Medgar Evers College Name: BIO 3022-50-Genetics Lab Final Exam Prof.Small MULTIP
ID: 95098 • Letter: M
Question
Medgar Evers College Name: BIO 3022-50-Genetics Lab Final Exam Prof.Small MULTIPLE CHOCE· Choose tho ene alternative that best-plate, the statenrate armente queria 1) Pelytene dhemsomes of Drowphda saivary glands each consist of maltiple idenical DNIA strands that are alligned in parallel arrays How could these arise? A) melosis followed by minosis B) replication followed by mitosis C) special association with histone protins E) fertilization by multiple spen ESSAY, Weite your answer in the space previded or on a separate sheet of paper 2) Under what conditions does one espect a 9.33.3 ratio? 3) Answer the follow ing questions abo DNA eation fron onlon cells.7 pts a. Where n DNA found in the b Discuss the action of the sop idetergmt) on the cell. Whut is the purpose of the soap in this activiny c. What was the purpose of the sodium chlande ? Include a discussion of polarity and dat ged partide. d. Why was the cold ethanol added to the soap and salt mixture ?Explanation / Answer
(1)
(D)Replication without separation
The chromosomes in the cells of salivary glands in Drosophila undergo repeated rounds of DNA replication without cell division. Thus forming a giant polytene chromosome.
(2)
9:3:3:1 phenotypic ratio associated with a dihybrid cross
It is a classic Mendelian example of independent assortment
(3)
(a)DNA is found in the nucleus of a cell
(b) soaps emulsify and dissolve the cell membrane thereby causing cell lysis
(c) Sodium chloride helps to remove proteins that are bound to the DNA and aid in its precipitation.
NaCl splits into Na+ and Cl- ions, the positively charged Na+ ions neutralize the negative charges on DNA