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Biological Molecules > nucleic acids DNA AND RNA > Flashcards

nucleic acids DNA AND RNA Flashcards

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Organic Chemistry 101 flashcards
1
Q

where is dna found

A

dna is found in the chromosomes in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells and inside some types of viruses

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2
Q

what are the essential roles of DNA in organisms

A

storage and transfer of genetic information of an organism
contains the genetic material- the information needed for the development and functioning of every organism.
it is the hereditary material- the molecule used to pass genetic information to offspring.

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3
Q

structure of nucleotides

A

dna is a polynucleotide- its a polymer made up of nucleotides . nucleotides are phosphate esters of pentose sugars.
the three components of nuelcotides are
1)phosphate group
2) pentose sugar
3)nitrogenous base

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4
Q

what is the pentose sugar in DNA

A

-deoxyribose

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5
Q

what is the pentose sugar in RNA

A

-ribose

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6
Q

the nitrogenous base is linked to the c1 carbon 1 atom of the pentose sugar. the phosphate group is linked to either c3 or c5 of the pentose sugar by covalent bonds formed by condensation reactions.

A

different bases are
adenine
guanine
thymine
cytosine
uracil

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7
Q

what is the difference in structure between RNA and DNA

A

the pentose sugar in RNA nucleotides is deoxyribose whereas the pentose sugar in DNA nucelotides is ribose. The bases in DNA are adenine, guanine, thymine and cytosine whereas in RNA nucleotides, bases can be adenine, guanine, cytosine and uracil instead of thymine
in general dna is made of a few thousand nucelotides whereas rna is made of a few hundred nucleotides. rna is found in the cytoplasm whereas DNA is found in chromosomes in the nucleus. DNA is a longer molecule because it carries alot of encoded genetic information

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8
Q

definition of a nucleotide

A

A molecule that consists of a pentose (5 carbon) sugar, a phosphate group and a nitrogenous base. it is a monomer of nucleic acids.

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9
Q

what are phosphorylated nucleotides

A

phosphorylated nucleotides contain more than one phosphate group.

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10
Q

what is AMP what does it stand for

A

adenosine monophosphate is a nucleotide consisting of one phosphate group

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11
Q

what is ADP

A

adenosine diphosphate is a phosphorylated nucleotide as it contains two phosphate groups.

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12
Q

what is ATP

A

adenosine triphosphate is a phosphorylated nucleotide and it contains three phosphate gorups

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13
Q

nucleotides can be components of of co enzymes for example adenine nucleotides are components of which co enzyme

A

NADP co enzyme of photosynthesis
AND NAD co enzyme of respiration

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14
Q

the organic bases found in nucleotides are either purine or pyrimidine bases
what are purine and pyrimidine bases

A

purine bases have double ring structures
adenine and guanine are purine bases
pyrimidine bases have a single ring structure
cytosine and thymine are pyrimidine bases
uracil is also a pyrimidine base

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15
Q

a nucleotide is formed when a phosphate group. pentose sugar and nitrogenous base are joined together by condensation reactions.

A

a nucleotide is formed when a phosphate group. pentose sugar and nitrogenous base are joined together via condensation reaction

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16
Q

what do two nucleotides joined together via condensation reaction form

A

a dinucleotide

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17
Q

how are polynucleotides formed

A

dinucleotides are joined together by further condensation reactions to form polynucleotides

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18
Q

what reaction can be used to break down a polynucleotide into its original nucleotides

A

hydrolysis reactions

19
Q

what does the condensation reaction occur between in nucleotides

A

the condensation reaction occurs between the hydroxyl group on the pentose sugar of one nucleotide and the phosphate group of an adjacent nucleotide. this forms a phosphodiester bond and a molecule of water.

20
Q

what covalent bond does the condensation reaction form

A

a phosphodiester bond

21
Q

what is the phosphodiester bond between

A

the phosphodiester bond forms between carbon 3 on one nucleotide and the phosphate group of another nucleotide.

