A1.2 Nucleic acids Flashcards

1
Q

deoxyribonucleic acid (DNA)

A

the molecule thst provides long-term stored genetic information for all orginisima on earth

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2
Q

DNA’s 4 nitrogenous bases

A
  1. adenine
    2.thymine
    3.cytosine
  2. guenine
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3
Q

what do we call sequences of nitrogenous bases

A

genetic messages or genes (messages code for amino acids- building blocks of proteins, a cells identity and function is determined by its ability to synthesis protieins )

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4
Q

what are both polymers of nucleotides

A

DNA and RNA

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5
Q

indivisual nucleotides consists of 3 major groups

A
  • one phosphate group
  • one give-carbon monosccharide(aka pentose sugar)
  • one nitrogenous base
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6
Q

how does the nucleotides bond together?

A

the pentose sugar of one nucelotide is covalently bonded to the nexts nucleotides photphate group

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7
Q

what type of reaction forms when nucleotides bond together?

A

condensation reactions (reqquires lots of energy to break making the chain stable)

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8
Q

the difference between RNA nitrogenous bases and DNA nitrogenous bases

A

theres a total of 5 nitrogenous bases:
RNA has: adenine uracil cytosine and guinine
DNA has: adnenine thymine cytosine and gunine

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9
Q

what makes RNA and DNA’s nucleotides different

A

-all the nucleotides found in RNA contain ribose as their pentose sugar and the nucleotides of DNA contain deoxyribose
-uracil only occurs in RNA
-thymine only occurs in DNA

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10
Q

how many chains/ stands of DNA and RNA

A

DNA has two chains connected together by hydrogen bonds
RNA is coposed of one chain

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11
Q

complementary bases in DNA

A

(A) and (T)
(C) and (G)
the two chains are upside down in comparison to eachother but parallel because theyre said to be antiparallel

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12
Q

DNA info

A
  • double stranded / chains
  • all nucleotides contain deoxyribose sugar
  • thymine is one of the four nutrigenous bases
  • act as a permanent genetic code for cell/organism
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13
Q

RNA info

A
  • single stranded molecule
  • all nucleotides contain ribose sugar
  • uracil is one of the four nutrigenous bases
  • doesnt contain a permanent genetic code, except in RNA viruses
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14
Q

ribose molecular formula

A

C5H10O5

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15
Q

deoxyribose molecular formula

A

C5H10O4

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16
Q

why is there less oxygen on the deoxyribose molecular formula

A

this is because the carboxyl group -OH bonded to a carbonthat is called alcohol group, in ribose thers the -OH group in deoxyribose its just the H

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17
Q

specific exmaples of nucleic acids

A
  • messanger RNA (mRNA)
  • transfer RNA (tRNA)
  • Ribosomal RNA (rRNA)
  • Adenosine Triphosphate (ATP)
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18
Q

messanger RNA (mRNA)

A

Its synthesised from a gene
mRNA leaves the nucleus and represents the genetic information necissary to make a protein

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19
Q

transfer RNA (tRNA)

A

they are special genes of DNA
when a specific protein is syntheisied specific amino acid must be added to the amino acid chain in a specific order. tRNA transfers the correct amino acids into a growing chain of amino acids

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20
Q

Ribosomal RNA (rRNA)

A

a special gene of DNA
along with synthesised proteins, rRNA is used to create an organelle called ribosomes

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21
Q

Adenosine Triphosphate (ATP)

A

single nucleotide nucleic acid.
its used as a type of chemical energy
the purpouse of cellular respiration is to convert energy contain in food molecules into energy of ATP. like when muscles contract ATP is used as an energy source.

22
Q

triplet Condon

A

triplet codons are the three-letter sequences in DNA or RNA that represent specific amino acids or serve as stop signals during protein synthesis.

