centromere is the major constituent of a chromosome.
centromere is the major constituent of a chromosome.
what is the major constituent of a chromosome?
centromere
the polycentric chromosome is when more than 1 centromere are present in a chromosome. polycentric chromosome is produced by chromosomal aberrations like deletion, duplication and trans location. it is specifically deadly for cell because at the time of anaphase the polycentric chromosome fails to move to the two opposite poles of spindle fiber; as a result the chromosome is fragmented, which causes the death of the cell. in some algae polycentric chromosome are found normally. in those organism the chromosome instead of remaining at specific position remain dispersed throughout the chromosome. this kind of chromosome is also known as holocentric chromosome.
polycentric chromosome
dioxygen is used in cellular respiration and many major classes of organic molecules in living organisms contain oxygen, such as proteins, nucleic acids, carbohydrates, and fats, as do the major constituent inorganic compounds of animal shells, teeth, and bone. most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. oxygen is continuously replenished in earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. another form (allotrope) of oxygen, ozone (), strongly absorbs ultraviolet uvb radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. however, ozone present at the surface is a byproduct of smog and thus a pollutant.
oxygen