Podcast
Questions and Answers
What is the direction of helical rotation for A-DNA?
What is the direction of helical rotation for A-DNA?
- Counterclockwise
- Undefined
- Right (correct)
- Left
Which form of DNA is most prevalent within cells?
Which form of DNA is most prevalent within cells?
- A-DNA
- Z-DNA
- B-DNA (correct)
- Supercoiled DNA
What type of groove in DNA acts as a binding site for regulatory proteins?
What type of groove in DNA acts as a binding site for regulatory proteins?
- Narrow groove
- Flat groove
- Minor groove
- Major groove (correct)
What is the number of residues per turn of helix in Z-DNA?
What is the number of residues per turn of helix in Z-DNA?
Where is DNA located in eukaryotic cells?
Where is DNA located in eukaryotic cells?
Which class of DNA-binding proteins is primarily involved in chromatin structure?
Which class of DNA-binding proteins is primarily involved in chromatin structure?
Which of the following best describes the primary function of DNA?
Which of the following best describes the primary function of DNA?
Histones are rich in which types of amino acids?
Histones are rich in which types of amino acids?
Which form of DNA has a flat major groove?
Which form of DNA has a flat major groove?
What type of structure do purines have?
What type of structure do purines have?
Which nitrogenous base is found only in RNA?
Which nitrogenous base is found only in RNA?
Which statement about histones is true?
Which statement about histones is true?
What is the role of the phosphate group in a nucleotide?
What is the role of the phosphate group in a nucleotide?
Which component distinguishes DNA from RNA?
Which component distinguishes DNA from RNA?
Which of the following is NOT a purine?
Which of the following is NOT a purine?
What is the polymer of DNA composed of?
What is the polymer of DNA composed of?
What is formed when a base is covalently linked to the number 1 carbon of a sugar?
What is formed when a base is covalently linked to the number 1 carbon of a sugar?
Which bond is involved in the linkage of phosphate groups to the 5′ carbon of a nucleoside?
Which bond is involved in the linkage of phosphate groups to the 5′ carbon of a nucleoside?
What does the primary structure of DNA refer to?
What does the primary structure of DNA refer to?
In the secondary structure of DNA, which base pairs with thymine (T)?
In the secondary structure of DNA, which base pairs with thymine (T)?
What is the nature of the two strands of DNA in the double helix?
What is the nature of the two strands of DNA in the double helix?
Which of the following forms a high-energy compound?
Which of the following forms a high-energy compound?
What structural form describes the winding of two DNA strands around each other?
What structural form describes the winding of two DNA strands around each other?
What type of bond connects nucleotides in a DNA strand?
What type of bond connects nucleotides in a DNA strand?
What indicates a deviation from Chargaff’s rules in nucleic acid analysis?
What indicates a deviation from Chargaff’s rules in nucleic acid analysis?
Which of the following types of histone molecules is not commonly found in nature?
Which of the following types of histone molecules is not commonly found in nature?
What type of disease inheritance pattern is NOT associated with mutations in mitochondrial DNA?
What type of disease inheritance pattern is NOT associated with mutations in mitochondrial DNA?
Which chromosome structure would be degraded first in an apoptotic cell?
Which chromosome structure would be degraded first in an apoptotic cell?
Which factor does NOT increase the melting temperature of DNA?
Which factor does NOT increase the melting temperature of DNA?
What is the basic packaging unit of chromatin?
What is the basic packaging unit of chromatin?
What is the length of DNA that forms the nucleosome core?
What is the length of DNA that forms the nucleosome core?
What type of chromatin is more transcriptionally active?
What type of chromatin is more transcriptionally active?
What is the size of the chromosome when fully condensed?
What is the size of the chromosome when fully condensed?
How many histones are typically present in a nucleosome core?
How many histones are typically present in a nucleosome core?
What type of DNA structure do eukaryotic nuclear chromosomes have?
What type of DNA structure do eukaryotic nuclear chromosomes have?
What is the characteristic of heterochromatin?
What is the characteristic of heterochromatin?
