All about DNA/RNA Flashcards

Purpose of Nucleotides? Metabolic intermediates, chemical messengers, cofactors, building blocks of nucleic acids
Role of Nucleic Acids? Genetic information and Structural role
What does a nucleotide consist of? Phosphate+sugar+base
What does a nucleoside consist of? Sugar + base
What is larger? Pyrimidine or Purine? Purine
What is stronger? A-T/U or C-G? C-G because it has 3 bonds. Therefore, the more CG bonds, the higher the melting temp
Examples of Purines? A,G
Pyrimidines? C,T,U
Difference between DNA and RNA sugars? DNA has H, RNA has OH
Are A,T,C,G,U the only bases? Nope, minor ones exist too
Which carbon is the phosphate of the standard AMP attached to? Carbon 5 (but it can attach in other places too)
Typical pattern of DNA strand? 5' end with phosphate, then sugar, phosphate.....finally 3' end
Backbone of DNA is hydrophobic or hydrophilic? hydrophilic
Base pairs are hydrophobic or hydrophilic? Hydrophobic
Which is more susceptible to alkaline hydrolysis? DNA or RNA? RNA because of the OH that can get deprotanated easily
How many nucleotides long are oligonucelotides? Less than 50
Light absorbance of nucleic acids? 260 nm
Shape of the bases? flat
Two important features that help shape nucleic acids? Base-stacking and base-pairing
PH of bases? near neutral
What is primary NA structure? sequence
Secondary Nucleic Acid Structure? local interactions and patterns such as watson crick
Tertiary Nucleic Acid Structure? 3 Dimensional longer range involving other moleucles
What are the 3 forms of DNA? A,B,Z
Which DNA form doesn't exist in nature A form
What DNA form is the most common? B form
What DNA form is the thinnest? Z form
How many bases per turn in the Watson Crick Model? 10.5 bases per turn
Pattern of DNA groves? 1 major grove, then 1 minor grove, repeat
Which DNA forms are right handed? A and B
Which DNA forms are left handed? zform
What is perpendicular to the DNA backbone axis? base pairs
True or False? Z form is more elongated than B form. TRUE
Which DNA form is favored in the absence of water? A form of DNA, only occurs in the lab though
Which DNA has the largest diameter (widest)? A form of DNA
If one DNA stand is 5' A T C G 3', what is the other strand? 3' T A G C 5'
T or F? Palindromes can occur on the same and opposite strands? TRUE
What forms the hairpin loop? GGATACTCGATCC ACTC
Palindromes need at least ____ base pairs. 4 base pairs
Double stranded palindrome can form what? cruciform structure
T or F? 3 and 4 stranded DNA structures exist yes
Are prokaryote RNA mono or polycistronic? It can be both. The mRNA can contain 1 or more genes.
Are eukaryote mRNA mono or polycistronic? strictly monocistronic
Helical RNA is typically in what form? A form
T or F? Helical RNA in the Z form exists True but only in labs
T or F? Helical RNA in B form exists False. Never has been observed
Riboenzymes are an example or primary, secondary, or teritiary RNA structure? tertiary
What happens to UV absorption as DNA strands break? Absorbance changes
What is Tm? Temperature where half the DNA is denatured. It is different for different DNA strands
What happens to Tm as G+C base pairs increase? Tm goes up because it is harder to break.
Hybrid duplexes form when the DNA strands are ________. Complementary
In hybridization, rank the strengths of nucleic acid bonds. RNA:RNA>RNA:DNA>DNA:DNA
Applications of NA Hybridization? Research of relatedness of species, forensic medicine, diagnostic tests, drugs
Give 3 examples of 3 important spontaeous but rare reactions changing Nucleic Acids: Deamination, Depurination, Dimer Formation
Give 3 examples of reactive chemicals that can affect nucleic acids: 1)Deaminating agents such as Nitrites,nitrates, nitrosamines, bisulfuite. 2) alkylating agents that disrupt base pairing such as dimethylsulfate 3) oxidizing agents
What is the purpose of DNA methylation (alkylation)? It can provide natural protection. Happens in E-coli naturally
What does methylation of cytosine do to DNA structure? Leads some DNA segments to assume the Z form
What does the human genome project do? Determination of DNA sequence.
What is the maximum number of nucleotides synthesized in the lab? Usually 70-80 though it can be more (rarely)
What are the 3 functions of nucelotides? energy carriers, componenets of enzyme cofactors, regulatory molecules
Examples of energy carriers: amp, adp, atp, adensosine
Examples of enzyme cofactors: coenzyme A, NAD,FAD
Examples of Regulatory molecules cAMP,cGMP,ppGpp