Answer:
A mutation in <u>DNA </u>results in a change in <u>RNA </u>that sometimes produces a <u>protein </u>with altered structure and function.
Explanation:
DNA is the hereditary material which causes gene expression in our body by producing protein. The type of protein which is produced by DNA totally depends upon the sequence of nucleotides in the DNA. But, DNA molecule does not produce protein directly. Initially it produces RNA (mRNA, tRNA, rRNA) by the process of transcription, the nucleotides in the RNA are complimentary to those in DNA. In short, the message regarding the structure and composition of the type protein to be produced by DNA is first decoded from DNA in the form of RNA. These RNA molecules then synthesize the protein as per the instructions from DNA by the process of translation.
But, in case a mutation occurs in the DNA which causes a change in it's nucleotide/nucleotides, the protein which will be produced will be different in the structure and function than the protein which was supposed to be synthesized. It happens because, a triplet of nucletiodes in the DNA and hence RNA specifies a particular type of amino acid and several amino acids are joined in a long chain to form polypeptide which ultimately forms protein. But, if any nucleotide in the triplet is changed due to mutation it may change the amino acid and if amino acid will change the protein will also get altered.
Answer:
B) Nitrogen-fixing bacteria and lightning
Explanation:
Nitrogen cycle is the natural process in which atmospheric nitrogen is converted into nitrite and nitrate with the help of bacteria.
Nitrogen cycle is directly dependent on nitrogen-fixing bacteria and lightning.
As bacteria are responsible for most of the chemical conversion in the nitrogen cycle such as nitrogen fixation (first step) is done by soil bacteria (Cyanobacteria) that form ammonia, which is toxic to plants; nitrification in which ammonia is converted into nitrites and nitrates with the help of Nitrobacter and denitrification bacteria involve Pseudomonas, and Achromobacter which convert nitrite and nitrate into nitrogen.
The lightning breaks nitrogen molecules and allow it to combine with oxygen in atmosphere which further dissolve in rain and form nitrates.
Hence, the nitrogen cycle is most directly dependent upon nitrogen-fixing bacteria and lightning and the correct option is B.
Age, Diet, lifestyle choices, environment and RES
Correct question: A fast swimming strong body fish such as a <u>salmon</u> which is adapted to clear fast and strong water current would most likely be found in which aquatic zone? Options in the attached file
Answer:
Source of a river zone
Explanation:
The fishes body is directly correlated with their environment and the pressures they receive from it. Those animals that are used to living in clear waters, with fast currents must be very strong, must have a hydrodynamic torpedo-like body and big and strong caudal fin to propel against the currents. These animals are used to living in water masses such as the source of a river zone.
Rivers belong to lotic environments, characterized by constant moving water.
- Profundal zone: Sunlight can not reach this zone, so there are no plants. The Water movement is very limited, and in most cases, water is not clear.
- Littoral zone: Is the transition zone, near the shore, where the light easily reaches the bottom. Usually, there is plenty of vegetation fixated to the bottom.
- Wetland zone: In general these are calm water, very rich in diversity, and a proper breeding area for a wide variety of fish.
- Source of a River zone: Rivers flow from higher to lower areas. They originate at the top of the mountains and fastly descend to finally end in a lake or in the sea.
Some species of salmons characterize by living in the sea during sexual maturity, but whenever they need to breed, they go back to the area where they were born. This is in sweet water. They swim in the river until they reach the place where they are going to oviposit. In order to do this, they need to swim against the current. Many times, females die trying to reach this special place.