A1.2: Nucleic Acids Flashcards

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1
Q

State the two primary functions of nucleic acids.

A
  • Pass information between generations
  • Code for protein production
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2
Q

State the two types of nucleic acids used in cells.

A
  • DNA; Deoxyribonucleic acid
  • RNA; Ribonucleic acid
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3
Q

Outline the meaning and implication of DNA being the genetic material of all living organisms.

A

DNA carries all the genetic information of all living organisms through generations

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4
Q

State why RNA viruses do not falsify the claim that all living things use DNA as the genetic material. ​​

A

Viruses are not considered living organisms as they are not made of cells

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5
Q

​List the three components of a nucleotide.

A
  • Pentose sugar (Ribose/Deoxyribose)
  • Nitrogenous base
  • Phosphate group
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6
Q

Identify and label the carbons of a pentose sugar.

A
  • starts at 0 from the top and increases sequentially in a clockwork direction
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7
Q

Draw the basic structure of a single nucleotide (using circle, pentagon and rectangle).

A
  • 1C in pentagon connects nitrogenous base
  • 5C in pentagon connects phosphate group
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8
Q

Define “backbone” as related to nucleic acid structure.

A

DNA and RNA have a backbone of repeating phosphate and sugar formed when nucleotides combine in a condensation reaction

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9
Q

Explain how nucleotides connect to form a nucleic acid polymer.

A
  • A covalent bond forms between the phosphate group attached to the 5′ C of one deoxyribose sugar and the –OH group attached to the 3′ C of another sugar, releasing one molecule of water with the use of energy.
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10
Q

State the names of the nitrogenous bases found in DNA and RNA.

A

DNA:
- Thymine
- Adenine
- Cytosine
- Guanine

RNA:
- Uracil
- Adenine
- Cytosine
- Guanine

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11
Q

State a similarity and a difference between the nitrogenous bases.

A

Similarity:
- All contain Nitrogen atoms

Difference:
- Different molecular structures

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12
Q

Outline how the sequence of bases in a nucleic acid serves as a ‘code.’

A
  • The order of different types of nucleotides arranged in DNA or RNA serves as a code for storing genetic info in all living organisms
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13
Q

Define gene.

A

A gene is a specific sequence of nitrogenous bases in DNA nucleotides that code for the making of a protein

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14
Q

Describe the condensation reaction that forms a polymer of RNA from RNA nucleotides.

A
  • The 3’ C of the ribose sugar in one nucleotide links with phosphate group on the 5’ C of the ribose sugar in another nucleotide
  • H is lost from the 3’ C (OH) and OH is lost from Phosphate group thus, forming H2O
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15
Q

Identify the monomer and polymer of an RNA molecule.

A

Monomer:
- Nucleotides

Polymer:
- RNA chain

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16
Q

Draw a short section of an RNA polymer (using circle, pentagon and rectangle)

A
  • Pentose sugar is Ribose
  • Same position of nitrogenous base and phosphate group
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17
Q

Describe the structure of a DNA double helix.

A
  • two sugar-phosphate backbones hydrogen bond between the nitrogenous bases to create a double helix
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18
Q

Outline the complementary base pairing rule, including the type and number of bonds between bases.

A
  • Only certain bases between RNA and DNA strand or within a DNA strand can match as a result of their structure and ability to create H bonds
  • A = T (or U); Connected with 2 H bonds
  • G = C; Connected with 3 H bonds
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19
Q

Define antiparallel in relation to DNA structure.

A
  • Two different strands of the DNA double helix run in opposite directions; at each end, one strand is 5’ and the other is 3’
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20
Q

Compare and contrast the structures of DNA and RNA.​

A
  • both are nucleic acids

DNA:
- made of 2 strand of nucleotides connected in the middle at the bases via H bonds
- contains the bases: adenine, thymine, cytosine, guanine
- contains a deoxyribose sugar (H on 2C)

RNA:
- made of only 1 strand of nucleotides
- contains the bases: adenine, uracil, cytosine, guanine
- contains a ribose sugar (OH on 2C)

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21
Q

Compare and contrast the functions of DNA and RNA.

A

DNA:
- Pass information between generations of cels
- Codes for making RNA during transcription

RNA:
- Codes for making proteins during translation (mRNA, tRNA and rRNA involved)

22
Q

Compare and contrast the location of DNA and RNA in prokaryotic and eukaryotic cells.

A

DNA (Eukaryotic):
- located in the nucleus
- due to endosymbiosis, can also be found in chloroplasts and mitochondria

DNA (Prokaryotic):
- Nucleoid
- Plasmids

RNA (Eukaryotic):
- made in the nucleus during transcription and transported to the cytoplasm for translation

RNA (Prokaryotic):
- Cytoplasm

23
Q

Outline the role of complementary base pairing in maintaining the DNA sequence during DNA replication.

A
  • enzyme DNA Polymerase III builds a new strand by reading the DNA template and adding the complementary DNA nucleotide
  • Thus, replication builds 2 identical DNA molecules
24
Q

​Outline the role of complementary base pairing in transmitting the genetic code in transcription and translation.

A
  • enzyme RNA Polymerase builds an RNA strand by reading the DNA template and adding the complementary RNA nucleotide
25
Q

Outline why there is a limitless diversity of DNA base sequences.

