Podcast
Questions and Answers
What is one of the main functions of cyclic nucleotide monophosphates?
What is one of the main functions of cyclic nucleotide monophosphates?
Which of the following is an example of a nucleotide triphosphate?
Which of the following is an example of a nucleotide triphosphate?
What role do coenzymes like Coenzyme A and NAD play in metabolism?
What role do coenzymes like Coenzyme A and NAD play in metabolism?
How do nucleotide triphosphates function in relation to diphosphate forms?
How do nucleotide triphosphates function in relation to diphosphate forms?
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Which of the following aspects is NOT included in the summary of knowledge about nucleotides and DNA?
Which of the following aspects is NOT included in the summary of knowledge about nucleotides and DNA?
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What is the primary function of genes in genetics?
What is the primary function of genes in genetics?
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Which of the following best describes the role of genetic material?
Which of the following best describes the role of genetic material?
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What was the significant conclusion drawn from Avery et al.'s experiments with S.pneumoniae bacteria?
What was the significant conclusion drawn from Avery et al.'s experiments with S.pneumoniae bacteria?
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Which component of chromatin was first debated as the genetic material before the truth was realized in 1944?
Which component of chromatin was first debated as the genetic material before the truth was realized in 1944?
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What discovery related to genetic material was made around 1869?
What discovery related to genetic material was made around 1869?
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What should be considered when identifying genetic material?
What should be considered when identifying genetic material?
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Why was the tetranucleotide theory misleading about the genetic material?
Why was the tetranucleotide theory misleading about the genetic material?
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Which of the following statements about DNA is incorrect?
Which of the following statements about DNA is incorrect?
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What type of bonds link the nucleotides in the sugar-phosphate backbone of DNA?
What type of bonds link the nucleotides in the sugar-phosphate backbone of DNA?
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Which statement about base pairing in DNA is accurate?
Which statement about base pairing in DNA is accurate?
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What property of DNA allows it to serve as a template for replication?
What property of DNA allows it to serve as a template for replication?
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Which of the following pairs of bases is linked by three hydrogen bonds?
Which of the following pairs of bases is linked by three hydrogen bonds?
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What is true about the strands of DNA?
What is true about the strands of DNA?
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What aspect of DNA structure allows it to encode complex genetic information?
What aspect of DNA structure allows it to encode complex genetic information?
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Which type of structure is defined as the arrangement of the DNA double helix?
Which type of structure is defined as the arrangement of the DNA double helix?
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The sugar-phosphate backbone of DNA serves which primary function?
The sugar-phosphate backbone of DNA serves which primary function?
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What type of bond creates the torsional force in a DNA molecule?
What type of bond creates the torsional force in a DNA molecule?
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What is the structure of eukaryotic DNA primarily packed into?
What is the structure of eukaryotic DNA primarily packed into?
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How many base pairs are approximately found in a human chromosome?
How many base pairs are approximately found in a human chromosome?
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What structure is used to package DNA in eukaryotic cells?
What structure is used to package DNA in eukaryotic cells?
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Which of the following describes the nature of prokaryotic DNA?
Which of the following describes the nature of prokaryotic DNA?
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What is a characteristic feature of the double helix of DNA?
What is a characteristic feature of the double helix of DNA?
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Which of the following best describes a nucleosome?
Which of the following best describes a nucleosome?
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What is the approximate length of the bacterial chromosome in E. coli compared to the cell size?
What is the approximate length of the bacterial chromosome in E. coli compared to the cell size?
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What is the structure of chromatin during M-phase?
What is the structure of chromatin during M-phase?
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What characterizes euchromatin?
What characterizes euchromatin?
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Which type of DNA is found in the cytoplasm of prokaryotes?
Which type of DNA is found in the cytoplasm of prokaryotes?
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What is the primary function of mitochondrial DNA in eukaryotic cells?
What is the primary function of mitochondrial DNA in eukaryotic cells?
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What did Chargaff demonstrate about DNA in 1948?
What did Chargaff demonstrate about DNA in 1948?
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Which pair of scientists is credited with elucidating the structure of DNA as a double helix?
Which pair of scientists is credited with elucidating the structure of DNA as a double helix?
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What is a characteristic of heterochromatin?
What is a characteristic of heterochromatin?
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During which phase of the cell cycle does chromatin condense tightly?
During which phase of the cell cycle does chromatin condense tightly?
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What is the role of a nucleotide in the structure of DNA?
What is the role of a nucleotide in the structure of DNA?
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What type of bond joins nucleotides together in a DNA strand?
What type of bond joins nucleotides together in a DNA strand?
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What role does non-coding DNA play in the genome?
What role does non-coding DNA play in the genome?
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What type of DNA is found in some bacterial cells and may encode traits like drug resistance?
What type of DNA is found in some bacterial cells and may encode traits like drug resistance?
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What is the significance of the 'antiparallel' nature of DNA strands?
What is the significance of the 'antiparallel' nature of DNA strands?
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Which statement best describes a purine?
Which statement best describes a purine?
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What is the maximum length variation for DNA chains mentioned in the content?
What is the maximum length variation for DNA chains mentioned in the content?
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Which of the following correctly describes the components of a nucleotide?
Which of the following correctly describes the components of a nucleotide?
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Study Notes
Molecular Genetics (BHS016-1)
- Course is taught by Dr Taiwo Shittu
- Course code is BHS016-1
Nucleic Acids (BHS016-1 Topic 1)
- Learning outcomes include:
- Recall the chemical structures and key elements of nucleotides
- Explain the formation of nucleic acids from individual nucleotides
- Describe the 3D structure of DNA
- Understand various functions of nucleic acids and nucleotides
What is Genetics?
- Genetics is the study of heredity.
- Heredity is controlled by genes.
