fbpx

Classic Layout

Chromosomal Aberration: Structural and Numerical

What is Chromosomal Aberration? Any type of change in the structure and number of chromosomes due to certain irregularities during cell division is known as chromosomal aberration. Broadly such aberrations are divided into two major groups. Structural aberration Numerical aberration Again, structural aberrations are of 4 types. Such as: Deletion …

Read More »

Solenoid Model: The Second Level of Packing

In the nucleosome model of chromosome, we have discussed about the fundamental organizational unit of chromosome termed as nucleosome. That article gave us a simplistic idea about how the repeated nucleosomes are arranged. The figure in the right hand side clarifies that the nucleosome model provides us with the insight …

Read More »

Nucleosome Model of Chromosomes

Let’s kick off this discussion with a simple calculation about the length of DNA in a single diploid human cell. We know according to Watson and Crick model of double helix DNA, each two base pairs has a distance of 3.4 A. There are approximately 6.4 billion base pairs (bp) …

Read More »

The Microsporangium & the Male Gametophyte

Microsporangium: The sporangium that is connected with the production of microspores (pollen grains) eventually development of male gametophyte is known as microsporangium. Microsporangia are produced on stamen where each stamen has a bilobed anther (each lobe has two microsporangia), connective and anther filament. When anther produces four elongated microsporangia, the …

Read More »

Programmed Cell Death

The acronym of PCD is Programmed Cell Death. The death of a cell in any form, mediated by an intracellular program is called programmed cell death. PCD is carried out in a biological process, which gives advantage during an organism’s life cycle. History The concept of PCD was used by …

Read More »

ভাইরাস অন্য কোন জীবিত কোষ ছাড়া বংশবৃদ্ধি করতে পারেনা। কিন্তু কেন?

ভাইরাস কোন বাহকের দেহ ছাড়া বাঁচতে পারলেও মৃতের মত আচরণ করে এবং বংশবৃদ্ধি করতে পারেনা। এই তথ্যটা আমরা যখন থেকে ভাইরাসের বৈশিষ্ট্য পড়ে আসছি সেদিন থেকেই জানি। সবাই জানি। কিন্তু কেন এমন হয়? আচ্ছা T2 bacteriophage ভাইরাসের নাম তো শুনেছি সবাই। এই ভাইরাস বংশবৃদ্ধির জন্য ব্যাকটেরিয়ার দেহ বেছে নেয় কেন? …

Read More »
0
Would love your thoughts, please comment.x
()
x