Answer:
c. Tubulin
Explanation:
Tubulin protein is polymerized to form the cylindrical structures of microtubules. Microtubules form the spindle apparatus during cell division. The spindle microtubules become attached to the kinetochores of chromosomes and mediate the alignment of chromosomes at the equator of cells during metaphase. The shortening of spindle microtubules is responsible for the movement of sister chromatids during anaphase. The same event also moves the homologous chromosomes during anaphase-I.
Any failure in the formation of the spindle apparatus would not allow the proper separation of chromosomes. Therefore, the cell with abnormal chromosome separation might have a faulty or no tubulin.
Answer:
Outer Core of Earth
Explanation:
The outer layer of core of earth consists of iron as a major constituent. Due to internal high temperature and low pressure (as compared to the inner core) , the iron in this layer exists as liquid iron. Since the earth is rotating continuously on its axis, the liquid iron is also rotating thereby producing magnetic field. Due to magnetic field , this sphere of earth is known as magnetosphere.
Answer:
C. Chromosomes
Explanation:
During fertilization in sexual reproduction, the nucleus of the male sperm cell fuses with the nucleus of the female egg cell. Chromosomes from the sperm combine with chromosomes from the egg to give the new cell a unique genetic make-up.
Answer/Explanation:
The replication of DNA is semi-conservative, as each new molecule of DNA inherits one of the parental strands each, and one new strand each. DNA is replicated using the enzyme DNA polymerase, which synthesises a new strand by adding nucleotides in a sequence through complementary base pairing with the template strand. This occurs before the mitosis stage of the cell cycle, where the cell divides. Before this cell division happens, the cell has to pass certain checkpoints controlled by enzymes which ensure environmental conditions are optimal for dividing, and that the new DNA is free from errors.