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Questions and Answers
After a tautomeric shift, adenine bonds with?
After a tautomeric shift, adenine bonds with?
- Cytosine (correct)
- Guanine
- Thymine
- Uracil
What happens during a tautomeric shift?
What happens during a tautomeric shift?
Hydrogen atoms move from a nucleotide base with altered bonding properties.
When a tautomeric shift occurs, the resulting nucleotide is an ______ of the nucleotide prior to the shift.
When a tautomeric shift occurs, the resulting nucleotide is an ______ of the nucleotide prior to the shift.
structural isomer
The nucleic acid sequence in mRNA is determined by what?
The nucleic acid sequence in mRNA is determined by what?
If a frameshift mutation causes a stop codon to be inserted into the DNA sequence, what will happen?
If a frameshift mutation causes a stop codon to be inserted into the DNA sequence, what will happen?
A nucleotide deletion in DNA replication will cause what?
A nucleotide deletion in DNA replication will cause what?
UV light damages DNA by causing what?
UV light damages DNA by causing what?
What happens to the covalent bonds in light repair?
What happens to the covalent bonds in light repair?
Excision repair of thymine dimers is possible because there are 2 strands of DNA.
Excision repair of thymine dimers is possible because there are 2 strands of DNA.
Excision repair can be used to repair thymine dimers as well as other types of damaged DNA.
Excision repair can be used to repair thymine dimers as well as other types of damaged DNA.
How often does ultraviolet light result in the formation of thymine dimers?
How often does ultraviolet light result in the formation of thymine dimers?
What protein cuts the damaged DNA strand?
What protein cuts the damaged DNA strand?
Which protein has a helicase function?
Which protein has a helicase function?
What synthesizes the new DNA strand?
What synthesizes the new DNA strand?
A mutation has occurred that prevents the UvrA and UvrB from forming a complex. What result will this have on the damaged DNA?
A mutation has occurred that prevents the UvrA and UvrB from forming a complex. What result will this have on the damaged DNA?
A mutation has occurred that has made UvrD non-functional. What result will this have on the damaged DNA?
A mutation has occurred that has made UvrD non-functional. What result will this have on the damaged DNA?
What is the difference in the DNA sequence of the normal individual and that of the individual with sickle cell anemia?
What is the difference in the DNA sequence of the normal individual and that of the individual with sickle cell anemia?
What is the difference in the amino acid sequence of the normal individual and that of the individual with sickle cell anemia?
What is the difference in the amino acid sequence of the normal individual and that of the individual with sickle cell anemia?
A single point mutation in the DNA sequence leads to a change in the protein structure, which leads to a change in the protein's function and causes sickle cell anemia.
A single point mutation in the DNA sequence leads to a change in the protein structure, which leads to a change in the protein's function and causes sickle cell anemia.
The process by which two haploid gametes unite to form a zygote is called ______ reproduction.
The process by which two haploid gametes unite to form a zygote is called ______ reproduction.
Crossing over during prophase occurs commonly in?
Crossing over during prophase occurs commonly in?
What are some characteristics of meiosis II?
What are some characteristics of meiosis II?
Name the order of meiosis I starting from the earliest.
Name the order of meiosis I starting from the earliest.
What is a haploid?
What is a haploid?
What is a diploid?
What is a diploid?
What is a polyploid?
What is a polyploid?
What is a tetraploid?
What is a tetraploid?
What is triploid?
What is triploid?
A zygote is created when 2 haploid cells called what fuse?
A zygote is created when 2 haploid cells called what fuse?
When 2 haploid gametes unite, they create a diploid cell called?
When 2 haploid gametes unite, they create a diploid cell called?
During anaphase II of meiosis, ______ are separated.
During anaphase II of meiosis, ______ are separated.
Which two key events occur at the beginning of meiosis but not mitosis?
Which two key events occur at the beginning of meiosis but not mitosis?
During what phase do homologous chromosomes align along the center of the cell as bivalents?
During what phase do homologous chromosomes align along the center of the cell as bivalents?
What do mitosis and meiosis have in common?
What do mitosis and meiosis have in common?
What is the correct order of meiosis I?
