MULTIPLE CHOICE. Choose the one alternative that best completes the statement or

Question

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise? A) meiosis followed by mitosis B) replication followed by mitosis C) special association with histone proteins D) replication without separation E) fertilization by multiple sperm ESSAY. Write your answer in the space provided or on a separate sheet of paper 2) Under what conditions does one expect a 9:3:3:1 ratio? 3) Answer the following questions about DNA extration fron onion cells. 7 pts a. Where is DNA found in the cell? b. Discuss the action of the soap (detergent) on the cell. What is the purpose of the soap in this activity c. What was the purpose of the sodium chloride ? Include a discussion of polarity and charged part d. Why was the cold ethanol added to the soap and salt mixture?

Explanation / Answer

1. Option D is correct.
Polytene chromosomes are giant chromosomes that are formed due to repeated DNA replication without separation.

2. When two genes are unlinked, a phenotypic ratio of 9:3:3:1 ratio is obtained in a dihybrid cross.
See image.

3a. In eukaryotes, the genomic DNA is found in the nucleus. Organellar genomes are found in mitochondria and chloroplasts.
In prokaryotes, the genomic DNA (Nucleoid) is found naked in the cytoplasm.

3b. Soap molecules are amphipathic. They are salts of long chain fatty acids. They contain a polar head and a non-polar tail. They help in breaking cell wall and cell membrane by causing aggregation of cellular components.

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.