Question

What observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? List and discuss them.

Short answer

Answer: The key observations and experiments that support the conclusion that DNA serves as the genetic material in eukaryotes include the Avery-MacLeod-McCarty experiment, Hershey-Chase experiment, the discovery of DNA structure by Watson and Crick, the process of DNA replication, and the Central Dogma of Molecular Biology.

Step-by-step solution

Understanding eukaryotes and genetic material

Eukaryotes are organisms with complex cells containing membrane-bound organelles, including a nucleus where genetic material is stored. DNA (deoxyribonucleic acid) is the genetic material in eukaryotes, as it carries the genetic instructions for the development, functioning, growth, and reproduction of an organism.

1. Avery-MacLeod-McCarty experiment

In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty conducted an experiment to prove that DNA is the genetic material responsible for the transformation of harmless bacteria into pathogenic bacteria. They isolated DNA from the harmful strain and mixed it with harmless strain. The harmless strain acquired the virulent trait, supporting the idea that genetic material is made of DNA.

2. Hershey-Chase experiment

Alfred Hershey and Martha Chase carried out an experiment in 1952 that provided further evidence for DNA being the genetic material. They used a virus named T2 bacteriophage, which infects bacteria. They labeled the protein coat of the virus with radioactive sulfur and the DNA with radioactive phosphorus. After the infection process, they observed that the radioactive DNA was found inside the bacteria, while the radioactive protein coat was left outside, indicating that DNA is the genetic material transferred during infection.

3. Structure of DNA

James Watson and Francis Crick discovered the double helix structure of DNA in 1953. They proposed that DNA is a self-replicating molecule capable of faithfully copying the genetic information and passing it to the next generation. This structure provided a strong basis for understanding how DNA serves as the genetic material in any organism, including eukaryotes.

4. DNA replication

The process of DNA replication, during which the DNA molecule is duplicated, further supports the role of DNA as the genetic material. This replication is semi-conservative, meaning that each new double-stranded DNA molecule consists of one original strand and one newly synthesized strand. This process ensures that the genetic information is accurately passed on to the next generation of cells and helps maintain the continuity of genetic material in eukaryotes.

5. Central dogma of molecular biology

The Central Dogma of Molecular Biology, proposed by Francis Crick, states that genetic information flows from DNA to RNA to proteins. This flow of information supports DNA's role as the genetic material because genes (sequences of DNA) are transcribed into RNA, which is then translated into proteins that perform essential functions in the organism. This process takes place in all eukaryotes, further supporting DNA's role as the genetic material. In conclusion, the Avery-MacLeod-McCarty experiment, Hershey-Chase experiment, the discovery of DNA structure by Watson and Crick, the process of DNA replication, and the Central Dogma of Molecular Biology are key observations and experiments that provided evidence for DNA's role as the genetic material in eukaryotes. These findings have contributed to our understanding of how genetic information is stored, transmitted, and expressed in living organisms.