3B- Dna replication Flashcards
What is the conclusion of Rosalind Franklin’s work?
Provided critical X-ray diffraction images suggesting DNA’s helical structure
Franklin’s work laid the groundwork for understanding DNA’s structure.
What did Watson and Crick contribute to the understanding of DNA?
Proposed the double helix model of DNA
Their model explained how DNA could replicate and carry genetic information.
What are Chargaff’s Rules?
Adenine pairs with thymine, and guanine pairs with cytosine
These rules are fundamental for understanding base pairing in DNA.
What is the structure of DNA composed of?
Nucleotides, phosphate groups, deoxyribose, and nitrogenous bases
The four nitrogenous bases are adenine, thymine, guanine, and cytosine.
What is the shape of DNA?
Double helix
The double helix structure is essential for DNA’s stability and function.
What are the 3’ and 5’ ends in DNA?
3’ end has a hydroxyl group, and 5’ end has a phosphate group
These ends are crucial for DNA replication directionality.
What is the purpose of DNA replication?
To make an exact copy of the DNA for cell division
DNA replication ensures that each new cell has the same genetic information.
What is the leading strand in DNA replication?
The strand synthesized continuously in the 5’ to 3’ direction
This strand allows for faster replication as it follows the replication fork.
What are Okazaki Fragments?
Short DNA fragments synthesized on the lagging strand
They are created because the lagging strand is synthesized in short bursts.
What is the role of DNA Polymerase III?
Extends the DNA in the 5’ to 3’ direction during replication
It is essential for synthesizing both leading and lagging strands.
What is the main function of DNA Polymerase I?
Removes RNA primers and replaces them with DNA nucleotides
This action ensures the continuity of the DNA strand.
Fill in the blank: The four nitrogenous bases in DNA are _______.
adenine, thymine, guanine, cytosine
These bases are critical for the encoding of genetic information.
True or False: DNA replication requires a template.
True
The template is essential for accurate base pairing during replication.
Griffiths Experiments
● Was the first to observe bacterial transformation-the process where some
bacteria take up genetic material from the environment
● Observed that mice died when Griffith mixed heat-killed S-strain bacteria with
live, harmless bacteria from the R-strain
● Concluded based on observations that bacteria had been transformed-DNA
had been acquired by a bacterium
Avery Experiments
Averyʼs team built on Griffithʼs experiments by identifying that the
chemical/transforming factor in Griffithʼs experiments was DNA and that DNA is
what transmits genetic information from one generation to the next
Hershey Chase Experiments
Concluded that DNA was the transforming factor and not proteins by using
radioactive phosphorus and radioactive sulfur to track DNA and proteins, respectfully
