Lecture Oct 23, 2024, (end L.7, start L.8)

Question 1

What is alternative splicing?

Answer 1

Splicing is done at different poitns, depending on the required cell

Question 2

What are the 100% conserved sequences on an intron

Answer 2

Start= 5’ GU
Branch point= A
End= AG 3’

Question 3

How does splicing occur?

Answer 3

U1 binds to start of intron,
U2 binds to end of intron
U4/U6 and U5 bind together at branch point

Question 4

What is actin?

Answer 4

protein for muscle cells

Question 5

What does the Poly-A tail do?

Answer 5

The final maturation step for pre-mRNA

Question 6

What signal is used to tell the enzyme where to cut?

Question 7

What does the poly-A binding protein do?

Question 8

How does the RNA know when to terminate?

Answer 8

It doesn’t?

Question 9

Where does the export RNA leave to go to the cutoplasm

Answer 9

nuclear pore complex

Question 10

What does acellular mean?

Question 11

Lecture #8

Question 12

Why are 3 nucleiotides used for 1 a.a?

Answer 12

Because we need to be able to code 20 a.a (why?), and that allows us to do that

Question 13

Feautures of genetic code

Answer 13

• no commas
• no overlap
• degenrate
• universal

Question 14

What does ATG code for?

Answer 14

methionine

Question 15

What is a codon?

Answer 15

One unit of the
nucleotide triplet which
specifies an amino acid

Question 16

What do the stop codons code for?

Answer 16

none

Question 17

Names for the 3 kinds of stop codns

Answer 17

amber

Question 18

Do all stop codons stop the translation?

Answer 18

No, only if they’re within frame

Question 19

What does ORF stand for? What is it?

Answer 19

Open reading frame. Includes both START and STOP codon within frame

Question 20

How many different reading frames can a strand have?

Answer 20

6

Question 21

What is genetic code degeneracy

Answer 21

When one amino acid has multiple nucleiotide codes

Question 22

Stop codons

Answer 22

TAG, TGA, TAA (all start with a T, switch the G and A, and double A)

Question 23

What are the color names for the stop codons?

Answer 23

TAG (amber), TGA (ochre), TAA (opal)

Question 24

How many reading frames are there? How many open reading frames are there

Answer 24

6 different reading frames on a dsDNA, but always only 1 open reading frame

Question 25

What direction is DNA read?

Answer 25

5’ to 3’ ALWAYS

Question 26

What mutation causes sickle cell anemia?

Answer 26

A point mutation on the β-hemoglobin primary sequence. 6th codon, GAA to GUA

Question 27

What amino acid change causes sickle cell anemia?

Answer 27

Glutamic acid (neg charge and polar) to valine(non-polar)

Question 28

Point mutations at ____ codon
position typically makes a larger
change

Answer 28

1st