Tag: membranous and non-membranous organells

• Hammerling's nucleocytoplasmic experiments state that the cytoplasm is the centre for all the metabolic activities in the cell and the nucleus is the controlling centre. 

• This experiment was conducted using Acetabularia.

• Acetabularia is a genus unicellular or single-celled green algae belonging to the family Polyphysaceae which are found in subtropical waters.

• They are gigantic in size and complex in form, therefore, used in experiments in cell biology.

• So, the correct answer is 'Acetabularia'.

• Chromatin material which remains condensed during interphase is called heterochromatin.
  
• Heterochromatin refers to the certain regions of DNA found on the chromosomes of a eukaryotic cell.
  
• The heterochromatin gets darkly stained due to the highly condensed nature of the DNA in these regions and has higher ribonucleic acid content.
• This heterochromatin is made up of high copy number tandem repeats (repetitive nucleotides).
• So, the correct answer is 'Heterochromatin'.

• The DNA present in the nucleus undergoes transcription to form the messenger RNA or mRNA.
  
• The mRNA formed within the nucleus is transported out of the nucleus and into the cytoplasm of the cell and gets attached to the ribosomes. 
• It then synthesis proteins in the cytoplasm which is required by the cell for various cellular activities.
• So, the correct answer is 'RNAs'.

• Messenger RNA is formed in the nucleus.
  
• The process by which mRNA is formed from the DNA present in the nucleus is called transcription.
• The mRNA formed within the nucleus is transported out of the nucleus and into the cytoplasm of the cell and gets attached to the ribosomes. 
• It then synthesis proteins in the cytoplasm which is required by the cell for various cellular activities.
  
• So, the correct answer is 'Nucleus'.

• The mitochondria is a double-membraned cell organelle, known as the powerhouse of the cell which is present in all eukaryotic cells.
  
• The nucleus is enclosed by the nuclear envelope which is a double-layered membrane that consists of nuclear pores to regulate the transportation of substances such as RNA into and out of the nucleus. 
• The chloroplast is also covered by a double membrane which is known as the chloroplast envelope.
• So, the correct answer is 'Mitochondria, nucleus and chloroplast'.

The nucleus contains a viscous liquid called nucleoplasm. It contains chromosomes and nuclei. It is surrounded by a nuclear membrane and it helps in the exchange of material between nucleus and cytoplasm. So, the correct answer is option B.

Algae are a very large and diverse group of eukaryotic organisms, ranging from the microscopic unicellular Chlorella and the diatoms to giant multicellular kelps, the large brown alga. Diatoms are algae (most commonly known as phytoplanktons) with secondary chloroplasts derived from an endosymbiotic red alga. Yeats is also a eukaryote belonging to the kingdom Fungi. However, the Blue-green algae or Cyanobacteria is the most primitive photosynthetic bacteria (prokaryotic- the absence of well-defined nucleus) cell which is quite small and usually unicellular, though they often grow in colonies large enough to see.
Hence, the correct answer is option A.