Table of Contents
What is Chromonema and Chromomere?
Chromomeres contain genes and sometimes clusters of genes within their structure. Aggregates of chromomeres are known as chromonemata. Cohesive proteins SMC3 and hRAD21(plays a role in sister chromatid cohesion) are found within chromomeres at high concentrations, and maintain the proper structure of chromomeres.
Is Chromonema and Chromonemata same?
chromonema is the coiled central thread of a chromatid along which chromomere lies. chromonemata is the coiled filament in which the genes are located, which extends the entire length of a chromosome.
Is Chromonemata and chromatid same?
Under electron microscope (magnification of about 2 lacs), chromosomes at metaphase stage are visible clearly as a double structure consisting of two chromonemata which become inter-wined with each other, has its own set of chromomeres and is known as chromatid. Thus, there are 2 chromatids in a chromosome.
What is centromere and chromomere?
The key difference between centromere and chromomere is that centromere is a constricted region that joins sister chromatids together in a chromosome while chromomere is a linearly arranged bead-like structure present along the length of the chromosome.
What is heterochromatin and euchromatin?
Heterochromatin is defined as the area of the chromosome which is darkly stained with a DNA specific stain and is in comparatively condensed form. Euchromatin is defined as the area of the chromosome which is rich in gene concentration and actively participates in the transcription process.
Which is made the chromonema?
Chromonema is a spirally coiled core of the chromosomes on which the genes are located. During the prophase of mitotic division, the chromosome material appears as thin filaments. These thin filaments are known as chromonema. These chromonema represent the chromatids in the early stages of condensation.
What is chromatin vs chromatid?
As mentioned above, chromatin is composed of DNA and histones that are packaged into thin, stringy fibers. The chromatin undergoes further condensation to form the chromosome. A chromatid is either of the two strands of a replicated chromosome. Chromatids connected by a centromere are called sister chromatids.
What is Chromomere in biology?
: one of the small bead-shaped and heavily staining masses of coiled chromatin that are linearly arranged along the chromosome.
What is a centromere Class 11?
Centromere is a constriction present on the chromosomes where the chromatids are held together. Chromosomes are divided into four types based on the position of the centromere.
What is methylation and acetylation?
Methylation and acetylation of DNA and histone proteins are the chemical basis for epigenetics. From bacteria to humans, methylation and acetylation are sensitive to cellular metabolic status. Methylation and acetylation likely initially evolved to tailor protein activities in microbes to their metabolic milieu.
Who invented Chromonema?
De Robertis was a zoologist who discovered the tissue differentiation in zygote when zygote transforms into an adult. This term was first used by Vijdovsky in 1912. Since now we are well aware of the chromonema therefore the correct answer to the question is option D. i.e Vijdovsky.