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AP Biology
Chapter 10 & 15 - heritary & chromosome abnormalities, guided notes & definition
Question | Answer |
---|---|
Heredity | Transmission of genetic information from parent to offspring |
Genetics | The science of heridity |
Genetic variation | Differences, between parents and offspring |
Phenotype | The physical appearance of an organism |
Traits | Heritable differences |
Alleles | The alternative forms of a gene |
Genes | Hereditary factors |
Locus | A segment of the DNA that has the information for controlling some aspect of the structure or function of the organism |
Genotype | Genetic constitution of an organism, mostly expressed by symbols |
Mendel's principle of segregation | says that before sexual reproduction occurs, the 2 alleles carried by an individual parent must become separated |
Punnett square | A grid showing the possible combinations of eggs and sperm at fertilization |
Mendel's principle of independent assortment | States that members of any gene pair segregate from on another independently of the members of the other gene pairs |
How does the "blending hypothesis" differ from the "particulate hypothesis" for the transmission of traits? | They were cross pollinated true breeding parents. |
What are a few of the advantages of Mendel's choice of the garden pea as a model organsim? | They were available in many varieties with heritable features; Each pea plant has male and female structures; pea plants can self-fertilize; Mendel could cross polinate; simple genetically; gene had 2 alleles, one dominant to other |
Define the Law of Segregation. | Before sexual reproduction occurs the 2 alleles carried by an individual parent must become separated. |
How does the Law of Segregation, in the pea plants, apply to the F1 and the F2 generations? | (blank) |
When does the segregation of alleles occur? | Meiosis 1 |
What is the difference between an allele and a gene? | Alleles are genes governing the variation of the same character that occupy corresponding positions on homologous chromosomes. |
What is the difference between an allele and a gene? | Genes are a segment of DNA that serves as a unit of hereditary information. |
Homozygous | Having a pair of identical alleles for a particular locus. |
Heterozygous | Having a pair of unlike alleles for a particular locus. |
Phenotype | The physical or chemical expression of an organisms genes. |
Genotype | The genetic makeup of an individual. |
What is the purpose of a test cross? | Determines the indentity of the unknown allele. |
When 2 traits are on different (non-homologous) chromosomes, how are they inherited? | (blank) |
Use the rules of probability to determine the expected ratio of offspring showing 2 recessive traits in the trihybrid cross (PpYyRr X Ppyyrr). | (blank) |
Describe and give an example of incomplete dominance. | Yr mixing with a YR. The YR is more dominant. |
How does codominance compare to incomplete dominance? | Incomplete dominance does not have complete power of what a child will look like. |
How is blood type an example of multiple alleles? | It takes a combination of alleles to make up your blood type. Example O = ii and AB = IA IB |
What is pleiotrophy? | When one gene affects more than one phenotypic character. Example: dwarfism, gigantism, sickle cell anemia, and cystic fibrosis |
Define and give and example of epistasis. | When one gene makes another. Example = albinism |
What is observed when traits are polygenic? | The offspring of a person has a greater chance of having lighter of darker skin color depending if the parents had a genotypes with more AABBCC than aabbcc. Polygenic traits include height, eye color, intelligence. |
The expression of phenotypes is often a result of both | environment and genes. |
Genetic disorder that results from defective ion transport. | Cystic Fibrosis |
Genetic disorder that results from abnormal lipid metabolism in the brain. | Tay-Sachs |
Genetic disorder that results from a hemoglobin defect. | Sickle cell anemia |
Genetic disorder that has an autosomal dominant inheritance pattern that is a common cause of dwarfism in which a mutation causes an abnormality of cartilage formation. | Achondroplasia |
Genetic disorder that has an autosomal dominant inheritance pattern and causes mental and physical deterioration. | Huntington's disease |
How can a parent learn the risks of having a child with a genetic disorder? | A genetic counselor can help parents understand their situation and give them the probability of their child inheriting a particular condition. |
Describe some of the pieces of information that scientiests discovered that contributed to the "Chromosome Theory of Inheritance"? | Experimental evidence from improved microscopy and animal breeding led us to a better understanding of chromosomes and genes beyond Mendel. |
Summarize the Chromosomal Theory of Inheritance. | How you can predict what the offspring will look like based on the parents genetic code. |
Why was Thomas Hunt Morgan's choice of the fruit fly a good model organism? | Because it was prolific, 2 week generations, 4 pairs of chromosomes XX=female, XY=male |
Describe Morgan's first mutant. Why was it so significant from the wild type? | It had white eyes and it was unusual because the wild flys normally have red eyes. |
Show the cross P, F1, F2 for the white-eyed male mutant. | Red eye female X White eye male → all red eye offspring → 75% red eye female X 25% white eye male |
What happens when we trace the inheritance of traits found on the same chromosome? | You can trace how the offspring got certain trait - linkage occurs |
What is recombination and when does it occur? | The process that leads to new gene combinations. It occurs whenever gametes come together. |
How is recombination frequency calculated? | 1. Add the number of individuals in the 2 recombinate classes of offspring 2. Divide by the total number of offspring 3. Multiply by 100 |
What determines sex in humans? | Chromosomes. XX = Female, XY = Male |
In what ways are sex-linked traits distinct from autosomal traits? | 22 Pairs of autosomal traits and 2 sex chromosomes. |
Why are sex-linked recessive traits more common in human males than females? | Male X-linked alleles are hemizygous. They only need one recessive allele to be expressed. |
How many X chromosomes are typically expressed in humans and cats? | 2 X Chromosomes |
How many Barr bodies would be found in a person with: XXY____ XO___ XXX____ | (blank) |
Define aneuploidy and when does it occur? | Any chromosomal aberation in which there are either extra or missing copies of certain chromosomes. It occurs during meiotic (or rarely mitotic) division when chromosomes fail to separate. |
What is polyploidy and when does it occur? | The condition of having more than 2 sets of chromosomes per nucleus. It occurs when chromosomes don't separate during miosis or from the fertilization of an egg by more than one sperm. |
Describe the non-disjunction Down Syndrome. | Has varying degrees of mental retardation, short stature, cardiac deformities, mostly found in children whose mother is +35. |
Describe the non-disjunction Edwards Syndrome. | Ear deformities, heart defects, and spasticity, usually die by age 1. |
Describe the non-disjunction Patau Syndrome. | Multiple defects, usually dies by 3 months old. |
Describe genomic imprinting and give an example. | The expression of a gene in a given tissue or developmental stage is based on its parental origin. An example would be a person inherits Prader-Willi Syndrome from their father and a person inherits Angel-man Syndrome from their mother. |