- Genes are units of biological information.
- Genes are units of inheritance.
Why is Genetics Important?
- Areas of study where genetics is important:
- Biomedical science (e.g., heart damage from cancer drugs linked to faulty genes)
- Biological science (e.g., extracting oldest genetic information from rhino tooth)
- Forensic Science (e.g., genetic evidence used to solve crimes)
Basic Structure of the DNA Molecule
- Details on the basic structure of DNA molecules will be discussed later.
How to Identify Genetic Material?
- Unknown before the 1950s.
- Key characteristics for genetic material:
- Contains complex information
- Replicates faithfully
- Encodes the phenotype
- Phenotype: Definition of observable characteristics.
How Do We Know It Is DNA?
- History of key discoveries around DNA starting from 1869
- Definition of chromatin
- Importance of the tetranucleotide theory and its role in misdirection
- Avery et al's work in 1944
Timeline of DNA as Genetic Code
- Timeline of key DNA discoveries during the various years
How Do We Know It is DNA? (Experiments)
- Avery et al studied 2 types of pneumonia bacteria
- One (S) caused disease in mice, The other (R) did not.
- Heated S bacteria loss its disease causing ability
- Mixing heated S bacteria with R bacteria transformed the R bacteria into disease-causing bacteria.
- Experiment determined the transforming molecule
- Diagram of the experiment
1944 - Avery, MacLeod and McCarty
- Experiment: Determined the chemical nature of the transforming substance
- Methods, results, and conclusions of the experiment
How Can DNA Carry Information?
- Kossel’s work in late 1800s
- DNA contains four nitrogenous bases.
- Definition of purine and pyrimidine
- Levene demonstrated DNA was a polymer of nucleotides
- Definition of a nucleotide
How Can DNA Carry Information?
- Structure of a nucleotide
- Chargaff's demonstration in 1948 of the fixed ratios of nucleotides
- Fixed ratios of A/T and C/G for all DNA analyzed
- Watson and Crick's discovery in 1953 of the DNA structure as a double helix
- DNA is a double helix molecule made of two anti-parallel strands.
- Pairing of A-T and C-G
Primary Structure of DNA
- How nucleotides bonded together to form polymers via phosphodiester bonds
- Definition of covalent
- Definition of 5' and 3'
Phosphodiester Bond Formation
- Diagram of phosphodiester bond
Phosphodiester Bonds = Backbone
- Phosphodiester bonding produces a polymer with a sugar-phosphate backbone.
Secondary Structure of DNA
- Chargaff’s rules related to base pairing
- Bases pair via hydrogen bonding
- Adenine to thymine by 2 hydrogen bonds
- Guanine to cytosine by 3 hydrogen bonds
- Definition of hydrogen bond
Base Pairing = Interior
- Linear polynucleotide strands pair to form a double-stranded molecule
- Pairing A-T or C-G called complementary base pairing
- Complementary strands are antiparallel
Summary of Basic DNA Structure
- DNA consists of 2 polynucleotide strands
- Sugar-phosphate backbone on outside of molecule
- Nitrogenous bases on the inside
- Hydrogen bonds join bases of 2 strands
- Adenine pairs with thymine, Guanine with cytosine
- 2 polynucleotide strands are complementary and antiparallel
How Can DNA Carry Information?
- Genetic material must contain complex information
- Extremely long sequences "spelling" coded instructions
- Genetic material must replicate faithfully, via complementary base pairing
- Genetic material must encode the phenotype
Tertiary Structure of DNA
DNA Structure
- Definitions of Primary, Secondary and Tertiary structures
DNA Is a Double Helix
- Phosphodiester bonds cause torsional force twisting double-stranded DNA molecule
B-DNA Structure
- Diagram of the structure of B-DNA
DNA Requires Further Packing
Prokaryote DNA Simple Structure
Bacterial DNA Folded In Twisted Loops (Diagram)
Eukaryotic DNA Shows Complex Packing (Diagram)
Double Helix Packed Into Nucleosomes
Nucleosomes Packed Into 30 nm Fibre
- Diagram of the process
30 nm Fibre Packed Into Larger Coils
- Diagram of the process
700 nm Coiled Coil Forms Chromosome
Eukaryotic DNA Shows Complex Packing (Detailed diagram and description)
DNA Packing Alters During Cell Cycle
- Chromatin (DNA and proteins) structure changes during the cell cycle.
- Tight packing during M-phase (condensation during prophase, and deccondensation during telophase)
- Loose packing in interphase (euchromatin)
- Tight packing in interphase (heterochromatin)
- Definitions of euchromatin and heterochromatin
Functions of DNA and Nucleotides
- DNA functions in eukaryotic and prokaryotic cells
- Provides instructions for building proteins (genes)
- Provides instructions for controlling gene expression (regulatory regions)
- Contains non-coding DNA
- Other types of DNA (mitochondrial DNA, chloroplast DNA, plasmid DNA)
- Functions of nucleotides: act as cell signaling molecules (cyclic nucleotide monophosphates), coenzymes (coenzyme A, NAD), nucleotide triphosphates to provide energy
Functions Of Nucleotides
Summary – You should Now Know
To-Do List
- Tasks related to reviewing DNA structure, writing definitions, diagrams of deoxynucleotides joining
- Further notes and diagrams on histones, chromosome packing, chromatin (euchromatin and heterochromatin)
- Table summarizing the functions of DNA and nucleotides
Before Next Week's Lecture
- Reading about chromosome structure from textbooks (e.g. Pierce Genetics 6th ed. Chapter 2 and 11)
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Description
Test your knowledge on nucleotides, DNA, and their functions in genetics. This quiz covers various aspects of genetic material, coenzymes, and significant experiments that shaped our understanding. Perfect for those studying genetics or molecular biology!
