Which parts of the nucleotide make up the rungs of the DNA ladder?
Thymine, cytosine, adenine and guanine.
2 of 17
What does each nucleotide in a DNA molecule contain?
A phosphate group, a five-carbon sugar (deoxyribose) and an organic base.
3 of 17
Adenine and Guanine are __ bases. Thymine and and Cytosine are ___ bases.
Purine; Pyrimidine.
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Why are the two chains of nucleotides said to be anti-parallel?
They run in opposite directions. The bases of one chain link up with the bases of the other by hydrogen bonding.
5 of 17
What are the differences between purines and pyrimidines?
Pyrimidines have single rings whereas purines have double rings.
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Polynucleotides are held together by _____ bonds.
Phosphodiester. (formed from a condensation reaction)
7 of 17
Define 'gene'
Is a sequence of DNA nucleotides that code for a polypeptide.
8 of 17
Describe the process of DNA replication.
Helicase unwinds the nucleotides, beginning at the replication fork. RNA polymerase synthesises a short RNA primer. DNA polymerase extends RNA primer with complimentary DNA, then digests RNA primers replaces with DNA. DNA ligase join fragments
9 of 17
The leading strand is synthesised continuously in the 5' to 3' direction by DNA ____. Parental strand provides a new template for the new strand's synthesis.
Polymerase.
10 of 17
Explain what is meant by the term semi-conservative replication.
2 helices of DNA are produced and they are identical. They are each made up of one original strand and one new strand.
11 of 17
Describe how the structure of RNA differs from that of DNA.
RNA has ribose. It contains uracil instead of thymine. It is single stranded and there are 3 forms.
12 of 17
State the components of a DNA molecule.
A deoxyribose sugar, a phosphate group and nitrogenous bases.
13 of 17
Discuss how RNA and DNA are different.
DNA is two-stranded when RNA is one. DNA contains A T C and G and RNA has U instead of T. The sugar present in DNA is deoxyribose whereas in RNA it is ribose.
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DNA codes for the structure of polypeptides. State the role of messenger RNA (mRNA)
It carries the genetic information outside the nucleus and transfers it to the ribosomes for protein synthesis.
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Describe how the two nucleotide chains are bonded together.
Hydrogen bonds between the bases in complementary base pairings. Purine to pyrimidine. A-T and C-G.
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What do RNA and DNA both have?
A phosphate backbone.
17 of 17
Other cards in this set
Card 2
Front
Which parts of the nucleotide make up the rungs of the DNA ladder?
Back
Thymine, cytosine, adenine and guanine.
Card 3
Front
What does each nucleotide in a DNA molecule contain?
Back
Card 4
Front
Adenine and Guanine are __ bases. Thymine and and Cytosine are ___ bases.
Back
Card 5
Front
Why are the two chains of nucleotides said to be anti-parallel?
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