Neil

Question 1

Expression vector

Answer 1

A plasmid or virus designed for gene expression in cells. Used to introduce specific gene into target cell and lead to protein synthesis

Question 2

Shuttle vector

Answer 2

A plasmid designed so it can propagate in two different host species

Question 3

Describe the two mechanisms of protein evolution

Answer 3

Gradual accumulation of mutations that in some way enhance the protein

Recombination which results in chimeras (hybrid proteins) with enhanced properties

Question 4

An example of a virus with a single stranded DNA genome is:

Answer 4

M13 bacteriophage

Question 5

An example of an organism with a double stranded RNA genome is

Answer 5

Blue tongue virus

Question 6

A retrovirus has a _______ genome

Answer 6

Single standard RNA

Question 7

E. Coli had a ___________________ genome

Answer 7

Circular double stranded

Question 8

Humans have a _______________

Answer 8

Linear double stranded DNA genome

Question 9

Give an example of an organism with a linear single stranded DNA

Answer 9

Parovirus

Question 10

Give an example of an organism with a circular single stranded DNA genome

Answer 10

Porcine circovirus (PCV)

Question 11

Describe gene expression in viral RNA genomes.

Answer 11

In many viruses genes are encoded by RNA not DNA

RNA can be D-S or S-S

In many cases RNA is reverse transcribed into DNA and then translated normally

Question 12

Describe the effect of orientation on translation of single stranded RNA genomes

Answer 12

Positive sense: can be directly translated even in the absence of a cap or poly A tail

Antisense: first converted into a positive sense ssRNA molecule by RNA dependent RNA pol.

Ambisense: parts can be translated directly but other parts have to be converted to positive sense first

Question 13

Enhancers can occur in a variety of positions with respect to genes:

Answer 13

Up/downstream
Distal
Adjacent
Internal

Question 14

Need direct contact between _________ and _________ for activation

Answer 14

Enhancer

Promoter

Question 15

What role do snRNAs play?

Answer 15

Found in splicing speckles

Involved in processing of pre mRNA

Always associated with snRNPs

Question 16

Twintrons

Answer 16

Intron within an intron

Removed in a two step process

Question 17

Describe the role of small nuclear RNAs (snoRNA)

Answer 17

Involved in chemical modification of rRNAs

Pan-editing: insertion of uracil

Methylation

Question 18

Describe micro RNAs (miRNA)

Answer 18

Control gene expression: fold back RNA to form stem loops, cut into individual loops by drosha. Cut again by dicer

Silence endogenous mRNAs so there are not translated

Question 19

C value

Answer 19

Total amount of DNA in haploid genome

Question 20

C value paradox

Answer 20

Apparent lack of correlation between organisms c value and morphological complexity due to variations in repetitive DNA

Question 21

In bacteria, genome size is related to _________ and _________

Answer 21

Complexity

Environmental

Question 22

In viruses and bacteria __________ is proportional to ________

Answer 22

Genome size

Gene number

Question 23

How many chromosomes do bacteria have?

Answer 23

Most have one but some contain additional replicants that can be considered to be either mega plasmids or mini chromosomes

A few have more than one true chromosome

Question 24

Chromosome copy number size variation

Answer 24

Genes closer to origin can have high copy number (up to 4) in dividing cells due to multiple initiations

Question 25

Operons

Answer 25

Genes transcribed together but translated separately

Question 26

Overall gene function can be investigated by _____________:
______________
______________
_______________

Answer 26

Gene inactivation by
Homologous recombination
Transposon mutagenesis
RNA interference

Question 27

Differential splicing

Answer 27

Means that one gene can produce more than one protein

E.g. Human slo gene contains 35 exons and generates 500 mRNA species. Encoded protein involved in sound reception in cochlea, variants detect different frequencies

Question 28

RNA editing can:

Answer 28

Result in multiple proteins from a single message

Question 29

Repeated genes/clusters

Answer 29

Multiple similar genes. Normally occurs when genes required in high frequencies.

Eg. rRNAs

Question 30

Multigene family

Answer 30

Multiple different genes

Eg. Haemoglobin needs to be expressed in different forms over lifetime

Question 31

Describe the two types of pseudogenes

Answer 31

Conventional: mutations have occurred in a gene sequence and caused it to become non functional

Processed: gene sequence contains neither introns or promoters. Derived from DNA copies of mRNA which have become incorporated into the genome