6.1: DNA and RNA Structure Flashcards
In the year __, ________ _______ performed ______ _____ of DNA.
- 1950
- Rosalind Franklin
- X-ray crystallography
What did Rosalind Franklin’s work reveal for DNA?
- a pattern that was regular and repetitive
During the same time as Franklin, who analyzed DNA samples from different species? What rule held true for all species? (3)
- Edwin Chargaff
- The amount of adenine equals the amount of Thymine - The amount of cytosine equals the amount of guanine
Nucleotide Structure: what is the structure of a purine? Which base pairs are included in purines?
- double ring structure
- A, G
Nucleotide Structure: What is the structure of pyrimidines? What bases are included?
- single ring structure
- C, U, T
What type of bonds hold base pairs together, and are they strong?
- hydrogen bonds
- weak, easily breakable
How many hydrogen bonds do adenine and thymine have?
2
How many hydrogen bonds do cytosine and guanine have?
3
How do hydrogen bonds aid in DNA replication?
- hydrogen bonds allow for the DNA strands to be easily separated during the replication process
Who combined the findings of Franklin (Helix shape) and Chargaff (base pairing) to create the first 3D, double helix model of DNA?
Watson and crick
What are the key features of DNA? (2)
- double stranded helix
- DNA strands are anti parallel
What is the structure of DNA’s double-stranded helix? (2)
- sugar-phosphate (deoxyribose) backbone
- centre has nucleotides pairing
DNA strands are anti parallel. What does this mean in terms of strand direction? (2)
- one strand runs 5’ to 3’
- other strand runs opposite, upside down direction 3’ to 5’
What free group is located at DNA strand’s 5’ end?
Phosphate group
What free group is located at a DNA strand’s 3’ ends?
Hydroxyl group (OH)
What is the key function of DNA? (2)
- primary source of heritable information
- genetic information is stored in and passed from one generation to the next through DNA
What is the exception to how DNA is the primary source of heritable information?
- RNA is the primary source of heritable information in some viruses
How does DNA look like in Eukaryotic cells? (2)
- found in nucleus
- Linear chromosomes
How does DNA look like in prokaryotic cells?
- located in the nucleotide region
- chromosomes are circular
Prokaryotes and some eukaryotes contain plasmids. What are plasmids? (2)
- accessory DNA (ex. Bacteria)
- small, circular DNA molecules that separate from the chromosomes
How do plasmids replicate? Which organisms are they mostly found in?
- independently from the chromosomal DNA
- prokaryotes
What do plasmids contain that are very important?
- genes that may be useful to the prokaryote when it is in a particular environment, but may not be required for survival
Plasmids can be manipulated in laboratories. Generally, how can labs form recombinant plasmid DNA? (1)
- plasmids can be removed from bacteria, then a gene of interest can be inserted into the plasmid to form recombinant plasmid DNA
Give an in-depth explanation of how labs can form recombinant plasmid DNA.
- When the recombinant plasmid is inserted back into the bacteria, the gene will be expressed
- Bacteria can exchange genes found on plasmids with neighbouring bacteria
- Once DNA is exchanged, the bacteria can express the gene acquired. This helps with survival of prokaryotes
What does RNA stand for? How many strands? What base pairs and what quantities are they?
- ribonucleic acid
- single-stranded
- A=U
- C=G
What does DNA stand for? How many strands, and what nucleotides are included in what quantities?
- deoxyribonucleic acid
- double stranded - A=T
- C=G
What is a key difference between RNA and DNA that we have not mentioned in other cards?
- RNA has ribose sugar (pentose)
- DNA had deoxyribose (pentose with one less oxygen atom)
