Explanation:
The nucleus (plural, nuclei) houses the cell's genetic material, or DNA, and is also the site of synthesis for ribosomes, the cellular machines that assemble proteins. Inside the nucleus, chromatin (DNA wrapped around proteins, described further below) is stored in a gel-like substance called nucleoplasm.
Mosses,ferns and thallophytes
The genes involved in pattern formation and organization of body parts are called homeobox genes, which are a large family of similar genes.
The h<span>omeobox genes direct the formation of many body structures during early development of the embryo. </span>
Both parents must be carriers, which means they have the heterozygous gene (one uppercase letter & one lower case letter). They will still carry that mutated gene (because they have a lower case letter), and their offspring will have a 25% chance of getting a recessive disorder. The percentage is low but still possible.
Answer:
<u>Light microscope</u>:
- use a beam of light to produce magnified images
- can be used to examine living cells and tissues
<u>Scanning electron microscope</u>:
- use a beam of electrons to produce magnified images
- can be used to examine DNA
- can be used to examine cells
<u>Transmission electron microscope</u>:
- use a beam of electrons to produce magnified images
- can be used to examine DNA
- can be used to examine cells
Explanation:
Light microscope: is a commonly used microscope also known as compound microscope. Magnifies images from 40X upto 1000X. It uses ray of visible light to produce a magnified image. The light microscope can be used to view specimen of both living and dead cells or tissues. However, it doesn't give a detailed view of a specimen like electron microscope.
Scanning electron microscope: It uses electron beam as an illuminating source. It has a much higher resolving power than light microscope because it uses electrons instead of light. It magnifies object upto 500000 times the actual size. Internal structures can also be viewed. However, only dead specimen can be used because the beam of electrons can kill the cells. They are of two types:
- <u>Scanning electron microscope(SEM): </u>an electron beam passes over the specimen's surface and displaces electrons which are then focused on a screen to form an image. Images appear in 3-D
- <u>Transmission electron microscope: </u>electromagnets magnify the image by passing beam of electrons through a thin specimen. Images appear in 2-D
