Podcast
Questions and Answers
Which of the following correctly describes the relationship between genotype and phenotype?
Which of the following correctly describes the relationship between genotype and phenotype?
- Genotype is the physical expression of traits, while phenotype is the genetic makeup.
- Phenotype determines the genetic makeup, which in turn influences the genotype.
- Genotype and phenotype are interchangeable terms for the same concept.
- Genotype is the genetic makeup of an organism, while phenotype is the traits expressed by that genetic makeup. (correct)
During gamete formation, what process leads to the segregation of alleles, ensuring each gamete carries only one allele for each gene?
During gamete formation, what process leads to the segregation of alleles, ensuring each gamete carries only one allele for each gene?
- Mitosis
- Replication
- Fertilization
- Segregation (correct)
How do homologous chromosomes contribute to genetic diversity during meiosis?
How do homologous chromosomes contribute to genetic diversity during meiosis?
- By carrying the same genes and exchanging genetic material through crossing over. (correct)
- By replicating to produce identical sister chromatids.
- By preventing crossing over and genetic recombination.
- By ensuring each daughter cell receives an identical set of genes.
What is the fundamental difference in the formation of monozygotic and dizygotic twins?
What is the fundamental difference in the formation of monozygotic and dizygotic twins?
In genetics, what does it mean for a trait to be 'dominant'?
In genetics, what does it mean for a trait to be 'dominant'?
Which of the following best describes the purpose of a karyotype?
Which of the following best describes the purpose of a karyotype?
If a karyotype shows an individual with 47 chromosomes, including an extra chromosome at pair #21, which condition is indicated?
If a karyotype shows an individual with 47 chromosomes, including an extra chromosome at pair #21, which condition is indicated?
What is the primary purpose of constructing and analyzing a pedigree?
What is the primary purpose of constructing and analyzing a pedigree?
Why is meiosis important for sexual reproduction?
Why is meiosis important for sexual reproduction?
During which phase of meiosis does crossing over occur, and why is this event significant?
During which phase of meiosis does crossing over occur, and why is this event significant?
What is the end result of Meiosis I?
What is the end result of Meiosis I?
How does mitosis differ from meiosis in terms of the genetic makeup of the daughter cells?
How does mitosis differ from meiosis in terms of the genetic makeup of the daughter cells?
What is the purpose of polar bodies produced during oogenesis?
What is the purpose of polar bodies produced during oogenesis?
How does spermatogenesis differ from oogenesis in terms of the number of viable gametes produced?
How does spermatogenesis differ from oogenesis in terms of the number of viable gametes produced?
What is the significance of Gregor Mendel's experiments with pea plants in the field of genetics?
What is the significance of Gregor Mendel's experiments with pea plants in the field of genetics?
In Mendel's experiments, what does the term 'true-breeding' refer to?
In Mendel's experiments, what does the term 'true-breeding' refer to?
Which of Mendel's principles states that genes have multiple variations called alleles, and some alleles are dominant while others are recessive?
Which of Mendel's principles states that genes have multiple variations called alleles, and some alleles are dominant while others are recessive?
What is the possible genotype for someone with Type A blood?
What is the possible genotype for someone with Type A blood?
Why is the Rh factor important during pregnancy?
Why is the Rh factor important during pregnancy?
What genetic phenomenon is exemplified by a red flower crossed with a white flower producing pink offspring?
What genetic phenomenon is exemplified by a red flower crossed with a white flower producing pink offspring?
Flashcards
Genotype
Genotype
The genetic makeup of an organism.
Phenotype
Phenotype
The traits expressed by a genotype; physical characteristics.
Homozygous
Homozygous
Having two identical alleles for a trait.
Heterozygous
Heterozygous
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Segregation
Segregation
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Allele
Allele
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Punnett Square
Punnett Square
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Homologous Chromosomes
Homologous Chromosomes
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Haploid Cells
Haploid Cells
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Diploid Cells
Diploid Cells
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Karyotype
Karyotype
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Pedigree
Pedigree
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Meiosis
Meiosis
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Mitosis: Cell Type
Mitosis: Cell Type
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Meiosis: Cell Type
Meiosis: Cell Type
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Gametogenesis
Gametogenesis
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Oogenesis
Oogenesis
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Spermatogenesis
Spermatogenesis
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Mendel's Principles
Mendel's Principles
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Incomplete Dominance
Incomplete Dominance
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Study Notes
- Genes and Meiosis Review
Definitions
- Genotype: The genetic makeup of an organism.
- Phenotype: The traits expressed by a genotype.
- Homozygous: Having two identical alleles for a trait.
- Heterozygous: Having two different alleles for a trait.
- Segregation: Separation of alleles during gamete formation.
- Allele: A different form of a gene.
- Punnett Square: A tool used to predict genetic cross outcomes.
- Homologous Chromosomes: A pair of chromosomes with the same genes.
- Haploid: Cells with one set of chromosomes.
- Diploid: Cells with two sets of chromosomes.
Monozygotic vs. Dizygotic Twins
- Monozygotic:
- Arise from one fertilized egg.
- Have 100% identical DNA.
- Always the same gender.
- Twins tend to look alike.
- Formed when a single embryo splits.
- Dizygotic:
- Arise from two separate eggs.
- Share 50% of the same DNA.
- May or may not be the same gender.
- Twins may look different.
