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Flashcards in 2.3* Deck (149)
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What is a double helix?

Shape of a DNA molecule, due to coiling to two sugar-phosphate backbone strands into a right handed spiral configuration.


What is a monomer?

A molecule that when repeated makes up a polymer. Amino acids are the monomers of proteins. Nucleotides are the monomers of nucleic acids.


What is a nucleotide?

Molecule consisting of a five-carbon sugar, a phosphate group and a nitrogenous base.


What is a large molecule containing many nucleotides?

A polynucleotide.


What is a nucleotide?

Nucleotides are biological molecules that participate in nearly all biochemical processes. They are phosphate esters of pentose sugars, where a nitrogenous base linked to the carbon atom 1 of the sugar residue, and a phosphate group is linked to either carbon atom 5 or carbon atom 3 of the sugar residue, by covalent bonds formed by condensation reactions.


What do nucleotides form?

Nucleotides form the monomers of nucleic acids, DNA and RNA. In RNA the nucleotide pentose sugar is ribose. In DNA the nucleotide pentose sugar is deoxyribose.


When do nucleotides become phosphorylated nucleotides?

When they contain more than one phosphate group.


Give some examples of phosphorylated nucleotides.

ADP adenosine diposphate
ATP adenosine triphosphate
ATP is an energy-rich end-point of most energy-releasing biochemical pathways, and it is used to drive most energy-requiring metabolic processes in cells.


What do nucleotides help regulate?

Many metabolic pathways, for example by ADP and AMP (adenosine mono-phosphate)


What may nucleotides be components of?



Give some examples of nucleotides that act as co-enzymes.

Adenine nucleotides are components of the co-enzymes NADP - nicotinamide adenine dinucleotide phosphate, which is used in photosynthesis, and of NAD (nicotinamide adenine dinucleotide), which is a co-enzyme used in respiration, and of FAD (flavine adenine dinucleotide) and co-enzyme A (both also involved in respiration).


Where is DNA found?

DNA is found in the nuclei of all eukaryote cell, within the cytoplasm of prokaryotic cells and is also inside some types of viruses.


What does DNA carry?

DNA is the hereditary material and carries coded instructions used in the development and functioning of all known living organisms.


What is DNA one of the most important?

DNA is one of the most important macromolecules that make up the structure of living organisms, the others being proteins, carbohydrates and lipids.


What is the structure of the polymer of DNA

DNA is a polymer as its made up of many repeating monomeric units called nucleotides.


A molecule of DNA consists of two stands made up of?



What does each DNA nucleotide consist of?

Each DNA nucleotide consists of a phosphate group, a five-carbon sugar called deoxyribose, and one of four nitrogenous bases; adenine, guanine, thymine or cytosine.


What type of bond exists between the sugar residue and the phosphate group in DNA?

A covalent bond.


What is the covalent bond between the sugar residue and the phosphate group in a nucleotide called? - DNA

A phosphodiester.

look at pg 87 for a diagram on condensation bonds.


How do nucleotides in DNA differ?

DNA consists of just four types of nucleotide. In each nucleotide the phosphate and sugar groups are the same but the organic (nitrogen) base differs.


What are the full names for the bases in DNA?

Adenine always pairs with thymine and Guanine always pairs with cytosine.


How are the two anti-parallel DNA strands joined to each other?

Hydrogen bonds between the nitrogenous bases.


Why do matching base pairs have to pair?

A purine always pairs with a pyrimidine to give equal sized rungs on the ladder.


Why do the DNA 'rungs' twist around an imaginary axis into a double helix?

To give the molecule stability.


What bases are purines?

Adenine and guanine


What bases are pyrimidines?

Thymine and cytosine


What bonds allows the nucleotides to unzip for transcription and replication?

hydrogen bonds.


Nucleotides with adenine as the base can make how many bonds with nucleotides with thymine as the base?



Nucleotides with guanine as the base can make how many bonds with nucleotides with cytosine as the base?



What is the upright part of the large DNA molecule that resembles a ladder formed by?

A sugar-phosphate backbone of the anti-parallel polynucleotide strand.