Nucleic Acid, Replication, Transcription and mRNA processing Part 2 - (Week 5) Flashcards
If Avery, Macleod and McCarty found that samples of heat killed bacteria treated with RNase and DNase transformed bacteria, but samples treated with protease did not, what conclusion would they have made?
Protein is the genetic material
How did the building of a structural model of DNA come about?
- Maurice Wilkins and Rosalind Franklin produced a picture of the DNA molecule
- using X-ray crystallography
- diffraction pattern gives info on molecular structure
What did Watson and Crick developed?
- molecular structure of nucleic acid
- 3 dimensional structure of DNA (double helix)
- built a model where backbones were antiparallel (their subunits run in opposite directions)
What is the chemical structure of DNA?
- a polymer made of nucleotides
- sugar group, phosphate group and a base
- bases: adenine, thymine, guanine, cytosine
What holds the strands of DNA together?
- hydrogen bonds between bases on adjacent strands
- A&T and G&C
How is DNA transformed to proteins?
- bases on a single strand of DNA act as a code
- letters from 3 letter codons
- codes for amino acids (building blocks of proteins
What is the cycle of DNA to proteins?
- DNA to RNA, transcription
- RNA to Proteins, translation
Whats is base pairing?
- discovered by Watson and Crick
- Purine & Pyrimidine, width = consistent with X-ray data
- pairing = specific dictated by base structures
- A paired with T
- G with C
- Chargaff’s rules
In humans, 20% of bases in DNA = cytosine. What % of the bases are expected to be thymine?
30% - (20 + 30) = 50%, half of base pairs
What are nucleotides?
- building blocks of nucleic acids
- organic molecules that serve as the monomer units for forming nucleic acid polymers deoxyribose acid (DNA) + ribonucleic acid (RNA)
- composed of 3 subunit molecules:
+ nitrogenous base
+ 5-carbon sugar
+ phosphate group
What are nucleic acids?
- polymeric macromolecules assembled from nucleotides
What are nucleosides?
- 5-carbon sugar molecule attached to a nitrogenous base
What are the structural elements of nucleotides?
- the nitrogenous base (nucleobase) + indicated by “base” and “glycosidic bond” (sugar bond).
Uracil is used in DNA. True or False?
False - it is used in RNA as a pyrimidines
What are the two types of nucleic acids?
RNA and DNA
Information about ribonucleic acid (RNA):
- converts the genetic info contained within DNA to a format used to build proteins
- RNA has only one strand, and is made up of nucleotides
- molecules = variable in length, but = much shorter than DNA polymers
- contains ribose sugar molecules
- A,G,C,U
Information about deoxyribonucleic acid (DNA):
- replicates + stores genetic info
- consists 2 strands arranged in a double helix, made up of nucleotide subunits
- DNA = much longer polymer than RNA
- sugar in DNA = deoxyribose, containing one less hydroxyl group
- A,T,G,C
What are some differences between DNA and RNA?
- RNA has a hydroxyl group on the 2’ carbon of its sugar
- contains uracil instead of thymine, + is usually single stranded
- hydrogen bonds between base pairs
Both DNA and RNA consist of repeating units of nucleotides. Which is NOT a component of a nucleotide found in RNA?
Thymine
What is the structure of a DNA strand?
- polynucleotide chains have nitrogenous bases linked to a sugar-phosphate backbone
- nucleotides = linked by phosphodiester (C-O-P-O) to form a DNA strand
- phosphodiester bonds of the DNA give the polarity of the DNA strand (5’ phosphate & 3’ hydroxyl end)
What are phosphodiester bonds?
- when exactly 2 of the hydroxyl groups in phosphoric acid react with hydroxyl groups on tother molecules to form 2 ester bonds
What are esters?
- function group in organic chemistry
- carbon bound to 3 other atoms
What are hydrogen bonds?
- weak force that forms a special type of dipole-dipole attraction which occurs when a hydrogen atom = bonded to a strongly electronegative atom
- weaker than an ionic bond/ covalent bond but stronger than van der waals forces
