Answer:
Sickle cell anemia is an inherited condition in which there aren't enough healthy red blood cells to carry oxygen through an individual's body. The red blood cells of a healthy individual are flexible and round, and they move through blood vessels with no problem, transporting oxygen successfully. However, a person with sickle cell anemia has rigid, sticky red blood shaped like sickles or crescent moons. These cells often get stuck in small blood vessels, which can slow or block blood flow and oxygen delivery to different parts of the body.
The sickle cell anemia trait is found on a recessive allele of the hemoglobin gene, while the regular red blood cell trait is found on the dominant allele. This means that a person must have two copies of the recessive allele (one from their mother and the other from their father) to be born with this condition. People who have one dominant and one recessive allele or both dominant alleles will have healthy red blood cells.
Stratification in the field of ecology refers to the vertical layering of a habitat; the arrangement of vegetation in layers. ... strata) of vegetation largely according to the different heights to which their plants grow. The individual layers are inhabited by different animal and plant communities (stratozones).
It is separated by the endocardium !
Answer:
b. During replication there is both a leading strand and a lagging strand
.
c. Each replication bubble has two replication forks.
Explanation:
Eukaryotic chromosomes have multiple origins of replication to replicate the long chromosomes at a higher rate.
The two DNA strands have opposite polarity, that is, 5' end of the one DNA strand is present opposite to the 3' end of the other DNA strand. DNA replication occurs only in 5' to 3' direction and the direction of the movement of the replication fork is also 5' to 3' direction.
To allow the DNA replication in 5' to 3' direction on both strands, one strand is replicated discontinuously in the direction opposite to the movement of the replication fork.
The discontinuously replicated strand is lagging strand while the other one is the leading strand.
DNA replication in eukaryotes occurs bidirectionally as two replication forks are formed at each replication bubble, one at each end of the replication bubble.
The presence of multiple origins of replication and the bidirectional process allows the replication of large eukaryotic DNA at a considerable fast speed.
