Tag: botany

• The kinetochore is the region which is present in the center of the chromosome near the centromere or the primary constriction.
• The spindle fibers which are formed from the centrioles are required to pulled the chromosome towards the poles of the dividing daughter cells.
• The spindle fiber of the centrioles are attached to the kinetochore which is a protein ring or made up of protein which forms bonds with tubulin protein of the spindle fiber, so that the chromosomes can be pulled apart towards the poles. 
• Therefore the answer option 'kinetochores' is correct.
  

Enzymes are present inside cells for catalyzing chemical reactions. While genetic material is present inside the nucleus as storage of information for all the cellular activities in the form of genes. Genetic material replicates during cell division. It can also undergo mutation during replication. 

Chromosomes are heavily coiled DNA, a DNA molecule is negatively charged and has to be therefore stained with basic dyes like Basic fuchsin, Methylene green and carmine.while safranin is used to stain cell walls of plants and bacteria (counter stain)

There is a single, long, double-stranded, linear DNA molecule in a chromosome. The DNA contains biological and genetic information. It is highly coiled and folded, however this packing varies during the cell cycle.

The nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

An inactivated X-chromosomes : female have XX chromosomes and male have XY chromosomes ,for balance Xlinked gene between male and female,one X chromosome undergo inactivated during the female embryo development this is termed as X chromosomes inactivation

(a) Basic Fuchsin-  It is a green crystalline dye. It includes staining of tissues sections.

Chromosome condensation is the dramatic re-organization of the long thin chromatin strands into the compact short chromosomes that occur in mitosis and meiosis. Here, the unfolding of proteins takes place, the DNA coils, dehydration takes place. However, there is no addition of water molecule or hydration that takes place during condensation.

Centromere provides structure to the cell. The sister chromatids are linked together at the centromere. During mitosis, spindle fibers attach to the centromere via kinetochore. Their physical role is to act as the site of assembly of the kinetochore, a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation, i.e., binding microtubules and send signals to the cell cycle machinery.

Chromosomes are the carrier of genetic information in form of DNA. The secondary constrictions are used as a point of identification of chromosomes. These are always constant in their positions and hence, can be used as markers that identify particular chromosomes. A satellite chromosome or SAT chromosome has a chromosome segment that is separated from the main body of the chromosome by such a secondary constriction.