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A Level: Biology > Nucleotides And Nucleic Acids > Flashcards

Nucleotides And Nucleic Acids Flashcards

(59 cards)

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1
Q

What are the two types of nucleic acids

A

DNA

RNA

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2
Q

What are the monomer and polymer of a nucleic acid

A

Monomer- nucleotide

Polymer-nucleic acid

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3
Q

What are the 3 components of a nucleotide

A

Phosphate
Pentose (5C) sugar
Organic nitrogenous base

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4
Q

Name the elements found in dna and rna nucleotides

A 
Carbon
Hydrogen
Nitrogen
Phosphorus 
Oxygen
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5
Q

What reactions take place to make a nucleotide

What does this mean

A

Two condensation reactions

2 water molecules are released

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6
Q

Name the bases present in dna and rna

A

DNA-ATGC

RNA-AUGC

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7
Q

What happens during the formation of nucleic acids

A

The phosphate group at the 5th carbon of pentose sugar of one nucleotide forms a covalent bond with the OH group at the third carbon of pentose sugar of an adjacent nucleotide

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8
Q

What is another name for the covalent bond formed between nucleotides

A

A phoshodiester bonds

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9
Q

Describe the strands in DNA

A

It’s double stranded

They run antiparallel

Each strand has a phosphate group at one end and a hydroxyl group at other

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10
Q

How are dna strands attached together

A

By hydrogen bonds

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11
Q

What happens to the strands of dna

A

They coil into a helix called a double helix

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12
Q

Name two purines

A

Adenine

Guanine

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13
Q

What is a purine

A

2 rings of carbon atoms

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14
Q

Name the two Pyrimidines

A

Thymine

Cytosine

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15
Q

What is a pyrimidine

A

Has 1 ring of carbon

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16
Q

Which bases form two hydrogen bonds

A

Adenine

Thymine

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17
Q

Which bases form 3 hydrogen bonds

A

Guanine

Cytosine

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18
Q

What is chargraffs rule

A

Adenine must pair with thymine
Guanine must pair with cytosine

There are equal amounts of A and T
There are equal amounts of G and C

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19
Q

What is the job of RNA

A

DNA stores all genetic info but is too big to fit out the nucleus

Short sections of dna molecule corresponding to a single gene are transcribed into a short messenger RNA molecule (single stranded)

This can leave the nucleus and go to the ribosome for protein synthesis

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20
Q

What is mRNA

A

A polymer composed of many nucleotide monomers - it’s a polynucleotide

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21
Q

Three similarities between RNA and DNA

A

5 carbon sugar
Bases of CGA
Has a phosphate group

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22
Q

Three differences between RNA & DNA

A

rna single stranded dna double stranded
Rna has uracil instead of thymine in dna
Rna has ribose sugar and dna has deoxyribose sugar

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23
Q

Explain the dna precipitation (peas) experiment

A

Peas mashed up
Washing liquid added
Add protease enzyme
Add ethanol on top -causes dna to precipitate out of the solution
White strands of dna form between the same and layer of alcohol

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24
Q

Where does dna replication occur

Study These Flashcards
A

In the nucleus

25
Explain the stages of semiconservative DNA replication
1) the DNA helix unwinds by action of gyrase enzyme 2) Strands separate by action of helicase enzyme which breaks the hydrogen bonds between complimentary bases 3) Free DNA nucleotides are attracted and with the complimentary bases and hydrogen bonds form 4) DNA polymerase forms the sugar phosphate backbone by forming phosphodiester bond
26
What enzyme unwinds the dna helix
Gyrase
27
What enzyme separate strands in DNA replication
Helicase
28
What bonds form in the sugar phosphate backbone
Phosphodiester bond
29
Why do we call semiconservative DNA replication that
Because two identical copies of DNA are made and each DNA molecule has one original strand and one new strand each original strand acts as a template
30
Describe nitrogen 15
Heavy - dense- bottom of test tube
31
Describe nitrogen 14
Light- less dense- forms at top of test tube
32
Why is the sequence of organic bases in DNA important
The sequence of bases determines the sequence of amino acid’s in the primary structure
33
What is an advantage of the double helix structure
It gives the molecule stability
34
What is a codon
Three bases that code for an amino acid
35
What does it mean by non-overlapping
Each nucleotide is only part of one triplet of bases
36
What is the de-generative code
There are a lot more codons than amino acids
37
What is the universal code
The same specific base triplets code for the same amino acids in all living organisms
38
What is Protein synthesis used for and where does it occur
Used for making proteins it happens in the nucleus and at the ribosomes
39
Define Gene
The sequence of nucleotide bases in DNA which determine the sequence of amino acid in the polypeptide chain
40
What is the purpose of transcription Where does it occur
Makes mRNA from DNA Occurs in the nucleus
41
Explain the process of transcription
1) The enzyme DNA helicase unwinds and unzips the DNA helix 2) Hydrogen bonds are broken the DNA helix unwinds in the region of the chromosome that codes for the gene 3) Complimentary RNA nucleotides come into position to form a complimentary copy of the gene known as mRNA 4) RNA polymerase joins RNA nucleotides to make the mRNA this is a condensation reaction 5) Phosphodiester bonds formed between the RNA nucleotides this forms the sugar phosphate backbone
42
What is the strand of DNA that contains coded information called
The sense strand
43
What does the antisense strand to do during transcription
It acts as a template which means the RNA strand carries the same base sequence as the Sense strand
44
What does DNA helicase do
Breaks hydrogen bonds between base pairs so that the section of DNA containing the gene unzips
45
What does RNA polymerase do in transcription
Forms phosphodiester bonds between RNA nucleotides to make messenger RNA forms of sugar phosphate backbone
46
What is the purpose of translation and where does it occur
At the ribosome and it makes a protein from messenger RNA
47
What is the purpose of ribosomal RNA
How old is the messenger RNA in position while it is translated into a specific sequence of amino acid
48
What is the ribosome composed of
Two subunits one large and one small and these are composed of proteins and ribosomal RNA
49
What happens during translation
2) Transfer RNA with the complimentary anticodon to start the code on comes into the ribosome and binds to the mRNA start codon 4) the Next transfer RNA with the anti codon complimentary to the next codon it brought in to the ribosome 5) The peptide bond forms between the two amino acid’s 6) This is catalysed by an enzyme called peptidyl transferase 7) The stages are repeated with another amino acid being added each time to the polymer
50
What is the overall job of the codon
Codons on a mRNA determine the specific transfer RNA that comes into position
51
What is the role of transfer RNA
To bring in specific amino acid’s to the ribosome in the correct order
52
What are the amino acid’s then join together bye
Peptide bonds
53
Name the enzyme that catalyse is translation
Peptidyl transferase
54
What does ATP stand for
Adenosine Triphosphate
55
Describe the structure of adenosine
There are three phosphate’s, a pentose sugar and a nitrogenous base which is Adenine
56
What is ATP used for
Energy transfer in all cells of living organisms
57
In ATP what is not stable
The phosphate bonds are not stable this means ATP is not a good long-term store of energy
58
What is ADP
Where ATP loses a phosphate, bond is broken as this is the hydrolysis reaction and water is used
59
Name 4 properties of ATP
It is small so it’s easily to move into and out of cells It is soluble in water Releases energy in small quantities Energy is contained in the bonds between phosphate is large enough for cell reactions

A Level: Biology (18 decks)

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