What is the length of mitochondrial DNA?
What is the length of mitochondrial DNA?
What process separates double-stranded DNA into single strands?
What process separates double-stranded DNA into single strands?
Which condition does NOT contribute to the denaturation of DNA?
Which condition does NOT contribute to the denaturation of DNA?
What is the melting temperature (Tm) of DNA?
What is the melting temperature (Tm) of DNA?
What characteristic affects the melting temperature (Tm) of DNA?
What characteristic affects the melting temperature (Tm) of DNA?
What type of enzyme removes nucleotides from the ends of a nucleic acid?
What type of enzyme removes nucleotides from the ends of a nucleic acid?
Which of the following nucleotides is NOT found in DNA?
Which of the following nucleotides is NOT found in DNA?
How many hydrogen bonds are formed between guanine and cytosine in DNA?
How many hydrogen bonds are formed between guanine and cytosine in DNA?
In B-form DNA, what is the width of the double helix in nanometers?
In B-form DNA, what is the width of the double helix in nanometers?
Flashcards
DNA Location in Eukaryotes
DNA Location in Eukaryotes
DNA in eukaryotes is found inside the nucleus, within chromosomes, and also in mitochondria.
DNA Location in Prokaryotes
DNA Location in Prokaryotes
In prokaryotes, DNA is located in the cytoplasm, often in a region called the nucleoid, and also on plasmids.
DNA Function
DNA Function
DNA stores genetic information, transmits it to the next generation, and controls protein synthesis within cells.
DNA Structure
DNA Structure
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Nucleotide Components
Nucleotide Components
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Purines in DNA
Purines in DNA
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Pyrimidines in DNA
Pyrimidines in DNA
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Pentose Sugar
Pentose Sugar
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DNA Forms
DNA Forms
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B-DNA
B-DNA
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A-DNA
A-DNA
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Z-DNA
Z-DNA
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Histones
Histones
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Chromatin
Chromatin
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DNA-binding proteins
DNA-binding proteins
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Major Groove
Major Groove
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Phosphate group
Phosphate group
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Nucleoside
Nucleoside
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Nucleotide
Nucleotide
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Primary structure of DNA
Primary structure of DNA
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Base Pairing Rules (Chargaff's Rules)
Base Pairing Rules (Chargaff's Rules)
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Antiparallel Strands
Antiparallel Strands
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Double Helix
Double Helix
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3' and 5' ends
3' and 5' ends
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Single-stranded DNA
Single-stranded DNA
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Histone molecules type
Histone molecules type
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Mitochondrial DNA mutations
Mitochondrial DNA mutations
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Apoptotic chromosome degradation
Apoptotic chromosome degradation
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DNA melting temperature
DNA melting temperature
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Nucleosome
Nucleosome
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Chromatin
Chromatin
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Heterochromatin
Heterochromatin
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Euchromatin
Euchromatin
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DNA Types
DNA Types
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Mitochondrial DNA
Mitochondrial DNA
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Nucleosome Structure
Nucleosome Structure
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Chromatin Structure
Chromatin Structure
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Mitochondrial DNA mutation rate
Mitochondrial DNA mutation rate
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Maternal inheritance of mtDNA
Maternal inheritance of mtDNA
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DNA denaturation
DNA denaturation
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DNA renaturation
DNA renaturation
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Melting temperature (Tm)
Melting temperature (Tm)
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Nucleases
Nucleases
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Purine Nucleotide
Purine Nucleotide
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Width of B-form DNA
Width of B-form DNA
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Study Notes
Human Genetics and Molecular Biology
- This presentation focuses on DNA, its structure, function, and associated concepts.
DNA Site
- Eukaryotes: DNA is located inside the nucleus and mitochondria.
- Prokaryotes: DNA is in the cytoplasm and often exists as non-chromosomal DNA (plasmids).
DNA Function
- Storing genetic information: transmitted to the next generation through replication.
- Controlling protein synthesis: enabling cells to perform their functions via transcription and translation.
