Chapter 12 DNA and RNA Vocabulary Review provides a comprehensive overview of the fundamental building blocks of genetic material. This review is crucial for understanding the intricate processes of gene expression and the role of mutations in shaping genetic diversity.
The chapter delves into the chemical structure of DNA and RNA, comparing their key differences. It explores the four different nucleotides that constitute these molecules and explains the concept of base pairing, which determines the sequence of nucleotides and the genetic code.
DNA and RNA Structure
DNA and RNA are essential biomolecules that play crucial roles in storing and transmitting genetic information. Understanding their structure is fundamental to comprehending their function.DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are both composed of nucleotide subunits. Each nucleotide consists of a nitrogenous base, a ribose sugar (in RNA) or deoxyribose sugar (in DNA), and a phosphate group.
The nitrogenous bases are adenine (A), cytosine (C), guanine (G), and thymine (T) in DNA, while uracil (U) replaces thymine in RNA.The nucleotides are linked together through phosphodiester bonds, forming a chain. In DNA, the two strands of nucleotides are arranged in a double helix structure, held together by hydrogen bonds between the complementary base pairs: A with T and C with G.
RNA typically exists as a single-stranded molecule, although some forms can fold into complex structures.
| Characteristic | DNA | RNA |
|---|---|---|
| Sugar | Deoxyribose | Ribose |
| Nitrogenous Bases | A, C, G, T | A, C, G, U |
| Structure | Double helix | Single-stranded (usually) |
| Location | Nucleus | Nucleus, cytoplasm, and ribosomes |
| Function | Stores genetic information | Carries genetic information, participates in protein synthesis |
Nucleotides and Base Pairing
The four different nucleotides found in DNA and RNA are adenine, cytosine, guanine, and thymine (in DNA) or uracil (in RNA). These nucleotides are arranged in a specific sequence, forming the genetic code.Base pairing is the process by which complementary nucleotides bind together through hydrogen bonds.
In DNA, adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G). In RNA, adenine pairs with uracil (A-U) instead of thymine.Examples of base pairs and their complementary relationships include:* A-T (DNA) or A-U (RNA)
C-G (DNA and RNA)
Gene Expression, Chapter 12 dna and rna vocabulary review
Gene expression is the process by which the information encoded in DNA is used to produce proteins. It involves two main steps: transcription and translation.Transcription occurs in the nucleus, where an enzyme called RNA polymerase binds to a specific region of DNA and synthesizes a complementary RNA molecule.
This RNA molecule, called messenger RNA (mRNA), carries the genetic information from the nucleus to the cytoplasm.Translation occurs in the cytoplasm, where ribosomes bind to the mRNA and read the sequence of nucleotides. Each codon (three-nucleotide sequence) on the mRNA corresponds to a specific amino acid.
The ribosome assembles the amino acids in the correct order, forming a polypeptide chain, which eventually folds into a functional protein.
RNA polymerase is the enzyme responsible for synthesizing RNA molecules during transcription. Ribosomes are complex structures composed of RNA and protein that facilitate translation by binding to mRNA and assembling amino acids into proteins.
Mutations and Genetic Disorders
Mutations are changes in the DNA sequence that can occur due to various factors, such as errors during DNA replication or exposure to environmental mutagens. Mutations can be classified into two main types: point mutations and chromosomal mutations.Point mutations involve changes in a single nucleotide, such as a substitution, insertion, or deletion.
Chromosomal mutations affect larger regions of DNA, such as duplications, deletions, or inversions.Mutations can have a significant impact on gene expression and cellular function. They can disrupt the reading frame of a gene, resulting in the production of a non-functional protein.
Mutations can also alter the regulation of gene expression, leading to abnormal levels of protein production.Examples of genetic disorders caused by mutations include:* Sickle cell anemia (caused by a point mutation in the beta-globin gene)
- Cystic fibrosis (caused by a deletion mutation in the CFTR gene)
- Huntington’s disease (caused by an expansion mutation in the HTT gene)
FAQ Compilation: Chapter 12 Dna And Rna Vocabulary Review
What is the difference between DNA and RNA?
DNA is a double-stranded molecule, while RNA is a single-stranded molecule. DNA contains the genetic code, while RNA is involved in protein synthesis.
What are the four different nucleotides found in DNA and RNA?
The four nucleotides found in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). The four nucleotides found in RNA are adenine (A), uracil (U), guanine (G), and cytosine (C).
What is base pairing?
Base pairing is the process by which nucleotides in DNA and RNA form hydrogen bonds with each other. Adenine pairs with thymine (or uracil in RNA), and guanine pairs with cytosine.
