Answer:E. Adenine and Guanine
Explanation:
They are double <u>double carbon- nitrogen rings with four nitrogen atoms</u> bases found in DNA and RNA. Purines always pair with pyrimidines(cytosine and thymine) to form a double helix structure.This precise paring ensured that the DNA has a complementary structure.
This paring of purines with pyrimidines is by hydrogen bonds. This is to ensure easily unwinding during replication, that is formation of new DNA molecules.
purines bases are also used for cell protein synthesis fro cell division.
Answer:
Hydrogen
Explanation:
Hydrogen combines with carbon, creating a vacuum like effect
Well, there can't be because the atomic number the the number of protons in the nucleus of an atom, meaning that every element has their special amount of protons silicon can only be that number and other elements can't be that number.
Answer:
I don't know exactly what the growth of lichens symbolizes in general, but I found the information about what does it mean for California state:
In 2016, according to The Mercury News (mercurynews dot com), Lace Lichen
becomes state symbol of California. The president of the California Lichen Society, Shelly Benson, said: " Lichens are widely overlooked. Our main mission was really to create more awarness about lichens and their role in the ecosystem."
As Lichen, widespread and may be long-lived, was chosen for a state symbol, its growth may symbolize the increase of state strength.
Explanation:
Answer is D. The phosphate group of membrane lipids are negatively charged.
The cell or plasma membrane is a bilayer of phospholipids. The two phospholipids layers are opposite to each other. Each phospholipid molecule consists of a phosphate group and a lipid. The phosphate form inner and outer layers of hydorphilic and are negatively charged 'heads' and lipid forms the tail, hydrophobic and non-polar. Since phosphate is negatively charged it repels negatively charged molecules and do allow them to pass through it.