Nucleic acids

What are nucleic acids and their primary functions?

Nucleic acids store, transmit, and help express hereditary information.

What are the two types of nucleic acids?

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

What is the role of DNA?

DNA stores hereditary information responsible for inherited traits in all eukaryotes, prokaryotes, and many viruses.

What is the role of RNA?

RNA serves as the hereditary molecule in another large group of viruses and is involved in protein synthesis.

What are the three major types of RNA involved in protein synthesis?

Messenger RNA (mRNA), Ribosomal RNA (rRNA), and Transfer RNA (tRNA).

What is a nucleotide?

A nucleotide is a monomer of nucleic acids, consisting of a phosphate group, a five-carbon sugar, and a nitrogenous base.

What are the components of a nucleotide?

A phosphate group, a five-carbon sugar (deoxyribose or ribose), and a nitrogenous base (A, T, G, C).

What distinguishes ribonucleotides from deoxyribonucleotides?

Ribonucleotides have ribose as their sugar and an -OH group on the 2'-carbon, while deoxyribonucleotides have deoxyribose and an H instead at the 2'-carbon.

What are purines and pyrimidines?

Purines (adenine and guanine) have two carbon-nitrogen rings, while pyrimidines (cytosine, uracil, and thymine) have one carbon-nitrogen ring.

What is a polynucleotide?

A polynucleotide is a chain of nucleotides linked together by phosphodiester linkages.

What is a phosphodiester linkage?

A phosphodiester linkage is a bond between the phosphate group of one nucleotide and the hydroxyl group of the sugar of another nucleotide.

What is the sugar-phosphate backbone?

The sugar-phosphate backbone is a repeating pattern of sugar and phosphate groups in a polynucleotide chain.

What direction is the sugar-phosphate backbone oriented?

The backbone is directional, typically written in the 5' to 3' direction.

How do nucleotides polymerize?

Nucleotides polymerize via condensation reactions, forming phosphodiester linkages.

What is the role of polymerases in nucleic acid synthesis?

Polymerases catalyze the polymerization of nucleotides into nucleic acids.

What are activated nucleotides?

Activated nucleotides are nucleoside triphosphates that have additional phosphate groups added to raise their potential energy.

What happens during the polymerization of activated nucleotides?

The energy released from the condensation reaction compensates for the decrease in entropy, making it a spontaneous reaction.

What is the significance of the 5' and 3' ends of nucleic acids?

One end has an unlinked 5' phosphate group, and the other end has an unlinked 3' hydroxyl group, defining the directionality of the strand.

What is the primary structure of DNA?

The primary structure of DNA is represented by the sequence of bases listed in the 5' to 3' direction.

What is the potential energy source in activated nucleotides?

The potential energy is primarily stored in the bonds between the phosphates.

What is the result of hydrolysis of ATP?

Hydrolysis of ATP releases energy and results in ADP and AMP, along with inorganic phosphate (Pi).

What happens when ATP reacts with water?

One of the bonds between two phosphates is replaced with a lower potential energy bond, releasing energy.

What is the role of ATP in cellular activities?

ATP serves as the cellular energy currency, driving various cellular activities independent of nucleotide polymerization.

Why do phosphate groups carry a large amount of potential energy?

They are negatively charged and repel each other, creating strong covalent bonds when linked together.

What are the two types of sugars found in nucleotides?

Deoxyribose in DNA and ribose in RNA.

What distinguishes deoxyribose from ribose?

Deoxyribose has an —H bound to the 2′ carbon, while ribose has an —OH group.

What is a nucleoside?

A structure formed when a nitrogenous base is attached to a pentose sugar.

What is the structure of guanosine monophosphate?

It consists of a guanine base, a ribose sugar, and one phosphate group.

How are DNA and RNA different in terms of base pairing?

In DNA, adenine pairs with thymine (A-T), while in RNA, adenine pairs with uracil (A-U).

What is the structure of the DNA molecule?

A double helix formed by two polynucleotide chains wrapped around each other.

What holds the two strands of DNA together?

Hydrogen bonds between complementary base pairs.

What are the complementary base pairs in DNA?

Adenine pairs with thymine (A-T) and guanine pairs with cytosine (G-C).

What is the significance of complementary base pairing in DNA?

It allows the sequence of one polynucleotide chain to determine the sequence of its partner.

What is the role of the parent DNA strand during replication?

It serves as a template for the assembly of a complementary chain.

How do RNA molecules differ from DNA molecules?

RNA molecules are mainly single-stranded and can fold back to form double-helical regions.

What base does uracil replace in RNA?

Uracil replaces thymine (T) found in DNA.

What is a hybrid double helix?

A temporary structure formed when an RNA chain pairs with a DNA chain during transcription.

What is the significance of the sugar-phosphate backbone in DNA?

It forms the structural framework of the DNA molecule, with the bases extending inward.

What is the orientation of the DNA strands?

The strands are antiparallel, running in opposite directions.

How many hydrogen bonds form between A-T and G-C pairs?

A-T pairs form two hydrogen bonds, while G-C pairs form three hydrogen bonds.

What is the function of the nitrogenous bases in DNA?

They carry the genetic information and determine the sequence of nucleotides.

What is the role of hydrogen bonds in DNA structure?

They stabilize the double helix by holding the base pairs together.

What are the four nitrogenous bases found in DNA?

Adenine (A), thymine (T), cytosine (C), and guanine (G).

What are the four nitrogenous bases found in RNA?

Adenine (A), guanine (G), cytosine (C), and uracil (U).

What is the significance of the 5′ carbon in nucleotides?

It is where phosphate groups bond to the ribose or deoxyribose sugar.

What is the process of polymerization in nucleotides?

It involves linking nucleotides together to form nucleic acids like DNA and RNA.