Answer:
Because of the chemical and structural nature of the phospholipid lipid by layer the lipid soluble molecule can just pass the lipid membrane and some small molecules can also pass freely.
Explanation:
as we know that the homeostasis is an important process for a living cell to maintain it self so for the the exchange of materials between the external and internal environment is must so for that it exchange material with the outside environment of the cell.as the cell membrane is semipermeable(mean allow some molecule to pass(lipid soluble) and not others(lipid non soluble) to pass through the membrane.the cell membrane is selectively permeable due to its nature and chemical composition the chemical composition is lipid and phosphate and glycerol(head) with fatty acid that may b saturated or unsaturated(tail).so finally all those molecule which are polar can not pass through the membrane and non polar can pass the membrane.The size of the molecule is also a factor on which the permeability depends.
Gradient should be in the blank, hope that helps
the breakdown of chlorophyll reveals the carotenoid pigments of a leaf.
I hope this helps!
Answer:
D) Because sticky ends can be temporarily held together by hydrogen bonding between the two strands.
Explanation:
Restriction enzymes cut the DNA at specific restriction sites and by the mechanism of action they can form two types of ends:
- sticky ends-single-stranded overhangs are formed
- blunt ends-without overhangs.
The main advantage of sticky ends (their overhangs) is that they can complementary bind to another overhand formed by the same restriction enzyme. So, for example in cloning, if the DNA of interest and plasmid vector are cut with the same restriction enzyme, that forms sticky ends, fragment of DNA will fit into a bacterial plasmid in one direction.
On the other hand, blunt ends can be inserted into vector in both directions: head-to-tail or tail-to-head.
Answer/Explanation:
First, initiator protein unwinds a short stretch of the DNA double helix. <u>The length of the DNA double helix about to be copied must be unwound. </u> In addition, the two strands must be separated, much like the two sides of a zipper, by breaking the weak hydrogen bonds that link the paired bases. Once the DNA strands have been unwound, they must be held apart to expose the bases so that new nucleotide partners can hydrogen-bond to them. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.
