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.
Science
This is true because humans can only know so much due to unexplored lands, water depth, and evidence of extinction being hidden.
If a moving object loses mass, how can it keep its momentum constant?
A. by speeding up
Answer:
1.Carbon dioxide is converted to sugar used for food. - 1. Location- A
2.Carbon trapped in fossil fuels is converted to carbon dioxide. - 2. Location- C
3.Organic carbon is converted to fossil fuels. -3. Location- E
4.Carbon dioxide is converted to carbonates.- 4. Location- D
5.Sugar is broken down and converted to carbon dioxide. - 5. Location- F
Explanation
1. Carbon dioxide is converted to sugar used for food: The carbon dioxide is converted into sugars by the process of photosynthesis, which occurs in the green plants. Plants trap carbon dioxide and sunlight from the atmosphere, to synthesize their food.
2. Carbon trapped in fossil fuels is converted to carbon dioxide: The fossil fuel produced deep inside the earth, acquired by the factory. From the factory the carbon dioxide liberated to the atmosphere.
3. Organic carbon is converted to fossil fuels: The organic carbon obtained after the degradation of organic matter is responsible for the synthesis of fossil fuels.
4. Carbon dioxide is converted to carbonates: The carbon dioxide from the atmosphere gets dissolved with water of the water body and termed as carbonic water.
5.Sugar is broken down and converted to carbon dioxide: The glucose or sugar as a source of food in plants gets broken down into carbon dioxide and water by the process of respiration.
