Central Dogma

Question 1

What is central dogma?

Answer 1

• process by which instructions in DNA are converted into functional product

Question 2

Transcription

Answer 2

• DNA is transcribed into mRNA

Question 3

What is the difference between the sense strand and the template strand?

Answer 3

• The strand which is not transcribed but has same sequence as mRNA is sense strand
• the transcribed strand that has a sequence complementary to mRNA is template strand

Question 4

What are promoters?

Answer 4

• DNA has special sequences called promoters
• the RNA polymerase recognizes at start of gene (so the RNA polymerase knows where a gene begins and which to transcribe)

Question 5

Translation

Answer 5

• Convert the mRNA you have to proteins (ribosomes)

Question 6

What is the three-frame problem?

Answer 6

• the translation mix is artificial, in an actual cell, ribosome would pick the right reading frame
• right reading frame always starts with AUG - codon for methionin (start codon)

Question 7

Polysome

Answer 7

• many ribosomes can bind to same transcript

Question 8

Wobble pairing

Answer 8

• some tRNA’s can use more than one codon, the 5’ codon does not always perfectly line up with 3’ so can pair with more than one

Question 9

Sickle cell anemia

Answer 9

• the crises are often precipitated by changes in oxygen concentration
• come from individuals not having correct shape for red blood cells
• trait: missense mutation, changes single amino acid in protein

Question 10

What are the two types of mutations?

Answer 10

1) point mutation - small changes in single gene

2) chromosomal - changes that affect large portion of chromosome/affect many genes

Question 11

What are the types of point mutations? (they are smaller changes then chromosomal)

Answer 11

• Silent mutations: do not effect protein sequence
• Missense mutation: changes one amino acid to another
• Nonsense mutation: change amino acid to a stop codon thus truncating the protein. Stops it.
• Frame shift mutation: result from insertion or a deletion/changes the reading frame from point onward

Question 12

What are some types of chromosomal mutations?

Answer 12

• deletions: remove large piece of chromosome including many genes
• duplications: duplicate large chunks of chromosome
• inversion: when piece of DNA flips around, re-entering the chromosome in reverse orientation
• translocations: result when piece of DNA jumps from one chromosome to another - when two trade place

Question 13

What happens if mutation is somatic/or if mutation is germ line mutation?

Answer 13

• if mutation is somatic: change could kill the cell, make sick, cancerous (somatic cells do not make gametes, so they will not be transferred)
• if germ line: does produce gametes, could transmit to progeny, this is how lead to natural selection/new species