What is the correct order of meiosis I?
Trisomies 21, 18, 13, or abnormalities in the number of the sex chromosomes are most likely due to what?
Trisomies 21, 18, 13, or abnormalities in the number of the sex chromosomes are most likely due to what?
Polyploidy is generally a lethal condition in?
Polyploidy is generally a lethal condition in?
Organisms possessing chromosomes that occur in one or more complete sets are termed what?
Organisms possessing chromosomes that occur in one or more complete sets are termed what?
Aneuploidy refers to an alteration in the number of particular what?
Aneuploidy refers to an alteration in the number of particular what?
During which phase of meiosis I are bivalents segregated?
During which phase of meiosis I are bivalents segregated?
What two suffixes refer to a complete set of chromosomes?
What two suffixes refer to a complete set of chromosomes?
In a certain cell a pair of sister chromatids is attached to kinetochore microtubules from just one pole. This cell must be in?
In a certain cell a pair of sister chromatids is attached to kinetochore microtubules from just one pole. This cell must be in?
Some characteristics of Trisomy 21 or Down syndrome are?
Some characteristics of Trisomy 21 or Down syndrome are?
During meiosis I, what does it separate?
During meiosis I, what does it separate?
A diploid cell divides by a process called what to produce haploid cells?
A diploid cell divides by a process called what to produce haploid cells?
What are the characteristics of meiosis II?
What are the characteristics of meiosis II?
In what phase of meiosis are the replicated chromosomes condensed, the homologous chromosomes form bivalents, and crossing over occurs?
In what phase of meiosis are the replicated chromosomes condensed, the homologous chromosomes form bivalents, and crossing over occurs?
What is the end result of mitosis in a diploid organism?
What is the end result of mitosis in a diploid organism?
Unlike animals, plants often possess more than two sets of chromosomes. Plants thus exhibit what?
Unlike animals, plants often possess more than two sets of chromosomes. Plants thus exhibit what?
Synapsis is the process of forming what?
Synapsis is the process of forming what?
Which process involves a physical exchange between chromosome segments of the bivalent?
Which process involves a physical exchange between chromosome segments of the bivalent?
What is the significant result of meiosis?
What is the significant result of meiosis?
A human gamete contains how many chromosomes?
A human gamete contains how many chromosomes?
At what stage of meiosis I do the joined pairs of sister chromatids reach their respective poles and decondense?
At what stage of meiosis I do the joined pairs of sister chromatids reach their respective poles and decondense?
In prometaphase I of meiosis, the nuclear envelope is completely broken down into vesicles and the what is entirely formed?
In prometaphase I of meiosis, the nuclear envelope is completely broken down into vesicles and the what is entirely formed?
Because meiosis I produces 2 haploid nuclei, it's called?
Because meiosis I produces 2 haploid nuclei, it's called?
The bivalents are organized along the metaphase plate with their sister chromatids randomly aligned in a double row. What phase of cell division is this?
The bivalents are organized along the metaphase plate with their sister chromatids randomly aligned in a double row. What phase of cell division is this?
What describes an animal that is 2n-1?
What describes an animal that is 2n-1?
What metaphase I event provides a mechanism for vast genetic diversity?
What metaphase I event provides a mechanism for vast genetic diversity?
The end result of meiosis II is?
The end result of meiosis II is?
Flashcards
Tautomeric Shift
Tautomeric Shift
A change in the structure of a nucleotide base, usually involving the movement of a hydrogen atom. This can result in the base pairing with an incorrect nucleotide, leading to mutations.
Frameshift Mutation
Frameshift Mutation
A type of mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence. This shifts the reading frame of the genetic code, often leading to non-functional proteins.
UV-Induced Thymine Dimers
UV-Induced Thymine Dimers
A process where UV light damages DNA by causing covalent bonds to form between adjacent thymine nucleotides. This creates a thymine dimer, disrupting the normal structure of DNA.
