An alpha helix is a:
1. primary structure of a protein
2. secondary structure of a protein
3. tertiary structure of a protein
4. quaternary structure of a protein

Why is cellulose so difficult for most animals to digest?
1. they don’t have the proper enzyme to break the bonds between subunits
2. cellulose is made up of chitin, which is indigestible
3. the bonds holding cellulose subunits together are extremely strong, stronger than in any other macromolecule
4. there are many hydrogen bonds holding the subunits together

Catalytic efficiency of two different enzymes is compared by their :
1. Product

2. Molecular size

3. Km value

4. pH optimum value

A ribbonlike structure consisting of three protein components and extending across the region of synapsed chromosomes during the prophase of meiosis, is called:
1. Phragmoplast
2. Phragmosome
3. Synaptonemal complex
4. Recombination nodule

Which statement regarding enzyme inhibition is correct?
1. Competitive inhibition occurs when a substrate competes with enzyme for binding to inhibitor protein
2. Competitive inhibition occurs when a substrate and the inhibitor compete for active site on the enzyme
3. Non-competitive inhibition of an enzyme can be overcome by adding a large amount of substrate
4. Non-competitive inhibitors often bind to the enzyme irreversibly

The structure that helps in cell wall formation, DNA replication and respiration in bacteria is :
1. Mesosome

2. Chromatophores

3. Pilus

4. Nucleoid

Cell membrane carbohydrates participate in
1. transporting substances between two protein layers
2. cell-to-cell recognition
3. attaching the membrane to cytoskeleton
4. cell adhesions

The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over is called:
1. Centromere

2. Centrosome

3. Chiasmata

4. Tetrad

Organisms prefer sexual mode of reproduction in adverse conditions because:
1. It leads to a rapid proliferation of numbers
2. It requires two individuals that can support the progeny
3. It is less energy consuming than the asexual mode of reproduction
4. It provides protection and increases variations that may help progeny to survive

A molecule of ATP is structurally most similar to :
1. RNA nucleotide

2. DNA nucleotide

3. amino acid

4. fatty acid