Answer:
Due to urease activity, bacteria are able to use urea as a sole nitrogen source and produce ammonia, which increases the pH in the proximal environment, causing Ca2+ and CO32- to precipitate as CaCO3.
Answer:
Prokaryotic cell:
Prokaryotic cell do not have the nucleus and their DNA is present in the cytoplasm. The membrane bound cell organelle are absent in the prokaryotic cells. The ribosome of prokaryotic cell is 70'S. Transcription and translation is coupled in prokaryotic cells.
Eukaryotic cells:
Eukaryotic cell have well defined nucleus and their DNA is present inside the nucleus. The membrane bound cell organelle are present in the eukaryotic cells. The ribosome of eukaryotic cell is 80'S. Transcription and translation is not coupled and takes place in separate compartments in eukaryotic cells.
RNA polymerase is the enzyme that connects and proofreads them.
The correct answer is phototrophism.
Phototrophism is said to be the growth of a plant toward a source of light.
It is response to the stimulus of light and is seen when a plant bends towards the direction that light is coming from. Response by plants to a stimulus is called tropism. The word or prefix "photo" means or refers to light. Therefore phototropism simply means response to light.
Phototropism can be especially evident in the jungle where the jungle floor gets very little light. If a tall tree falls to the ground, it leaves a gap in the canopy through which sunlight streams to the ground. Many jungle plants growing on the ground will bend towards the gap and rapidly grow towards the source of light.
Answer:
c. a high percentage of very long chain saturated fatty acids
Explanation:
Saturated fatty acids do not have double bonds (they are saturated with hydrogens), so their tails are relatively straight. Unsaturated fatty acids, on the other hand, contain one or more double bonds, which often produces an elbow or bend. (You can see an example of an unsaturated bent tail in the phospholipid structure diagram that appears at the beginning of this article.) Saturated and unsaturated phospholipid fatty acid tails behave differently when the temperature drops:
- At colder temperatures, the straight tails of saturated fatty acids can be tightly bound, producing a dense and quite rigid membrane.
- Phospholipids with unsaturated fatty acid tails cannot bind so closely due to the bent structure of their tails. For this reason, an unsaturated phospholipid membrane remains fluid at lower temperatures than a saturated phospholipid membrane.
Most cell membranes contain a mixture of phospholipids, some with two saturated (straight) tails and others with a saturated tail and an unsaturated (folded) tail. <u>Many organisms — fish, for example — can adapt physiologically to cold environments by changing the proportion of unsaturated fatty acids in their membranes, that is, increasing the proportion of saturated long-chain fatty acids.</u>
In addition to phospholipids, animals have an additional component in their membrane that helps them maintain fluidity. Cholesterol, another type of lipid that is embedded between the membrane phospholipids, helps decrease the effects of temperature on fluidity.
