Topic 1 - More Biological molecules Flashcards
what does DNA stand for
Nucleic Acid
deoxyribonucleic acid
what’s DNA’s function ?
Nucleic Acid
it’s used to store genetic information - all the information needed for an organism to grow and develop from a fertilised egg to a fully grown adult
what does RNA stand for
Nucleic Acid
ribonucleic acid
what is the function of RNA ?
Nucleic Acid
to transfer genetic information from the DNA to the ribosomes.
what type of molecules are DNA and RNA
Nucleic Acid
nucleic acid
what are RNA and DNA polymers of ?
Nucleic Acid
nucleotides
what’s the structure of a nucleotide ? Draw it
Nucleic Acid
a phosphate group joined to a pentose sugar which is joined to a nitrogen containing organic base
what’s the pentose sugar in RNA ?
Nucleic Acid
ribose
what are the four possible bases in DNA
Nucleic Acid
Adenine and thymine. cytosine and guanine
what are the four bases in RNA
Nucleic Acid
adenine and uracil. guanine and cytosine
what’s a polynucleotide
Nucleic Acid
polymer of nucleotides
how are polynucleotides formed
Nucleic Acid
a condensation recruit between the phosphate group of one nucleotide and the pentose sugar of another. this forms a phosphodiester bond. Catalysed by DNA polymerase.
What’s the structure of DNA ?
Nucleic Acid
DNA is made of two polynucleotide strands in a double helix structures. two dna polynucleotide strands consist of nucleotides joined together by phosphodiester bonds. nucleotides consist of a phosphate group a pentose sugar (deoxyribose) and a nitrogen containing base. the polynucleotide strands join together by hydrogen bonding between the bases. each base can only join with one particular base this is called complimentary vase pairing( adenine and thymine have 2 hydrogen bonds and cytosine and guanine have 3). the two anti parallel polynucleotide strands twist to form the dna double helix
Who discovered the DNA double helix ?
Nucleic Acid
Crick and watson
what’s the structure of RNA
Nucleic Acid
a relatively short polynucleotide chain (not a double helix) it’s much shorter than most DNA polynucleotides
What does semi conservative replication allow for
Nucleic Acid
genetic continuity throughout generations of cells
Explain the process of semi conservative replication
Nucleic Acid
- the enzyme DNA helicase breaks down the hydrogen bonds between the bases on the two polynucleotide DNA strands. this causes the helix to unwind to form two single strands.
- each original strand acts as a template for a new strand. complimentary base pairing means that free floating dna nucleotides are attracted to their complimentary exposed bars on each original template strand- A to T and C to G.
- Condensation reactions join the nucleotides together of the new strand to form phosphodiester binds making a polynucleotide chain this is catalysed by the enzyme dna polymerase. hydrogen bonds form between the bases on the original and new strands.
- each new dna molecules contains one strand from the original molecule and one new strand.
what does semi conservative replication mean ?
Nucleic Acid
each new dna molecule has a strand from the original dna molecule and a new strand.
what end is the active side of DNA polymerase complimentary to ? What does this result in ?
Nucleic Acid
DNA polymerase is complimentary to the 3’ end of the template strand, so enzymes can only add nucleotides to the new strand at the 3’ end.
This means that the new strand is made in a 5’ to 3’ direction as DNA polymerase moves down the template strand in a 3’ to 5’ direcion and the 2 strands are antiparallel.