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Questions and Answers
What genetic trait did Morgan discover through his experiments with Drosophila melanogaster?
What genetic trait did Morgan discover through his experiments with Drosophila melanogaster?
- Eye color mutation (correct)
- Wing size variation
- Body color change
- Tail length alteration
What characteristic of Drosophila melanogaster made it particularly suited for genetics research?
What characteristic of Drosophila melanogaster made it particularly suited for genetics research?
- It can survive in various environments.
- It produces a large number of offspring quickly. (correct)
- It has a high mutation rate.
- It has numerous and complex traits.
In Morgan's experiments, which allele was identified as recessive for eye color?
In Morgan's experiments, which allele was identified as recessive for eye color?
- w+ (wild type)
- W (white)
- R (red)
- w (mutant) (correct)
What was the outcome when mutant white-eyed male Drosophila were crossed with wild-type females?
What was the outcome when mutant white-eyed male Drosophila were crossed with wild-type females?
What segregation pattern was noted in the progeny of Morgan’s eye color experiment?
What segregation pattern was noted in the progeny of Morgan’s eye color experiment?
What did Morgan conclude regarding the location of the gene for eye color?
What did Morgan conclude regarding the location of the gene for eye color?
What were the phenotypes studied by Morgan in his experiments?
What were the phenotypes studied by Morgan in his experiments?
What indicates that a gene was unambiguously linked to a chromosome?
What indicates that a gene was unambiguously linked to a chromosome?
What was the outcome when white-eyed females were crossed with red-eyed males in the experiment?
What was the outcome when white-eyed females were crossed with red-eyed males in the experiment?
What term describes the failure of chromosomes to disjoin during meiosis as explained by C.B. Bridges?
What term describes the failure of chromosomes to disjoin during meiosis as explained by C.B. Bridges?
Which of the following best explains Morgan's findings about the inheritance of eye color in Drosophila?
Which of the following best explains Morgan's findings about the inheritance of eye color in Drosophila?
What significant contribution did C.B. Bridges make to genetics?
What significant contribution did C.B. Bridges make to genetics?
What genetic disorder is caused by mutations in the dystrophin gene?
What genetic disorder is caused by mutations in the dystrophin gene?
Why are males predominantly affected by Hemophilia A?
Why are males predominantly affected by Hemophilia A?
What concept describes the transmission of properties of chromosomes that explains Mendel’s principles?
What concept describes the transmission of properties of chromosomes that explains Mendel’s principles?
What may cause nondisjunction during meiosis?
What may cause nondisjunction during meiosis?
What type of complex is formed by DNA and proteins in eukaryotic cells?
What type of complex is formed by DNA and proteins in eukaryotic cells?
What is the consequence of chromosome packing during cell division?
What is the consequence of chromosome packing during cell division?
Which of the following describes the basic chromosome number for humans?
Which of the following describes the basic chromosome number for humans?
What is the term used for cells that contain four sets of chromosomes?
What is the term used for cells that contain four sets of chromosomes?
What field of genetics involves the microscopic examination of chromosomes?
What field of genetics involves the microscopic examination of chromosomes?
How many chromosomes do most human somatic cells contain?
How many chromosomes do most human somatic cells contain?
What happens to the chromosomal composition during cell division?
What happens to the chromosomal composition during cell division?
What do we call the set of chromosomes that defines the haploid genome?
What do we call the set of chromosomes that defines the haploid genome?
What type of chromosome do female grasshoppers possess that male grasshoppers do not?
What type of chromosome do female grasshoppers possess that male grasshoppers do not?
What is the expected ratio of male to female zygotes produced during fertilization in grasshoppers?
What is the expected ratio of male to female zygotes produced during fertilization in grasshoppers?
In humans, what chromosome pairs with the X chromosome during meiosis in males?
In humans, what chromosome pairs with the X chromosome during meiosis in males?
Which of the following statements is true regarding the structure of the human Y chromosome?
Which of the following statements is true regarding the structure of the human Y chromosome?
What characterizes the chromosomes in grasshoppers compared to other animals, including humans?
What characterizes the chromosomes in grasshoppers compared to other animals, including humans?
What type of chromosomes are X and Y classified as?
What type of chromosomes are X and Y classified as?
How many types of sperm are produced during meiosis in males regarding sex chromosomes?
How many types of sperm are produced during meiosis in males regarding sex chromosomes?
In the context of heredity, what did many biologists suspect by 1910?
In the context of heredity, what did many biologists suspect by 1910?
What is Mendel’s Principle of Independent Assortment associated with?
What is Mendel’s Principle of Independent Assortment associated with?
In autosomal dominant inheritance, how many copies of the abnormal gene are required to display a trait?
In autosomal dominant inheritance, how many copies of the abnormal gene are required to display a trait?
Which condition exemplifies autosomal dominant inheritance?
Which condition exemplifies autosomal dominant inheritance?
What is the probability of a child inheriting both defective copies of a gene if both parents are carriers of an autosomal recessive trait?
What is the probability of a child inheriting both defective copies of a gene if both parents are carriers of an autosomal recessive trait?
What is the function of the protein produced by the CFTR gene, related to cystic fibrosis?
What is the function of the protein produced by the CFTR gene, related to cystic fibrosis?
Which of the following statements regarding carriers of autosomal recessive traits is true?
Which of the following statements regarding carriers of autosomal recessive traits is true?
What genetic alteration is responsible for Huntington’s Disease?
What genetic alteration is responsible for Huntington’s Disease?
How do autosomal dominant and autosomal recessive traits differ in terms of expression?
How do autosomal dominant and autosomal recessive traits differ in terms of expression?
