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.
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Answer:
B
Explanation:
if you were a female and had this done to you, you would then understand.
The correct option is D.
Both carbohydrates and fat produce energy within the cell, but the amount of energy produce by fat for each one gram of food is much more than that of carbohydrate. Fat in the food is absorbed into the body in form of triglycerides.
<span>Similarities</span> between Gymnospermes and Angiospermes:
<span>·
</span>Having seed-Gymnospermes and Angiospermes are types of plants bear seeds. They belong
to a single class known as Spermatophyta. Spermatophyta or seed
plants are those <span>plants that produce seeds.</span>
<span>·
</span>Diferentiation- The sporophyte (diploid
multicellular stage in the life cycle of a plant) of both,<span> Gymnospermes and Angiospermes,</span> is differentiated into root, stem, and leaves.
Differences between Gymnospermes and Angiospermes:
<span>·
</span>Seed-Although both
have seeds, differences between them are huge. Gymnospermes have bare, non-encased seeds. The term
"gymnosperm" in Greek means "naked seeds".
On the other hand, seeds of Angiospermes are enclosed within an ovary,
usually in a fruit.
<span>·
</span>Pollination- In Gymnospermes, the pollination is
by wind, unlike most Angiosperms, who use insects, mammals or birds. Gymnosperm flowers are often difficult to spot
because they are not out to attract flying pollinators.
