DNA is essentially a storage molecule. It contains all of the instructions a cell needs to sustain itself. These instructions are found within genes, which are sections of DNA made up of specific sequences of nucleotides. In order to be implemented, the instructions contained within genes must be expressed, or copied into a form that can be used by cells to produce the proteins needed to support life.
The instructions stored within DNA are read and processed by a cell in two steps: transcription and translation. Each of these steps is a separate biochemical process involving multiple molecules. During transcription, a portion of the cell's DNA serves as a template for creation of an RNA molecule. (RNA, or ribonucleic acid, is chemically similar to DNA, except for three main differences described later on in this concept page.) In some cases, the newly created RNA molecule is itself a finished product, and it serves an important function within the cell. In other cases, the RNA molecule carries messages from the DNA to other parts of the cell for processing. Most often, this information is used to manufacture proteins. The specific type of RNA that carries the information stored in DNA to other areas of the cell is called messenger RNA, or mRNA.
How does transcription proceed?
Transcription begins when an enzyme called RNA polymerase attaches to the DNA template strand and begins assembling a new chain of nucleotides to produce a complementary RNA strand. There are multiple types of types of RNA. In eukaryotes, there are multiple types of RNA polymerase which make the various types of RNA. In prokaryotes, a single RNA polymerase makes all types of RNA. Generally speaking, polymerases are large enzymes that work together with a number of other specialized cell proteins. These cell proteins, called transcription factors, help determine which DNA sequences should be transcribed and precisely when the transcription process should occur.
Answer:
22. C
23. C
24. Not clear, maybe 18%
25. Left ventricle, because according to the graph nearly 50% of the organ contains mitochondria, more than the left atrium.
Explanation:
22. Active transport requires cell's energy to move molecules, usually in the form of ATP.
23. This is a trick question, you might think it is diffusion or osmosis, but is is exocytosis. Diffusion and osmosis don't require vesicles for transport. It isn't endocytosis, because that is moving molecules inside the cell. The question asks for moving out the cell.
24. Look at the chart, it is less than 20, but more than 10 and more than halfway. I am not sure exactly the percentage, I would approximate it to be 18%.
25. Most likely left ventricle.
please give thanks :)
Answer:
dark reaction
Explanation:
The light reactions of photosynthesis take place in the thylakoid membrane, whereas the dark reactions are located in the chloroplast stroma.
Answer:
antibodies are produced in response to infection and that these antibodies are designed to specifically target particular antigens and bind tightly to them.
It's b because decomposers do not make food they break it down
