Podcast
Questions and Answers
What technology significantly reduced the cost of human genome sequencing to less than $1,000 in 2018?
What technology significantly reduced the cost of human genome sequencing to less than $1,000 in 2018?
What are genes primarily responsible for?
What are genes primarily responsible for?
Which of the following best describes the structure of DNA?
Which of the following best describes the structure of DNA?
How many base pairs are estimated to be in the human genome?
How many base pairs are estimated to be in the human genome?
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What is the main purpose of DNA packaging in the nucleus?
What is the main purpose of DNA packaging in the nucleus?
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What is the chromosomal feature used in traditional methods to identify chromosomes?
What is the chromosomal feature used in traditional methods to identify chromosomes?
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Which genetic variation is common among humans?
Which genetic variation is common among humans?
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What does the presence of 3,000 genetic diseases in humans suggest about mutations?
What does the presence of 3,000 genetic diseases in humans suggest about mutations?
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What did Mendel predict about genes?
What did Mendel predict about genes?
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What is the approximate diameter of a nucleosome?
What is the approximate diameter of a nucleosome?
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Which organism did Mendel choose for his experiments?
Which organism did Mendel choose for his experiments?
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How do chemical modifications to histones affect gene expression?
How do chemical modifications to histones affect gene expression?
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In Mendel’s F1 generation from a monohybrid cross, what was the phenotype ratio observed in the F2 generation?
In Mendel’s F1 generation from a monohybrid cross, what was the phenotype ratio observed in the F2 generation?
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What is the term for alleles that express themselves in the presence of another?
What is the term for alleles that express themselves in the presence of another?
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What is euchromatin?
What is euchromatin?
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Which of the following reflects Mendel's law of segregation?
Which of the following reflects Mendel's law of segregation?
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What does epigenetics involve?
What does epigenetics involve?
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What was a key aspect of Mendel's experimental strategy?
What was a key aspect of Mendel's experimental strategy?
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Which of the following is NOT a characteristic of heterochromatin?
Which of the following is NOT a characteristic of heterochromatin?
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How can abnormal epigenetic patterns affect health?
How can abnormal epigenetic patterns affect health?
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Which trait was NOT one of the seven traits studied by Mendel?
Which trait was NOT one of the seven traits studied by Mendel?
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What is the result of the fertilization process according to Mendel?
What is the result of the fertilization process according to Mendel?
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Which component is part of the histone code that influences gene expression?
Which component is part of the histone code that influences gene expression?
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What accounts for the ability of cells to express certain genes while keeping others inactive?
What accounts for the ability of cells to express certain genes while keeping others inactive?
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What is the primary role of DNA in living organisms?
What is the primary role of DNA in living organisms?
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Which part of the DNA structure is responsible for its directionality?
Which part of the DNA structure is responsible for its directionality?
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Who were the scientists credited with revealing the 3-D structure of DNA?
Who were the scientists credited with revealing the 3-D structure of DNA?
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What are the four types of bases found in the nucleotides of DNA?
What are the four types of bases found in the nucleotides of DNA?
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What is the importance of phosphodiester bonds in DNA?
What is the importance of phosphodiester bonds in DNA?
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Which characteristic of DNA contributes to its stability and ability to be inherited intact?
Which characteristic of DNA contributes to its stability and ability to be inherited intact?
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What defines the nucleotide as the monomer of DNA?
What defines the nucleotide as the monomer of DNA?
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What is one function of the 'codescript' as described in life forms?
What is one function of the 'codescript' as described in life forms?
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What does the term 'semiconservative' refer to in DNA replication?
What does the term 'semiconservative' refer to in DNA replication?
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Which statements best describes the characteristics of the leading and lagging strands?
Which statements best describes the characteristics of the leading and lagging strands?
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What role do Okazaki fragments play in DNA replication?
What role do Okazaki fragments play in DNA replication?
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Which enzyme is primarily responsible for synthesizing new DNA strands during replication?
Which enzyme is primarily responsible for synthesizing new DNA strands during replication?
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What is the function of DNA ligase in DNA replication?
What is the function of DNA ligase in DNA replication?
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What initiates the process of DNA replication?
What initiates the process of DNA replication?
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Which of the following processes occurs at the origin of replication?
Which of the following processes occurs at the origin of replication?
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Which statement about the replication direction is correct?
Which statement about the replication direction is correct?
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Which property allows RNA to sometimes form double-stranded regions?
Which property allows RNA to sometimes form double-stranded regions?
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What is the primary role of messenger RNA (mRNA) in a cell?
What is the primary role of messenger RNA (mRNA) in a cell?
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Which statement correctly describes the difference between RNA and DNA nucleotides?
Which statement correctly describes the difference between RNA and DNA nucleotides?
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Which type of RNA is the most abundant in a cell?
Which type of RNA is the most abundant in a cell?
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What distinguishes the sugar components of RNA and DNA?
What distinguishes the sugar components of RNA and DNA?
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Which aspect of RNA contributes to its short half-life?
Which aspect of RNA contributes to its short half-life?
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What is the primary function of transfer RNA (tRNA)?
What is the primary function of transfer RNA (tRNA)?
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Which type of RNA does NOT encode for proteins?
Which type of RNA does NOT encode for proteins?
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Study Notes
Key Concepts in Genetics, Heredity, and DNA
- Introduction to genetics: Covers history, overview, and applications.
