Podcast
Questions and Answers
What defines the polarity of a DNA strand?
What defines the polarity of a DNA strand?
- Presence of double bonds between bases
- Chemical makeup of purines and pyrimidines
- Number of base pairs along the strand
- Arrangement of phosphate and sugar groups (correct)
Which base pairing occurs between the strands of DNA?
Which base pairing occurs between the strands of DNA?
- A-C and G-T
- G-T and A-C
- C-G and A-T (correct)
- A-G and C-T
What structural feature of DNA allows for the specific recognition of base sequences by proteins?
What structural feature of DNA allows for the specific recognition of base sequences by proteins?
- Antiparallel orientation
- The helical twist of DNA
- Major and minor grooves (correct)
- Presence of histones
In the context of DNA replication, what is the term used to describe the mechanism of copying DNA?
In the context of DNA replication, what is the term used to describe the mechanism of copying DNA?
Which of these is an exception to the central dogma of molecular biology?
Which of these is an exception to the central dogma of molecular biology?
What is the primary reason for DNA's acidic nature?
What is the primary reason for DNA's acidic nature?
What is the direction in which DNA and RNA sequences are conventionally written?
What is the direction in which DNA and RNA sequences are conventionally written?
Where is DNA predominantly located within eukaryotic cells?
Where is DNA predominantly located within eukaryotic cells?
Which end of a DNA strand contains the phosphate group?
Which end of a DNA strand contains the phosphate group?
What type of bonding is primarily involved in the attachment of proteins to specific DNA sequences?
What type of bonding is primarily involved in the attachment of proteins to specific DNA sequences?
What is the primary reason for the difference in chromosome number between somatic cells and gametes?
What is the primary reason for the difference in chromosome number between somatic cells and gametes?
Which element is crucial for the attachment of the mitotic spindle during mitosis?
Which element is crucial for the attachment of the mitotic spindle during mitosis?
Which of the following statements about heterochromatin is correct?
Which of the following statements about heterochromatin is correct?
What is the role of chromatin remodeling complexes?
What is the role of chromatin remodeling complexes?
What happens to introns during RNA processing?
What happens to introns during RNA processing?
Which of the following is NOT a feature of nucleosomes?
Which of the following is NOT a feature of nucleosomes?
How do histone tails contribute to gene regulation?
How do histone tails contribute to gene regulation?
Which term describes mobile genetic elements that replicate and insert themselves into various genomic locations?
Which term describes mobile genetic elements that replicate and insert themselves into various genomic locations?
Which of the following correctly describes the structure of chromosomes during interphase?
Which of the following correctly describes the structure of chromosomes during interphase?
Epigenetic marks, such as DNA methylation, influence which of the following?
Epigenetic marks, such as DNA methylation, influence which of the following?
Flashcards
DNA Replication
DNA Replication
The process where a DNA molecule is copied, creating two identical DNA molecules.
DNA polarity
DNA polarity
DNA has a 5' end (phosphate) and a 3' end (hydroxyl group), which are crucial for its directionality.
Base Pairs
Base Pairs
Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G) in DNA.
Antiparallel strands
Antiparallel strands
The two DNA strands run in opposite directions.
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DNA double helix
DNA double helix
The twisting structure of DNA.
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Major and Minor Grooves
Major and Minor Grooves
Uneven 'grooves' in the DNA double helix structure.
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DNA Transcription Factor
DNA Transcription Factor
A protein that binds to specific DNA sequences.
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DNA Location (Nucleus)
DNA Location (Nucleus)
Most DNA is found in the cell nucleus.
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Mitochondrial DNA
Mitochondrial DNA
DNA found outside of the nucleus, inside the mitochondria.
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Central Dogma Exceptions
Central Dogma Exceptions
Not all biological processes follow the typical DNA to RNA to protein flow.
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Human genome
Human genome
The complete set of DNA in a human, comprising 23 pairs of chromosomes (46 total).
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Chromosome Condensation
Chromosome Condensation
Occurs during mitosis only, where chromosomes compact to a visible, rod-like structure. At other times, they appear as 'spaghetti'.
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Centromere
Centromere
The region of a chromosome where the mitotic spindle attaches to pull the chromosomes apart in mitosis.
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Replication Origin
Replication Origin
The specific point on a chromosome where DNA replication starts.
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Telomere
Telomere
The protective caps at the ends of chromosomes, allowing for the efficient copying of chromosome ends during cell replication.
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Heterochromatin
Heterochromatin
Less active, highly condensed DNA regions during interphase, primarily consisting of repetitive satellite DNA sequences.
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Euchromatin
Euchromatin
More active, less condensed DNA regions during interphase.
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Exon
Exon
Regions of a gene that are incorporated into the final RNA product after transcription.
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Intron
Intron
Regions of a gene that are removed from the RNA molecule before translation.
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Chromatin Remodeling Complex
Chromatin Remodeling Complex
Protein complexes that reposition nucleosomes to allow access of DNA to transcription and replication enzymes.
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DNA Structure and Function
- DNA is a double helix structure with two strands running antiparallel (5' to 3' and 3' to 5').
- The strands are held together by hydrogen bonds between complementary base pairs (A-T and G-C).
- DNA's structure allows it to be copied and used as a template for other molecules (central dogma).
- The 5' end has a phosphate group, and the 3' end has a hydroxyl group. This polarity is important for DNA replication and function.
- Base pairs form between strands due to hydrogen bonding.
- A-T and G-C are the complementary base pairs.
- DNA sequences are always written 5' to 3'.
DNA Replication
- DNA replication is semi-conservative, meaning each new DNA molecule consists of one original strand and one new strand.
- Cells have mechanisms for copying DNA accurately.
- DNA replication follows chemical properties of the existing DNA.
Chromatin Structure
- Chromatin is DNA bound to proteins (histones).
- Nucleosomes are the basic units of chromatin structure.
- Nucleosomes are made up of DNA wrapped around histone proteins.
- Heterochromatin is tightly packed DNA, typically inactive.
- Euchromatin is less tightly packed, allowing for transcription.
- Histone tails are points of modification that affect chromatin structure.
DNA & Proteins
- Proteins bind to DNA, interacting with major and minor grooves in the double helix.
- This binding allows sequences of DNA to be recognized by proteins that regulate gene expression.
Human Genome
- The human genome consists of 46 chromosomes (23 pairs).
- All body cells contain the same DNA.
- Chromosomes condense during mitosis.
- Sperm and egg cells contain only half (23) the number of chromosomes.
- Important regions include telomeres, centromeres, origin points, which are parts of a functional and stable chromosome.
Transposons
- Transposons are mobile genetic elements within the genome.
- They multiply and insert themselves at different places on DNA (genome).
Epigenetics
- Histone modifications and DNA methylation alter chromatin structure, affecting gene activity without altering the underlying DNA sequence.
- These changes, called epigenetic marks, control gene expression patterns.
Chromosomes
- Chromosomes, during interphase, are less condensed forms of DNA, known as euchromatin.
- Chromosomes are highly condensed forms during mitosis, known as heterochromatin.
- Chromosome structures have replication origins, centromeres and telomeres.
Nucleus
- Most DNA is contained within the cell nucleus.
- Other locations for DNA include mitochondria.
Mitochondrial DNA
- Mitochondrial DNA is inherited maternally.
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