🩷 3.1.5.1- Structure Of Dna And Rna Flashcards
What does DNA stand for ?
Deoxyribonucleic acid
What does RNA stand for ?
Ribonucleic acid
What type of molecules are DNA and RNA ?
Information carrying molecules
In all living cells, what does DNA hold ?
Genetic information
What does RNA transfer genetic information from and to ?
From DNA to the ribosomes
What are ribosomes formed from?
RNA and proteins
What are both RNA and DNA polymers of ?
Nucleotides
What is each nucleotide formed from ?
A pentose, a nitrogen containing organic base and a phosphate group
What is the phosphate called in DNA ?
Deoxyribose
What are the possible nitrogen containing organic bases in DNA?
Adenine and thymine or cytosine and guanine
What is the phosphate in RNA called ?
Ribose
What are the possible nitrogen containing organic bases in RNA?
Adenine and uracil or cytosine and guanine
What type of bond is formed when a condensation reaction occurs between 2 nucleotides ?
A phosphodiester bond is formed
What are the polymers of nucleotides?
Nucleic acid
Compare dna and rna
Both dna and rna are polynucleotide chains
DNA is longer than rna
DNA is double stranded whereas rna is single stranded
What are DNA double strands referred to as being and what does this mean?
They are referred to as being anti parallel. This means one strand is inverted when compared to the other.
What bond holds two DNA strands together ?
Hydrogen bonds
Why is DNA very stable ?
Due to the many hydrogen and phosphodiester bonds
DNA strands are held together by hydrogen bonds, why does this help it functionally?
This helps the DNA molecule as it can be easily unzipped in DNA replication and protein synthesis
DNA is a large molecule which is coiled up, why is this a good functionally ?
It is good for storage i.e. lots of information can be stored in a relatively small space.
What are the base pairs which code for proteins protected by ?
The sugar phosphate backbone
What does the sequence of the base pairings determine ?
The structure of proteins, including enzymes
Give the 5 steps of DNA semi conservative replication
1- DNA helically breaks the hydrogen bonds and the two strands unwind
2- Free floating DNA nucleotides line up by the complementary base pairings. This happens opposite both parent strands.
3- DNA polymerase joins adjacent nucleotides via phosphodiester bonds to form two new strands
4- Hydrogen bonds form between the bases of the new strand and the original strand and the helix reforms
5- There is now an identical copy of the DNA in two new cells. One strand in the original parent strand and the other in the newly formed strand. Hence semi conservative replication.
What end of the nucleotides is dna polymerase complementary to?
DNA polymerase is complementary to the 3’ (prime) end of the 3’ nucleotides