- Mendelian genetics: Describes inheritance patterns discovered by Gregor Mendel.
- Linkage and recombination: Explains how genes located on the same chromosome are inherited together, while also discussing the process of recombination.
- Identification of DNA as the hereditary material: Discusses the experiments of Griffith and Avery, Macleod & McCarthy proving DNA is the genetic material
- Quantitative genetics: Investigates how multiple genes influence traits.
- DNA, structure, and function: Details the double helix structure.
- DNA – mutation, recombination and repair: Covers methods of DNA repair and mutation types.
- The central dogma: Explains how genetic information is passed from DNA to RNA to protein.
A Whistle-Stop Tour of 150 Years of Genetics - History
- 1860s: Mendel published research on inheritance of unit factors. Cytologists described chromosomes and their behavior during mitosis and meiosis.
- 1900s: Mendel's work was rediscovered. Chromosomes were recognized as unit factors. The term "gene" replaced unit factors.
- 1905: William Bateson coined the term "Genetics" to describe the study of inheritance.
- 1940s: DNA was confirmed to be the genetic material, not protein.
- 1950s: Watson and Crick described the double-helical structure of DNA. This marked the beginning of the molecular biology era.
- 1960s: The triplet code and the pathway of information flow: “DNA makes RNA makes protein” was discovered.
Key Discoveries & Developments in Genetics
- 1970s: Restriction enzymes were discovered, making recombinant DNA technology possible. Expression of human growth hormone in E. coli was demonstrated.
- 1980s: Recombinant DNA technology became commercialized. Methods were developed to make transgenic plants and animals.
- 1990s: Genome sequencing of humans, plants, fruit flies, nematodes, and other organisms advanced significantly.
- 2000s: First complete human genome sequence published in 2003. Cost was approximately $3 billion. Technology for expression profiling was advanced. RNA interference and genome editing tools (e.g., CRISPR) emerged. Cost of whole genome sequencing fell dramatically to less than $1,000 in 2019.
Genetics & Disease
- Mendelian Disorders: Diseases caused by a mutation in a single gene. There are over 3,000 known Mendelian disorders. Examples include Achondroplasia, Cystic Fibrosis, and Huntington's Disease.
- Autosomal Dominant Disorders: Features, on average 50% of children are affected with the disease. Examples include Achondroplasia
- Autosomal Recessive Disorders: Features, on average 25% of children are affected with the disease. Examples include Retinitis Pigmentosa, in 1/1800 births in Ireland
- X-linked Disorders: Features, affects males more often. Examples include Haemophilia.
Genomics & Heredity
- Genomics: Large-scale analysis of the genome. Includes the study of sets of genes in a given species, and the study of whole sets of proteins.
- Human Genome Sequencing Project: Identified the sequence of the human genome (3 billion base pairs) in 2003, costing $2-3 billion. This cost has substantially decreased over the years.
- Cost-per-Genome Trend: A descending graph illustrating the declining cost of sequencing, demonstrating technological advancements.
- Pharmacogenomics: Research into how genes affect the response to drugs, allowing physicians to prescribe drugs based on patient's genetic profile.
- Examples of related diseases: Familial combined hyperlipidaemia Familial hypercholsterolaemia Dominant otosclerosis Adult polycystic kidney disease
The Cell Cycle & Mitosis/Meiosis
- Cell Division: Mitosis for somatic (non-reproductive) cells & Meiosis for gametes. The cell cycle (including interphase) is the series of events in the life of a typical eukaryotic cell that involves growth and reproduction.
- Mitosis: Cell duplication to yield two identical daughter cells.
- Meiosis: Cell division that produces four distinct daughter cells. Involved in gamete formation to enable sexual reproduction, ensuring that offspring receive half of their genetic material from each parent. Meiosis also involves crossing over.
DNA Structure & Function
- DNA molecule: Composed of two long chains in a double helix.
- Structure of DNA: Each chain is composed of nucleotides (adenine, thymine, guanine, and cytosine); connected by phosphates & sugars.
- DNA Structure: The double-helix structure of DNA is crucial for information storage & genetic material transmittance between generations.
RNA & Transcription
- Transcription: Using DNA as a template, synthesizes RNA.
- Different types of RNA: Messenger RNA (mRNA), Ribosomal RNA (rRNA), Transfer RNA (tRNA), and other non-coding RNAs.
- Central Dogma: DNA → RNA → Protein describes the flow of genetic information.
- Regulation of Gene Expression: Controlling the process of gene expression by controlling transcription, regulating how much of a gene is expressed (or when) and which cells within the body or organism the gene is expressed in.
Additional Points
- Human Karyotype: A visual display of an organism's chromosomes used to identify abnormalities, including whether an individual is male / female.
- Genetic Maps: Graphical representations showing the relative positions of genes along chromosomes, usually created by tracking recombination rates (frequency of crossing-over).
- Gene Therapy: Using a method, in principle, to insert a normal copy of a mutated gene into a particular cell type, to correct or replace the faulty protein.
- Genetic Diseases: Mutations, caused by variations in DNA, could cause disease, e.g., haemophilia, cystic fibrosis, Huntington's disease, X-linked ichthyosis, fragile X syndrome, duchenne muscular dystrophy, sickle cell disorder, and the examples highlighted in charts throughout the material
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