Excision Repair
Excision Repair
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UvrC
UvrC
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UvrD
UvrD
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DNA Polymerase
DNA Polymerase
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Sickle Cell Anemia
Sickle Cell Anemia
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Point Mutation
Point Mutation
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Sexual Reproduction
Sexual Reproduction
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Meiosis
Meiosis
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Haploid
Haploid
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Diploid
Diploid
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Polyploid
Polyploid
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Triploid
Triploid
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Tetraploid
Tetraploid
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Synapsis
Synapsis
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Crossing Over
Crossing Over
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Random Assortment
Random Assortment
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Trisomy
Trisomy
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Nondisjunction
Nondisjunction
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Euploid
Euploid
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Aneuploid
Aneuploid
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Metaphase I
Metaphase I
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Anaphase I
Anaphase I
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Telophase I
Telophase I
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Metaphase II
Metaphase II
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Anaphase II
Anaphase II
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Four Haploid Daughter Cells
Four Haploid Daughter Cells
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Characteristics of Trisomy 21
Characteristics of Trisomy 21
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Study Notes
Tautomeric Shifts and Mutations
- A tautomeric shift in adenine causes it to bond with cytosine.
- Tautomeric shifts involve the movement of hydrogen atoms, altering the bonding properties of nucleotide bases.
- Resultant nucleotide after a tautomeric shift is a structural isomer.
- Frameshift mutations can introduce stop codons, resulting in non-functional short proteins.
- Nucleotide deletions during DNA replication lead to incorrect amino acid insertions.
DNA Damage and Repair Mechanisms
- UV light induces DNA damage by forming covalent bonds between adjacent thymine nucleotides.
- Light repair involves breaking covalent bonds between thymine dimers.
- Excision repair relies on the presence of two DNA strands to be effective.
- Excision repair can fix various types of DNA damage, including thymine dimers.
- UV light frequently causes thymine dimers due to energy facilitating covalent bonding.
Repair Proteins and Functions
- UvrC is the protein responsible for cutting damaged DNA strands.
- UvrD has helicase function to unwind DNA during repair.
- DNA polymerase synthesizes new DNA strands following repair.
- If UvrA and UvrB cannot form a complex, damaged DNA remains unrecognized.
- If UvrD is non-functional, cut damaged segments remain attached to healthy strands.
Nucleotide Differences and Genetic Mutations
- Sickle cell anemia results from a single base change in DNA sequence.
- The alteration leads to a change in a single amino acid within proteins.
- Point mutations can change protein structure and function, causing diseases like sickle cell anemia.
Meiosis Overview
- The union of two haploid gametes to form a zygote is classified as sexual reproduction.
- Crossing over typically occurs during prophase I of meiosis I, enhancing genetic diversity.
- Meiosis II involves separating sister chromatids, creating haploid daughter cells.
Chromosome Sets and Definitions
- A haploid cell contains one set of chromosomes.
- Diploid cells have two sets of chromosomes, and polyploid cells contain three or more sets.
- Triploid cells consist of three chromosome sets, while tetraploid cells have four sets.
Meiosis and Genetic Diversity
- During metaphase I, homologous chromosomes align as bivalents.
- Characteristics of meiosis II include sister chromatids separation and similar sorting events to mitosis.
- Anaphase I is where bivalents are segregated, ensuring genetic diversity through random alignment.
Chromosomal Abnormalities
- Trisomies and chromosomal number abnormalities result from nondisjunction during meiosis.
- Polyploidy is typically lethal in mammals but can be common in plants.
- Euploid organisms have complete sets of chromosomes, whereas aneuploidy refers to specific chromosome number alterations.
Major Events in Meiosis
- Characteristics of Trisomy 21 (Down syndrome) include short stature and mental impairment.
- The end result of meiosis I is two haploid nuclei, leading to the term reduction division.
- During telophase I, joined sister chromatids reach poles and decondense.
Final Outcomes of Meiosis
- Meiosis II culminates in four haploid daughter cells, essential for sexual reproduction.
- Human gametes contain 23 chromosomes, half the diploid number.
- The metaphase plate organization during metaphase I promotes genetic variability through random alignment.
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Description
Prepare for your Biology Exam #4 with these flashcards focusing on tautomeric shifts and their impact on nucleotide bonding. Each card presents key terms and definitions that will enhance your understanding of nucleic acids and molecular biology concepts.
