Gene Expression: From Gene to Protein - PowerPoint Presentation

Slide1

Gene Expression: From Gene to ProteinSlide2

Which of the following can be the final product of an expressed gene?

mRNA

tRNArRNApolypeptideSlide3

Which of the following can be the final product of an expressed gene?

mRNA

tRNArRNA

polypeptideSlide4

Which of the following terms does not pertain to translation?

anticodon

tRNAaminoacyl-tRNA

synthetase

polypeptide

rRNA

DNASlide5

Which of the following terms does not pertain to translation?

a

nticodontRNA

aminoacyl-tRNA

synthetase

polypeptide

rRNA

DNASlide6

The template strand of a given gene includes the sequence 3



-G C C A C G T A T C A G-5

What is the sequence of the

nontemplate

strand?

3



-C G

G

T G C A T A G T-5



5



-C G G T G C A T A G T-35-C G G U G C A U G U-33-C G G U G C A U G U-5Slide7

The template strand of a given gene includes the sequence 3



-G C C A C G T A T C A G-5

What is the sequence of the

nontemplate

strand?

3



-C G

G

T G C A T A G T-5



5



-C G G T G C A T A G T-35-C G G U G C A U G U-33-C G G U G C A U G U-5Slide8

Which of the following is the best example of gene expression?

A frog adapts to variation in its environmental temperature.

Mouse fur color results from pigment formed by gene-encoded enzymes.DNA is replicated during the S phase of the cell cycle.

The percent of A versus a alleles in a population is altered by natural selection.

Mutation alters the sequence of a region of DNA.Slide9

Which of the following is the best example of gene expression?

A frog adapts to variation in its environmental temperature.

Mouse fur color results from pigment formed by gene-encoded enzymes.DNA is replicated during the S phase of the cell cycle.

The percent of A versus a alleles in a population is altered by natural selection.

Mutation alters the sequence of a region of DNA.Slide10

The ability of genes from one species to be expressed in a different species is possible because of which property of the genetic code?

the near universality of the genetic code

All species in E

ukarya

use the same genetic code.

Gene expression

doesn

’

t utilize the genetic code.RNA codons are the same in all organisms, but

DNA codons are different.

Gene expression in the

laboratory is tolerant of

genetic differences.Slide11

The ability of genes from one species to be expressed in a different species is possible because of which property of the genetic code?

the near universality of the genetic code

All species in Eukarya

use the same genetic code.

Gene expression

doesn

’

t utilize the genetic code.

RNA codons are the same in all organisms, but

DNA codons are different.

Gene expression in the

laboratory is tolerant of

genetic differences.Slide12

In the transcription process, as diagrammed in Figure 17.7 and below, in which process (1, 2, or 3) does the RNA polymerase bind to the promoter, is the RNA transcript released, and is the RNA transcript extended?

1; 2; 3

2; 3; 1

3; 2; 1

1; 3; 2Slide13

In the transcription process, as diagrammed in Figure 17.7 and below, in which process (1, 2, or 3) does the RNA polymerase bind to the promoter, is the RNA transcript released, and is the RNA transcript extended?

1; 2; 3

2; 3; 1

3; 2; 1

1; 3; 2Slide14

Which of the following components

doesn

’t form part of the transcription complex at a eukaryotic promoter?

TATA box

start point

transfer RNA

transcription factors

RNA polymeraseSlide15

Which of the following components

doesn

’t form part of the transcription complex at a eukaryotic promoter?

TATA box

start point

transfer RNA

transcription factors

RNA polymeraseSlide16

Which of the following is not a modification made to eukaryotic mRNA before it goes to the cytosol?

The 5



end is capped

A poly-A tail is added to the 3



end

Introns are removed

Exons are joined together

Spliceosomes

are removedSlide17

Which of the following is not a modification made to eukaryotic mRNA before it goes to the cytosol?

The 5



end is capped

A poly-A tail is added to the 3



end

Introns are removed

Exons are joined together

Spliceosomes

are removedSlide18

Which of the following is not a difference between prokaryotic and eukaryotic transcription?

Part

of the RNA polymerase specifically recognizes and binds to the promoter in bacteria; in

eukaryotes,

transcription factors mediate the binding of

polymerase.