- Formed when two separate eggs are fertilized.
Formation of Triplets
- Monozygotic: One egg splits into three embryos.
- Dizygotic: Three separate eggs are fertilized.
Dominant Traits
- A dominant trait is expressed when only one dominant allele is present.
- Examples of dominant traits that aren't necessarily common:
- Widow's peak
- Short big toe
- Polydactyly (extra finger)
Karyotype
- A picture of all the chromosomes in a cell, arranged in pairs.
Karyotype Interpretation
- Sex Determination:
- XX indicates a female.
- XY indicates a male.
- Chromosome Labeling:
- Autosomes consist of the first 22 pairs of chromosomes.
- Sex chromosomes are the 23rd pair.
- Down Syndrome (Trisomy 21): 47, +21 Indicates an extra chromosome 21.
- Klinefelter Syndrome: 47, XXY indicates an extra X chromosome in males.
- Turner Syndrome: 45, X indicates a missing X chromosome in females.
- Jacob's Syndrome (Supermale): 47, XYY indicates an extra Y chromosome in males.
- Edwards' Syndrome (Trisomy 18): 47, +18 indicates an extra chromosome 18.
- Triple X Syndrome (Superfemale): An extra X chromosome is present in females.
- Patau Syndrome (Trisomy 13): 47, +13 Indicates an extra chromosome 13.
- Cri-Du-Chat Syndrome (5p deletion syndrome): 46, 5p- Indicates a missing part of chromosome 5.
Pedigree
- A chart that shows the inheritance of a trait through generations of a family.
Meiosis
- Cell division process that creates sex cells.
Steps of Meiosis
- End of Meiosis I: Separation of homologous chromosomes.
- End of Meiosis II: Separation of sister chromatids.
- Meiosis I:
- Chromosomes pair up, crossing over occurs.
- Pairs line up in the middle.
- Pairs are pulled apart to opposite ends.
- Two new cells form.
- Meiosis II:
- Chromosomes condense again.
- Chromosomes line up in the middle.
- Sister chromatids are pulled apart.
- Four unique sex cells are formed.
Mitosis vs. Meiosis
| Characteristic | Mitosis | Meiosis |
|---|---|---|
| Original Parent Cell | Diploid | Diploid |
| Number of Daughter Cells Produced | 2 | 4 (sperm in males; 1 egg in females) |
| Daughter Cells Haploid or Diploid | Diploid | Haploid |
| Daughter Cells Identical to Parent | Yes | No |
| Daughter Cells Identical to Each Other | Yes | No |
| Cell Type | Somatic | Sex |
Products of Meiosis
- Sperm Cells: 4 viable sperm cells are created per meiosis.
- Egg Cells: 1 viable egg cell and 3 polar bodies are created per meiosis.
Polar Bodies
- Small, non-functional cells that help discard extra chromosomes during female meiosis.
- 3 polar bodies are produced.
Gametogenesis
- The process of making gametes through meiosis.
Oogenesis and Spermatogenesis
- Oogenesis: The process of making egg cells in females.
- Spermatogenesis: The process of making sperm cells in males.
Development of Egg and Sperm Cells
- Egg Cell: All eggs are made when her mother is pregnant with the female.
- Sperm Cell: Sperm production starts with the first group of sperm and produces more during puberty.
Changes at Puberty
- Eggs: One egg matures and is released each month.
- Sperm: Production of millions of sperm daily through spermatogenesis begins.
Gregor Mendel
- Considered the "Father of Genetics."
- He studied pea plants.
Mendel's Experiment
- P Generation: Mendel cross-bred plants with contrasting traits (e.g., tall and short).
- F1 Generation: All offspring showed only one dominant trait (e.g., all tall).
- F2 Generation: He self-pollinated the F1 plants, and the recessive trait reappeared in a 3:1 ratio.
True-Breeding
- An organism consistently passes down a trait when self-pollinated or bred with an organism of the same kind.
Mendel's Principles
- You inherit genes from your parents.
- Those genes have multiple variations called alleles.
- Some alleles are dominant, and some are recessive.
Dihybrid Crosses
- Identify genotypes, create a Punnett square, find genotype and phenotype ratios.
Blood Types
- A, B, AB, O
Blood Type Characteristics
| Blood Type | Antigens | Possible Genotypes | Can Donate To | Can Receive From | Antibodies |
|---|---|---|---|---|---|
| A | A | AA, AO | A, AB | A, O | Anti-B |
| B | B | BB, BO | B, AB | B, O | Anti-A |
| AB | A and B | AB | AB | A, B, AB, O | None |
| O | None | OO | A, B, AB, O | O | Anti-A, Anti-B |
Rh Factor
- A protein found on red blood cells.
- Important during pregnancy because if a mother carries an Rh+ baby, her immune system may attack the baby's red blood cells.
Blood Type Frequency
- Most Common: O+
- Least Common: AB-
Exceptions to Mendel’s Principles
- Incomplete Dominance: Blend of traits occurs when neither allele is completely dominant; for example, Red (RR) x White (WW) → Pink (RW) flowers.
- Codominance: Both alleles are fully expressed without blending; for example, Black chicken (BB) x White chicken (WW) → Black and White chicken (BW).
- Multiple Alleles: More than two allele options exist for a trait; for example, blood types (A, B, O).
- Polygenic Traits: Multiple genes influence a single trait; for example, skin color or height.
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