Nucleic Acids and Nucleotides Overview

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Questions and Answers

What is the main function of DNA in the cell?

To store genetic information. (correct)

To transport nutrients.

To create proteins in the cytoplasm.

To serve as an energy source.

What characterizes nucleotides?

They consist of a sugar, a nitrogen base, and a phosphate group. (correct)

They are exclusively found in RNA.

They are made up of only a sugar and a nitrogen base.

They lack a phosphate group.

Which statement about the pentose sugars in RNA and DNA is correct?

Deoxyribose has an oxygen atom at the 2' position.

RNA contains ribose while DNA contains deoxyribose. (correct)

Both RNA and DNA contain the same pentose sugar.

Ribose is absent in both RNA and DNA.

What distinguishes a nucleoside from a nucleotide?

Nucleotides consist of a nitrogen base, sugar, and phosphate. Signup and view all the answers

Which nitrogenous bases are found in RNA?

A, U, C, G Signup and view all the answers

What type of bond links nucleotides in nucleic acids?

Phosphodiester bond Signup and view all the answers

Which of the following is a characteristic of ribonucleotides?

Presence of ribose sugar. Signup and view all the answers

In which cellular location is RNA primarily found?

Cytoplasm Signup and view all the answers

Which nitrogen bases are classified as purines?

Adenine and Guanine Signup and view all the answers

What type of bond forms between the 3' carbon of one nucleotide and the 5' carbon of another?

Phosphodiester bond Signup and view all the answers

What is the correct pairing of nitrogen bases in DNA?

Adenine with Thymine Signup and view all the answers

Which of the following correctly identifies pyrimidines?

Uracil and Cytosine Signup and view all the answers

In the context of DNA structure, which statement is true about the strands of DNA?

They are antiparallel. Signup and view all the answers

Which nucleotide is equivalent to uridylic acid?

UMP Signup and view all the answers

What type of bond connects the nitrogen bases in the DNA double helix?

Hydrogen bond Signup and view all the answers

Which of the following is NOT a component of nucleotides?

Glucose Signup and view all the answers

Study Notes

Nucleic Acids (DNA and RNA)

DNA stores genetic information, permanently located in the cell nucleus.
RNA is temporary, found in the cytoplasm, and its presence depends on cellular needs. mRNA is a type of RNA that carries instructions, while other RNA types have functional roles.
Nucleic acids are polymers constructed from nucleotide monomers.
DNA and RNA are examples of nucleotide polymers.

Nucleotides Occurrence in the Cell

Nucleotides are the monomers of nucleic acids.
Important energetic compounds include ATP, ADP, AMP, GTP, GDP, GMP, CTP, CDP, CMP, TTP, TDP, TMP.
These energetic compounds are crucial for cellular processes.
DNA and RNA are polymers made up of nucleotides.

Nucleotide & Nucleoside

Nucleotides are composed of a sugar, a nitrogenous base, and a phosphate group.
Nucleosides consist of a sugar and a nitrogenous base.
RNA contains oxyribose sugar; DNA contains deoxyribose sugar.

Nucleoside Composition

Nucleosides are composed of a pentose sugar and a nitrogenous base, without a phosphate group.
Ribonucleoside (R=OH) and 2'-Deoxyribonucleoside (R=H) are examples of nucleosides.

Nucleotide Composition

Nucleotides consist of a pentose sugar, a nitrogenous base, and a phosphate group.
Nitrogenous bases include A, T, C, G.
The phosphate group is attached to the sugar.

Pentose Sugars in RNA and DNA

RNA contains ribose sugar.
DNA contains deoxyribose sugar.
The carbon atoms in the sugar are numbered with primes (') to differentiate them from the nitrogenous bases.

Types of Nucleic Acids

RNA (Ribonucleic acid)
DNA (Deoxyribonucleic acid)
Both are polymers of nucleotides linked by phosphodiester bonds.

Chemical Structure of Nucleic Acids - Monomers

Nucleotides are the monomers.
Pyrimidines link to the pentose sugar via C1' to C1'.
Purines link to the pentose sugar via N9 to C1'.
Examples include deoxyadenosine 5'-triphosphate (dATP) and cytidine 5'-monophosphate (CMP).

Nitrogen Bases

Purines have two carbon-nitrogen rings (C1'-N9).
Examples include adenine (A) and guanine (G).
Pyrimidines have one carbon-nitrogen ring (C1'-N1).
Examples include cytosine (C), thymine (T), and uracil (U).

Nomenclature of Nucleotide

Nucleotides are named based on their nitrogenous base.
Adenine is denoted as dATP (deoxyadenosine triphosphate), guanine is dGTP (deoxyguanosine triphosphate), and so on.

Types of Bonds in DNA

Glucosidic bonds connect the sugar and nitrogenous base.
Phosphodiester bonds link successive nucleotides.
Hydrogen bonds form between complementary base pairs (C-G, A-T).

Formation of the 3' to 5' Phosphodiester Bond

Covalent bonds form between the phosphate group and two 5-carbon ring carbohydrates (pentoses) across two ester bonds. This is a strong covalent bond.
The phosphodiester bond forms the linkage between the 3' carbon atom of one sugar and the 5' carbon of another.

DNA Helix

DNA is a large molecule made of nucleotides.
Nucleotides consist of a deoxyribose sugar, a phosphate group, and a nitrogenous base.

The Most Common Organic Bases

The most common organic bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).

Bonding

Adenine (A) pairs with Thymine (T) via two hydrogen bonds.
Cytosine (C) pairs with Guanine (G) via three hydrogen bonds.

DNA Properties – Model of Watson and Crick (1953)

DNA has a 3-dimensional structure.
DNA has two antiparallel polynucleotide chains.
The chains run in opposite directions (5' to 3' and 3' to 5').
The structure has a sugar-phosphate backbone on the outside and nitrogenous bases on the inside.
The strands are held together by hydrogen bonds between the bases.
Each turn of the helix has about 10 base pairs.
The helix has a diameter of 2 nanometers.
The helix has major and minor grooves.

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Description

This quiz covers the essential concepts of nucleic acids, specifically DNA and RNA, along with their structures and functions. You will explore the differences between nucleotides and nucleosides, their roles in cellular processes, and the significance of energetic compounds. Test your understanding of these fundamental biological molecules.