Because they have to go through the non-polar, hydrophobic tales of the phospholipid bilayer. Polar and non-polar do not like to be together
Answer;
- Endotoxin
Explanation;
-Endotoxins are part of the outer membrane of the cell wall of Gram-negative bacteria. Endotoxin is invariably associated with Gram-negative bacteria whether the organisms are pathogenic or not.
-They are large molecules consisting of a lipid and a polysaccharide composed of O-antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram-negative.
Answer:
A. 4 right handed coil:0, left- handed coil
Explanation:
According to MENDELION CROSS:
We will get NN, Nn,Nn,nn
NN, Nn, Nn are the 3 right handed coiling and nn is left handed coiling.
But in case of shell coiling in snails, maternal inheritance is applied in which offspring is decided only by phenotype.
Maternal traits: Here,female parent has right handed shell coiling. so, all the offsprings will have the same.
Hence, the phenotypic ratio will be:
4 Right handed coil: 0 Left handed coil
Answer:
Bacteriophages (phages) are viruses that infect only bacteria and do not infect mammalian or plant cells. Phages are ubiquitous in the environment. Phages or bacteriophages were chosen as a model system for their simplicity, as they only contained protein-coated nucleic acid. Alfred D. Hershey and Martha Chase (who were part of the bacteriophage group) in 1952 studying the infection of the bacterium Escherichia coli by the T2 phage show that the information definitely resides in the DNA. They used phage with either [32P] -labeled DNA or [35S] -labeled proteins to infect the bacteria. Immediately afterwards, they centrifuged the sample so that the infected bacteria remain in the pellet and the virus capsids (proteins) remain in the supernatant. [35S] is found in the supernatant, whereas [32P] is found in bacteria. After one cycle of infection, it was observed that when phage labeled in the [35S] proteins were used, only 1% of the radioactivity was incorporated into the progeny. But when phages were [32P] labeled, more than 30% of the radioactivity was in the progeny. They showed directly that what is transmitted from one progeny to another is the DNA and not the proteins, despite having first "diluted" in a bacterium.
Explanation:
Bacteriophages are viruses that infect bacteria in a specific way. Bacteriophages, like other known viruses, are found in an intermediate zone between living organisms and inert matter. Bacteriophages bind to the host pathogenic bacterium, introduce their genetic material, replicate inside it and destroy it. Hersey, along with his assistant Martha Chase, used phages because they knew that T2 phages were made up of 50% proteins and 50% nucleic acids and that phages entered bacteria and reproduced. As the progeny carried the same infection traits, the genetic material of this had to be transmitted to the offspring, but the mechanism was unknown. These scientists carried out an experimental work with the T2 virus, a bacteriophage that infects the bacterium Escherichia coli, which it reproduces by attaching itself to the outer wall of the bacterium, injecting its DNA into it where it replicates and directs the synthesis of the phage's own proteins. Phage DNA is encapsulated within proteins and produces phages, which lyse or disrupt the cell and release phage from progeny. They infected a culture of bacteria with radioactively labeled phages: the protein coat with sulfur (35S) and its DNA with phosphorus (32P). After infection, they separated the phages from the bacteria by violent shaking using a mixer (hence the name of the experiment). By centrifugation the much smaller phages remained in the supernatant and the much larger bacteria in the pellet. 85% of the radioactivity corresponding to DNA appeared in the pellet and 82% of the protein in the supernatant. This result supported the idea that DNA was the only component of the bacteriophage that penetrated the interior of the bacteria and, having the ability to form new phages, constituted the genetic material.
Answer:
c. recognize a member of their own species.
Explanation:
Imprinting is a form of social earning that occurs in a critical period based on early experience, in which an animal develop a sense of identity usually within few hours or days after birth.
In birds, for example in ducks, once an egg is hatched, the ducklings imprints on the first moving object they see which happens to be the mother. In other to keep track of the mother, they learn to respond to a characteristic sound that have been emitted by the mother. Through imprinting, they are able to distinguish their mother from the rest of the ducks. Imprintng helps birds to form an identity during early stage at birth, which helps them to recognize members of their own species.
