Advertisements
Advertisements
प्रश्न
Name the scientist who put forward the most popular model of DNA.
उत्तर
James Watson and Francis Crick proposed the double helix or spiral staircase structure of the DNA molecule in 1953. They were awarded the Nobel Prize for this discovery in 1962.
APPEARS IN
संबंधित प्रश्न
What is DNA?
What is DNA copying?
State the importance of DNA copying.
Which life process ensures that a plant or animal species will not disappear from this earth?
Which type of reproduction :
does not involve gametes?
Write down the different methods of asexual reproduction.
Fill in the following blank with suitable word :
the process of...........ensures continuity of life on earth.
What is the importance of DNA copying in reproduction? Explain with an example.
The protozoan having a flagellum at its one end is :
(a) Amoeba
(b) Paramecium
(c) Hydra
(d) Leishmania
In the list of organisms given below, those which reproduce by the asexual method are :
(i) banana
(ii) yak
(iii) yeast
(iv) Amoeba
(a) (ii) and (iv)
(b) (i), (iii) and (iv)
(c) (i) and (iv)
(d) (ii), (iii) and (iv)
In asexual reproduction, two offsprings having the same genetic material and the same body features are called :
(a) callus
(b) twins
(c) clones
(d) chromosomes
Name two animals which undergo external fertilisation.
Name two animals which undergo internal fertilisation?
What type of fertilisation takes place in birds?
List any two different forms asexual reproduction.
Bryophyllum can reproduce by its ______.
Give reason for the following:
Vegetative propagation is practised for growing only some type of plants.
Explain the term Reproduction.
Explain the term: Pollination.
Multiple choice question.
In ovule, meiosis occurs in ______
Multiple choice question.
Point out the odd one.
The number of meiotic and mitotic divisions necessary for development of female gametophyte in angiosperms is ______.
In vitro pollen germination and pollen tube elongation can be induced by ______.
Nervous system develops from ______ of embryonic layer.
What is morula?
What is the use of tablet ‘Saheli’?
What are the causes for the extinction of animals?
Match the following.
| Column I | Column II |
| Fission | Spirogyra |
| Budding | Amoeba |
| Fragmentation | Yeast |
What will happen if you cut planaria into small fragments?
Why is vegetative propagation practiced for growing some type of plant?
Name two organisms that reproduce through budding.
Identify the homologous pair.
How is reproduction in Hydra different from that in Amoeba?
Give reason for the following:
All multicellular organisms cannot give rise to new individuals through fragmentation or regeneration.
