common techniques Flashcards

1
Q

What are some techniques used to study genes?

A

PCR

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2
Q

What is PCR?

A

A technique to amplify DNA fragments

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3
Q

What is needed for PCR?

A

DNA sample

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4
Q

What are primers in PCR?

A

Short DNA sequences complementary to the start of the target fragment.

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5
Q

What is DNA polymerase?

A

An enzyme that synthesizes new DNA strands.

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6
Q

Why is DNA polymerase important in PCR?

A

It withstands high temperatures without denaturing.

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7
Q

What is the first step of PCR?

A

Heat to 95°C to break hydrogen bonds and separate DNA strands.

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8
Q

What happens after DNA strands are separated in PCR?

A

The mixture is cooled to 50-65°C so primers can bind (anneal).

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9
Q

What is the next step after primer annealing in PCR?

A

Heat to 72°C to activate DNA polymerase.

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10
Q

How does DNA polymerase function in PCR?

A

It lines up free nucleotides to form complementary DNA strands.

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11
Q

What happens at the end of a PCR cycle?

A

Two new DNA copies are formed.

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12
Q

How does PCR amplify DNA?

A

Each cycle doubles the DNA amount (e.g.

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13
Q

Why is PCR useful?

A

It rapidly produces large amounts of DNA for analysis.

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14
Q

What is electrophoresis?

A

A technique that uses electrical current to separate DNA

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15
Q

What is the gel used in electrophoresis?

A

Agarose gel.

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16
Q

What is the purpose of buffer solution in electrophoresis?

A

It covers the gel and conducts electricity.

17
Q

Where are the wells placed in the gel?

A

Near the negative electrode (cathode).

18
Q

How are DNA samples prepared for electrophoresis?

A

They are mixed with loading dye to sink into the wells and make them visible.

19
Q

Why is a micropipette used in electrophoresis?

A

To carefully load DNA samples into the wells without damaging them.

20
Q

What happens after DNA samples are loaded into the wells?

A

An electric current is applied to the gel.

21
Q

Which way do DNA fragments move in electrophoresis?

A

Towards the positive electrode (anode) because DNA is negatively charged.

22
Q

How does DNA separate in electrophoresis?

A

Smaller fragments move faster and travel further through the gel.

23
Q

How long does electrophoresis typically run?

A

About 30 minutes or until the dye is ~2 cm from the end of the gel.

24
Q

What happens after electrophoresis is complete?

A

The gel is stained to visualize DNA fragments.

25
Q

How is DNA fragment size measured?

A

In bases or base pairs (e.g.

26
Q

Can electrophoresis be used for RNA?

27
Q

How is protein electrophoresis different from DNA/RNA electrophoresis?

A

Proteins are denatured with a chemical to give them the same charge.

28
Q

What is a use of protein electrophoresis?

A

Identifying proteins in urine or blood samples to diagnose diseases.

29
Q

What are restriction enzymes?

A

Enzymes that recognize specific palindromic sequences and cut DNA at these sites.

30
Q

What is a palindromic sequence in DNA?

A

A sequence that reads the same in opposite directions on complementary strands.

31
Q

How do restriction enzymes recognize where to cut?

A

They bind to specific recognition sequences complementary to their active site.

32
Q

Do all restriction enzymes cut at the same recognition sequence?

33
Q

How can restriction enzymes be used to isolate a DNA fragment?

A

If recognition sequences flank the desired DNA fragment

34
Q

What type of reaction do restriction enzymes use to cut DNA?

A

A hydrolysis reaction.

35
Q

What are sticky ends in DNA fragments?

A

Small tails of unpaired bases left after a restriction enzyme cut.

36
Q

Why are sticky ends useful in DNA manipulation?

A

They help DNA fragments anneal to other DNA with complementary sticky ends.