DNA Flashcards

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1
Q

What does DNA stand for?

A

Deoxyribonucleic acid

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2
Q

What are the four nitrogenous bases found in DNA?

A

Adenine, Thymine, Guanine, Cytosine

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3
Q

What are the four nitrogenous bases found in RNA?

A

Adenine, Uracil, Guanine, Cytosine

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4
Q

What type of bond holds the nitrogenous bases together in DNA?

A

Hydrogen bond

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5
Q

What is the structure of DNA often described as?

A

Double helix

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6
Q

What is the sugar component in DNA?

A

Deoxyribose

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7
Q

What is the purpose of proofreading by DNA polymerase during replication?

A

To correct errors in nucleotide sequence

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8
Q

What is the overall result of DNA replication?

A

Two identical DNA molecules

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9
Q

During DNA replication, what enzyme is responsible for unwinding the double helix?

A

Helicase

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10
Q

Function of DNA helicase?

A

break Hydrogen bonds between bases

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11
Q

What is the role of DNA in protein synthesis?

A

DNA contains the genetic information that determines the sequence of amino acids in proteins

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12
Q

What is the function of mRNA in protein synthesis?

A

To carry the genetic information from DNA to the ribosome for protein synthesis

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13
Q

What is the function of tRNA in protein synthesis?

A

To bring amino acids to the ribosome during protein synthesis

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14
Q

What are the short pieces of DNA made on the lagging strand called?

A

Okazaki fragments

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15
Q

What enzyme is responsible for adding complementary nucleotides during DNA replication?

A

DNA polymerase

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16
Q

What is the role of ribosomes in protein synthesis?

A

To catalyze the formation of peptide bonds between amino acids

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17
Q

What is a codon?

A

A three-nucleotide sequence on mRNA that codes for a specific amino acid

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18
Q

What is an anticodon?

A

A three-nucleotide sequence on tRNA that is complementary to a codon on mRNA

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19
Q

What is the start codon in protein synthesis?

A

AUG (methionine)

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20
Q

What is the role of primase in DNA replication?

A

To synthesize RNA primers for DNA polymerase to start replication

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21
Q

What is the purpose of DNA ligase during replication?

A

To join Okazaki fragments on the lagging strand

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22
Q

What is the function of the lagging strand during DNA replication?

A

To synthesize discontinuously in short Okazaki fragments

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23
Q

What is the function of the leading strand during DNA replication?

A

To synthesize continuously in the 5’ to 3’ direction

24
Q

What is the function of DNA helicase in protein synthesis?

A

To unwind the DNA double helix during transcription and replication

25
Q

What is the replication fork?

A

The point at which the double helix is unwound during replication

26
Q

What is the role of RNA polymerase in protein synthesis?

A

To synthesize RNA from a DNA template during transcription

27
Q

What is the function of the 5’ cap and poly-A tail in mRNA?

A

To facilitate mRNA transport, stability, and translation

28
Q

What is the genetic code?

A

The set of rules by which information encoded in mRNA is translated into proteins

29
Q

Which bases are Purine?

A

Adenine & Guanine

30
Q

Which bases are Pyrimidine?

A

Thymine & Cytosine

31
Q

Why does DNA replication make an exact copy?

A

To have the correct genetic information, DNA in the daughter cell must be the exact same as the parent cell

32
Q

What is a nucleotide?

A

The basic building block of nucleic acids

  • RNA and DNA are made of long chains of nucleotides.
  • Consists of a sugar molecule (ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.
33
Q

Name the 3 components of a nucleotide

A

Phosphate group

Pentose sugar

Organic base (containing nitrogen)

34
Q

DNA is a stable molecule because…

A
  • The phosphodiester backbone protects the chemically reactive base pairs.
  • C-G base pairs contain 3 hydrogen bonds, so the more C-G base pairs in a DNA molecule the more stable it is.
  • Interactive forces between base pairs add further stability (‘base stacking’)
35
Q

Name the 3 Scientists who discovered the structure of DNA

A

James Watson

Francis Crick

Rosalind Franklin

36
Q

What are the 3 main differences between RNA and DNA?

A
  • sugar in RNA has an extra group called ribose (not deoxyribose)
  • DNA contains nitrogen base thymine, RNA contains nitrogen base uracil instead
  • RNA is single stranded, DNA is double stranded
37
Q

Name the bond between the deoxyribose and the phosphate in a nucleotide

A

phosphodiester

38
Q

Describe how 2 RNA nucleotides form a dinucleotide

A

A condensation reaction occurs between the hydroxyl (OH) group on the 3’ carbon of Ribose on 1 nucleotide and the hydroxyl group of the phosphate group on another nucleotide.

39
Q

What is a leading strand?

A

New strand of DNA that is synthesized around the replication fork

40
Q

What is a lagging strand?

A

A lagging strand is one of two strands of DNA found at the replication fork, or junction, in the double helix; the other strand is called the leading strand

41
Q

Phosphate and sugar join with what bond?

A

Ester bond

42
Q

A base and sugar join with what bond?

A

Glycosidic bond

43
Q

What is the nitrogen and carbon containing molecule comprising a one ring structure?

A

Pyrimidine

44
Q

What is the nitrogen and carbon containing molecule comprising two ring structures?

A

Purine

45
Q

What are the strong bonds formed between adjacent nucleotides in a polynucleotide?

A

Phosphodiester

46
Q

What is the general name for a five carbon sugar?

A

Pentose sugar

47
Q

The phosphate group, pentose sugar and organic base of a DNA or RNA nucleotide are joined through which type of reaction?

A

Condensation reaction

48
Q

What enzyme prevents DNA from supercoiling during replication

A

Topoisomerase

49
Q

What is the function of ligase?

A

Glue okazaki fragments together

50
Q

Why is the replication process semi-conservative

A

One strand in each new dna is old and one is new

51
Q

Primase function

A

Makes primers on the DNA so that DNA polymerase can start building

52
Q

Which direction does DNA polymerase build in

A

5’ to 3’

(Complementary to 3’ to 5’ on the original strand)

53
Q

When does replication happen in a cell?

A

During interphase - before cell division

54
Q

DNA Polymerase

A

Replicates existing DNA molecules to build new strands of DNA

55
Q

Which protein binds to the DNA strands to keep them separated

A

SSB protein