Proteins & Genes

Question 1

Transcription
(What it does & where it occurs?)
- DNA –> mRNA

Answer 1

Transcription occurs to make a protein from the genes within DNA
- DNA is first transcribed into an
mRNA molecule
- The ‘m’ is for “messenger”
It occurs in the nucleus of
eukaryotes and in the cytoplasm
of prokaryotes

Question 2

RNA

Answer 2

Has similar similar shape as DNA but single helix
- Has nitrogenous bases that are mostly similar to DNA
- Uracil, in place of Thymine,
pairs with Adenine

Pairs :
Uracil & Adenine
Guanine & Cytosine

Question 3

Transcription - Initiation Process

• RNA polymerase
• Transc. bubble
• Re-wound

Answer 3

1. RNA polymerase locates a promoter region of the DNA
   - Promoter will be ahead of a particular gene
2. A transcription bubble forms where DNA is partially separated or unwound
3. The DNA is re-wound behind the RNA polymerase

Question 4

Transcription - Elongation Process
-1 side –> temp.
- RNA poly. –> form mRNA

Answer 4

1. One side of DNA becomes the template strand
2. RNA polymerase adds nitrogenous bases to form mRNA

Question 5

Transcription - Termination Process

Answer 5

1. mRNA is set free

Question 6

Transcription - Post Processing

• Stabilizing
• Caps
• Introns & Extrons

Answer 6

Post-processing occurs in the nucleaus of eukaryotes before migrating to cytoplasm

During the process :
1. Stabilizing proteins are added to
prevent degradation
2. Caps are added to the ends of
mRNA
3. Introns are spliced out (removed);
exons stay put in mRNA

Question 7

Genetic Code

Answer 7

Conists of nitrogenous base pairs that code in triplets
- Each possible triplet codes for an amino acid

Question 8

Translation (Protein Synthesis)

(What it does and where it occurs?)

• mRNA –> proteins

Answer 8

Consists of using mRNA to build proteins

Takes place in cytoplasm
- Ribosomes help the synthesis
process

Composed of large and small
subunits

Question 9

Translation - Initiation Process

• tRNA –> start codon

Answer 9

tRNA interacts with start codon to begin process
- The ‘t’ is for “transfer”

Question 10

Translation - Elongation Process

• tRNA enter –> bring AA
• condons –> which AA is needed
• AA attrcted to chain –> tRNA leaves

Answer 10

More tRNAs come in, bringing amino acids with them
- Codons tell tRNAs which amino
acids are needed
- As amino acid is attached to
growing chain, tRNA leaves

Question 11

Translation - Termination Process

• S codon –> ribsosome –> release P & mRNA

Answer 11

Stop codon tells ribosome to release protein and mRNA

Question 12

Gene Regulation - Prokaryotes

Answer 12

Proteins must be synthesized at the
right times & in the right amounts
(gene expression)

Prokaryotes regulate transcription to
control gene expression
- Because transcription and translation occur in the same place

Question 13

Gene Regulation Eukaryotes

Ep.Transcrip.Translat.P.Transl.

Answer 13

Proteins must be synthesized at the
right times & in the right amounts
(gene expression)

Eukaryotes have multiple ways to
regulate gene expression
- Epigenetic: when DNA is unwound
- Transcriptional: when RNA is transcribed
- Translational: when RNA is translated to
protein
- Post-translational: occurs after protein is made