Genetic Mutations and Molecular Biology

These flashcards cover key concepts related to genetic mutations, molecular biology, and techniques in genetics, preparing the student for the exam.

What is a mutation?

A heritable change in the DNA sequence.

What is the difference between somatic and germline mutations?

Somatic mutations affect body cells and do not get passed to offspring, while germline mutations affect gametes and can be inherited.

What is the difference between gene and chromosome mutations?

Gene mutations occur at the nucleotide level, while chromosome mutations involve the structure or number of chromosomes.

What is a base substitution?

The alteration of a single nucleotide in the DNA sequence.

What distinguishes transitions from transversions?

Transitions are substitutions between the same type of base (purine to purine or pyrimidine to pyrimidine), while transversions are substitutions between different types of bases.

What are insertions and deletions in the context of mutations?

They involve the addition or removal of nucleotides, which can lead to frameshift mutations.

What is a frameshift mutation?

A mutation caused by insertions or deletions that shifts the reading frame of the gene.

What are in-frame insertions and deletions?

They involve the addition or removal of a set of three nucleotides (a codon), preserving the reading frame.

What are expanding nucleotide repeats?

Mutations where the number of copies of a specific set of nucleotides increases, often affecting genetic disorders.

How can strand slippage cause expansion of nucleotide repeats?

When DNA polymerase slips during replication, it can lead to repeated sequences if not corrected.

What does anticipation mean in genetics?

The tendency for genetic disorders to worsen or appear at an earlier age in successive generations.

What are three effects base substitutions can have on amino acid sequences?

Missense (incorrect amino acid), nonsense (premature stop codon), and silent (no change in amino acid).

What is a forward mutation?

A mutation that changes the wild type into a mutant phenotype.

What is a reverse mutation?

A mutation that restores the wild type from a mutant phenotype.

What is a suppressor mutation?

A mutation that hides the effect of another mutation, restoring the original phenotype.

What distinguishes intragenic from intergenic suppressor mutations?

Intragenic suppressor mutations occur in the same gene, while intergenic suppressor mutations happen in different genes.

What is the difference between spontaneous and induced mutations?

Spontaneous mutations arise naturally, while induced mutations are caused by external factors like chemicals or radiation.

How does strand slippage contribute to mutations?

It causes misalignment of the newly synthesized DNA strand and template strand, leading to insertions or deletions.

What is the concept of unequal crossing over?

A misalignment during meiosis leading to insertions or deletions of genetic material.

What is depurination?

The loss of a purine base from the DNA, potentially leading to mutations during DNA replication.

How do base analogs cause mutations?

They mimic natural DNA bases and can mispair during replication, leading to transitions.

What are intercalating agents?

Molecules that slip between DNA bases, causing frameshift mutations by distorting the DNA structure.

What are transposable elements (transposons)?

Sequences of DNA that can move within the genome and may cause mutations.

What is mismatch repair?

A mechanism that corrects incorrectly paired nucleotides after DNA replication.

What is direct repair?

A process correcting specific types of DNA damage without removing the damaged base.

What is recombinant DNA technology?

Techniques used to manipulate DNA for research and genetic engineering.

What are restriction enzymes?

Enzymes that cut DNA at specific sequences, enabling DNA cloning and recombinant DNA technology.

What is gel electrophoresis?

A method used to separate DNA fragments by size using an electric field.

How does CRISPR-Cas9 work for genome editing?

It uses a guide RNA to direct Cas9 to a specific DNA sequence for targeted cleavage.

What is gene therapy?

A treatment approach that aims to correct defective genes responsible for disease development.

What does PCR stand for?

Polymerase Chain Reaction, a method used to amplify DNA.

What are the key components of a PCR reaction?

Template DNA, primers, dNTPs, DNA polymerase, and a buffering solution.

How does DNA fingerprinting work?

Uses variations in DNA sequences to identify individuals based on unique patterns.

What is genomics?

The study of the structure, function, evolution, and mapping of genomes.

What is a haplotype?

The specific set of SNPs (single nucleotide polymorphisms) on a single chromosome.

What is the Human Genome Project?

An initiative to sequence and map all the genes of the human genome.

What is bioinformatics?

An interdisciplinary field combining computer science and biology to analyze biological data.

What are orthologs?

Genes in different species that evolved from a common ancestor.

What are paralogs?

Gene duplicates within the same species that evolve new functions.

What is the purpose of a probe in molecular biology?

A DNA or RNA molecule used to detect the presence of complementary sequences.

What is population genetics?

The study of genetic variation within populations and how it changes over time.

What is a gene pool?

The total collection of alleles in a population at a given time.

What is the Hardy-Weinberg equilibrium?

A principle stating that allele frequencies in a population remain constant under certain conditions.

How can you test for Hardy-Weinberg equilibrium?

By using a chi-square test to compare observed genotypic frequencies with expected frequencies.

What is genetic drift?

Random fluctuations in allele frequencies in a population due to sampling error.

What is the concept of natural selection?

The process by which traits that enhance survival and reproduction become more common in a population.

What does fitness refer to in evolutionary biology?

The reproductive success of an organism relative to others in the population.

What is anagenesis?

Evolution in a single lineage without branching.

What is cladogenesis?

The branching evolution resulting in new species from a common ancestor.

What is a molecular clock?

A method that uses mutation rates to estimate the time of evolutionary events.

What are reproductive isolating mechanisms?

Biological factors that prevent gene exchange between different species.

What is speciation?

The evolutionary process by which new species arise from existing ones.

What is the difference between pre-zygotic and post-zygotic barriers?

Pre-zygotic barriers prevent fertilization, while post-zygotic barriers occur after fertilization.

What are hybrid inviability, hybrid sterility, and hybrid breakdown?

Types of post-zygotic barriers that affect the viability or fertility of hybrids.

What is balancing selection?

A natural selection process that maintains genetic diversity in a population.

What is phylogeny?

The evolutionary history of a group of organisms depicted in a phylogenetic tree.

What is a phylogenetic tree?

A diagram showing evolutionary relationships between species.

What does it mean for a phylogenetic tree to be rooted?

It has a defined common ancestor from which all organisms in the tree descend.

What is the relationship between effective population size and genetic drift?

Smaller populations experience more significant effects of genetic drift.

What is the role of mutation in population genetics?

Mutations introduce new genetic variations, affecting allele frequencies.

What is the impact of migration on allele frequencies?

Migration introduces new alleles to a population, changing genetic makeup over time.

What is the significance of the Hardy-Weinberg Law?

It provides a mathematical model for studying genetic variation in populations.

What factors influence gene flow between populations?

The amount of migration, and the differences in allele frequencies between populations.

What is the effect of inbreeding on population genetics?

Inbreeding increases the likelihood of expressing deleterious recessive traits.

What are the consequences of genetic drift?

Loss of genetic variation, fixation of alleles, and divergence between populations.

What distinguishes positive from negative assortative mating?

Positive assortative mating favors similar individuals, while negative favors dissimilar individuals.

What techniques can be used to study gene expression?

Microarrays and RNA sequencing (RNA-seq).

What is the process of annotation in bioinformatics?

Identifying and describing functional elements in genomic sequences.

What is metagenomics?

The study of genetic material recovered directly from environmental samples.

What is the transcriptome?

The full range of RNA transcripts produced in a cell at a given time.

What is the proteome?

The complete set of proteins expressed by a genome at a specific time.

What is a sampling error in genetics?

Differences in allele frequencies due to the limited size of the sample population.

What is the role of the lac Z gene in recombinant DNA technology?

Used as a selectable marker to identify recombinant bacteria based on their ability to produce beta-galactosidase.