Nucleic Acids and Their Functions

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Questions and Answers

What is the primary function of nucleotides in biological systems?

Build nucleic acids (correct)

Synthesize proteins

Transport oxygen

Form cell membranes

Which component is NOT part of the structure of nucleotides?

Nitrogen base

Phosphate group

Amino acid (correct)

Pentose sugar

Which statement accurately describes the bonding within a polynucleotide?

Nucleotides are linked by peptide bonds.

Hydrogen bonds connect the nitrogen bases.

Ionic bonds form between nucleotide sugars.

Phosphodiester bonds join the nucleotides. (correct)

What is an example of a high-energy nucleotide?

Adenosine triphosphate Signup and view all the answers

What type of bond is formed between the pentose sugar of one nucleotide and the phosphate group of another?

Ester bond Signup and view all the answers

In the context of nucleic acids, what does the term 'polarity' refer to?

The orientation of the nucleotide chain Signup and view all the answers

Which of the following is a pyrimidine nucleotide?

Uridine Signup and view all the answers

Which compound serves a regulatory function in cellular processes?

Cyclic adenosine monophosphate Signup and view all the answers

Which of the following correctly identifies a type of nucleic acid?

Ribonucleic acid Signup and view all the answers

What is a defining component of a nucleotide?

Nitrogenous base linked to a pentose sugar Signup and view all the answers

Which nitrogenous bases are classified as purines?

Adenine and Guanine Signup and view all the answers

Which statement about pentose sugars is true?

Deoxyribose contains one less oxygen than ribose Signup and view all the answers

What type of bond links the nitrogenous base to the sugar in nucleotides?

N-glycosidic bond Signup and view all the answers

Which is a correct example of a nucleoside?

Adenosine Signup and view all the answers

Identify the correct pairing of a nucleotide and its corresponding nucleoside.

Adenosine - Adenylic acid Signup and view all the answers

What function do nucleic acids primarily serve within organisms?

Storage and expression of genetic information Signup and view all the answers

Study Notes

Nucleic Acid Structure and Function

Nucleic acids are polymers of nucleotides linked by phosphodiester bonds. Their primary function is to store and express genetic information.
There are two types of nucleic acids: Ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA).
Nucleic acids are made up of Nucleotides.

Nucleotides and Nucleosides

A nucleotide is composed of a nitrogenous base linked to a pentose sugar, with a phosphate group attached.
A nucleoside is composed of a nitrogenous base linked to a pentose sugar.
Nucleotides can be broken down into: Nucleoside + Phosphate group.

Nitrogenous Bases

There are two families of nitrogenous bases: Purines and Pyrimidines.
Purine bases include Adenine (A) and Guanine (G).
Pyrimidine bases include Cytosine (C), Thymine (T) and Uracil (U).

Pentose Sugars

There are two types of pentose sugars:
- Ribose (present in RNA).
- Deoxyribose (present in DNA). Deoxyribose is a modified form of ribose, where an oxygen atom has been removed from carbon 2.

Phosphate Group

The phosphate group (H3PO4) attaches to carbon 5 of the ribose sugar through an ester bond.

Nucleic Acids Structure and Nomenclature

In nucleotides and nucleosides, the nitrogenous base is linked to the C1 of the sugar by an N-glycosidic bond.
Nucleotides are named based on their nucleoside base and the number of Phosphate groups attached.
- For example, Adenosine monophosphate (AMP) is composed of Adenosine (NB) and one phosphate group.

Biological Importance of Nucleotides and Nucleosides

Building blocks of nucleic acids (DNA and RNA).
High-energy source, like adenosine triphosphate (ATP).
Constituents of coenzymes like Flavin adenine dinucleotide (FAD) and Nicotinamide adenine dinucleotide (NAD).
Serve regulatory functions, like cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP).
Synthetic nucleotide analogue drugs are used in chemotherapy.
Pyrimidines are precursors of metabolic intermediates, like UDP-glucose and CDP-choline.

Polymerisation of Nucleotides

Nucleotides are linked together by a 3′, 5′ phosphodiester bond.
The 3′-OH of one nucleotide is attached to the phosphate group of the next nucleotide.
This results in a phosphate group being attached by two ester bonds to the carbon 3’ and 5’ of two successive nucleotides.
Enzymes called nucleases can hydrolyze these phosphodiester bonds.
Polynucleotides have two terminals:
- Free 3′ hydroxyl (-OH) at one end called the 3′-end.
- Free 5′ phosphate group at the other end called the 5′-end.
Nucleic acids have a defined polarity due to the directionality of the 3′, 5′ bond.

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Description

Explore the structure and function of nucleic acids, including DNA and RNA. This quiz covers essential topics like nucleotides, nitrogenous bases, and the role of pentose sugars. Test your knowledge on the building blocks of genetic information.