Molecular pathology

Question 1

background knowledge

The se…………., po………. and faithful repl………… of a gene on its particular chromosome is important in pathology

Any changes= ………… can result in disease

Answer 1

The sequence, position and faithful replication of a gene on its particular chromosome is important in pathology

Any changes= mutations can result in disease

Question 2

DNA duplex can be ‘melted’ or denatured into two single strands:

• He……….
• Under conditions of ………

On cooling the DNA strands will re-………….. (anneal) to form the ………..

Only ………………… strands anneal (h……………….)

Denaturation and hybridisation form the core of all molecular diagnostic techniques

DNA double helices> ……. temp or high …… > denaturation to single strands (nucleotide pairs broken > slowly cool or lower pH > rena………… rest……. DNA double ………….. (nucleotide pairs ………………)

Answer 2

DNA duplex can be ‘melted’ or denatured into two single strands

• Heating
• Under conditions of pH

On cooling the DNA strands will re-associate (anneal) to form the duplex

Only complementary strands anneal (hybridisation)

Denaturation and hybridisation form the core of all molecular diagnostic techniques

DNA double helices> high temp or high Ph > denaturation to single strands (nucleotide pairs broken > slowly cool or lower pH > renaturation restores DNA double helices (nucleotide pairs re-formed)

Question 3

Replication of DNA

• E…………… process
• Following denaturation= each s………… strand is used as a ……………
• DNA …………….. add A, T, G, C bases = follows c…………… rule
• Two new ………….. double-stranded molecules are formed
• Occurs in cell division = whole …………… are …………….
• Forms the basis of …………… chain reaction (PCR)

Answer 3

• Enzymatic process
• Following denaturation= each single strand is used as a template
• DNA polymerases add A, T, G, C bases = follows complementary rule
• Two new identical double-stranded molecules are formed
• Occurs in cell division = whole chromosomes are duplicated
• Forms the basis of polymerase chain reaction (PCR)

Question 4

Important enzymes involved with DNA replication

Helicase = Unzips the DNA strand

Primase = RNA ………, tells the next enzyme where to ………..

Reverse transcriptase (RT) = production of copy ………. (cDNA) from ………..

Restriction endonucleases = ……… nucleic acids at specific sites into r……………… fra………… = different restriction enzymes recognise a specific short seq……….. of b……….

Ligases = …………. lengths of …………… acids

Answer 4

Helicase = unzips the DNA strand

Primase = RNA primer, tells the next enzyme where to begin
DNA polymerase = adds nucleotides

Reverse transcriptase (RT) = production of copy DNA (cDNA) from RNA

Restriction endonucleases = cut nucleic acids at specific sites into restriction fragments = different restriction enzymes recognise a specific short sequence of basis

Ligases = join lengths of nucleic acids

Question 5

Key points

The chemical and physical properties of DNA and RNA are exploited in all molecular diagnostic tests

The most important of these are:

• C…………………
• D………………..
• H……………………..
• R………………..

Answer 5

Key points

The chemical and physical properties of DNA and RNA are exploited in all molecular diagnostic tests

The most important of these are:

• Complementarity
• Denaturation
• Hybridisation
• Replication

Question 6

Changes to Normal DNA structure

Mutation - alteration within …… leading to a change in the product which the DNA codes for.

Translocation = the abnormal ………….. of parts of chromosomes

Amplification = is an i………. in the number of c……….. of a particular g………..

Deletion = Ra……… in si……. from a si……… base to a whole gene del………

Insertion = usually ………. ……… pairs added along the sequence

Inversion - a stretch of DNA is ………… and ………… in the same place but in the opposite ……………

The ………….. of the mu………… within the sequence is more important as this will affect the f………….

Answer 6

hanges to Normal DNA structure

Mutation - alteration within DNA leading to a change in the product ;which the DNA codes for.

Translocation = the abnormal position of parts of chromosomes

Amplification = is an increase in the number of copies of a particular gene

Deletion = Range in size from a single base to a whole gene deletion

Insertion = usually extra base pairs added along the sequence

Inversion - a stretch of DNA is removed and inserted in the same place but in the opposite orientation

The position of the mutation within the sequence is more important as this will affect the function