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.
Lit is located between the
left ventricle and left atrium.Left atrium is known to be one of the four chambers of heart
that receives oxygenated blood from the right and left pulmonary veins. This blood
is pumps to the left ventricle through the mitral valve. However, left
ventricle is responsible for pushing oxygenated blood through the aorta to the rest
of the body.
Answer:
D. Gross primary productivity is the total amount of solar energy captured by producers through photosynthesis over time.
Explanation:
The gross primary productivity of an ecosystem represents the rate at which the producers of the system capture the solar energy so that they can perform the process of photosynthesis. Therefore, GPP is the total amount of photosynthetic energy captured per unit area over a given time period. Producers consume the part of the GPP for their own respiration and maintenance. Therefore, gross primary productivity is the sum total of the growth of producers per unit area per unit time and the energy used by them for respiration.
The increase in the high fiber diet reduces the risk of colon cancer is suggested by the researchers. The effect of high fiber dietary intake add bulk to the digestive system. It also reduces the time required by the food to travel from the colon. Our food often contains some carcinogenic contents, so the interaction of such carcinogens may also be reduced due to the high fiber diet and also reduces the risk of intestinal tract. The bacteria in the lower intestine breaks the fibers into butyrate, which inhibits the growth of tumors of the colon and rectum.
Biodiversity depends on a species' ability to reproduce itself. If a species cannot reproduce then it will die out. This depends on the climatic conditions of the region. If there is a natural disaster for example, it will affect a species' ability to reproduce. This reduces the number of diverse species on earth. Biodiversity is the recognised variety of different types of life found on the earth. It also measures the variety of number and variety of plants, animals and other organisms found in different ecosystems.
