The gradual evolution for the family Equidae (horse family) has been well documented within the fossil record.
Answer:
E2F transcription factors
Explanation:
The E2F transcription factors (TFs) encode intracellular factors associated with the control of the cell cycle. E2F are TFs that bind to promoter consensus sequences in order to activate transcription. These TFs control the expression of target genes involved in cell proliferation including, among others, genes for DNA replication and mitotic activation. Moreover, the E2F proteins also may act as a link between cell fate and the cell cycle. The retinoblastoma (Rb) is a protein that modulates the activity of the E2F family of TFs, and it has been shown that the Rb/E2F pathway is a key molecular mechanism associated with cell proliferation.
<h2>Given statement is false</h2>
Explanation:
According to dispersive model of DNA replication,DNA molecules are hybrids of parental and daughter DNA;In this model each individual strand is a combination of original and new DNA
Meselson and Stahl did an experiment on DNA replication using E.coli bacteria
- E.coli was grown in a medium containing heavy isotope of nitrogen,bacteria took up the nitrogen and used to synthesize new biological molecules,including DNA
- It was grown for many generations,the nitrogenous bases of the bacteria's DNA were all labelled with heavy nitrogen
- Bacteria were then switched to light nitrogen isotope and allowed to grow for several generations
- They then measured the density of the DNA using density gradient centrifugation
- This method separates molecules such as DNA into bands by spinning them at high speeds in the presence of another molecule, such as cesium chloride
- Each DNA produced two DNA molecules each with one new strand and one old strand called semi conservative replication(half of the parental DNA conserved in daughter DNA)
- Each DNA strand act as a template for synthesis of new strand
- Hence,dispersive model of DNA was eliminated and semi-conservative model of DNA replication was proved by the above experiment