22
Q

hydrolysis reactions
a dinucleotide can be broken down into two nucleotides by a hydrolysis reaction
what does this reaction require

A

this reaction requires water as two hydrogen atoms and a oxygen atoms are added to the dinucleotide, breaking the phosphodiester bond to form two nucleotides.

23
Q

structure of DNA

A

DNA molecules consist of two very long polynucleotide strands twisted around each other to form a double helix. the two anti parallel polynucleotide strands run anti parallel to each other.Dna molecules are very long to carry alot of encoded genetic information

24
Q

what is the sugar phosphate backbone

A

the sides of the dna double helix are made from pentose sugar and phosphate groups forming sugar phosphate backbones. this contributes to the stability of dna molecules.

25
Q

why are the strands referred to as running in opposite directions

A

because the third and fifth carbon molecules on the deoxyribose sugars of the two strands face different directions.

26
Q

where is the phosphate group attached to the c5 of the deoxyribose sugar

A

the 5th end of the molecule

27
Q

the 3’ end is where

A

where the phosphate group is attached to c3 of the deoxyribose sugar.

28
Q

what forms the rungs of the dna double helix

A

the two strands of dna are held together by hydrogen bonds between the bases

29
Q

what type of bond joins the polynucleotide strands together by linking the nitrogenous bases together

A

hydrogen bonds

30
Q

what do the hydrogen bonds allow the two strands of DNA to do in order for transcription and replication to occur

A

the hydrogen bonds allow the two dna strands to unzip (separate) in order for transcription and replication to occur.

31
Q

why do the hydrogen bonds give the strands the ability to unzup ( separate) during transcription and translation

A

because they are weak forces of attraction, they can be easily broken

32
Q

how many hydrogen bonds do adenine and thymine form in the base pair

A

2 hydrogen bonds

33
Q

how many hydrogen bonds do cytosine and guanine form in the base pair

A

3 hydrogen bonds

34
Q

what happens in order for the rungs of the ladder to be the same width

A

a purine always pairs with a pyrimidine on opposite strands allowing the molecule to twist into a double helix which confers stability to it.

35
Q

the more c-g pairings the more stable the molecule why

A

because c-g form three hydrogen bonds between every base pair

36
Q

explain how to extract DNA from a sample

A

1) whilst wearing eye protection, macerate the sample, grind it with a pestle and mortar this breaks down the cell walls
2) add a strong detergent such as washing up liquid, this breaks down the cell membranes
3) add salt to break down the hydrogen bonds between DNA and water molecules
4) add protease enzymes this breaks down the proteins associated with DNA.
5) add ethanol this will cause the DNA to precipitate out of the solution
6) using a glass rod, spooling the dna out it can then be purified and concentrated

37
Q

why must the temperature be kept constant throughout the extraction

A

to reduce the eznyme activity, to reduce the break down of DNA

38
Q

why does detergent break down the membrane

A

the detergent disrupts the membrane structure, disrupts phospholipid bilayer and phospholipids form suspension in aqueous solutions

39
Q

RNA is also a nucleotide
what does rna stand for

A

ribonucleic acid

40
Q

what are the functions of RNA

A

it acts as a messenger molecule that helps transfer genetic information from DNA to ribosomes for protein synthesis
has roles in the synthesis and regulation of proteins
ribosomes are formed of RNA and proteins
rna has many forms mrna, trna and r rna

41
Q

how many polypeptide chains is RNA composed of

A

unlike DNA, rna is composed of a single polynucleotide strand
rna polynucleotide strands are also shorter than DNA chains

42
Q

the pentose sugar in RNA is

A

ribose

43
Q

whats the difference between ribose and deoxyribose

A

ribose has one extra oxygen atom than dexoyribose

44
Q

whats the difference in bases in RNA and DNA

A

RNA does not have thymine, instead has uracil

Biological Molecules (8 decks)

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