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Biology > 3.1.5 nucleic acids are important information carrying molecules > Flashcards

3.1.5 nucleic acids are important information carrying molecules Flashcards

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1
Q

What is DNA?

A

-stands for deoxyribonucleic acid
-an example of a nucleic acid
-DNA is a polynucleotide, made up of many nucleotides joined together
-holds the genetic information in all living cells

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2
Q

What is RNA?

A

-stands for ribonucleic acid
-a single polynucleotide strand, made up of many nucleotides joined together.
-transfers genetic information from DNA to the ribosomes

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3
Q

Name the 4 bases in a DNA molecule

A

-Adenine
-Cytosine
-Guanine
-Thymine

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3
Q

What does a DNA nucleotide consist of?

A

-phosphate group
-deoxyribose (a pentose sugar)
-a nitrogenous base

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4
Q

Explain how bases pair in a DNA molecule

A

-through complementary base pairing
-A and T bond to each other with 2 weak hydrogen bonds
-C and G bond together with 3 weak hydrogen bonds

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5
Q

What is a pentose sugar?

A

A sugar which contains 5 carbon atoms

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6
Q

Describe the structure of DNA

A

-made up of 2 polynucleotide strands
-double helix shape
-the strands are held together by weak hydrogen bonds between complementary base pairs.
-has a sugar-phosphate backbone which is held together by phosphodiester bonds

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7
Q

What is a phosphodiester bond?

A

-the bond between the pentose sugar molecule and the phosphate group
-forms the sugar-phosphate backbone in DNA and RNA
-in DNA the deoxyribose sugar is linked to the phosphate group by a phosphodiester bond

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8
Q

How is a phosphodiester bond formed?

A

-in a condensation reaction between two nucleotides

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9
Q

Key feature of the phosphodiester bonds

A

They are strong covalent bonds, so they create a strong sugar-phosphate backbone.

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10
Q

What is the function of the sugar-phosphate backbone?

A

To give the DNA molecule a stable structure, that does not easily denature

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11
Q

What is the function of the weak hydrogen bonds between complementary base pairs?

A

The two strands can split easily for transcription and replication

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12
Q

Why is DNA double-stranded?

A

So that replication can occur using one strand as a template

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13
Q

Why is DNA so long?

A

So it can store lots of genetic information

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14
Q

Why is DNA coiled?

A

To make it compact so that it fits into the nucleus

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15
Q

What is the function of complementary base pairing?

A

They can both act as templates during semi-conservative replication.
Allows identical copies to be made as new nucleotides can join the exposed bases

16
Q

Why are the DNA bases in sequence?

A

To determine the structure of proteins during protein synthesis

17
Q

Why is DNA in a double helix shape?

A

To protect the weak hydrogen bonds between bases

18
Q

Name the 4 bases in an RNA molecule

A

-Adenine
-Cytosine
-Guanine
-Uracil

19
Q

Name the pentose sugar in a DNA molecule

A

Deoxyribose

19
Q

Name the pentose sugar in an RNA molecule

A

Ribose

20
Q

Describe the structure of an RNA molecule

A

-made up of one polynucleotide strand (single stranded)
-the polynucleotide strands are relatively short
-the sugar-phosphate backbone of the polynucleotide chain is linked by phosphodiester bonds between the ribose sugar and the phosphate group.

21
Q

What is the function of mRNA/messenger RNA?

A

-a copy of one gene in your DNA
-leaves the nucleus to carry the copy of the genetic code of one gene to a ribosome
-this occurs when a gene is copied during protein synthesis, as each 3 bases code for a specific sequence of amino acids
-mRNA is shorter in size, short lived and single stranded

21
Q

What is the function of tRNA/transfer RNA?

A

-to transfer amino acids to the ribosomes during protein synthesis
-it is single stranded but forms a cloverleaf shape, held in place by hydrogen bonds

22
Q

What is the function of rRNA/ribosomal RNA?

A

-to combine with a protein to make a ribosome
-ribosomal RNA makes up the bulk of ribosomes

23
Q

What is the anti-sense strand?

A

The name given to the polynucleotide strand in a DNA molecule that codes for the protein.

24
Q

What is the sense strand?

A

The name given to the polynucleotide strand in a DNA molecule which is simply there for support.

25
Q

What is a purine?

A

-a base which has 2 rings of atoms in its structure and is therefore larger
-includes guanine and adenine

25
Q

What is a pyrimidine?

A

-a base which has only one ring of atoms in its structure
-includes cytosine, thymine and uracil

26
Q

Why is RNA susceptible to hydrolysis?

A

It has a hydroxyl group on the 2’ carbon of the ribose sugar molecule
-this means it is useful as a transport molecule with a short lifespan

Biology (14 decks)

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