Busy. Please wait.
Log in with Clever

show password
Forgot Password?

Don't have an account?  Sign up 
Sign up using Clever

Username is available taken
show password

Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Didn't know it?
click below
Knew it?
click below
Don't Know
Remaining cards (0)
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Bio Exam II

Gene expression

Flow of genetic info - Crick (1956) - DNA to RNA to Protein - In cells it's unidirectional (goes in one direction)
Originally "1-gene, 1-enzymes" - not all proteins are enzymes -revised to : 1 gene- 1 protein but not all proteins are single polypeptides - revised to 1 gene- 1 polypeptide * still not 100% accurate
Processes - Transcription: DNA to RNA - Translation: RNA to polypeptide ( ribosomes use info in RNA to make polypeptide)
RNA composition and types - ribonucleic acid - DNA: deoxyribose; ATCG, double strand - RNA: ribose; AUCG; single strand
Ribose - contains an -OH where DNA only has an -H ( DNA is more stable)
Uracil - pyrimidine base - used instead of thymine in RNA - same structure as thymine minus on methyl group (-CH3) - Complementary to adenine
3 types of RNA - mRNA: Messenger; encodes AA sequence - rRNA: ribosomal; part of ribosome structure - tRNA: transfer; carries AA's to ribosome during translation
The genetic code - order of amino acids - mechanisms for A,U,C,G - reads 3 bases @ a time - Crick figured it out
Codons - 3 bases= 1 amino acid - 4 bases (AUCG) so there are 64 possible combos
The genetic code -Unambiguous: each codon codes for 1 AA - degenerate: several codons coding for same AA
Genetic Codon - 1 start codon: AUG: starts translation - 3 stop codons: UAA,UGA,UAG: stops translation
Reading Time - codons must be grouped correctly - mutations can result in frame shift ( deletion specifically)
Genetic Code is mostly universal - minor exceptions in some microbes and mitochondria - generally the same across viruses, & cellular life
Transcription (1st part of gene expression) - synthesis of RNA complementary to DNA - 3 stages
Transcription Initiation - DNA is template for RNA synthesis & reads on 3'-5' direction - one strand in transcribed (template strand) ; other strand not transcribed - RNA synthesized in 5'-3' direction
Components of Transcription initiation - Promoter: specific DNA sequence on transcribed strand (promoter region not transcribed) - RNA polymerase: makes new RNA strand; binds promoter; unwinds helix; begins transcription
RNA synthesis ex. Non Transcribed Strand: 5' A-T-G-A-C-T 3' Transcribed "template" Strand: 3' T-A-C-T-G-A 5' RNA: 5' A-U-G-A-C-U 3'
Transcription Elongation - RNA synthesis; anti- parallel to template strand - Uses RNA nucleotide triphosphate
Transcription Termination - specific DNA sequence signals RNA polymerase to stop (not a stop codon) - RNA transcription stops & polymerase falls off - results in completed RNA strand
mRNA modification - only in eukarytoes - transcription to pre-mRNA; not useful for protein synthesis - Add 5' Cap to get out nucleus - Add ploy-A-tail to get out nucleus; provide protection; and ribosome recruitment
RNA Splicing - exons: coding region in pre-mRNA - introns: non-coding region in pre-mRNA - splicing: process of removing introns from pre-mRNA - occurs in nucleus
Translation -mRNA to polypeptide - occurs in ribosomes (cytoplasm or surface of ER)
Components - tRNA; small RNA mol; single strand about 80 nucleotides - 3D structure, intramolecular base-pairing
tRNA function - binds specific AA - brings AA into ribosome - binds correct codon to mRNA - AA can be added to polypeptide
Anti Codon - 3 specific bases on loop of tRNA - complementary to codon on mRNA
Many different tRNA's - all general same shape - each w/ different anti-codon, carries diff. AA - made by aminoacyl-tRNA synthetases
Ribosomes - carries out translation - protein + rRNA
rRNA - ribosomal RNA - transcribed from DNA- not translated into protein
Ribosome function - works as a large enzyme complex - catalyzes reaction b/w mRNA, charged tRNAs, & polypeptides
Translation Initiation - small ribosomal subunit binds mRNA and tRNA- met - moves along mRNA until reaches AUG - initiation factors bring in large subunit (translation initiation complex)
Translation Elongation -repeating cycle - peptide bond formation -translocation - each cycle adds single AA
Translation Termination - stop codon not recognized by tRNA's - recognized by release factors (proteins)- bind to stop codon A site - cannot form new peptide bond - polypeptide released
Translation Termination results in... - release of polypeptide from p-site - release of mRNA - release of last tRNA - dissociation of ribosomal subunits
Created by: tennadeleta.
Popular Biology sets




Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
restart all cards