The hilum serves as the passageway for nerves and vessels
DNA fingerprints, such as those first used by Alec Jeffries, reveal variations in the locations of restriction enzyme recognition sites between different individuals.
DNA fingerprinting is a techniques that can identify the proportion of similarity or dissimilarity between two samples of gene. It is extensively used in forensics, to find the maternal and paternal relations. The principle of fingerprinting lies in recognizing the unique bands of DNA that are then matched with the other sample.
Restriction enzymes are also known by the name molecular scissors. These are endonucleases that cut the bases of DNA at the inside at specific locations only.
To know more about restriction enzymes, here
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Answer:
The correct option is: A carbon atom can complete its valence shell by forming four covalent bonds
Explanation:
Carbon is a chemical element that belongs to the group 14 of the periodic table. The atomic number of carbon atom is 6 and it is denoted by the chemical symbol C.
The electronic configuration of carbon is: 1s², 2s², 2p².
Therefore, there are 2 electrons in the first electronic shell and 4 electrons in the second electronic shell of the carbon atom.
<u>There are </u><u>four valence electrons </u><u>in a carbon atom and thus it can form four covalent bonds to complete its valence shell. Therefore, carbon atom is tetravalent.</u>
Answer:
The macromolecules that forms pumps and channels in the cell membrane, allowing the entry and exit of molecules to the cell are protein.
Explanation:
Membrane integral proteins are a type of macromolecule attached to the structure of the membrane and have ends in contact with the cytoplasm and the extracellular medium.
These <u>protein molecules can act as channels and transporters or pumps</u>, to facilitate the passage of substances through the membrane. An example of transmembrane channels are ion channels, while a protein transporter is the sodium potassium ATP-ase pump.
Membrane proteins can also act as surface receptors and enzymes linked to the cell membrane.
The other options are not correct because
:
- <em><u>Carbohydrates</u></em><em> can be found on the membrane bound to other molecules, such as glycoproteins and glycolipids, but they do not act as pumps or channels.
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- <em><u>Lipids</u></em><em> have the function of being the main component of the cell membranes.
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- <em><u>Nucleic acids</u></em><em> are found in the nucleus, and are not part of the cell membrane.</em>
Definitely advances in food and medicine. We have much more access to nutrition that allows us to grow and reproduce healthily. Access to healthcare keeps us from dying of things like strep throat or diarrhea, which are common maladies. This allows more people to live long enough to reproduce and give birth to healthy babies who will then make it through their birth and live longer. I hope I helped :)
