Proteins 1

Question 1

The Central Dogma

Answer 1

a scheme that underlies information processing at the level of gene expression
the flow defines the relation between the seq. of bases in DNA and the seq. of amino acids in a protein

DNA—–>RNA—–> Protein

Question 2

Flaws in the Central Dogma

Answer 2

• It states that such information cannot be transferred back from protein to either protein or nucleic acid
• The basic tenets of the scheme are correct but it is an oversimplification

Question 3

The Genome

Answer 3

all genetic information of an organism,
nucleotide sequences of DNA (or RNA in RNA viruses)

-includes both the genes (the coding regions) and the noncoding DNA, as well as mitochondrial DNA and chloroplast DNA

Question 4

Genomics

Answer 4

The study of the genome

Question 5

The Proteome

Answer 5

entire set of proteins that is, or can be expressed by a genome, cell, tissue or organism, at a given time, under defined conditions

The functional representation of the genome

Question 6

Proteomics

Answer 6

The study of the proteome

Question 7

Compare the size and complexity of the proteome with the genome

Answer 7

The proteome is much larger and more complex because there are various transcription pathways (alternative splicing of pre-mRNA) and post-translational modifications

Question 8

Examples of post-translational modifications

Answer 8

proteolytic cleavage, glycosylation and phosphorylation

Question 9

What does the proteome vary with?

Answer 9

• cell type
• developmental stage
• environmental conditions

It is NOT a fixed characteristic of the cell

Question 10

The function of a protein depends on what?

Answer 10

It’s 3D structure

amino acid seq. —-> 3D structure —-> function

Question 11

What is the C-value?

Answer 11

The amount of DNA per haploid genome

Question 12

The C-value paradox

Answer 12

There is no real correlation between genome size and complexity of the organism

Question 13

Why is there no correlation between genome size and complexity?

Answer 13

• the proportion of non-coding DNA varies with organism
• repetitive DNA
• genome duplication

Question 14

Polyploidy

Answer 14

The organism has more than 2 sets of chromosomes in its cells

Question 15

Ploidy

Answer 15

The mutation caused by the change in the no. of chromosomes in an organism

Question 16

Autopolyploidy

Answer 16

polyploids produced by the multiplication of chromosome sets that are initially from a single species (often sterile)

Question 17

Allopolyploidy

Answer 17

polyploids produced from 2 different species

Question 18

Causes of polyploidy

Answer 18

failure of cell division (by abnormal meiosis):

• fusion of a diploid and haploid gamete to form a triploid organism
• fusion of 2 diploid gametes to produce a tetraploid

Question 19

What does the C-value correlate with?

Answer 19

• cell size
• cell division rate
• body size
• metabolic rate
• developmental rate
• organ complexity
• geographical distribution
• extinction risk

Question 20

Non-coding RNA

Answer 20

referred to as the dark matter of the genome

• small non-coding RNA
• large non-coding RNA

Question 21

What makes analysing and investigating the proteome difficult?

Answer 21

proteins do not exist in isolation, they often interact with each other to form complexes with specific functional properties