Answer:
Generally the genetic composition of every individual are conserved in the DNA, which are expressed as Genes. <u>The part of DNA that codes fro a particular protein is called Gene. </u>These genes were inherited from individual parents by offspring during genetic processes, and are passed to next generation of initiated by the offspring.Therefore the type of characteristics or traits manifested by an individual are results of gene expressed in DNA.
<u>These traits are usually encoded as transcribed bases in mRNA, and when fully translated they are expressed as proteins . Thus each trait are translated protein. This explains the forms of transport of genetic materials from parents to offspring. </u>
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The inherited traits can expressed itself fully in the offsping irrespective of other characteristics, e.g a white man who marries a black woman and all the kids are white with long hair, shows dominance of the white allele, expressed as protein, despite the presence of the black allele. such black allele is said to be recessive.
The independent assortment of genes at meiosis, the crossing over at prophase 1, and separation of the chromosomes at Anaphase 1 and II together with random fertilization by million of genetically varied haploid sperm cells ensured that no two individual are 100 % genetically identical even if they are from the same parents.
The crossing over of genetic materials ensures mixing of these material to give a genetically unique organisms from mixture of the parents DNA. In addition the independent assortment of genes ensures that homologous chromosomes do not continue their 'journey' into the same sex-cells, and therefore the genetic component of the new sex-cells (sperm or oocytes ) and the resultant offspring varies
<u>Furthermore, segregation of genes into different sperm cells and eggs cells ensures random distribution of the DNA in million of sperm cells and therefore varied traits because this DNA distribution can not be the same in each sperm or egg cells, ensuring great variation in the eventual offspring.</u>
Explanation:
If the parental genotypes are homzygous, the F1 birds would be heterozygous while all the F2 offspring would have the wild-type phenotype.
<h3>Monohybrid crossing</h3>
Based on the assumption that the wild-type genotype is AA and the slow feathering genotype is aa.
A cross between AA and aa:
AA x aa
F1 Aa Aa Aa Aa
One F1 male (Aa) is then crossed with a wild-type female (AA):
Aa x AA
AA AA Aa Aa
Genotypic proportion: 2 AA:2 Aa
Phenotypic proportion = 100% wild-type
More on monohybrid crossing can be found here: brainly.com/question/1185199
Answer: it is positive
Explanation:
Lac operon is a cluster of 3 structural gene protein involves in lactose metabolism.
Inducible operons have proteins that can bind to either activate or repress transcription depending on the local environment and the needs of the cell. The lac operon is a typical inducible operon which operates both systems, the Lac is a repressor that turns off transcription of the operon which negatively controls it by binding to the operator.
Normally, the operons are turned off, they only take charge when glucose levels are low or in the presence of lactose for digestion. To do so, the cAMP–CAP protein complex serves as a positive regulator to induce transcription. One such sugar source is lactose. The lac operon encodes the genes necessary to acquire and process the lactose from the local environment, which includes the structural genes lacZ, lacY, and lacA. lacZ encodes β-galactosidase (LacZ), an intracellular enzyme that cleaves the disaccharide lactose into glucose and galactose. lacY encodes β-galactoside permease (LacY), a membrane-bound transport protein that pumps lactose into the cell. lacA encodes β-galactoside transacetylase (LacA), an enzyme that transfers an acetyl group from acetyl-CoA to β-galactosides. Only lacZ and lacY appear to be necessary for lactose catabolism.
CAP (catabolite activation protein) binds to the operator sequence upstream of the promoter that initiates transcription of the lac operon. The lac operon uses a two-part control mechanism to ensure that the cell expends energy producing β-galactosidase, β-galactoside permease, and thiogalactoside transacetylase (also known as galactoside O-acetyltransferase) only when necessary. However, for the lac operon to be activated, two conditions must be met as stated above. First, the level of glucose must be very low. Second, lactose must be present. If glucose is absent, then CAP can bind to the operator sequence to activate transcription. If lactose is absent, then the repressor binds to the operator to prevent transcription. If either of these requirements is met, then transcription remains off. The cell can use lactose as an energy source by producing the enzyme b-galactosidase to digest that lactose into glucose and galactose. Only when both conditions are satisfied is the lac operon transcribed.
