Which of the following organelles contain DNA?
(i) Mitochondria (ii) Chloroplasts (iii) Golgi bodies (iv) Ribosomes
(i) and (ii)
(ii) and (iii)
(i) only
(iv) only
Assertion: Mitochondria and chloroplasts have their own genome.
Reason: Endoplasmic reticulum and Golgi body are the cell organelles which have their own DNA.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false.
If both assertion and reason are false.
What are Singer and Nicolson known for?
One-gene-one-enzyme hypothesis
Plasma membrane modifications
Fluid-mosaic model of plasma membrane
Structure of DNA
In a 50 gm living tissue, what would be the amount of water
15- 25 gm
25 - 30 gm
35- 45 gm
70- 90 gm
The outermost limiting layer of mycoplasma is made up of
cell wall
cell membrane
mucilaginous sheath
slime layer
Specific proteins responsible for the flow of materials and information into the cell are called
membrane receptors
carrier proteins
integral proteins
none of these
Assertion : Nucleus is the controlling centre of a cell.
Reason : Pores in the nuclear envelop regulate the flow of materials in and out of the nucleus.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Nucleus is the controlling centre of a cell as it contains chromosomes and genes. Chromosomes contain the DNA which by transcription prepare RNA which in turn leads to the formation of proteins by translation. These proteins regulate the various metabolic processes going in the cell. Besides this, nucleus contains genetic information for reproduction, development & behaviour of an organism.
Nuclear membrane is double layered, semipermeable and is perforated by minute, circular nuclear pores. The pore controls the passage of macromolecules like tRNAs, mRNAs, ribosomal proteins, enzymes etc. during different processes of transcription, translation etc.