Central Dogma Flashcards by Anifowose Olasubomi

What did Watson and Crick mean by Central Dodgma

it means THE PROCESS flow in one direction

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How does DNA chnaged to protein

DNA is replicated then transcripted to RNA and then translated to protein

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What is the substrate that encodes its metabolism

DNA

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What are 3 fundamental rules of replication

semiconservative, bidirectional, semidiscontinous

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What DNA replication being semiconservative mean

each strand of template DNA is being copied

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DNA replication is bidrectional means

involves 2 replication forks moving in opposite direction

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DNA replication is semidicontinous means

leading strand copies continuously

lagging strand copies in segments (Okazaki fragment) which must be joined

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What enzyme starts the DNA replication process

Helicase which unwinds DNA

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How many origins of replication does Eukaryote have

multiple

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What happens after every 300 kbp of DNA

depending on the organism , there is a replication origin or replicator to ensure DNA replication occurs contunously

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In lower eukaryotes what is found to ensure DNA replication occurs continuously in chromosome

Autonomously replicating sequence (ARS) in 100-200bp

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In mammalian chromosomes, is there a specific sequence of origin

no, zones of replicators span between 500-50,000 bp

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How does the size of genome affect synthesis

the bigger the genome, the slower the synthesis

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What is the orientation for leading strand

5’ to 3’

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How many regions does DNA polymerase have

2 regions : insertion and post insertion site

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Describe insertion site of DNA polymerase

where incoming nucleotides bind

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Describe Post insertion site of DNA polymerase

where the newly made base pair resides when the polymerase moves forward

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What sits in the ACtive site of the DNA polymerase

2 magnesium ions

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What happens when polymerase mispairs dC with dT

exonuclease hydrolyzes the misplaced dC and polymerase incorporates correct nucleotide,dA

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How many DNA polymerase are in E.coli

atleast 5

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What is the primary function of DNA polymerase I

clean up

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What is the principal replication polymerase in E.coli

Polymerase III

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Which DNA polymerase is used to make okazaki fragments

DNA Pol alpha, has no proofreading

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which DNA polymerase is used in leading strand synthesis

DNA Pol E

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Which DNA Polymerase is used in lagging strand synthesis

DNA poL &

What enzyme makes a bond between a 3' OH and a 5'-PO4

DNA ligase

What activates the 5'-PO4 of the lagging tsrand

attachment of AMP

What happens when the 3'OH nucleophile attacks the 5'phosphate

displacement of AMP

Which DNA damage occurs from occasional incorporation of incorrect nucleotides

Mismatches

Which DNA damage arise from spontaneous deamination, chemical alkylation or exposure to free radicals

abnormal bases

Which DNA damage forms when DNA is exposed to UV light

pyrimidine dimers

Which DNA damage from from exposure to ionizing radiation, free radicals

Backbone lesions

What happens when the RNA primers are removed from the lagging strand

shortened at each cell division

the ends of DNA containing a tandem repetitive sequence called

Telomeres

-------- fix the problem of rnd replication

Telomeres

If nothing is done, chromosome shortening leads to

cell death

Which side of the chromosome does the telomere sequence (acting as a DNA) add to

3' side

How is the problem of linear ends being recognized as broken fixed

telemores, shelterin complex, the d-loop and t-loop

Where is DNA compacted in?

Nucleus

What are the 3 well-understood roles of RNA in living cells

Messenger RNAs, Transfer RNAs, Ribosomal RNAs

Which RNA encodes the amino acid sequence of all polypeptides

Messenger RNAs

Which RNA matches specific amino acids to triplet codons in mRNA during protein synthesis

Transfer RNA

which RNA is the constituents and catalytic appropriate amino acids

ribosomal RNA

which RNA appears to regulate the expression of genes, possibly via binding to specific nucleotide sequences

microRNA

does RNA act as genomic material in viruses TRUE/FALSE

true

which strand serves as template for RNA polymerase

DNA template strand

which strand is also known as non template strand

DNA Coding Strand

What similarities does DNA coding strand and RNA transcript have in common

they have the same sequence

Describe transcription initiation and elongation in E.COLI

1. RNA polymerase core binds to the DNA promoter 2. A bubble is formed and initiated. 3. then a promoter clearance is followed by elongation which is replaced by NusA 4. NusA dissociates, transcription is terminated and RNA polymerase is recycled.

Describe p-independent termination

RNA synthesis encounters a terminator sequence and an RNA hairpin is formed at a palindromic sequence, reducing the length of the RNA-DNA hybrid. mRNA is released

Describe p-dependent termination

p-helicase binds to a rut site and migrates along the mRNA to the elongating RNA polymerase, then separated the mRNA from the DNA template

Which RNA polymerase is responsible for the synthesis of pre-ribosomal RNA

RNA polymerase I

Which RNA polymerase is responsible for synthesis of mRNA

RNA polymerase II

Which RNA polymerase make tRNAs and some small RNA products

RNA polymerase III

WHICH organism have their own RNA polymerase

mitochondria

Which RNA polymerase do plants have responsible for synthesis of small interfering RNAs

RNA polymerase IV

How do mRNA mature in Eukaryotes

transcription and 5' capping

Is exon the coding or uncoding sequence

coding

is intron coding or uncoding sequence

uncoding

Which can be found on a mature mRNA intorns/ exons

exons

how is introns removed from the sequence

cleavage, polyadenylation and splicing

where does the poly A occur at

the 3' oh tail adding an extra RNA

How can retroviruses make DNA from RNA

they have genomes of ssRNA and the enzyme reverse transcriptase

What is the enzyme that makes DNA from the RNA

reverse transcriptase

Unless there is a need for protein synthesis, will the cell invest in it

no, they won't

Protein aretargeted to which location

cellular

Protein synthesis uses how mnay percent of chemical energy of a cell

90%

What brings amino acid to mRNA

adapter (tRNA)

How many nucleotide coding for an amino acid

triplet

Which is sufficient a four letter code in groups of 2 or groups of 3

groups of 3 (64)

which mRNA code does living organism use

non-overlapping

Where is replication and transcription taking place

nucleus

where is translation taking place

endoplasmic reticulum (ER)

What protects RNA as it moves to the ER

5' poly A and 3' OH POLY A tail