Answer:
DNA may be taken up by bacterial cells and be active.
Explanation:
To understand Avery, MacLeod, and McCarty's experiment, it is important to know Frederick Griffith's precursor experiment. The microbiologist worked at the British Ministry of Health's Pathology Laboratory with pneumococci (commonly known as the bacterium Streptococcus pneumoniae, then known as Pneumococcus, which causes pneumonia), which were previously classified into several types. When cultured in petri dishes in the laboratory, the pneumococci that synthesize their capsules generate 'smooth' colonies. Subcutaneous injection of liquid culture of these pneumococci into mice causes their death. However, in vitro culture also allows the emergence of rough colonies', whose bacteria have lost the ability to synthesize mucopolysaccharide (and therefore have no capsules). Rough mutants could no longer be classified with sera and, moreover, lost their virulence: mice inoculated with them remained alive, unlike inoculated with smooth pneumococci.
The nature of Griffith's transforming principle remained unclear until the work of Avery, MacLeod, and McCarty. They repeated the in vitro transformation of pneumococci at the Rockfeller Institute for Medical Research, but replaced heat-dead cells with a purified fraction of smooth bacterial extract (unable to cause disease alone) and treated the material with different enzymes, each capable of destroying a specific type of macromolecule. Experience has shown that this fraction retained its transforming capacity when treated with protein or RNA degrading enzymes, but lost that ability when treated with DNA degrading enzymes. These results indicated that the chemical nature of the 'transforming principle' was DNA.
Thus, we can conclude that in addition to identifying genetic material, Avery, MacLeod and McCarty experiments with different strains of Streptococcus pneumoniae demonstrated that DNA can be absorbed by bacterial cells and be active.
Answer:
It's C.
Explanation:
The punnet square is for the DNA makeup of any child with that mix of genetic information. Therefore, all children will have the same chance of inheriting the disease, no one has a higher or lower risk.
Explanation:
You didn't attach a picture so i'll just explain how to find the number of stomatas/mm^2.
first you find the surface by multiplying the length by the width
0.1*0.1=0.01mm^2
now you count the numer of stomatas in the picture
in0.01mm^2 you have.........................x stomatas
in 1mm you have ...............................y stomatas
y=100x
Answer:
The genes will be Rr or rr.
Explanation:
Becuase the first generation didn't have the trait, which means the second generation's grandparents had the trait. That's why, the second generation female is mixed, which means the male child can be rr or Rr.
