Answer:
Frederick Griffith was the first scientist who discovered that cell contains some components that can be transferred to another cell and cause a permanent change(transformation) in the new cell.
To prove this he performed an experiment in which he took two strains of <em>Streptococcus pneumoniae</em> which contain one rough strain and one smooth strain. Rough strain was non-virulent strain and smooth strain was virulent strain.
So he injected smooth and rough strain in mice and saw that mice die when virulent strain is injected and survive when non-virulent strain is injected. Then he injected heat killed virulent strain in which mice survived.
Then he added remain of heat killed bacteria with live smooth strain of bacteria and infected the mice and saw that the mice was killed by non-virulent smooth strain of streptococcus.
After this experiment he concluded that cells contain some component later identified as DNA which can be transferred to new population of cells and transform these new cells.
Answer:
Like a prokaryotic cell, a eukaryotic cell has a plasma membrane, cytoplasm, and ribosomes, but a eukaryotic cell is typically larger than a prokaryotic cell, has a true nucleus (meaning its DNA is surrounded by a membrane), and has other membrane-bound organelles that allow for compartmentalization of functions.
Explanation:
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Answer:
meiosis I
Explanation:
Reduction of the number of sets of chromosomes occurs during meiosis I.
During Meiosis I crossing over of genetic material occurs between chromosome pairs
Answer:
The axial skeleton includes all the bones along the body's long axis. ... The axial skeleton includes the bones that form the skull, laryngeal skeleton, vertebral column, and thoracic cage. The bones of the appendicular skeleton (the limbs and girdles) “append” to the axial skeleton.
Explanation:
Answer:
Blood vessels constrict
Explanation:
On seeing danger, impulses are sent to the adrenal medulla. It responds by secreting adrenaline into the bloodstream. This results in the following:
- Increased heartbeat
- Diversion of blood from alimentary canal and skin to skeletal muscles.
- Increased breathing rate and depth
- The liver releases more glucose.
These changes increase energy production especially in the skeletal muscles and prepare animal for sudden fight or flight.