DNA & Nucleotide Structure
- DNA is a polymer of deoxynucleotides linked by phosphodiester bonds.
- Each nucleotide comprises:
- A nitrogenous base (purine or pyrimidine).
- A 5-carbon sugar (deoxy-pentose).
- Phosphate.
- Purines: Adenine (A) and Guanine (G).
- Pyrimidines: Cytosine (C), Thymine (T), and Uracil (U).
- Thymine is primarily in DNA, while uracil is in RNA.
Pentose Sugar
- Deoxyribose is the sugar in DNA.
- Ribose is the sugar in RNA.
Phosphate
- One or more phosphate groups attach to the 5' carbon of the pentose sugar.
Nucleosides and Nucleotides
- Nucleosides: formed by covalently linking a base to the 1' carbon of a sugar (N-glycosidic bond).
- Nucleotides: formed by attaching one or more phosphate groups to the 5' carbon of a nucleoside (phospho-ester bond).
DNA Structure
- Primary structure: sequence of bases in the nucleic acid chain of DNA.
- DNA is composed of nucleotides (dNTPs).
- Nucleotides are connected by phosphodiester bonds.
- The strand has a 5' end with a phosphate group and a 3' end with a hydroxyl group.
- Secondary structure: double-stranded DNA, with A pairing with T and G pairing with C(Chargaff's rule), forming a double helix in antiparallel orientation 5'->3' and 3'->5'.
- Tertiary structure: Chromatin structure in which DNA interacts with DNA-binding proteins (histones and non-histones) to form a compact structure.
Chromatin Structure
- Chromatin is a complex of DNA and proteins.
- Two classes of DNA-binding proteins (histones): histones and non-histones.
- Histones: positively charged, forming ionic bonds with the negatively charged DNA. Their main function is to compact the DNA.
- Non-histones: involved in regulating the structure and function of chromatin.
- Nucleosome: the basic packaging unit of chromatin.
- The nucleosome comprises:
- DNA core: 140-150 base pairs of DNA wrapped around 8 histone proteins (2 each of H2A, H2B, H3, and H4).
- Linker DNA: 20-200 base pairs connecting the nucleosomes.
- The nucleosome comprises:
- Chromatin structure:
- Nucleosomes (beads on a string), coiled into 30 nm chromatin fiber, forming loops, culminating in chromatin fibers, leading to the chromosome structure that is evident in metaphase
Heterochromatin and Euchromatin
- Heterochromatin: more compact, less active regions of DNA, and usually gene-poor (AT rich).
- Euchromatin: less compact, more active, and gene-rich (GC rich). Euchromatin is susceptible to nuclease digestion.
Types of DNA
- Double-stranded linear: eukaryotic nuclear chromosomes.
- Double-stranded circular: mitochondrial, bacterial, plasmid, viral, and chloroplast DNA.
- Single-stranded circular: small viruses.
Mitochondrial DNA
- Circular double-stranded DNA molecule (approximately 16 kb).
- Encodes for several genes involved in energy production.
- Higher mutation rate than nuclear DNA.
- Inherited maternally.
Denaturation/Renaturation of DNA
- Denaturation (melting): unwinding of double-stranded DNA to single strands. Factors that cause denaturation include heat, alkaline pH, and chemicals like formamide and urea.
- Renaturation (reannealing): re-formation of double-stranded DNA from separated single strands. This occurs when the denaturing conditions are gradually reduced.
- Melting temperature (Tm): the temperature at which 50% of the DNA molecules are in their single-stranded state. Tm is higher for DNA regions with more G-C pairs than A-T pairs.
Nucleases
- Exonucleases: enzymes that remove nucleotides from the ends (5' or 3') of DNA.
- Endonucleases: enzymes that cut DNA within the molecule.
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Description
This quiz explores key concepts related to DNA, including its structure, function, and location in eukaryotic and prokaryotic cells. It delves into the functions of DNA in genetic information storage and protein synthesis, as well as the composition of nucleotides. Test your understanding of these fundamental aspects of molecular biology.
