Bio 101 Nucleic Acids DNA and RNA
34 flashcards covering Bio 101 Nucleic Acids DNA and RNA for the BIOLOGY-101 Biochemistry & Foundations section.
Nucleic acids, specifically DNA and RNA, are fundamental biomolecules that play crucial roles in the storage and expression of genetic information. According to the American Society for Biochemistry and Molecular Biology (ASBMB), understanding these molecules is essential for grasping the principles of genetics and molecular biology. This topic covers the structure, function, and differences between DNA and RNA, as well as their roles in protein synthesis and heredity.
In practice assessments, questions about nucleic acids often involve multiple-choice formats that test your knowledge of their structures, functions, and processes like transcription and translation. A common pitfall is confusing the roles of DNA and RNA; for instance, many candidates mistakenly attribute the function of protein synthesis solely to DNA, overlooking the critical role of mRNA. A practical tip for success is to visualize the processes of transcription and translation, as this can help clarify the distinct functions of each nucleic acid type.
Terms (34)
- 01
What is the structure of DNA?
DNA is a double helix composed of two strands of nucleotides running in opposite directions, held together by hydrogen bonds between complementary base pairs (adenine-thymine and guanine-cytosine). Each nucleotide consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base (Campbell Biology, chapter on DNA structure).
- 02
What are the main functions of RNA?
RNA serves several functions including acting as a messenger carrying instructions from DNA for controlling the synthesis of proteins (mRNA), forming the core of ribosomes (rRNA), and facilitating the translation of mRNA into proteins (tRNA) (Raven Biology, chapter on RNA).
- 03
How many types of RNA are there?
There are three main types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), each serving distinct roles in protein synthesis (Campbell Biology, chapter on RNA).
- 04
What is the role of mRNA in protein synthesis?
mRNA carries the genetic information from DNA to the ribosome, where it serves as a template for assembling amino acids into proteins during translation (Raven Biology, chapter on protein synthesis).
- 05
What base pairs with adenine in DNA?
In DNA, adenine pairs with thymine through two hydrogen bonds, ensuring the stability of the double helix structure (Campbell Biology, chapter on DNA structure).
- 06
What is the difference between DNA and RNA?
The primary differences between DNA and RNA include the sugar in their nucleotides (deoxyribose in DNA vs. ribose in RNA), the presence of thymine in DNA and uracil in RNA, and DNA's double-stranded structure compared to RNA's single-stranded form (Raven Biology, chapter on nucleic acids).
- 07
What is the function of tRNA?
tRNA's primary function is to transport specific amino acids to the ribosome during protein synthesis, matching its anticodon with the corresponding codon on the mRNA (Campbell Biology, chapter on translation).
- 08
What is a nucleotide composed of?
A nucleotide is composed of three components: a phosphate group, a five-carbon sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine) (Raven Biology, chapter on nucleic acids).
- 09
How does DNA replication occur?
DNA replication occurs through a semi-conservative mechanism where each strand serves as a template for the formation of a new complementary strand, resulting in two DNA molecules, each with one old and one new strand (Campbell Biology, chapter on DNA replication).
- 10
What enzyme is responsible for synthesizing RNA from a DNA template?
RNA polymerase is the enzyme responsible for synthesizing RNA from a DNA template during the process of transcription (Raven Biology, chapter on transcription).
- 11
What is the significance of the 5' and 3' ends of a DNA strand?
The 5' and 3' ends of a DNA strand refer to the directionality of the DNA molecule, which is crucial for processes like replication and transcription, as nucleotides are added to the 3' end during these processes (Campbell Biology, chapter on DNA structure).
- 12
What is the process of transcription?
Transcription is the process by which the genetic information in DNA is copied into messenger RNA (mRNA) by RNA polymerase, occurring in the nucleus of eukaryotic cells (Raven Biology, chapter on transcription).
- 13
What are the complementary base pairs in RNA?
In RNA, adenine pairs with uracil, and guanine pairs with cytosine, differing from DNA where adenine pairs with thymine (Campbell Biology, chapter on RNA structure).
- 14
How does the genetic code relate to protein synthesis?
The genetic code consists of codons, which are sequences of three nucleotides in mRNA that correspond to specific amino acids, guiding the assembly of proteins during translation (Raven Biology, chapter on the genetic code).
- 15
What is the role of ribosomes in protein synthesis?