23
Q

triplet condon codes

A

for one of the 20 amino acids in DNA
64 combination types of nucelotides

24
Q

shortest vs longest DNA chain

A

50 million base pairs - 260 million base pairs

25
5' and 3' designations
they refer to the fifth and third carbon atoms in ribose and deoxyribose sugars
26
what are the two strands that run antiparallel to eachother
one strand is 5'3' the other is 3'5'
27
transcription
process in which genetic information encoded in DNA is copied into RNA
28
translation
process by which ribosomes use the genetic information carried by the mRNA to synthesis proteins.
29
nitrogenous base of DNA grouped into 2 types
- prymidines - purines
30
purine
double ring size - adenine -guenine
31
pyrmidines
single ring size - thymine -cytosine
32
puritines and prymidines in double helix bonding
when two strands bond to creat a double helix, a purine is always bonded to a prymidine - this makes the DNA stands at a consistant distance frome eachother with three rings in total - stable double helix
33
approximate length of DNA molecule
2m
34
"packing" for and uses?
in order to fit the very long strands of the DNA molecule a very efficient packing solution is invilved using histones
35
process of packing with histones
within the nucleus there are proteins called histones DNA wraps itself around 8 then 1 to hold the strucutre
36
whats the structure with histones called?
nucleosome
37
whats the DNA called that extends one nucleosome to another called?
linker DNA
38
what did biologist think in the middle decades of the 20th century
whether genetics was made of nucleic acid or proteins because there was only 4 types of nucleotides but 20 different types of amino acids
39
Alfred Hershy and Martha Chase
1951 and 1952 worked in cold spring harbour in NY experimented using bacteriophage and the bacterium eschericha coli
40
bacteriophage
a type of virus that infects bacteria composed of a protein outer coat and a inner core of DNA.
41
what happend when a virus infects a cell
the virus takes over the metabolism of the cell resulting in multiple virus of the type being formed using molecules such as nucleotides in their synthesis
42
Alfred Hershy and Martha Chase use of radioisotopes called
radio iscotope labelling
43
radioisotopes
radioactive forms of elements that can be detected within molecules , the particles released during their decay allow the specific radioisotope used to be detected.
44
what did the researches hershey and mathra do
they grew bacteriophage viruses in two different types of culture one with radioactive phospherous 32- the virus produced here had DNA in their viral core labelled with the detectable phorpherous 32. another culture with radioactive sulfur 35- the detectable radioactive iscotope was detected on the protein outer coat of the viruses produced. sulfur was detected on the protein because dna doesnt have sulfur and it couldve been one of the 20 amino acids.
45
using both bacteriophages from culture to infect bacterium e.coli
the bacterium that was infected by the phospherous 32 had radiactive detected inside the cell indicating DNA. however the bacteriophage with sulfure 35, the bacterium had no radioacivity inside the cell. DNA contains phospherous and not sulfur allowed them to condlude that DNA was the genetic material not protein.
46
hypothesis of DNA in the 1900
that DNA existed as tetranucleotide molecule:in repeating sets of units of the four nucleotides
47
erwin chargaff
1940s develeoped a research technique designed to show the proportions of nitrogenous base types found in various sources of DNA. involving paper chromatography
48
erwin chargaff results
same DNA ratios exist in most biological sources he experimented with.
49
chargaff's rule
DNA contains the same number of adenine as thymine nucleotides s well as the same number of cytocine and guenine nucleotides
50
importance of chargaff's rule
showed the tetronucleotide theory is false, if it was correct then all 4 nucleotides proportions would be equal we now know that the proteins in the nucleus of the cell where primarily histone proteins helping form nucleosomes.
51
Hershey-Chase experiment showed
The Hershey-Chase experiment showed that DNA, not protein, is the genetic material. They used viruses to infect bacteria. They tagged DNA with radioactive phosphorus and protein with radioactive sulfur. When the viruses infected the bacteria, only the radioactive DNA was found inside the bacteria, not the protein. This proved that DNA, not protein, carries the genetic information and passes it on when cells divide.