3.1.5 Nucleic acids are Important Information-Carrying Molecules Flashcards

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1
Q

Basic function of DNA and RNA

A

DNA is to store genetic information

RNA transfers information to ribosomes

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2
Q

Components of a nucleotide

A

Phosphate group

Penrose sugar (for DNA, deoxyribose and for RNA, ribose)

Nitrogen containing carbon base (for DNA, A,T,G,C and for RNA, A,U,G,C)

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3
Q

Explain 5’3’ prime direction

A
  • Phosphate binds to 5th carbon of penrose sugar
  • Next nucleotide joins to 3rd carbon of penrose sugar
  • Condensation recation occurs
  • Phosphodiester bond is formed
  • Appropriate enzyme, DNA/RNA polymerase
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4
Q

How many hydrogen bonds form between base pairs A,T and A,U

A

2 hydrogen bonds

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5
Q

How many hydrogen bonds form between base pairs G,C

A

3 hydrogen bonds

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6
Q

Describe the structure of ribonucleic acid (5)

A
  • Polymer of nucleotides
  • Pentose sugar is ribose
  • Organic bases are A,U,G,C
  • mRNA = single stranded, linear polynucleotide, it’s a single stranded copy of a gene and takes information to the ribosome
  • tRNA = single stranded polynucleotide coded into cloverleaf shape, brings amino acids to ribosome during protein synthesis
  • rRNA = found in the ribosomes along with protein
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7
Q

Provide the function of: sugar phosphate backbone

A
  • Provides strength and stability
  • Protects information coded in bases and hydrogen bonds
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8
Q

Provide the function of: DNA being a longer molecule

A

Holds lots of information

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9
Q

Provide the function of: DNA having a helix structure

A

Compact

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10
Q

Provide the function of: DNA having a base sequence

A

Codes for amino acids and therefore proteins

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11
Q

Provide the function of: DNA being double stranded

A

Allows SCR - each strand acts as a template

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12
Q

Provide the function of: DNA having complementary base pairing

A

Accurate replication

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13
Q

Provide the function of: DNA having weak hydrogen bonds between bases

A

Easily broken in SCR

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14
Q

Provide the function of: DNA having many hydrogen bonds

A

Strong and stable

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15
Q

The double helix

A

2 polynucleotide chains held together by hydrogen bonds between complementary base pairs

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16
Q

The structure of the double helix is _______________

A

Antiparallel

17
Q

Describe the structure of DNA (6)

A
  • Polymer of nucleotides
  • Each nucleotide contains one deoxyribose, one phosphate group and one organic nitrogen base
  • Phosphodiester bonds between then nucleotides
  • Double helix - weak hydrogen bonds between complementary base pairs
  • Organic bases: A,T,G,C
18
Q

Explain semi-conservative replication

A
  1. 2 strands separated by breaking hydrogen bonds between complementary base pairs with DNA helicase
  2. Separate strands act as template for replication and determine order of nucleotide bases. Free nucleotides within the nucleus are attracted and exposed to complementary base pairs on template strands
  3. Hydrogen bonds form between these
  4. DNA polymerase joins nucleotides in 5’3’ prime directions through condensation reactions forming phosphodiester bonds
  5. 2 DNA molecules are formed, each with one original and one new strand
19
Q

Explain Meelson Stahl experiment

A

See notes

20
Q

Which scientists discovered the structure of DNA

A

Watson and Crick

21
Q

Why do nucleotides only join in the 5’3’ prime direction?

A
  • DNA polymerase
  • Specific
  • Only complementary with 3’ end
  • 5’3’ ends are different and anti parallel