Answer:
In 1928, Fred Griffith performed an experiment revealing that genetic material can be passed between two different stains of the bacteria.
Explanation:
In 1928, Frederick Griffith, a British bacteriologist conducted some experiments to develop a pneumonia vaccine. He used mice and two strains of Streptococcus pneumoniae bacteria, known as R and S in his experiments.
The live R strain bacteria had a rough appearance and were nonvirulent. When he injected R bacteria into mice, they did not cause pneumonia. The live S strain bacteria had a smooth appearance due to their polysaccharide coating and were virulent. When injected into mice, the mice died as a result of pneumonia. The polysaccharide coating protected the S bacteria from the immune system of the mice.
Griffith then injected mice with heat-killed S bacteria (the heat killed the bacterial cells) and they did not cause pneumonia in mice. But when he injected a combination of non-lethal R bacteria and non-lethal heat-killed S bacteria into mice, the mice died from pneumonia. When he examined the blood sample from the dead mice, he found that the blood sample contained live S bacteria. This finding leads him to the conclusion that the nonvirulent R-strain bacteria had been "transformed" into virulent and lethal S-strain bacteria by taking up a "transforming principle" from the heat-killed S bacteria.
This experiment was then used for additional experiments conducted by Avery, McCarty, McLeod and then by Hershey and Chase. They found the evidence that the transforming principle from Griffith's experiment was actually the hereditary material, DNA. The DNA of the S strain bacteria had survived the heating process. This DNA that contains the genes for the production of the protective polysaccharide coating was taken up by the R strain bacteria. The transformed R strain bacteria were now protected from their host's immune system and this process of transferring genetic information between different bacterial strains is known as transformation.
Answer:
The correct answer is 'If molecules are small enough, then they can pass through the semipermeable membrane because they can cross the semipermeable membrane from their small pores or openings'.
The correct answer is C) the fluorescent cells can help track the movement of cells.
Explanation:
In the last years, geneticists and scientists created animals that glow in the dark by inserting a Green Fluorescent Protein or GFP gene found in some species of jellyfish. This protein was used in animals such as rabbits, rats, and even chickens. One of the key reasons for this is that by inserting fluorescence scientists can better observe the development and movement of cells. This includes analyzing cells reproduction and growing in embryos of "glowing" animals or inserting the protein in specific cells or organs in an organism to observe how these change or move. Thus, the purpose of studying fluorescent rabbits is that "the fluorescent cells can help track the movement of cells".
Answer:
Cardiac muscle tissue
Explanation:
Myocardium or heart muscle is a special type of muscle (differ than striated and smooth) and it is the main tissue of the walls of the heart.
Heart muscle consists of individual heart muscle cells (cardiomyocytes) which are joined together by intercalated discs. It also contains collagen fibres and other substances that form the extracellular matrix.
Heart muscle has a "special" mode of contraction: action potential triggers the release of calcium ions from the cell's internal store, the sarcoplasmic reticulum.
Answer:
c . milk
Explanation:
Colloid are those whose particles are larger than the size of molecule.The size of particle is one nano meter.Collide particle range is between 1 to 1,000 nano meter. Every collide particle is consist of two parts colloidal particle and dispersion medium.
Milk is one of them.Collide are made form solid liquid and gas.
milk is the example of liquid collide.
