L9: Nucleic Acids Flashcards
How do nucleic acids relate to our unique hereditary information?
They store it in DNA and RNA
Nucleic acids, such as DNA and RNA, are polymers of what?
Nucleotides
What are the three building blocks of a nucleotide?
- Sugar (ribose or 2-deoxyribose)
- Nitrogenous base
- Phosphate group(s)
True or false: a nitrogenous base is a nucleobase
True
What do you call a nucleobase + sugar?
Nucleoside
What do you call a nucleoside + phosphate?
Nucleotide
True or false: Nucleotides can be cyclic
True
True or false: In a nucleoside, the sugar and nucleobase are joined by a phosphodiester bond
False. The nucleobase and sugar are linked by a b-N-glycosidic link
What are the two classifications of nucleobases?
- Pyrimidines
2. Purines
What is the difference between a pyrimidine and a purine?
Pyrimidines consist of a pyrimidine ring. Purines consist of a pyrimidine ring fused to an imidazole ring.
What are the three pyrimidine nucleobases?
- Cytosine
- Uracil
- Thymine
What are the two purine nucleobases?
- Adenine
2. Guanine
Fill in the gap:
ATP and GTP are examples of _____________ nucleotides
multiphosphorylated
Cyclic adenosine monophosphate (ATP with one phosphate group) is produced by which enzyme?
Adenylate cyclase
True or false:
cAMP is an important molecule in protein synthesis
False. It is an important cell-signalling molecule
How does caffeine relate to cAMP?
Caffeine prevents the breakdown of cAMP, thus improving cell signalling
True or false: GTP is similar to ATP
True. It is an important molecule in protein synthesis and cell signalling
Fill in the gaps:
DNA’s sugar-phosphate backbone is made by linking a ______(1)______ group on one nucleotide to the _______(2)________ sugar on the next, using a _______(3)_______ bond.
(1) Phosphate
(2) 2-deoxy ribose
(3) Phosphodiester
The nitrogenous bases are joined to the sugar-phosphate backbone by what bond?
beta-N-glycosidic link
How many hydrogen bonds form between adenosine and thymine?
2
How many hydrogen bonds form between guanine and cytosine?
3
Which of the following methods is commonly used for forensic use?
A) ‘Fingerprint’ analysis
B) DNA sequencing
C) Somatic gene therapy
D) Genetic engineering
A) ‘Fingerprint’ analysis
In genetic engineering, a human gene can be inserted into a bacterium to make it produce insulin, for example. Into which specific part of the bacterium is the gene inserted?
The plasmid
What is the ‘central dogma’?
“Once (sequential) information has passed into protein it cannot get out again” (Crick, 1958)
What type of bond joins an amino acid to tRNA?
Ester bond
The 3’ end of tRNA always ends with which bases?
CCA