A
  • DNA has 4 different bases (4^x where x is the # of bases); storing information can be done based on all the possible combinations that can be made from this sequence (4^4, 4^20, etc)
  • DNA molecules don’t take up much space making the possible combination count for long strands seem limitless
26
Q

Define universal in relation to the genetic code.

A

All living organisms use DNA as their genetic code

27
Q

Outline why conservation of the genetic code across all forms of life is evidence of common ancestry.

A

This means that the genetic code was carried by the LUCA of all life and has been passed over time to all its descendants

28
Q

Identify and label the 5’ and 3’ ends on a diagram of DNA.

A
  • 5’ end is the open phosphate group
  • 3’ end is the open sugar
29
Q

Identify and label the 5’ and 3’ ends of the daughter DNA strands on a diagram of the DNA replication fork.

A
  • top strand; 5’ to 3’ (continuous)
  • bottom strand 5’ to 3’ (discontinuous)
30
Q

Outline the impact of DNA directionality on DNA replication.

A

Dictate the structure of both DNA and RNA

31
Q

Identify and label the 5’ and 3’ ends of RNA on a diagram of the transcription bubble.

A
  • Open phosphate group (5’ C)
  • Open sugar (3’ C)
32
Q

Outline the impact of DNA directionality on transcription.

A

Ribosome is attached to the 5’ end of an mRNA and moves TO the 3’ end; translation is 5’ to 3’

33
Q

Identify and label the 5’ and 3’ ends of mRNA on a diagram the ribosome bound to mRNA.

A

left to right (5’ to 3’)

34
Q

​Outline the impact of RNA directionality on transcription.

A
  • Enzymes of transcription, RNA polymerase, can only add nucleotides to the 3’ end of a growing polymer of RNA nucleotides
  • 5’ phosphate end is ADDED TO the 3’ ribose end of the growing RNA strand; transcription is 5’ to 3’
35
Q

Compare and contrast the structures of purines and pyrimidines.

A

Purines:
- 2 ring structure
- Adenine and Guanine

Pyrimidines:
- 1 ring structure
- Cytosine and Thymine and Uracil

36
Q

State the type of bonds formed in DNA between a purine and a pyrimidine

A

H bonds

37
Q

Given a diagram of DNA, identify the four bases of DNA based on purine or pyrimidine and the number of hydrogen bonds.​

A

pk

38
Q

State two consequences of purine-to-pyrimidine bonding on the structure of DNA.

A
  • promotes DNA stability
  • have a consistent diameter throughout the entire molecule
39
Q

Describe the structure of eukaryotic DNA and associated histone proteins during interphase (chromatin).

A
  • DNA wraps around the histone
40
Q

Draw and label the structure of a nucleosome, including the H1 protein, the octamer core proteins, linker DNA and two wraps of DNA.​

A
  • 4 circles in a square composition; this is the octamer core proteins or of histones
  • DNA coils around the octamer of histones
  • H1 protein is a vertical line next to octamer where the two ends of the DNA coil go through
41
Q

​Identify nucleosome structures using molecular visualization software.

A

pk

42
Q

Outline the mechanism of histone-DNA association.

A

Due to the Phosphate groups in nucleotides, DNA is negatively charged and binds tightly to histone proteins using electromagnetic attraction

43
Q

State the experimental question being tested in the Hershey and Chase experiment.

A

whether it was protein or DNA that acted as the genetic material that entered the bacteria

44
Q

Outline the procedure of the Hershey and Chase experiment.

A

Determining whether proteins are the genetic material:
- Bacteriophage that had radioactive S on protein coat outside of the virus (as proteins contain S and not P)

Determining whether nucleic acids are the genetic material:
- Bacteriophage that had radioactive P on protein coat outside of the virus (as DNA contains P and not S)

The resulting infected bacteria populations were blended and centrifuged; heavier bacteria cell on the bottom (pellet), and lighter the virus components (supernatant)

45
Q

Explain how the results of the Hershey and Chase experiment supported the notion of nucleic acids as the genetic material.

A
  • More radioactive S was in the lighter supernatant
  • More radioactive P was in the heavier pellet

Thus, this supported the idea that DNA was the genetic material as it had transferred into the bacteria cells evident by the radioactive P

46
Q

Outline the use of radioisotopes as research tools.

A

Radioisotopes can be used as markers of certain elements on, for instance, bacteriophage to be tracked

47
Q

Explain the role of falsifiability in determining the structure and function of DNA.

A

Falsify:
- To prove wrong

It’s now understood that;
- DNA has a double helix made of 2 anti-parallel strands of nucleotides linked by hydrogen bonding between complementary base pairs

48
Q

Describe implications of Chargaff’s data that showed a 1:1 ratio of purine to pyrimidine in a sample of DNA.

A
  • Distribution of bases was not equal 25%; Adenine and Thymine shared similar percentages of abundance same with Cytosine and Guanine
  • This falsified the tetranucleotide hypothesis
49
Q

State the function of histone proteins

A
  • Packages DNA into nucleosomes through coiling
50
Q

importance of nucleosomes in DNA supercoiling?

A

To fit the length of DNA into the nucleus