The

RNA transcript is immediately useable as mRNA;

in eukaryotes, the

RNA transcript is

processed.

RNA

polymerase

requires

a primer in bacteria; in

eukaryotes,

it does

not.

Eukaryotic

transcription has a

polyadenylation

signal sequence; in

prokaryotes,

a transcription terminator causes the polymerase to detach

and

release the

transcript.Slide19

Which of the following is not a difference between prokaryotic and eukaryotic transcription?

Part

of the RNA polymerase specifically recognizes and binds to the promoter in bacteria; in

eukaryotes,

transcription factors mediate the binding of

polymerase.

The

RNA transcript is immediately useable as mRNA;

in eukaryotes,

the RNA transcript is

processed.

RNA

polymerase

requires

a primer in bacteria; in

eukaryotes,

it does

not.

Eukaryotic

transcription has a

polyadenylation

signal sequence; in

prokaryotes,

a transcription terminator causes the polymerase to detach and release the

transcript.Slide20

Which of the following is incorrectly identified in the figure (Figure 17.15)?

5

 and 3



ends

hydrogen bond

amino acid attachment site

anticodon loop

A

B

D

CSlide21

Which of the following is incorrectly identified in the figure (Figure 17.15)?

5

 and 3



ends

hydrogen bond

amino acid attachment site

anticodon loop

A

B

D

CSlide22

Aminoacyl-tRNA

synthetase is an enzyme whose function is to ________.link a

tRNA

to its amino acid

r

emove introns from a pre-RNA transcript

c

ause the RNA polymerase to detach from the DNAjoin together RNA nucleotides complementary to the DNA template stran

dSlide23

Aminoacyl-tRNA

synthetase is an enzyme whose function is to ________.link a

tRNA

to its amino acid

r

emove introns from a pre-RNA transcript

Cause the RNA polymerase to detach from the DNA

join together RNA nucleotides complementary to the DNA template strandSlide24

To show how sequence logos are made, the potential ribosome-binding regions from

10

Escherichia

coli

 genes are shown in a sequence alignment. The figure to the right is the sequence logo derived from the aligned sequences. In the sequence logo, the horizontal axis shows the primary sequence of the DNA by nucleotide position. Letters for each base are stacked on top of each other according to their relative frequency at that position among the aligned sequences, with the most common base as the largest letter at the top of the stack. The height of each letter represents the relative frequency of that base at that position

.

Scientific Skills ExerciseSlide25

In the sequence alignment (on the previous slide), how many of each base appear at position –9?

5 G, 4 A, 1 T, 0 C

7 G, 2 A, 1 C, 0 T4 G, 3 T, 3 A, 0 CSlide26

In the sequence alignment (on the previous slide), how many of each base appear at position –9?

5 G, 4 A, 1 T, 0 C

7 G, 2 A, 1 C, 0 T4 G, 3 T, 3 A, 0 CSlide27

In the sequence alignment,

how many of each base appear at position 0

? 8

A, 1 G, 1 T, 0 C

4

T, 3 C, 3 A, 0 G

10

T, 0 A, 0 C, 0

GSlide28

In the sequence alignment,

how many of each base appear at

position 0? 8 A, 1 G, 1 T, 0 C

4

T, 3 C, 3 A, 0 G

10

T, 0 A, 0 C, 0

GSlide29

In the sequence alignment, how many of each base appear at position 1

?

10 G, 0 C, 0 A, 0 T4 T, 3 C, 3 A, and 0 G10 T, 0 A, 0 C, 0 GSlide30

In the sequence alignment, how many of each base appear at position 1?

10 G, 0 C, 0 A, 0 T

4 T, 3 C, 3 A, and 0 G10 T, 0 A, 0 C, 0 GSlide31

The height of a stack of letters in a logo indicates the predictive power of that stack (determined statistically). If the stack is tall, we can be more confident in predicting what base will be in that position if a new sequence is added to the logo. For example, at position 2, all 10 sequences have a G; the probability of finding a G there in a new sequence is very high, as is the stack. For short stacks, the bases all have about the same frequency, so it’s hard to predict a base at those positions.

