagram show metabolism of phenylalanine-

Phenyl alanine. Phenylalanine hydroxy lace Tyroxine 1 - Tyroxin hyroxylane ( dihydroxy-phenylalanine) - DOPA carboxylake Dopamine popamine hydroxylate DOPA norepinephrine leN-methyl Epinephrine catechol-o-methyl N-methyl transferaxe tranx Jeraxe metanephrine monoamine oxidare VMA (vanilly mandelic Acid)

question 8-

answer - (e) all of the above

All the option are correct about endoplasmic reticulum.

Endoplasmic reticulum -

• electron microscopic studies of eukaryotic cells reveals that the presence of a network of reticulum of tiny tubular structure scattered in the cytoplasm that is called as Endoplasmic reticulum.
• Components of endoplasmic reticulum are cistranae, vesicles and tubules.
• Cistranae are long flattened and unbranched units arranged in stacks.
• Vesicles are oval membrane bound structure.
• Tubules are irregular, often branched tubed bounded by membrane.
• There are two form of endoplasmic reticulum- rough endoplasmic reticulum and smooth endoplasmic reticulum.
• Ribosomes are binds to rough endoplasmic reticulum.
• In smooth endoplasmic reticulum ribosomes and ribophorins are absent.
• The endoplasmic reticulum is continuous with outer nuclear envelope membrane.
• Endoplasmic reticulum forms a membrane network throughout the cell.

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