(SBI4U1) Molecular Biology Techniques

Question 1

Why is determining the sequence of DNA important? (4)

Answer 1

Solve crimes using DNA analysis
Determine paternity suits
Fetal screening for genetic disorders
Research to cure/treat diseases

Question 2

How do we sequence DNA? (3)

Answer 2

Break DNA in small pieces at specific sites
Copy or amplify DNA to et a large sample
Sort and analyse DNA

Question 3

How do we break DNA?

Answer 3

Can be cut into small fragments using restriction enzymes

Question 4

What do restriction enzymes do?

Answer 4

Recognize specific sequences of DNA and cut the DNA at these sites

Question 5

What are the sites the restriction enzymes cut the DNA at called?

Answer 5

Restricition sites

Question 6

What are restriction enzymes used for?

Answer 6

Used by prokaryotes to defend themselves against infection

Question 7

Restriction sites can now be used to _______ specific sequences of _______ that need to be _______

Answer 7

Isolate
Interest
Studied

Question 8

How do we amplify DNA?

Answer 8

We can make many copies of DNA segments by cloning using bacterial DNA call vectors

Question 9

What are bacterial vectors?

Answer 9

Circular portions of DNA

Question 10

What are bacterial vectors also known as?

Answer 10

Plasmids

Question 11

How is amplifying DNA by cloning using bacterial vectors accomplished? (3)

Answer 11

By cutting open the bacterial DNA (plasmid)
Cutting out the DNA sequence of interest using the same restriction enzyme
Inserting the DNA sequence cut out into the plasmid

Question 12

Why can DNA sequence be inserted into the cut plasmid?

Answer 12

Restriction enzymes leave sticky ends that are complementary on the bacterial plasmid and DNA of interest, thus when joined they base pair and stick together

Question 13

What is the Target DNA + Plasmid known as?

Answer 13

Recombinant DNA

Question 14

What is done to the recombinant plasmid?

Answer 14

Put back into the bacteria, to be multiplied as the bacteria reproduce

Question 15

What does PCR stand for?

Answer 15

Polymerase Chain Reaction

Question 16

What are the ingredients in PCR? (4)

Answer 16

DNA
Primers
Nucleotides
DNA polymerase

Question 17

What are the steps of PCR? (3)

Answer 17

Target DNA is heated (90 degrees Celsius) to separate DNA strands
Cooled (37 degrees Celsius) and primers are added to each DNA strand (starting point for DNA polymerase)
Heated to 70 degrees Celsius to activate DNA polymerase to attach bases to primer sequence, making 2 identical DNA strands

Cycle repeats

Question 18

What are the applications of amplifying DNA? (6)

Answer 18

Fetal screening
Analysis of mutations
Diagnosis of genetic disorders (Huntington's, CF, DMD)
Detection of microorganisms
Parental disputes
Forensic Science (DNA evidence)

Question 19

What is the main method of sorting and analysing DNA?

Answer 19

Gel Electrophoresis

Question 20

What does gel electrophoresis do?

Answer 20

Separates molecules according to size and electrical charge

Question 21

Gel electrophoresis:
___ fragments travel through a special gel towards a positive charge (DNA has a net ________ charge)
Gel is ______, so _____ DNA fragments can travel farther than _____ fragments

Answer 21

DNA
Negative
Porous
Small
Large

Question 22

Gel electrophoresis:

___ fragments separated by gel electrophoresis will generate a specific pattern of _____ called a ___ ___________

Answer 22

DNA
Bands
DNA fingerprint

Question 23

True or false:

Each person’s DNA fingerprint is the same

Answer 23

False, each person’s DNA fingerprint is unique

Question 24

What are the steps in gel electrophoresis? (4)

Answer 24

Restriction enzymes cleave DNA into smaller segments of various sizes
DNA segments are loaded into wells in a porous gel. The gel floats in a buffer solution within a chamber between two electrodes
When an electric current is passed through the chamber, DNA fragments move toward the positively-charged cathode
Smaller DNA segments move faster and farther than larger DNA segments

Question 25

What can DNA fingerprinting be used for? (2)

Answer 25

Parental disputes

Matching DNA at crime scenes to suspects

Question 26

What can gel electrophoresis be used for?

Answer 26

Research purposes (identifying target genes in disease, testing drugs, identifying conditions for disease progression)