Which two positions in the logo sequence have the 

most

 predictable bases, and which bases would you predict at those two positions in a newly sequenced gene

?

position

1 (T) and position 2 (G)

position

–10 (G) and position –7 (A)

position

0 (A) and position 2 (G)

position

0 (A) and position 1 (T

)Slide32

The height of a stack of letters in a logo indicates the predictive power of that stack (determined statistically). If the stack is tall, we can be more confident in predicting what base will be in that position if a new sequence is added to the logo. For example, at position 2, all 10 sequences have a G; the probability of finding a G there in a new sequence is very high, as is the stack. For short stacks, the bases all have about the same frequency, so it’s hard to predict a base at those positions.

Which two positions in the logo sequence have the 

most

 predictable bases, and which bases would you predict at those two positions in a newly sequenced gene

?

position

1 (T) and position 2 (G)

position

–10 (G) and position –7 (A)

position

0 (A) and position 2 (G)

position

0 (A) and position 1 (T

)Slide33

Which positions in the logo have the 

least

 predictable bases? How can you tell?All positions other than 1 and 2 have equally low predictive power because they have multiple bases in their stacks.

The four positions with the shortest stacks of bases have the lowest predictive power (–15, –14, –3, and 3).

The 13 positions that are each missing at least one base from the stack have the lowest predictive power

(–15, –13, –9, –8, –7, –3, –1, 0, 1, 2, 3, 4, and 7).

The 12 positions showing no bases have the lowest predictive power (–18, –17, –16, –12, –11, –6, –5, –4,

–2, 5, 6, and 8).Slide34

Which positions in the logo have the 

least

 predictable bases? How can you tell?All positions other than 1 and 2 have equally low predictive power because they have multiple bases in their stacks.

The four positions with the shortest stacks of bases have the lowest predictive power (–15, –14, –3, and 3).

The 13 positions that are each missing at least one base from the stack have the lowest predictive power

(–15, –13, –9, –8, –7, –3, –1, 0, 1, 2, 3, 4, and 7).

The 12 positions showing no bases have the lowest predictive power (–18, –17, –16, –12, –11, –6, –5, –4,

–2, 5, 6, and 8).Slide35

In the actual experiment, the researchers used 149 sequences to build their sequence logo, as opposed to just 10. Now there is a stack at each position, however short, because the sequence logo includes more data.Slide36

Which three positions in the sequence logo in the figure have the 

most

predictable bases? Name the most frequent base at each position.position –18 (T); position –5 (A); position 8 (A)

position 0 (A); position 1 (T); position 2 (G)

position 0 (T); position 1 (A); position 2 (C)

position –11 (G); position –10 (G); position –9 (G)Slide37

Which three positions in the sequence logo in the figure have the 

most

predictable bases? Name the most frequent base at each position.position –18 (T); position –5 (A); position 8 (A)

position 0 (A); position 1 (T); position 2 (G)

position 0 (T); position 1 (A); position 2 (C)

position –11 (G); position –10 (G); position –9 (G)Slide38

What gene feature is represented by the bases in positions 0–2?

the translation stop codon

the transcription start site ATG

the ribosome binding site

the translation start codon AUGSlide39

What gene feature is represented by the bases in positions 0–2?

the translation stop codon

the transcription start site ATG

the ribosome binding site

the translation start codon AUGSlide40

Based on the logo, what five adjacent base positions in the 5' UTR region (the untranslated region at the 5' end of the mRNA) are most likely involved in ribosome binding?

Positions –1 to 3 include the tallest stacks; therefore, they represent the most likely sequence for the ribosome binding site.

Positions –12 to –8 have the tallest stacks in the 5' UTR region; therefore, they represent the most likely sequence

for the ribosome binding site.

Positions –5 to –1 are adjacent to

the AUG start codon in the 5' UTR

region; therefore, they represent

the most likely sequence for the

ribosome binding site.Slide41

Based on the logo, what five adjacent base positions in the 5' UTR region (the untranslated region at the 5' end of the mRNA) are most likely involved in ribosome binding?

Positions –1 to 3 include the tallest stacks; therefore, they represent the most likely sequence for the ribosome binding site.

Positions –12 to –8 have the tallest stacks in the 5' UTR region; therefore, they represent the most likely sequence

for the ribosome binding site.

Positions –5 to –1 are adjacent to

the AUG start codon in the 5' UTR

region; therefore, they represent

the most likely sequence for the

ribosome binding site.