Chapter 2 Flashcards
What are 2 examples of nucleic acid?
DNA - in the nucleus carries genetic information
RNA - information carrying molecules - carry genetic information from DNA to ribosomes
Describe a nucleotide structure
Pentose sugar
Phosphate
Base
Describe the structure of a DNA nucleotide
Phosphate
Deoxyribose
cytosine, thymine, adenine, guanine
Describe the nucleotide structure of RNA
Phosphate
Ribose
cytosine adenine uracil and guanine
What bonds with cytosine?
Guanine
What bonds with adenine?
Thymine
Or uracil in RNA
What are bases joined together by?
Hydrogen bonds
How many hydrogen bonds are there between Cytosine and Guanine?
3
How many hydrogen bonds are between adenine and thymine?
2
What are the structural differences between DNA and RNA?
Deoxyribose in DNA ribose in RNA
DNA makes long chains RNA makes short chains
DNA is double stranded RNA is single stranded
DNA is ATCG and RNA is AUGG
Which bases are purines?
What does this mean?
Adenine and Guanine
2 ring carbon + nitrogen
What bases are pyramidines ?
What does this mean?
Thymine and cytosine
1 ring
What is semi conservative replication?
A type of replication which produces 2 chains each with one parental stand and one with a daughter strand
What enzyme is used to split the strands?
DNA helicase
What bonds do DNA helicase break ?
Hydrogen
What enzyme causes the nucleotides to bind together?
DNA polymerase
What bond does DNA polymerase make?
Phosphodiester bonds
As each strand contains ….. the original DNA the method is called …….
Half
Semi conservative replication
State to differences found between the nucleotides in RNA and DNA
RNA has a base of uracil whereas DNA had thymine
RNA had a ribose sugar whereas DNA has deoxyribose sugar
Nucleotides are joined by ….. reactions to form a ….. chain with a sugar ….. backbone and base …..
Condensation
Polynucleotide
Phosphate
Side arms
Describe how the proportion of DNA that contains 15N changes at each division when bacteria are grown on the 14N medium in the evidence for semi conservative replication
The proportion of 15N halves each time it was grown on the 14N medium