Term
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Definition
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Term
| Where does transcription take place? |
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Definition
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Term
| What (polymer) is synthesized during transcription? |
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Definition
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Term
What molecules make up mRNA?
Where are they found? |
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Definition
RNA Nucleotides
Floating in the nucleus |
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Term
| What enzyme is required for transcription? |
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Definition
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Term
| What is Base-Pair rule for DNA to RNA? |
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Definition
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Term
| What is the Base-Pair rule for 2 DNA strands? |
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Definition
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Term
| What synthesizes nucleic acids of DNA? |
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Definition
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Term
| What synthesizes nucleic acids of RNA? |
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Definition
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Term
| What is at the 5' end of DNA/RNA? |
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Definition
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Term
| What is at the 3' end of DNA and RNA? |
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Definition
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Term
| What way is DNA synthesized? |
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Definition
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Term
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Definition
| By adding nucleotides to its 3' end |
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Term
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Definition
Double-helix
Double stranded
Anit-Parallel |
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Term
| Which strand of DNA contains the blueprint for the pre-mRNA? |
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Definition
| Template (reading) strand |
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Term
| Which direction is DNA read? |
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Definition
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Term
| Which direction is pre-mRNA molecule constructed? |
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Definition
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Term
| Why is transcription called it? |
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Definition
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Term
| What is a transcription factor? |
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Definition
Protein that binds to specific DNA sequences
Controls "flow"/transcription of genetic info from DNA to mRNA |
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Term
| What signals the beginning of a gene? |
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Definition
| RNA polymerase joins with several transcription factor proteins at promoter, which is a special sequencd of base pairs on the DNA template strand that signals the beginning of a gene |
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Term
| What is the transcription initiation complex? |
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Definition
Transcription factor proteins and RNA polymerase
Moves along DNA template strand at 40 base pairs per second producing pre-mRNA |
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Term
| What is a terminator sequence? |
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Definition
Base pairs on DNA template strand
When reached by RNA polymerase it completes production of pre-mRNA and releases it into the nucleoplasm |
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Term
| Where does transcription initiation complex form on DNA? |
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Definition
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Term
| Would a cell transcribe all of its genes simultaneously? |
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Definition
| No, each cell specialized for certain functions and will transcribe needed genes when they are needed |
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Term
| Do all cells transcribe their genes at some point? |
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Definition
| No, some stay off all the time (heart cell in skull) |
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Term
| What is removed from pre-mRNA to make it mRNA? |
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Definition
| Introns/Extrons and a start codon |
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Term
What was added to the mRNA that was not present in the pre-mRNA?
Where is it located? |
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Definition
Methyl cap - 5' end; helps molecule through nuclear pore and attach to ribosome...final destination
Poly-A tail - 3' end |
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Term
| Where does mRNA leave the nucleus? |
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Definition
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Term
| What sequence of bases indicates starting point for polypeptide "blueprint"? |
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Definition
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Term
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Definition
Travels through cytoplasm
Carries genetic info from DNA or ribosomes for protein synthesis |
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Term
| Why are some poly-A tails longer than others? |
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Definition
| If mRNA is longer, could be more easily degraded and so there needs to be a longer poly-A tail to prevent it |
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Term
| What is the advantage of having the poly-A tail? |
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Definition
Promotes binding of mRNA to ribosomes and helps it export from nucleus
Protects mRNA from exonucleases |
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Term
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Definition
Sections of pre-mRNA that are noncoding
Don't provide useful info for production of polypeptide being synthesized
When removed, certain DNA sections code for different polypeptides |
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Term
| How does a human genome produce more polypeptides than genes it contains? |
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Definition
| Introns removed, can code for different polypeptide sequences |
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Term
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Definition
| Portions of pre-mRNA remaining from introns |
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Term
| What are the 4 steps of transcription? |
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Definition
- DNA Helicase unwinds DNA as hydrogen bonds break
- Free nucleotides of RNA pair w/ complimentary DNA bases
- RNA sugar-phosphate backbons forms by RNA polymerase
- Hydrogen bonds of DNA/RNA ladder break and new mRNA goes to the ribosomes in the cytoplasm through nuclear pores
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Term
| What type of biological molecule is an exonuclease? |
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Definition
| Enzyme, removes nucleotides from either 3' or 5' end |
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Term
| Where do free nucleotides in nucleus needed to produce mRNA strands come from? |
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Definition
| They come from the exonuclease that detaches them from the stand |
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Term
| How might biologists use transcription mechanisms to support the theory of evolution? |
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Definition
Universal genetic code
Everyone is related |
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Term
| mRNA is ____ from the ____ code. Then, the mRNA sequence is translated into a _____ sequence |
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Definition
transcribed
DNA
polypeptide |
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Term
| What is the significance of a "triplet code"? |
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Definition
Language of mRNA
Each triplet of nucleotides codes for 1 codon/amino acid |
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Term
| If mRNA has 300 nucleotices in coding region, how many amino acids would be in synthesized polypeptide? |
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Definition
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Term
| What is the Wobble Process and whose hypothesis was it? |
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Definition
If one sequence is damaged, there are other sequences to produce the same amino acid
Crick |
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Term
DNA-tac
mRNA-____
polypeptide sequence-____ |
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Definition
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Term
| What amino acid is at the beginning of every polypeptide? |
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Definition
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Term
| What are the 3 stages of translation? |
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Definition
| Initiation (STARTS), Elongation (GROWS), Termination (STOP CODON) |
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Term
| Where does the mRNA attach to when it leaves the nucleus |
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Definition
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Term
| What is the significance of AUG |
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Definition
mRNA attaches to ribosome as sequence AUG
Starts process of translation |
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Term
| How does the ribosome move as translation occurs? |
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Definition
Moves down the mRNA strand
Translocation |
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Term
| What makes up the ribosome and what are its 2 subunits? |
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Definition
rRNA and proteins
Smaller-binds to mRNA strand(several at 1 time)-many polypeptide chains synthesized at once
Larger-holds tRNA molecules in place while the covalent peptide bond is formed between the amino acids |
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Term
| What are tRNA molecules in a cell and what do they contain? |
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Definition
Short sequences of nucleotides(80)
Anticodon and carry a specific amino acid |
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Term
| Why is tRNA called transfer? |
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Definition
| It transfers the amino acids from the nucleus to the ribosomes |
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Term
| How many tRNAs are held in ribosomes at same time during elongation? |
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Definition
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Term
| What happens to unattached tRNA after its delivered amino acid? |
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Definition
| Returns to nucleus to get more genetic material (amino acids) |
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Term
| What occurs during translation? |
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Definition
1. Release factor stops elongation
2. amino acid attaches to water molecule |
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Term
| What does translation do? |
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Definition
| Copies a message from nucleus(genetic info) |
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Term
| How many permutations are possible when 3 bases are used? |
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Definition
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Term
| Why can translation not occur while transcription occurs in eukaryotic cells? |
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Definition
1. Needs to wait for instructions from the nucleus
2. tRNA needs to supply amino acids |
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