Cells will usually divide if they receive the proper signal at a checkpoint in the G1 phase of the cell cycle. In mammalian cells , this checkpoint is called the restriction point. The G1 phase is a phase of the cell cycle that takes place in eukaryotic cell division. In this phase the cell synthesizes mRNA and proteins in preparation for the subsequent steps leading to mitosis. It ends when the cell moves into the S phase of interphase.
Answer:
Explanation:
Parenchyma
1. They have thin cell wall.
2. Their cell wall is made up of cellulose.
3. They are unspecialized tissues.
4. The are found in soft part of the plant.
5. They undergo photosynthesis and can stored the food and also play important role in gaseous exchange.
6. There are spaces between the cells.
Collecchyma.
1. They are thick cell walls.
2. Their cell walls are made up of cellulose and lectin.
3. They are specialized tissues
4. They are found in plants leaves and petioles.
5 The do not undergo photosynthesis but act to give mechanical support to plants.
6. They have little intercellular spaces.
Parenchyma and collecchyma are both tissues found in plants..
Answer:
D
Explanation:
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Answer:
recognizes a hormone’s chemical structure
Explanation:
In living systems, chemical messengers called hormones are secreted into the body via the bloodstream or ducts by certain glands called endocrine glands e.g pancreas, hypothalamus etc. These hormones are meant to effect a physiological change in certain cells called TARGET CELLS.
In biology, a target cell is any receiving cell that has the ability to respond to signals and messengers like hormones. This responding ability of hormones is due to the possession of specific receptor sites for the specific hormones. The receptor on a particular target cell recognizes that specific hormone's chemical structure, hence, will only respond to it.
For example, an insulin hormone secreted by the pancreas will only be responded to by a target cell that recognizes the chemical structure of the insulin protein using its receptor molecule.
Answer:
The synthesis of new proteins