Zeff=Z –S

Chlorine would have a Z value of 17 (the atomic number of Chlorine). Continuing to use Chlorine as an example, the 10 inner electrons (S) would screen out the positive charge of ten protons. Therefore there would be and effective nuclear charge of 17-10 or +7.

TLS Online TPP Program

#Id: 8969

#Section 3: Genetics, Cellular and Molecular Biology

The amount of genetic variation by examining phenotypic variation was difficult because many traits, a complex interaction of many genes and environmental factors determines the phenotype

TLS Online TPP Program

#Id: 2240

#Section 3: Genetics, Cellular and Molecular Biology

The neutral-mutation hypothesis proposes that most molecular variation is neutral with regard to natural selection and is shaped largely by mutation and genetic drift.

TLS Online TPP Program

#Id: 8971

#Section 3: Genetics, Cellular and Molecular Biology

The Death of a Gene

When a gene is duplicated, the new copy is often dead-on arrival (lacks the regulatory elements). 

TLS Online TPP Program

#Id: 2244

#Section 3: Genetics, Cellular and Molecular Biology

When a nonfunctioning duplicate is fixed in the population, or a functioning gene becomes nonfunctional, the result is a genetic skeleton called a pseudogene.

Deletions are important in shaping the genome.

TLS Online TPP Program

#Id: 2245

#Section 3: Genetics, Cellular and Molecular Biology

Deletion plays a key role in gene trafficking.which is the movement of genes to new sites in the genome.

TLS Online TPP Program

#Id: 2246

#Section 3: Genetics, Cellular and Molecular Biology

Some people have an allele called Δ32 at the CCR5 locus in which 32 bp are deleted.

CCR5 that plays a role in inflammatory response. Unfortunately, this protein is also a key to human immunodeficiency virus (HIV) infection. The virus binds to a loop of the CCR5 protein and then enters the cell.

The missing part of the gene codes for the loop in the protein to which the virus attaches.