Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave cells
Answer:
Sarcomere
Explanation:
A myofibril or muscle fiber under an electron microscope shows alternate light band and dark bands. These bands give the skeletal muscle and cardiac muscle a striated appearance. The light band is called the I- band or isotropic band, and the dark band is known as A- band or anisotropic band. In the center of the I-band Z-line is present. It is discovered from a German term Zwischenscheibe (between the disc). The portion of myofibril between one Z-line to the next Z-line is called sarcomere.
Your answer is D
Biology is my best subject
Answer:
The correct option is <em>B) ultraviolet region, especially below a wavelength of 320 nm.</em>
Explanation:
Ultraviolet light carries an enormous amount of energy in it. It is invisible to the human eye. When UV light with enormous energy and wavelength lesser than 320nm, hits the DNA, it causes changes in the structure of the DNA. Mostly, it affects the thymine nitrogenous base regions and forms pyrimidine dimers. The structure of the DNA changes on all the sites where dimers form and hence, they cannot be properly transcribed.