Answer:
How does a bacterial cell protect its own DNA from restriction enzymes?
B. by adding methyl groups to adenines and cytosines
Explanation:
The restriction modification system is for the cells defense mechanism. This system is composed of a restriction endonuclease enzyme and a methylase enzyme and each bacterial species and strain has their own combination of restriction and methylating enzymes.
Bacteria have restriction enzymes, also called restriction endonucleases, which cut double stranded DNA at specific points into fragments. This restriction enzymes don’t cleave the bacteria's own DNA because restriction enzymes do not exist in the bacterial DNA sequence.
But is if the recognition sequences exist but the enzyme is methylation specific. Bacteria prevent their own DNA from chop down by restriction enzyme through methylation of the restriction sites. Methylation of DNA is a very familiar way to modify DNA function and bacterial DNA is highly methylated.
Answer: Ribose C5H10O5
Explanation:
Ribose is a carbohydrates with the formula C5H10O5. This molecule is pentose monosaccharide which has linear form of H−(C=O)−(CHOH)4−H. The hyoxyl groups lie in the same side in the form of Fischer Projections.
The number of hydrogen atoms are double in number of the oxygen atoms. The ribose sugar is found in the RNA.
It is the genetic material which is found in some of the organism that carries information from one generation to another.
Answer:
1. The species that can produce their food with the assistance of light energy coming from the Sun are termed as autotrophs. These species tend to produce chemical energy from light energy. Heterotrophs on the other hand refer to the species that lack the tendency of generating their food and are solely reliant upon the autotrophs for food.
2. The phenomenon that utilizes water and carbon dioxide and produces carbohydrates within the plants is known as photosynthesis. In the process, oxygen is also produced as a byproduct. The produced oxygen is further utilized by other species in the process of cellular respiration.
3. In the life of an organism, both oxidation and reduction perform an essential function. In the process of photosynthesis, the reduction of carbon dioxide is done and oxidation of water molecules is done. Therefore, it can be said that photosynthesis is an illustration of the oxidation-reduction reaction. Similarly, in cellular respiration, the molecules of oxygen are reduced and the molecules of glucose are oxidized, thus, it is also an illustration of an oxidation-reduction reaction.
4. In the light reaction phase of photosynthesis, the production of ATP, that is, the source of energy is done. Further in plants, the utilization of ATP is done to fix carbon dioxide within the glucose. In the process of cellular respiration, the energy within the carbohydrates is utilized to generate ATP at the time of the electron transport chain.
Answer :C) to prevent loss of ions to the surrounding water
Explanation :Basically,by closing the lamellae it prevents the entry of water by OSMOSIS , into high solute(ions) potential plasma .if the lamellae were not shut, osmosis drives water in, the fish produced hypotonic urine with resultant loss of ions,
Therefore with the closure of the lamellae, it countered continuous plasma ion loss, and ensure re-establishment of the water-ion balance in cells of muscle tissues and blood. Therefore, the net loss of plasma ions was cut down, and stability of the ion concentration ensured,as a result of a drop in the passive ion efflux to the surrounding aquatic medium.
Completed Ques.
The crucian carp (Carassius carassius) is a Northern European freshwater fish often inhabiting ponds that become hypoxic (have reduced oxygen levels) and even anoxic (have no oxygen) when the surface freezes during the winter. Surprisingly, when oxygen levels are normal, these fish lack the lamellae that provide a large surface area for gas exchange between water and blood: their gills are smooth. Yet when the level of oxygen in the water falls, the gill morphology undergoes a change: packing cells stop dividing and programmed cell death is induced, exposing gill lamellae that were buried in other tissue. With lamellae exposed, the gills have increased surface area for gas exchange. These changes in gill lamellar profile are reversible: investigators observed that the gills return to their normal structure within seven days after returning the fish to well-oxygenated water. (Jørund Sollid, Paula De Angelis, Kristian Gundersen, and Göran E. Nilsson. 2003. Hypoxia induces adaptive and reversible gross morphological changes in crucian carp gills. Journal of Experimental Biology 206:3667-73.)
