topic 7 nucleic acids

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What is the structure of DNA
The carbon atoms in deoxyribose are numbered, with the nitrogenous bases attach to C1 and the phopshate group is attached to C5 Nucleotides are joined by a covalent phosphodiester bond between the C5 phosphate group and the C3 hydroxyl group Hence on
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Outline the structure of nucleosomes
The DNA double helix contains major and minor grooves on its outer diameter, which expose chemical groups that can form hydrogen bonds The DNA of eukaryotes associates with proteins called histones DNA is wound around an octamer of
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How do nucleosomes help to supercoil DNA and aid the regulation of transcription
Nucleosomes serve two main functions: They protect DNA from damage They allow long lengths of DNA to be packaged (supercoiled) for mobility during mitosis / meiosis When supercoiled, DNA is not accessible for transcription Cells will have some segmen
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What is an intron?
A non-coding sequence of DNA within a gene (intervening sequence) that is cut out by enzymes when RNA is made into mature mRNA. It is not found in prokaryotic cells
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What is on exon?
The part of the gene which codes for a protein (expressing sequence)
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What is the first step of DNA replication in prokaryotes?
The cell produces lots of free nucleotides called deoxyribosnucluoside triphospahtes (dNTPs). 2 phosphate groups are removed during replication to release energy.
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What is the second step of DNA replication in prokaryotes?
Helicase uncoils the double strand of the DNA producing 2 template strands
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What is the third step of DNA replication in prokaryotes?
DNA polymerase adds the nucleotides in a 5' to 3' direction. On the leading strand they are added toward the replication fork. On the lagging strand they are added in the opposite direction.
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What is the fourth step of DNA replication?
RNA primase adds a short lengths of RNA attached by base pairing to the template strand. this acts as a primer. allowing DNA polymerase to bing and begin replication
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What is step 5 of DNA replication?
DNA polymerase III starts replication next to the RNA primer and adds nucleotides in a 5' to 3' direction, moving away from the replication fork
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What are Okazaki fragments?
the small lengths of DNA which are formed between RNA primers on the lagging strand
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What is step 7 of DNA replication?
the RNA primer is replaced with DNA by DNA polymerase. A nick or dent is left where 2 nucleotides are left unconnected.
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What how is the nick created in step 7 of DNA replication sealed?
DNA ligase seals it by making another sugar phosphate bond
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Card 2

Front

Outline the structure of nucleosomes

Back

The DNA double helix contains major and minor grooves on its outer diameter, which expose chemical groups that can form hydrogen bonds The DNA of eukaryotes associates with proteins called histones DNA is wound around an octamer of

Card 3

Front

How do nucleosomes help to supercoil DNA and aid the regulation of transcription

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Preview of the front of card 3

Card 4

Front

What is an intron?

Back

Preview of the front of card 4

Card 5

Front

What is on exon?

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