Flashcards
Polynucleotides and DNA
Cards in this deck (12)
- 1Complete the sentences: Nucleotides join together to form _______________. The nucleotides join up between the ___________ group of one nucleotide and the ________ of another. This forms a __________________ ________ (consisting of the phosphate group and two ester bonds). The chain of sugars and phosphates is known as the __________ - ____________ ______________Nucleotides join together to form POLYNUCLEOTIDES. The nucleotides join up between the PHOSPHATE group of one nucleotide and the SUGAR of another. This forms a PHOSPHODIESTER BOND (consisting of the phosphate group and two ester bonds). The chain of sugars and phosphates is known as the SUGAR-PHOSPHATE BACKBONE.
- 2What is the structure of DNA?2 polynucleotide strands joined together by hydrogen bonding between the bases by complementary base pairing
Double-helix shape
Two hydrogen bonds form between A + T
Three hydrogen bonds between C + G
Two polynucleotide strands are antiparallel - 3Outline the method of purifying DNA1. Break up the cells in sample
2. Make up a solution of detergent, salt and distilled water
3. Add the broken up cells
4. Incubate the solution in a water bath at 60°C for 15 minutes
5. Put solution in an ice bath to cool mixture down
6. Filter mixture using filter paper and funnel. Transfer a sample of of filtered mixture to a clean boiling tube
7. Add protease enzymes
8. Slowly dribble cold ethanol down the side of the tube, so that it forms a layer on top of the DNA-detergent mixture
9. If you leave the tube for a few minutes, the DNA will form a white precipitate, which can be removed using a glass rod - 4In DNA purification, why is the DNA-detergent mixture put into a warm water bath?The detergent in the mixture breaks down the cell membranes.
The temperature should be high enough to stop enzymes in the cell from working properly and breaking down the DNA - 5In DNA purification, why is salt in the mixture?The salt binds to the DNA and causes it to clump together
- 6In DNA purification, what is the role of protease?These will break down some proteins in the mixture (e.g. proteins bound to the DNA)
- 7Complete the sentences: The enzyme __________ unzips the DNA strands by breaking the __________ bonds between the _______The enzyme HELICASE unzips the DNA strands by breaking the HYDROGEN bonds between the BASES
- 8Complete the sentences: At the _________ strand, the ________________ nucleotides (free nucleotides) are attached to the __________ strand (in a 5’ to 3’ direction) continuouslyAt the LEADING strand, the PHOSPHORYLATED nucleotides (free nucleotides) are attached to the TEMPLATE strand (in a 5’ to 3’ direction) continuously
- 9Complete the sentences: At the ________ strand, fragments of nucleotides (_________ fragments) are added _____________ (5’ to 3’). This is because the DNA is being constantly ________ , the phosphorylated ____________ have to keep back-tracking up the strand when the nucleotides are added in the 5’ to 3’ direction.At the LAGGING strand, fragments of nucleotides (OKAZAKI fragments) are added DISCONTINUOUSLY (5’ to 3’). This is because the DNA is being constantly UNZIPPED, the phosphorylated NUCLEOTIDES have to keep back-tracking up the strand when the nucleotides are added in the 5’ to 3’ direction.
- 10Complete the sentences: DNA ____________ catalyses the addition of new ____________ basesDNA POLYMERASE catalyses the addition of new NUCLEOTIDE bases
- 11Complete the sentences: _________ eventually joins up the okazaki fragments at the _______ strandLIGASE eventually joins up the okazaki fragments at the LAGGING strand
- 12Complete the sentences: Two DNA molecules now exist, with one of the 2 strands of each molecule being the original (__________) DNA. This is ______-_______________replication.Two DNA molecules now exist, with one of the 2 strands of each molecule being the original (PARENT) DNA. This is SEMI-CONSERVATIVE replication.
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- User has deleted their subject information Flashcards on Polynucleotides and DNA, created by Deleted user on 05/03/2018.
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- Deleted user · Mar 2018
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- Mar 5, 2018
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- Created by Yinka F · Jan 24, 2018
- Copied by Yinka F · Mar 5, 2018
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