DNA I - Structure of Nucleic Acids

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My notes, cba putting in diagrams thjough
J yadonknow
Flashcards by J yadonknow, updated more than 1 year ago
J yadonknow
Created by J yadonknow over 6 years ago
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Question Answer
What are nucleic acids? DNA/RNA, macromolecules needed for the storage and expression of genetic information.
What is the central dogma of genetic information (GI)? The central dogma shows the flow of genetic information Replication/transcription/reverse-transcription/translation
How does RNA play a different role to DNA in the central dogma? RNA is less stable and more reactive, it's also more mobile. Essentially it's like a more disposable transcribed photocopy of DNA.
What is the structure of DNA? A five carbon sugar ring - 2'-deoxyribose Nitrogenous base A phosphate group
How does one refer to the different carbons of the nucleotide sub-unit? If in DNA C1 means the first carbon in the base. 1'C refers to the first carbon in the deoxyribose sugar.
What are the 5 bases of the nucleic acids? Which are double and single ringed? Adenosine/Guanine - Purine (double) Thymine/ Cytosine/Uracil - Pyrimidine (single)
What is a nucleoside? A nucleoside is formed when a base is linked to the 1'C of a deoxyribose/ribose molecule.
What are the names of the nucleosides that form DNA? Deoxycytidine Deoxythymidine Deoxyadenosine Deoxyguanosine
What are nucleotides? Nucleosides with one or more phosphates linked to the 5' Carbon of the pentose sugar
Name four examples of a nucleotide Deoxyadenosine monophosphate (dAMP) Deoxyguanosine monophosphate (dGMP) Deoxythymidine diphosphate (dTDP) Deoxycytidine triphosphate (dCTP)
What are the properties of the phosphate groups? Phosphate groups are able to donate a proton and allow nucleic acids to be acids. Always negatively charged, allow nucleic acids to have a 5'-3' polarity
Draw a diagram and state the nomenclature of two bonded amino acids 5'-3' polarity shown Covalent phosphodioester bond shown 5'-XY, or simply XY
How many hydrogen bonds are present in base pairs that follow Chargraff's base-pairing rule? A-T = 2 H bonds C-G = 3 H bonds
Why is it that DNA bases tend to follow this base-pairing rule? As it keeps the diameter of the DNA molecule relatively constant so that strands will normally be a consistent distance apart from each other. Always purine-pyrimidine, if you had C to A/T the base ring would be narrowed. If you had A/G the base ring would be wider (4 rings)
Describe the structure of the DNA molecule (8) 1. Double-stranded DNA forms a right-handed double helical structure. 2. The sugar-phosphate backbone is on the outside. 3. The strands are held together by base-pairing AND by hydrophobic interactions. 4. Diameter of the molecule is ~2nm. 5. Height of the molecule is ~3.4nm per turn. 6. There are 10 base pairs per turn. 7. Has major and minor grooves. 8. Size of the DNA molecule usually given as the number of base pairs. i.e. kb.
What is "base-stacking"? hydrophobic interactions between adjacent base-pairs in the DNA molecule and between bases above and below it (base-stacking.)
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