Flashcards
Chromosomes
Chromosomes
Structures in cells containing genetic material such as DNA.
Genes
Genes
Segments of DNA located within chromosomes that determine traits.
Chromatin
Chromatin
The complex of DNA and proteins found in eukaryotic cells.
Cytogenetics
Cytogenetics
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Karyotype
Karyotype
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Diploid
Diploid
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Tetraploid
Tetraploid
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Octoploid
Octoploid
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Sex Chromosomes
Sex Chromosomes
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X Chromosome
X Chromosome
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Y Chromosome
Y Chromosome
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Meiosis
Meiosis
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Autosomes
Autosomes
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Chromosome Theory of Heredity
Chromosome Theory of Heredity
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Morgan’s Experiment
Morgan’s Experiment
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Nondisjunction
Nondisjunction
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Duchenne Muscular Dystrophy
Duchenne Muscular Dystrophy
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Hemophilia A
Hemophilia A
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Independent Assortment
Independent Assortment
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Autosomal Inheritance
Autosomal Inheritance
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Autosomal Dominant Inheritance
Autosomal Dominant Inheritance
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Huntington's Disease
Huntington's Disease
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Autosomal Recessive Inheritance
Autosomal Recessive Inheritance
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Cystic Fibrosis
Cystic Fibrosis
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Genetic Disorders
Genetic Disorders
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Chromosome Composition
Chromosome Composition
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X-Linked Inheritance
X-Linked Inheritance
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F1 Generation
F1 Generation
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Meiotic Division
Meiotic Division
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Chromosomal Abnormalities
Chromosomal Abnormalities
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Study Notes
Chromosomes and Genes
- Chromosomes are structures within cells that contain the genetic material.
- Genes are physically located within chromosomes.
- Each chromosome contains a long DNA segment and proteins.
- In eukaryotic cells, the complex of DNA and proteins is called chromatin.
Cytogenetics
- The study of chromosomes using microscopes.
- Examines the chromosomal composition of cells.
- Chromosomes are best seen when cells are dividing.
Karyotype
- A complete set of chromosomes from a single cell.
- Diploid human cells have two complete sets of chromosomes, or a karyotype.
Chromosome Number
- Most species have an even number of chromosomes.
- The basic number of chromosomes in humans is 23.
- Most human cells are diploid (2n), meaning they have two of each chromosome.
- Some cells are tetraploid (4n), with four of each chromosome.
- Cells with eight of each chromosome are octoploid (8n).
Sex Chromosomes
- In many species, males and females have different chromosome numbers.
- In grasshoppers, females are XX and males are XO.
- In humans, males are XY and females are XX.
- The X chromosome is larger than the Y chromosome.
X and Y Chromosome Transmission
- During meiosis in females, the two X chromosomes separate, producing eggs containing a single X chromosome.
- During meiosis in males, the X and Y chromosomes separate, producing X-bearing and Y-bearing sperm.
- When sperm and egg unite, XX zygotes develop into females and XY zygotes develop into males.
Autosomes
- All chromosomes other than sex chromosomes are autosomes.
The Chromosome Theory of Heredity
- This theory states that genes are located on chromosomes.
- Thomas H. Morgan's experiments with fruit flies provided evidence for the chromosome theory.
- He discovered a gene for eye color in Drosophila.
Morgan’s Experiment
- Morgan discovered a mutant male fruit fly with white eyes.
- When crossed with wild-type females, all offspring had red eyes.
- When these offspring were intercrossed, only half of the male offspring had white eyes.
- This pattern suggested that the inheritance of eye color was linked to the X chromosome.
Morgan’s Additional Experiments
- He crossed heterozygous F1 females with white-eyed males, resulting in half of each sex having white eyes.
- He crossed white-eyed females with red-eyed males, resulting in all daughters with red eyes and all sons with white eyes.
Nondisjunction
- C.B. Bridges showed that exceptions to inheritance rules could be explained by chromosome behavior.
- Nondisjunction - when chromosomes fail to separate during meiosis.
Duchenne Muscular Dystrophy (DMD)
- Caused by mutations in the dystrophin gene, which is essential for maintaining muscle cell integrity.
- Results in progressive muscle weakness and degeneration.
- Largely affects males.
Hemophilia A
- Caused by mutations in the factor VIII gene, which is crucial for blood clotting.
- Results in prolonged bleeding.
- Females are typically carriers.
Mendel's Principle of Independent Assortment
- This principle states that different pairs of chromosomes align randomly at metaphase.
Autosomal Inheritance
- Refers to inheritance patterns of traits on autosomes (chromosomes 1-22).
Autosomal Dominant Inheritance
- Occurs when one defective gene is necessary for a trait to appear.
- A parent with an autosomal dominant condition has a 50% chance of passing the gene to their offspring.
Autosomal Dominant Example: Huntington's Disease
- Caused by mutations in the HTT gene.
- Mutations result in an abnormal huntingtin protein that damages brain cells.
- Inherited as a dominant trait, anyone who inherits the mutated gene will eventually develop the disease.
Autosomal Recessive Inheritance
- Requires two copies of an abnormal gene to be present for a trait to appear.
- Individuals with only one defective gene are carriers.
- When two carriers have a child, there is a 25% chance that the child will inherit both defective genes and express the trait.
Autosomal Recessive Example: Cystic Fibrosis
- Caused by mutations in the CFTR gene, which regulates ion movement in cells.
- Mutations result in defective protein causing thick mucus buildup in organs.
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Description
Explore the fundamental concepts of chromosomes and genes in this quiz. Learn about the structure of chromosomes, the role of genes, and how cells are studied in cytogenetics. Understand key terms like karyotype and chromosome number in the context of human genetics.
