Which of the following statements is NOT true of mitosis?
1. A single nucleus gives rise to two identical daughter nuclei.
2. The daughter nuclei are genetically identical to the parent nucleus.
3. The centromeres divide at the onset of anaphase.
4. Homologous chromosomes synapse in prophase.
In oocytes, the diplotene can last for months or years, since at this stage:
1. DNA proof reading and excision repair is performed
2. The proteins for metabolism are re-formed
3. The chromosomes condense and engage in RNA synthesis
4. The cell is temporarily withdrawn from the cell cycle
Assuming they all had the same number of carbon atoms, which of the following has the most C-H bonds?
1. an unsaturated fat
2. a polyunsaturated fat
3. a polysaccharide
4. a saturated fat
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