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L3. Activities of the cytoplasm is directed by the_____?
Nucleus
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L3. The part of the cell between the nuclear membrane and the cell membrane is the?
Cytoplasm
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L3.DNA makes RNA..RNA makes?
Protein
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L3. RNA is made in the nucleus and then does what?
Leaves the nucleus to do its job in cytoplasm
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L3.What is transcribed in the nucleolus?
Ribosomal RNA
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L3. Cells that secrete large quantities of protein need more:
Ribosomes & have larger nucleoli
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L3. What forms a ribosome?
4 different types of ribosomal RNA and the 82 ribosomal proteins that self assemble in the saline environment of the cytoplasm
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L3.What is the central dogma of molecular biology?
DNA makes RNA and RNA makes protein by Sir Francis Crick (w/ mRNA in mind)
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L3.Where does the transcription of DNA into complementary mRNA take place?
�Transcript Domains� in the equatorial plane of the nucleus
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L3.What is post-transcriptional processing?
The removal of the introns and joining of the exons
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L3. What small nuclear organelles cut out the introns and join the exons to form usable m-RNA?
Spliceosomes
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L3. A haploid genome contains how many structural genes?
25,000
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L3. All the RNA�s leave the nucleus through what?
Nuclear pores
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L3. Transfer RNA�s binds to a particular amino acid to do what?
Bring it to the right codon of the m-RNA so it can be incorporated into a protein
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L3. What is the carrier protein that RNA is attached to?
RanGTP
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L3. How is the RNA released into the cytoplasm?
The transport protein lining the nuclear pore binds to RanGTP, uses the energy of the high-energy phosphate bond to transport the RNA-RanGTP complex to the cytoplasmic side of the pore, and then releases the RNA and GDP into the cytoplasm
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L3. Ribosomes have to wait for what to specify the amino acid sequence of the protein?
They must wait for a messenger RNA
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L3. Messenger RNA carries what?
The code for the protein for the ribosome
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L3. What is a polyribosome?
Several ribosomes sharing the same strand of m-RNA
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L3. An enzyme specific for an amino acid uses ____ to attached an amino acid to a specific transfer RNA.
ATP
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L3. Transfer RNA-linked amino acid is activated by what?
By binding GTP
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L3. The anticodon on one end of a t-RNA _________bonds to the condon on the mRNA.
Hydrogen
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L3. The large subunit of the ribosome removes what to link each amino acid to the one before it?
Removes the GTP
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L3. Once the AA is linked to the one b4�the mRNA moves how far?
1 codon or 3 base pairs
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L3.When the ribosomes have finished making protens, what drops off?
m-RNA
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L3.M-RNA is tagged by?
Interfering RNA
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L3. The m-RNA is broken down by enzymes in cystoplasmic spots called?
P-bodies (structure unknown)
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L3. Adenosine phosphate, Uridine phosphate, Guanosine phosphate, cytidine phosphate are examples of what?
Ribonucleotides that return to the nucleus to be reassembled into RNA
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L3.What is the constant turnover of m-RNA?
2 hours
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L3. Protein function depends primarily on?
Shape
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L3. Chaperone proteins also known as heat shock proteins do what?
Catalyze the folding of proteins into the correct shapes
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L3. What happens if you have a fever?
More chaperone proteins are produced to keep the enzyme proteins and structural proteins in correct shapes
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L3. What is cytosol?
Cytoplasm that is not compartmentalized by membranes
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L3. Chaperonins are what?
Cytosolic chaperone proteins that are organized into 11x11 cylinders
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L3. What does a chaperonin consist of?
2 rings, each contains 8 monomers and a protrusion
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L3. What�s the job of the protrusion on the chaperonin?
Recognizes a protein in need of folding and guides it into the cavity formed by the rings
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L3. What supplies the energy to fold the proteins into conformity with the cavity?
Magnesium-activated ATPase
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L3. What are prions?
Misfolded proteins that can cause more proteins of the same type of fold incorrectly ex. Mad cow
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L3. Proteins needed in the nucleus are bound to what?
-
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L3. What is a proteasome?
- Is when a cytosolic protein is no longer needed and is broken down in this specialized organelle.
- It�s a small hollow cylinder 15 nm long and 11 nm in diameter. Made up of 4 rings staked
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L3. What are on each of 2 end rings of the proteasome?
It is made up of 7-alpha unit proteins
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L3. What are the 2 central rings of the proteasome made of?
They are made up of 7-beta unit proteins that each have a peptide-bond breaking site
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L3. How far apart are the peptide-bond-breaking sites of the beta-unit proteins of the proteasome?
They are 1.4 nm apart, which is the span of 6 peptide bonds
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L3. Making RNA in the nucleus is known as?
Transcription
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L3. Going from RNA to a protein is called what?
Translation
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L3. What breaks down peptides into free amino acids?
Cytosolic peptidases
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L3. What caps the end of a human proteasome?
Regulatory Protein
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L3. The regulatory protein will admit a protein to the proteasome only if its conjugated to a chain of 4 molecules of the small protein, ________?
Ubiquitin
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L3. What is the key step in the regulated destruction of cytosolic proteins?
Conjugation to ubiquitin
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L3. What enzymes prepare ubiquitin for conjugation?
E1, E2, E3
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L3. Which enzyme actually attaches ubiquitin to the protein?
E3 or ubiquitin ligase
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L3. Excess production of an E3 causes what?
Fatal Deficiency of the protein it tags for destruction
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L3. Insufficient production of an E3 can cause what?
It causes fatal excess of the protein
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L3. Theres an absence of E3 for cyclins in what kind of cells?
Cancer cells
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L3. Cancer is caused by the mutation of what protein?
P53, 55% of cancers have a defective p53
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