2.3 Nucleotides And Nucleic Acids Flashcards
Examples of Nucleic acids
DNA AND RNA
Nucleic acids
polymers that are made up of many repeating units (monomers) called nucleotides
What is each nucleotide formed from
A pentose sugar (a sugar with 5 carbon atoms)
A nitrogen-containing organic base
A phosphate group
Components of DNA nucleotides
A deoxyribose sugar with hydrogen at the 2’ position
A phosphate group
One of four nitrogenous bases - adenine (A), cytosine(C), guanine(G) or thymine(T)
Components of RNA nucleotides
A ribose sugar with a hydroxyl (OH) group at the 2’ position
A phosphate group
One of four nitrogenous bases - adenine (A), cytosine(C), guanine(G) or uracil (U)
Why is RNA more susceptible to hydrolysis and what does this mean
The presence of the 2’ hydroxyl group
This is why DNA is the storage molecule and RNA is the transport molecule with a shorter molecular lifespan
Nitrogenous base of DNA
Adenine, cytosine, guanine or thymine (A,T,C,G)
Nitrogenous bases of RNA
Adenine, cytosine, guanine or uracil (A,U,C,G)
What two structural forms to nitrogenous bases found in nucleotides of DNA and RNA
Purines and pyrimidines
What structural form are adenine and guanine
Purine- they have a double ring structure
What structural form do cytosine, thymine and uracil have
Pyrimidines- they have a single ring structure
Pentose sugar of DNA
Deoxyribose
Pentose sugar of RNA
Ribose
Number of strands in DNA
Double stranded (double helix)
Number of strands in RNA
Single stranded
What makes DNA and RNA polymer
they are made up of many nucleotides joined together in long chains
How are separate nucleotides joined together
Condensation reactions
Where do the condensation reactions occur (nucleotides)
between the phosphate group of one nucleotide and the pentose sugar of the next nucleotide
What does a condensation reaction between two nucleotides form
Phosphodiester bond
What does a Phosphodiester bond consist of
A phosphate group and two (di) ester bonds- phospho(di)ester
What is the chain of alternating phosphate groups and pentose sugars produced as a result of many phosphodiester bonds known as
the sugar-phosphate backbone (of the DNA or RNA molecule)
What does the synthesis of polynucleotides require
formation of phosphodiester bonds
What does the breakdown of polynucleotides require
the breakage of phosphodiester bonds
What happens in condensation reactions
A molecule of water is released
What happens in hydrolysis reactions
A molecule of water is added
What is energy required for in all organisms
Anabolic reactions
Moving substances across the cell membrane or moving substances within a cell
Anabolic reactions
Building larger molecules from smaller molecules
What is energy required for in animals
Muscle contraction – to coordinate movement at the whole-organism level
The conduction of nerve impulses
What is ATP used for in all known life forms
ATP from respiration is used to transfer energy in all energy-requiring processes in cells
What is Adenosine Triphsphate (ATP) and how does it link to DNA and RNA
A nucleotide
The monomers of DNA and RNA are also nucleotide
What is Adenosine triphosphate (ATP)
the energy-carrying molecule that provides the energy to drive many processes inside living cells
What type of nucleotide is ATP
a phosphorylated nucleotide
Phosphorylated
Phosphorylation involves the addition of phosphate to an organic compound
Why is ATP structurally similar to the nucleotides that make up DNA and RNA
ATP is another type of nucleic acid and hence it is structurally very similar to the nucleotides that make up DNA and RNA
What does Adenosine diphosphate (ADP) consist of
Sugar ribose, the base adenine and two phosphate groups
What does Adenosine triphosphate (ATP) consist of
Same ribose sugar and base adenine as ADP, but contains three phosphate groups
What is DNA and what is it made up of
a polynucleotide – it is made up of many nucleotides bonded together in a long chain
What are DNA molecules made up of
DNA molecules are made up of two polynucleotide strands lying side by side, running in opposite directions – the strands are said to be antiparallel
What is each DNA polynucleotide strand made up of
alternating deoxyribose sugars and phosphate groups bonded together to form the sugar-phosphate backbone
What type of bonding is involved in each DNA polynucleotide strand
These bonds are covalent bonds known as phosphodiester bonds
What are the strands known as
As the strands run in opposite directions (they are antiparallel), one is known as the 5’ to 3’ strand and the other is known as the 3’ to 5’ strand
What holds together the two anti parallel DNA polynucleotide strands
Hydrogen bonds
Where do the hydrogen bonds occur (DNA)
The same bases
What does the purine adenine bond with
The pyrimidines thymine- two hydrogen bonds formed between these bases (A and T)
What does the purine guanine pair with
The pyrimidines cytosine- three hydrogen bonds are formed between these bases (G and C)
What is the process of the hydrogen bonds between bases known as
Complementary base pairing with the pars known as complementary base pairs
Why is DNA referred to as a double helix
the three-dimensional shape formed by the twisting of the DNA molecule