D1.3 Mutation and Gene Editing
What is the term for a change in the DNA sequence that affects genetic information?
Mutation
What process results in the formation of two daughter cells from one parent cell?
Cell division (accept mitosis or binary fission)
What is the term for the process by which information from a gene is used in the synthesis of a functional gene product?
Gene expression
What is the first step in DNA replication?
Unwinding of the DNA double helix
What are the two types of nucleic acids found in cells?
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
Name one type of mutation discussed in class.
Substitution, insertion, deletion (accept any one)
Name the stage of the cell cycle during which DNA is replicated.
S phase (Synthesis phase)
What is the primary enzyme responsible for transcribing RNA from a DNA template?
RNA polymerase
Name the enzyme responsible for unwinding the DNA double helix during replication.
Helicase
What is the primary function of RNA in the cell?
The primary function of RNA is to transfer genetic information from DNA to the ribosome for the synthesis of proteins (translation).
How can mutations contribute to genetic diversity within a population?
Mutations introduce new alleles into the gene pool, leading to variations among individuals.
Describe the role of mitosis in multicellular organisms.
Mitosis is responsible for growth, repair, and asexual reproduction in multicellular organisms. It ensures that each daughter cell receives an identical set of chromosomes.
Explain the role of ribosomes in gene expression.
Ribosomes are the cellular structures where protein synthesis occurs. They read the mRNA sequence and catalyze the formation of peptide bonds between amino acids to build the polypeptide chain.
Describe the semi-conservative nature of DNA replication.
In semi-conservative replication, each newly synthesized DNA molecule contains one original (parental) strand and one newly synthesized (daughter) strand.
Describe the structure of a nucleotide, including its three components.
A nucleotide consists of a phosphate group, a pentose sugar (ribose in RNA, deoxyribose in DNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine).
What is the term for a specific type of mutation in which one nucleotide is substituted for another in the DNA sequence, resulting in a change in the amino acid sequence of the encoded protein?
Missense mutation
Describe the process of cytokinesis and explain how it differs between plant and animal cells.
Cytokinesis is the division of the cytoplasm that occurs after nuclear division (mitosis or meiosis). In animal cells, cytokinesis involves the formation of a cleavage furrow, which pinches the cell membrane inward to divide the cell into two daughter cells. In plant cells, cytokinesis involves the formation of a cell plate, which develops into a new cell wall between the two daughter cells.
Explain the difference between transcription and translation, including where each process occurs in the cell.
Transcription is the process of synthesizing RNA from a DNA template, and it occurs in the nucleus of eukaryotic cells. Translation is the process of synthesizing protein from an mRNA template, and it occurs in the cytoplasm at ribosomes.
Explain the role of DNA polymerase III in DNA replication and discuss its properties that make it well-suited for this function.
DNA polymerase III is the main enzyme responsible for synthesizing new DNA strands during DNA replication. It has a high processivity, meaning it can catalyze the addition of multiple nucleotides to the growing DNA strand without dissociating from the template. Additionally, DNA polymerase III has proofreading activity, allowing it to correct errors in base pairing during replication.
Compare and contrast the structure and function of mRNA, tRNA, and rRNA.
mRNA (messenger RNA) carries genetic information from the DNA to the ribosome and serves as a template for protein synthesis. tRNA (transfer RNA) carries amino acids to the ribosome and matches them to the appropriate codons on the mRNA during translation. rRNA (ribosomal RNA) is a structural component of ribosomes and catalyzes the formation of peptide bonds between amino acids during protein synthesis.
Describe the CRISPR/Cas9 system and explain how it is used for gene editing.
The CRISPR/Cas9 system is a genome editing tool that utilizes a guide RNA to target specific DNA sequences and the Cas9 enzyme to induce double-strand breaks in the DNA. This allows for precise modification of the genome, such as gene knockout, gene insertion, or gene correction.
Discuss the role of cyclins and cyclin-dependent kinases (CDKs) in regulating the cell cycle.
Cyclins are proteins that fluctuate in concentration throughout the cell cycle, binding to and activating cyclin-dependent kinases (CDKs). CDKs are enzymes that phosphorylate target proteins involved in cell cycle progression. The activation of CDK-cyclin complexes triggers key events in the cell cycle, such as entry into S phase and mitosis.
Describe the process of alternative splicing and its significance in gene expression.
Alternative splicing is a post-transcriptional modification in which different exons of a pre-mRNA transcript are spliced together in different combinations, leading to the production of multiple mRNA isoforms from a single gene. This process allows for the generation of protein diversity from a limited number of genes and plays a critical role in regulating gene expression.
Discuss the role of telomerase in DNA replication and its significance in maintaining genome stability.
elomerase is an enzyme that adds repetitive nucleotide sequences to the ends of linear chromosomes, known as telomeres. This process, called telomere elongation, counteracts the gradual shortening of telomeres that occurs with each round of DNA replication. Telomerase plays a crucial role in preventing the loss of genetic information and maintaining chromosome integrity.
Discuss the role of histones and chromatin remodeling complexes in regulating gene expression.
Histones are proteins that associate with DNA to form nucleosomes, the basic units of chromatin. Chromatin remodeling complexes are protein complexes that alter the structure of chromatin, making it more or less accessible to transcription factors and RNA polymerase. Together, histones and chromatin remodeling complexes regulate gene expression by controlling the accessibility of DNA to the transcriptional machinery.