Answer:
option B is correct
Explanation:
the effect of external physical factor on cell division is clearly seen on in density dependent inhibition( a phenomenon in which crowded cell stop dividing)
Answer:
Specie
Explanation:
They are a group that interbreed with each other, only, since they cannot produce fertile offspring with those of another species.
Answer:
All of these choices are correct.
Explanation:
Cell cycle is the process of growth and division of cell. It comprises of interphase and mitosis. In interphase the cell grows, replicates its genomic content and prepares itself for division. In mitosis the division occurs.
Cell cycle is controlled by a group of kinases called as Cyclin dependent Kinases (CDKs). They act by phosphorylating their substrates. They are of various types like Cdk1, Cdk2, Cdk4 etc. They become active when they bind to a regulatory protein called cyclin. They are also of various types like Cyclin A, Cyclin B, Cyclin C etc. Level of cyclin and corresponding CDK increases and decreases according to the stage of cell cycle. For example in S phase of cell cycle concentration of cyclin A and E shoots up. CDK2 is able to bind to these cyclin molecules and hence it becomes active.
Cell cycle has major checkpoints where the condition of cell is analysed before it proceeds to the next stage of cycle. If any abnormality is detected, repair mechanism is activated or the cell is killed. Checkpoints do not allow cell cycle to proceed in damaged cells.
p53 is a tumor suppressor protein which can halt cell cycle when it detects some abnormality in cell. It usually acts in G1/S checkpoint (before the DNA replication starts in cell) and G2/M checkpoint (before the cell division begins). Hence, all of the above statements are true.
Sorghum and millet are the grains that thrive well in arid environments. Sorghum is a close relative of the smaller millet, with the latter measuring only a third in size to sorghum. It is important to know that sorghum is sometimes called great millet.
Every 192 -gram cup of cooked whole sorghum or millet contains 22 grams compared to wheat (16 grams), brown rice (15 grams), and maize (16 grams).
Answer: Oxygen atom has 8 Protons
Explanation:
Oxygen atom (O) has an atomic number of 8, and a mass number of 16.
Recall that atomic number of any element is equal to the number of protons in its electronic shell, hence, the number of protons in oxygen atom is also 8
