<h2>Mitotic Cell Cycle</h2>
Explanation:
a. Cytochalasin: an inhibitor of actin microfilament
- Cytokinesis is the process by which cytoplasm is divided into two cells hence generation of two daughter cells
- In animal cells the division of cytoplasm starts with the assembly of contractile ring
- Contractile band consists of actin and myosin and catalyze cleavage furrow formation
- Cytochalasin is a drug that blocks the polymerization of actin filament
- When cytochalasin is added dividing cell fails to undergo in cytokinesis due to defective assembly of contractile band
b. Colchicine: an inhibitor of microtubule formation
- Colchicine tightly binds with free tubulin dimer and prevents its polymerization
- In this case mitotic spindle apparatus do not assemble and cells unable to do partitioning of chromosomes into two groups
- Thus cell division is arrested
c. Aphidicolin: an inhibitor of DNA Polymerase activity
- Aphidicolin is used to induce cell cycle arrest via specific inhibition of DNA Polymerase α
- It blocks the cell cycle at early synthesis(S) phase
d. Emetine: an inhibitor of ribosome activity
- It blocks the protein synthesis in eukaryotic cells by binding to small subunit(40 S) of ribosomes
- It interferes with the synthesis and activities of DNA and RNA
The correct answer is C. To store gastroliths that physically grind up food.
Explanation
The gizzards, are a special part of the digestive system of some animals such as birds, fish, and reptiles whose main function is to crush the food that the animal ingests, for this task, the gizzards contain in their interior gastroliths, a kind of polished stones, that grinds the food that the animal eats. The gizzards represent an important part for these animals because many of them do not have teeth to crush their food and feed on it. So, the correct answer is C. To store gastroliths that physically grind up food.
The behaviour of molecules in different phases of matter represents a balance between the kinetic energies of the molecules and the attractive forces between them.
All molecules are attracted to each other. At the same time, all molecules are in constant motion, and their kinetic energies increase with the temperature.
At very low temperatures, the kinetic energy of the molecules is low. The molecules cannot move fast enough to get away from the attractions of their neighbours. They are “glued” in place in a crystalline arrangement. The molecules are in the solid state.
At higher temperatures, the kinetic energy of the molecules is higher. The molecules will have enough energy to slide past their neighbours, but not enough energy to escape their attractions. The system is in the liquid state.
At very high temperatures, the kinetic energy of the molecules is so high that the molecules will be able to escape the attractions of their neighbours and move at will within the container. The system is in the gas state
