nucleic acids Flashcards by Kisana Ngwenya

what are the pyrimidine nitrogenous bases

cytosine, thymine and uracil

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what are the purine bases

adenine and guanine

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what are the common base tautomeric forms

lactam (keto) form

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what are the rare base tautomeric forms

lactim (enol)

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what does a tautomeric shift mean

spontaneous rearragment of the positoins of protons and electrons within a molecule

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what is a nucleoside

nitrogenous base+ sugar

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what is the sugar in a nucleoside

D-ribose or 2’-deoxy D ribose

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how is the base connected in a nucleoside

Beta- N glycosidic bond on the 1 carbon

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what is a nucleoTIDE

nucleoside + phosphate
- phospheric acid is exterified with an OH of the monosacc. mostly on the 3’ or 5’-OH

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what is 3’-5’ cylcic adenosine monosphosphate

derived from ATP
cAMP is used in signal transduction as an important second messenger

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what is this

cyclic adenosone monosphosphate

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DNA has deoxy ribose and what bases

AGCT

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What bases does ribose have

AGCU

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what is the nucleoside for the base Adenine

adenosine

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what is the nucleoside for the base cytosine

cytidine

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what is the nucleoside for base thymine

doexythimidine = thymidine

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what is considered the energy currency of the cell

ATP

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many antivirals are what analogs

nucleoside/nucleotide

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what is zidovudine

nucleoside analong reverse transciptase inhibtor

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zidovudine is a [blank] analog

nucleoside

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what is this image of

zidovuine

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what is emtricitabine

used for treatment of HIV infection in adults and treat meant

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emtricitabine is a [blank] analog

blank

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what is this image of

emtricitiabine

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what contains minor bases

rna specifically tRNA

what are minor bases in dna

methylated forms of major bases protect genetic informaiton

name 3 types of xanthines

hyoxanthine inosine (hypoxanthine + ribose) xanthine

where is inosine found

in tRNA essenstial for wobble base pairs

how are nucleid acids or polynicleotides joined together

phosphodiester linkages

what is the primary structure or the sequence

read from 5'to 3' end

how many OHs are in rna

how many Hs are in dna

what is RNAs problem

stability

why is Dna more stable than RNA

no 2-oH

Rna is susceptible to what

base catalyzed hydrolysis

what are chargaffs rules

G=c. A=T

who explained the base rations

erwin chargaff

what image is this

guanine matiching with cytosine

what image is this

adenine mathcing with thymine

replication is based on what

complementarity

what image is this explaning

the central dogma of molecular biolody

what are some characteristics of B DNA structure

- right handed helix - perpendicular to the helix - wide and deep major groove - narrow and deep minor groove - phosphate backones

what pitch does B DNA structure have

pitch = 10 bases per turn so 34 angstrons

what is the helix rise per base for B dna structure

3.4 angstrons

is dna antiparallel

yes

what is this image

syn- adenosine and anti adenosine

what structure is this

A-dna

what structure is this

b dna

what structure is this

z dna

helical B is what orientation

right handed

helical Z dna is what hand

left handed

what are telomeres

ends of linear chromosomes

what type of dna does telomere have

tetraplex or quaduplex dna

characteristics of the rna strucutre

- single stranded - wound back double helical regions that assume type A helix

what enzymes affect dna superstructures

toposisomerases, type 1, type 2

what is topoisomerase

relax supercoils in dna by causing a tansient nick that is sealed

what us Type 1 enzyme

supercoils by breaking only 1 strand ssDNA break

type 2 enzyme

relax or supercoils by breaking both strands dsDNA

what inhibitorsa are widely used anticancer and antibacterial agents

topoisomerase

what are bacterial plasmids

separate small circular moleculs that carry genes

dna packaging in prokaryotes

- circular dna bound to basic proteins to give bacterial chromosomes in the nucleoid

characteristics of dna packing in eukaryptes

- dna packages as chromatin - coilded around histone octamer - nucleosomes look like beads on a string - 1.8 turns

what are the name of the histones

H2A, H2B, H3, and H4

what are histones

small proteins rich in basic amino acids lysine and argine whose side chains have +'ve charge

what charge is dna

-ve

what is number of the last histone

what is alkylation

causes dna mismatch mutations that lead to cancer

what is used for forensic analysis when nuclear dna is too degraded

mitochondiral and chloroplast dna

uv irridation induced dna damage example

thymine dimers (cyclobutyl dimers)

since alkylating agents can cause to cancer what are they called

carinogenic

what is an example of an alkylating agents

mustard gas or nitrogen gas

what is the compound from food that is curred with NaO2 that causes dna mismatch mutations that lead to cancer

HNO2

nucleic acids Flashcards

test 2 (72 cards)