Ribosomes are the cellular machinery that facilitate the translation of mRNA into a polypeptide chain, coordinating the interaction between mRNA and tRNA (Campbell Biology, chapter on translation).
- 16
What is the significance of the promoter region in DNA?
The promoter region is a specific sequence of DNA that signals the start of a gene and is essential for the binding of RNA polymerase to initiate transcription (Raven Biology, chapter on gene regulation).
- 17
What is the function of the 5' cap and poly-A tail in mRNA?
The 5' cap protects mRNA from degradation and assists in ribosome binding, while the poly-A tail enhances stability and regulates the export of mRNA from the nucleus (Campbell Biology, chapter on mRNA processing).
- 18
What is the process of translation?
Translation is the process in which ribosomes synthesize proteins by decoding the mRNA sequence into a polypeptide chain, using tRNA to bring the appropriate amino acids (Raven Biology, chapter on translation).
- 19
What is a mutation in the context of DNA?
A mutation is a change in the nucleotide sequence of DNA, which can lead to changes in protein structure and function, potentially causing genetic disorders (Campbell Biology, chapter on mutations).
- 20
How are DNA and RNA synthesized?
DNA is synthesized by DNA polymerase during replication, while RNA is synthesized by RNA polymerase during transcription, both processes involving complementary base pairing (Raven Biology, chapter on nucleic acids).
- 21
What is the role of the spliceosome in mRNA processing?
The spliceosome is a complex that removes introns from pre-mRNA and joins exons together, producing a mature mRNA molecule ready for translation (Campbell Biology, chapter on RNA processing).
- 22
What are introns and exons?
Introns are non-coding sequences in a gene that are removed during mRNA processing, while exons are coding sequences that remain and are expressed in the final mRNA (Raven Biology, chapter on RNA processing).
- 23
What is the function of DNA ligase?
DNA ligase is an enzyme that joins Okazaki fragments on the lagging strand during DNA replication, sealing nicks in the sugar-phosphate backbone (Campbell Biology, chapter on DNA replication).
- 24
What is the central dogma of molecular biology?
The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein, outlining the processes of replication, transcription, and translation (Raven Biology, chapter on molecular biology).
- 25
What is a codon?
A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis (Campbell Biology, chapter on the genetic code).
- 26
What is the role of the start codon in translation?
The start codon (AUG) signals the beginning of translation and codes for the amino acid methionine, establishing the reading frame for the ribosome (Raven Biology, chapter on translation).
- 27
What is the role of aminoacyl-tRNA synthetase?
Aminoacyl-tRNA synthetase is an enzyme that attaches the appropriate amino acid to its corresponding tRNA, ensuring accurate translation of the mRNA sequence (Campbell Biology, chapter on translation).
- 28
What is the significance of the genetic code being degenerate?
The genetic code is degenerate because multiple codons can encode the same amino acid, providing a buffer against mutations and ensuring the robustness of protein synthesis (Raven Biology, chapter on the genetic code).
- 29
What is the function of the terminator sequence in DNA?
The terminator sequence signals the end of transcription, causing RNA polymerase to detach from the DNA and release the newly synthesized RNA molecule (Campbell Biology, chapter on transcription).
- 30
What is the difference between prokaryotic and eukaryotic transcription?
Prokaryotic transcription occurs in the cytoplasm and is coupled with translation, while eukaryotic transcription occurs in the nucleus and involves post-transcriptional modifications before mRNA is translated (Raven Biology, chapter on transcription).
- 31
What is the role of the 3' untranslated region (3' UTR) in mRNA?
The 3' UTR plays a role in regulating mRNA stability, localization, and translation efficiency, influencing gene expression post-transcriptionally (Campbell Biology, chapter on mRNA processing).
- 32
What is the role of DNA helicase?
DNA helicase is an enzyme that unwinds the double helix of DNA during replication, allowing the two strands to be copied (Raven Biology, chapter on DNA replication).
- 33
What is the role of the ribosome in translation?
The ribosome facilitates the decoding of mRNA into a polypeptide chain, providing a site for tRNA to bring amino acids and for peptide bonds to form (Campbell Biology, chapter on translation).
- 34
What is the function of the 5' UTR in mRNA?
The 5' UTR (untranslated region) is involved in the regulation of translation initiation and may contain elements that influence ribosome binding (Raven Biology, chapter on mRNA processing).