Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/32

Click to flip

32 Cards in this Set

  • Front
  • Back
Nucleotide
sugar (deoxyribose or ribose) with a phosphate group
purines
double ringed
- adenine, guanine
pyrimidines
single ring
- cytosine, thymine

CUT the PIE = Cytosine, Uracil, and Thymine are PYrimidines
DNA base pairing
- amount of A = amount of T
- amount of C = amount of G

Higher G/C content = more tightly bound the strands are
DNA
- double-stranded helix
- nucleotides = sugar (deoxyribose) + phosphate + nitrogenous base (A, T, C, G)
- Complementary base pairing (A/T, C/G)
- Strands are antiparallel: 5' end of one strand paired with 3' of other strand
- found in nucleus only
RNA
- single-stranded
- sugar = ribose
- Base pairing: A/U, G/C
- Found in nucleus and cytoplasm
mRNA
carries complement of DNA sequence and transports it from nucleus to ribosomes for protein synthesis
monocistronic
one mRNA strand codes for one polypeptide
tRNA
- in cytoplasm
- aids translation of mRNA
rRNA
- structural component of ribosomes and most abundant
- made in nucleolus
hnRNA
- heterogeneous nuclear RNA
- ribonucleoprotein complex that is the precursor for mRNA
Transcription
DNA to RNA
Requires:
- RNA polymerase
- Promoter
- Termination sequence
Post-transciptional RNA processing
exons (coding) and introns (non-coding)

- introns are removed and exons are spliced to form mature mRNA
- processing occurs in nucleus
degeneracy
accounts for the fact that a mutation in DNA does not always result in an altered protein
stop codons
UAA
UAG
UGA
aminoacyl-tRNA
- each aa has own
- has active site that binds both aa and corresponding tRNA, catalyzing their attachment to form aminoacyl-tRNA complex
- requires ATP
P site
peptidyl-tRNA binding site
- binds to tRNA attached to growing polypeptide chain
A site
aminoacyl-tRNA complex binding site
- binds incoming aminoacyl-tRNA complex
1) DNA --> DNA

2) DNA --> RNA

3) RNA --> protein
1) replication (new DNA made in 5' to 3' direction)

2) transcription (new RNA made in 5' to 3' direction)

3) translation (mRNA read in 5' to 3' direction)
DNA containing viruses
- viral DNA replicated
- viral mRNA transcribed using host machinery in nucleus
- some viruses must bring their own DNA and RNA pol (if they replicate and transcribe in cytoplasm)
RNA containing viruses
- viral RNA replicated and transcribed in cytoplasm
- RNA replicase transcribes new RNA to RNA template
- some viruses bring RNA replicase with them, or part of viral RNA functions as mRNA for making RNA replicase
retroviruses
- use RNA as a template for DNA (rather than RNA)
- use reverse transcripase to do this
provirus or prophage
Viral DNA intergrated into host chromosome
polycistronic
mRNA coding form more than one polypeptide
- found in prokaryotes
transformation
foreign chromosome fragment incorporates into host chromosome via recombination
conjugation
donor and recipient connect via sex pili to transfer F-factor
Hfr cells
high frequency of recombination
- transfered genes recombine with genome of recipient cells
transduction
fragements of chromosome are packaged into viruses
operon
- for gene regulation
- consists of:
operator gene, promotor gene, regulator gene (and inducer in inducible systems)
inducible system
- represor binds to operator, preventing RNA polymerase from binding and transcribing genes
- repressor is active until it binds to the inducer
- For transcription to occur: inducer must bind to the repressor
inducible system (summary)
- RNA pol binds to promotor = transcription occurs
- Repressor binds to operator = NO transcription
- Inducer binds to repressor = no binding to operator = transcription occurs
repressible system
- repressor is inactive until a it combines with a corepressor which can then bind to operator and prevent transcription