1.5 DNA and RNA Flashcards
(44 cards)
What is the monomer that makes up DNA and RNA?
A nucleotide
What is a nucleotide made up of?
A pentose sugar
A phosphate group
A nitrogenous base
What sugar makes up DNA?
Deoxyribose
What does DNA stand for?
Deoxyribonucleic acid
What is the general structure of DNA?
Made up of two polynucleotide strands
They run in opposite directions (anti parallel)
They twist round each other called a double helix
How are nucleotides bonded together?
In a condensation reaction
Held together by phosphodiester bonds
What is the function of DNA?
It codes for manufacture of particular proteins or RNA
The hereditary material which carries information of genetic code to pass on from cell to cell and generation to generation
What is the deoxyribose and phosphate group also called?
The sugar phosphate backbone
What are the complementary base pairs?
Adenine - Thymine
Cytosine - Guanine
What are the pyrimidines?
Thymine and Cytosine
They have a single ring therefore are smaller
What are the purines?
Adenine and Guanine
They have a double ring structure and are therefore bigger
What are the hydrogen connections between the bases?
A=T 2 hydrogen bonds Spikey letters (easier to grab)
G ≡ C
3 hydrogen bonds
Curley letters (harder to hold onto)
What are some features of DNA?
Long coiling molecule Sugar phosphate backbone Bases in sequence Complementary pairs Hydrogen bonds Helical structure
How does DNA having the property of a long coiling molecule help?
Makes it very compact
You can store a lot of genetic material in a small space
How does DNA having the property of a sugar phosphate backbone help?
It is a very strong molecule
Denatured at 86 degrees
Very stable
How does DNA having the property of bases in sequence help?
It allows a lot of variation
They form triplet codes to relate to one amino acid
Therefore 64 variations of the triplet
How does DNA having the property of a complementary base pairing help?
The replications are a lot more accurate
Mutations are rare
How does DNA having the property of a many hydrogen bonds help?
Weak hydrogen bonds are easily overcome
DNA can separate easily meaning replication is much simpler
Adds stability as there are many
How does DNA having the property of a helical structure help?
Protects more chemically reactive base pairs from physical and chemical forces
This allows genetic information not to be corrupted
What did Griffiths conclude about DNA in 1928?
That if a virile strain was heated and put with a non-virile then the DNA in the virile strain can survive the heating and be taken in by the non-virile strain making it now virile
Therefore DNA was important
What did Avery conclude about DNA in 1944?
That it was in fact DNA that contained the transformation for the virile strain
What was the first Hershey-Chase experiment involving?
A bacteriophage with a sulfur (S35) labeled protein capsule i.e radioactively labelled
When the cell became infected the labelled capsule remained on the outside
What was the second Hershey-Chase experiment involving?
A bacteriophage with a phosphorus labelled DNA
When the cell became infected we could see the phosphorus labelled DNA on the inside of the cell
What did Hammerling use to do his experiment on the part of the cell controlling characteristics? Why?
Acetabularia
It is a single cell organism
Has distinguishable parts (cap, stalk, foot)
Quick regenerative properties
Nucleus in the foot
