DNA replication occurs in the 5 prime (5') to 3 prime (3') direction.
I'm sure you've heard this many times. I tutor in genetics, and all of my students can rattle that off. Less understand what it means.
First, understanding what 5' and 3' mean is important. DNA is composed of a ribose sugar, a phosphate group, and a base (A,T,G,C). The sugar has a phosphate group attached to its fifth carbon, and a hydroxyl group on its 3rd carbon. Nucleotides (separate components of DNA) are linked by the phosphate group and the hydroxyl group. So, every nucleotide is linked at the phosphate group and the hydroxyl group besides two - the two nucleotides at either end of the strand of DNA. The one that leaves a phosphate group exposed is called the 5' end of DNA, and the one that leaves a hydroxyl group exposed is called the 3' end of DNA.
<span>A problem with many students just memorizing that replication occurs in the 5' to 3' direction is that there are two strands of DNA involved in replication. DNA polymerase (the major enzyme responsible for replication) reads the already existing strand of DNA in the 3' to 5' direction, and creates the new strand of DNA in the 5' to 3' direction (meaning that it adds nucleotides to the 3' end of the new strand).</span>
Answer:
Option C
Explanation:
Each starts out as a separate egg fertilized by a separate sperm
Answer:
Unicellular - Archaea and Bacteria
Multicellular - Eukarya
Explanation:
Domain is the highest taxonomic rank in the hierarchical biological classification system, above the kingdom level. There are three domains of life, the Archaea, the Bacteria, and the Eukarya.
Any characteristic, whether a physical trait, a behaviour, a physiological adaptation etc can make an organism more or less likely to survive in a particular environment.
<span>A dark colour could help a rabbit survive if it lives in a dark forest, because predators can't see it so well, but it would be less likely to survive in the arctic, where the environment is all white and it would show up. </span>
<span>In terms of the characteristics, think about: does it help the organism get food? Does it help protect the organism from predators? If it does, that organism is more likely to survive, and pass the characteristic on to it's offspring. If a bacterium has a characteristic of not being killed by antibiotics, this will help it to survive and breed.</span>
