Nucleic Acids and Their Components

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Questions and Answers

Which component of nucleotides is derived from phosphoric acid?

Phosphate (correct)

Nucleotide

Sugar

Heterocyclic base

What sugar component is found in DNA?

Fructose

D-ribose

D-deoxyribose (correct)

Glucose

Which base is not present in RNA?

Thymine (correct)

Cytosine

Adenine

Uracil

What type of bonds link the nucleotide units in DNA?

Phosphodiester bonds Signup and view all the answers

What feature characterizes the secondary structure of DNA?

Double helix Signup and view all the answers

How many nucleotide bases are there in DNA that are considered purines?

2 Signup and view all the answers

Watson and Crick were responsible for proposing which model of DNA?

Double helix model Signup and view all the answers

What is the correct sequence of the nucleic acid backbone?

Phosphate-sugar-phosphate-sugar Signup and view all the answers

Which type of RNA serves as the primary carrier of genetic information from the DNA in the nucleus to the site of protein synthesis?

Messenger RNA (mRNA) Signup and view all the answers

What is the main role of ribosomal RNA (rRNA) in the cell?

To form the structure of ribosomes Signup and view all the answers

Which statement about transfer RNA (tRNA) is true?

tRNA contains anticodons that are complementary to mRNA codons Signup and view all the answers

What distinguishes non-coding RNA (ncRNA) from other RNA types?

It is less than 200 nucleotides long Signup and view all the answers

Which of the following correctly describes the structure of RNA?

RNA is single-stranded and contains uracil Signup and view all the answers

What is the fundamental function of genes in relation to chromosomes?

They are the basic unit of heredity. Signup and view all the answers

What characterizes semiconservative replication?

One strand is from the parent and one is new. Signup and view all the answers

What is an Okazaki fragment?

Small pieces of DNA produced during replication. Signup and view all the answers

What is the role of the replication fork during DNA replication?

It separates the DNA strands. Signup and view all the answers

What are nicks in the context of DNA replication?

They are gaps or breaks between segments in the daughter strand. Signup and view all the answers

What is the role of RNA polymerase in transcription?

It catalyzes the synthesis of RNA from a DNA template. Signup and view all the answers

What distinguishes exons from introns in eukaryotic DNA?

Exons code for amino acids, while introns do not. Signup and view all the answers

What is a codon?

A sequence of three nucleotide bases on mRNA that corresponds to an amino acid. Signup and view all the answers

What is the possible consequence of mutations in DNA?

They may result in genetic diseases or be lethal. Signup and view all the answers

Which process represents the conversion of mRNA code into a protein structure?

Translation Signup and view all the answers

Study Notes

Nucleic Acids: Components

Nucleic acids transfer genetic information to new cells.
Two main categories: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
Both are long, linear polymers.

Ribonucleic Acid (RNA)

Primarily found in the cytoplasm of living cells.
Sugar component: D-ribose.

Deoxyribonucleic Acid (DNA)

Primarily found in the nuclei of cells.
Sugar component: D-deoxyribose.
Lacks an oxygen atom at the second position of the heterocyclic ring.
Both DNA and RNA sugars are in the β-configuration.

Nucleotides

Monomers of nucleic acids.
Composed of a heterocyclic base, sugar, and phosphate.
Heterocyclic bases classified as pyrimidines or purines.
Pyrimidines: Uracil, Thymine, Cytosine (U, T, C).
Purines: Adenine, Guanine (A, G).
Uracil and Thymine are only found in RNA and DNA, respectively.
Adenine and Guanine are present in both DNA and RNA.

DNA Structure

DNA is the largest known molecule.
Contains millions of nucleotide units linked by phosphodiester bonds.
Has a sugar-phosphate backbone, constant throughout the DNA molecule.
The order of bases determines the primary DNA structure.

DNA Secondary Structure

Proposed in 1953 by Watson and Crick.
DNA is a double helix formed by two strands entwined around each other.
Strands are complementary (A with T, G with C).

DNA Replication

DNA replicates to produce identical copies.
Semiconservative replication: each new DNA molecule contains one original strand.
Replication occurs at a replication fork, where the double helix unwinds.

RNA Structure

Long, unbranched polymer of nucleotides linked by 3' to 5' phosphodiester bonds.
Usually single-stranded, except in some viruses.
Found in the nucleus, cytoplasm, and mitochondria.
Three main types: mRNA, rRNA, tRNA

mRNA

Carries genetic information from DNA to the cytoplasm.
Involved in protein synthesis.
Short lifetime (usually less than an hour).

rRNA

Major component of ribosomes (sites of protein synthesis)
Constitutes about 65% of ribosome material.

tRNA

Delivers amino acids to the ribosomes during protein synthesis.
Smallest nucleic acid (73-93 nucleotides per chain).
Contains an anticodon that aligns with corresponding mRNA codons.

Polymerase Chain Reaction (PCR)

Mimics DNA replication in a test tube.
Used to amplify specific DNA regions.

Genetic Code

A series of three-letter words (codons) representing amino acids and start/stop signals.

Translation

Converts mRNA codons into amino acid sequences.
tRNA molecules bring amino acids to the ribosome.
Complementary base pairing determines the amino acid order.
Amino acids bond to form a protein with characteristic secondary/tertiary structures.

Mutations

Changes in the DNA base sequence.
Can be natural or induced.
Can be lethal or cause genetic diseases.

Recombinant DNA

Uses restriction enzymes and DNA ligases.
Isolates genes and inserts them into bacteria to produce proteins.

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Description

Explore the fascinating world of nucleic acids in this quiz, covering DNA and RNA structures, their components, and the essential role of nucleotides. Test your knowledge on the differences between ribonucleic and deoxyribonucleic acids, along with their sugar components and nitrogenous bases.