An experiment was performed to determine the mode of inheritance of two mouse genes, one for fur color and one for fur length. I
t is known that black fur (B) is dominant over white fur (b) and that long fur (L) is dominant over short fur (1). To determine how the genes are inherited, a cross was performed between two true-breeding mice, one with long black fur and one with short white fur. Their progeny, the Fi generation, all had long black fur. Five Fı male-female pairs were then crossed with one another. The F2 generation phenotypes for each cross are shown in
The F2 generation phenotypes for each cross are shown in Table 1. (See attachment) Which of the following is the mean number per cross of F2 generation offspring that are the result of crossing over?
Answer:
B, 2.2
Explanation:
The parental genotypes are long and black vs short and white. Therefore the phenotypes that result from crossing over are long and white, and short and black. (middle two rows of the table). If we add up the total number of offspring with these genotypes we get 6 long whites, and 5 short blacks.
The total is 11 from 5 crosses, so the mean is 11/5 = 2.2
Keratin has two main functions: to adhere cells to each other and to form a protective layer on the outside of the skin. In epithelial cells, keratin proteins inside the cell attach to proteins called desmosomes on the surface. The desmosomes act as anchors, holding the cells together.
Griffith's experiments with S. pneumoniae were significant because they showed that traits could be transferred from one organism to another and these transferred traits are known to be as heritable traits. In another experiment carried out by Hershey and Chase experiment it was confirmed by the results that DNA is actually the hereditary material not the protein.
Lysosomes contain about fifty different enzymes that break down all types of biological molecules including proteins, nucleic acids, lipids, and carbohydrates.
