1.2

Question 1

transcription

Answer 1

the synthesis of RNA using the info form DNA
- info is “rewritten”
- resulting RNA is transcript of the gene’s protein building instructions

Question 2

RNA processing

Answer 2

RNA molecules are spliced and have ‘5 cap and a poly-A tail put on their ends

Question 3

introns

Answer 3

any nucleotide sequence within a gene that is removed by RNA processing during production of the final RNA product.

Question 4

exons

Answer 4

a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Question 5

mRNA transport

Answer 5

mRNA formed in nucleus is transported out of nucleus to cytoplasm where it attaches to rRNA (ribosomes)

Question 6

translation

Answer 6

synthesis of a polypeptide using info in the mRNA

Question 7

polypeptide

Answer 7

a linear organic polymer consisting of a large number of amino-acid residues bonded together in a chain, forming part of (or the whole of) a protein molecule

Question 8

protein processing

Answer 8

protein folding and formation of disulfide bridges

Question 9

RNA polymerase

Answer 9

RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription - goes toward 5’ end

Question 10

what directs the folding of a polypeptide into a specific and unique shape?

Answer 10

its specific amino acid sequence (hydrophobic/hydrophilic/etc)

Question 11

examples of post-translational modifications that might be required to produce a mature protein

Answer 11

attachments of sugars, lipids, phosphate groups, etc
removal of amino acids
can be cleaved
chains can be synthesized

Question 12

free ribosomes

Answer 12

located in the cytosol
- synthesizes proteins that function in the cytosol

Question 13

bound ribosomes

Answer 13

attached to ER or nuclear envelope
- makes proteins of endomembrane system as well as proteins secreted from the cell

Question 14

endomembrane system

Answer 14

the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles and the plasma membrane.

Question 15

steps for a protein to be recognized as needing to be synthesized and inserted into the RER?

Answer 15

1. polypeptide synthesis begins on a free rRNA in the cytosol
2. an SRP binds to the signal peptide, halting synthesis momentarily
3. SRP binds to a receptor protein in the ER membrane, part of a protein complex that forms a pore
4. the SRP leaves, and polypeptide synthesis resumes with simultaneous translocation across the membrane
5. the signal peptide is cleaved by an enzyme receptor protein complex
6. the rest of the completed polypeptide leaves the ribosome and folds into tis final conformation

Question 16

SRP

Answer 16

signal recognition particle

Question 17

signal peptides can target polypeptides to what other parts of the cell?

Answer 17

mitochondria, chloroplasts, interior of the nucleus, and other organells NOT part of the endomembrane syst.

Question 18

signal peptides are like….

Answer 18

postal zip codes