UNIT 1 - KA2 Flashcards

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1
Q

What are the three parts In a nucleotide (DNA)

A

Phosphate , deoxyribose sugar , base

Check jotter for diagram

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2
Q

What is the full name for DNA

A

Deoxyribonucleic Acid

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3
Q

Sugar phosphate backbone

A
  • a strong chemical bond joins the nucleotides it forms between the deoxyribose sugar for one and the phosphate group of the next
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4
Q

What type of bonds hold the two strands of DNA together

A

Weak hydrogen bonds between bases hold the two strands of DNA together

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5
Q

Anti parallel strands

A
  • DNA strands have 2 ends
  • a 3’ end with deoxyribose sugar at the end
  • a 5’ end with phosphate at the end
  • the two strands run anti parallel to each other
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6
Q

What is the shape of a DNA molecule

A

The DNA molecule takes the shape of a twisted double helix with the sugar phosphate backbone (upright on the outside and the base pairs on the inside)

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7
Q

What does the base sequence of DNA do

A

The base sequence of DNA forms the genetic code

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8
Q

Draw a diagram of the structure of DNA

A

Check jotter for answer

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9
Q

When does DNA replication take place

A

DNA replication takes place just prior to cell division

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10
Q

Which enzyme is responsible for DNA replication

A

DNA polymerase is the enzyme responsible for DNA replication

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11
Q

What does DNA polymerase require to start replication

A

DNA polymerase needs primers to start replication

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12
Q

What is a primer

A

A primer is a short strand of nucleotides which binds to the 3’ end of the template DNA strand

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13
Q

Briefly describe what DNA polymerase does

A

DNA polymerase adds DNA nucleotides using complementary base pairing to the deoxyribose (3’) end of the new DNA strand which is forming

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14
Q

How should the two new DNA strands be made

A

The two strands of a DNA molecule run antiparallel to each other. Therefore the two new strands of DNA must be made in different ways

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15
Q

What happens prior to cell division (1st step of DNA replication)

A

Prior to cell division, DNA is replicated by an enzyme called DNA polymerase. DNA polymerase needs primers to start replication

(A primer is a short strand of nucleotides which binds to the 3’ end of the template DNA strand allowing DNA polymerase to add DNA nucleotides)

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16
Q

How are the two template strands formed (2nd step of DNA replication)

A

DNA is unwound and hydrogen bonds between bases are broken to form template strands

17
Q

How does DNA polymerase add DNA nucleotides (3rd step of DNA replication)

A

DNA polymerase adds DNA nucleotides , using complementary base pairing to the deoxyribose 3’ end of the new DNA strand which is forming

18
Q

Why are the two strands replicated in different ways (4th step of DNA replication)

A

DNA polymerase can only add DNA nucleotides in one direction resulting in the leading strand being replicated continuously and the lagging strand being replicated in fragments

19
Q

Which enzyme joins DNA on the lagging strand (5th step of DNA replication)

A

The fragments of DNA on the lagging strand are joined together by an enzyme called ligase

20
Q

Draw a diagram of the two new template DNA strands

A

Check jotter

21
Q

What is the technique polymerase chain reaction

A

PCR or polymerase chain reaction is a technique used to AMPLIFY DNA outside the body (in vitro)

22
Q

What are PCR primers (think of stage 2 of PCR)

A

PCR primers are short strands of nucleotides which are complementary to specific target sequences at the two ends of the region of DNA to be amplified

23
Q

Where does heat tolerant DNA polymerase add nucleotides to

A

Heat tolerant DNA polymerase adds nucleotides to the primers at the 3’ end of the original strand of DNA , leading to the replication of that region of DNA

24
Q

What are the three applications of PCR

A
  • forensics / solve crimes
  • settle paternity suits
  • diagnose genetic disorders
25
Q

What does the test tube which target DNA is added to contain

A

Target DNA added to test tube containing heat tolerant DNA polymerase , two types of primer + four types of DNA nucleotide

26
Q

What is the first step of PCR thermal cycle

A

STEP 1 - DNA heated to between 92-98 degrees C to separate the DNA strands

27
Q

What is the second step of PCR thermal cycle

A

STEP 2 - mixture cooled to between 50-65 degrees C to allow primers to bind to complementary target sequences

28
Q

What is the third step of PCR thermal cycle

A

STEP 3 - mixture heated to between 70-80 degrees C for HEAT TOLERANT DNA polymerase to amplify the region of DNA

29
Q

How many times should the PCR thermal cycle be repeated

A

Procedure repeated 20-30 more times DNA becomes amplified

30
Q

What does a primer allow

A

allows polymerase to add DNA nucleotides