Chapter 14 study guide-Palmtag PDF

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Chapter 14 Study guide for Palmtag...

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Chapter 14 Study Guide

Palmtag Bio 1010C

1. Give an example of a character and two traits of the character. A heritable feature that varies among individuals. i.e. peas, white/ purple flowers 2. How did Mendel’s hypotheses, regarding the flow of genetic information, differ from the blending hypothesis? Blending hypothesis the idea that genetic material contributed by the 2 parents mixes in a manner analogous to the way blue and yellow paints blend to make green The gene idea parents pass on discrete inheritable units (genes) that remain their separate identities in offspring Differences- In the blending hypothesis, genetic material provided by each of the 2 parents is mixed in the offspring, losing its individual identity 3. What is a true breed, what is a hybrid? In Mendel’s experiment describe the P, first filial, and second filial generation? True Breed- organisms that produce offspring of the same variety over many generations of self- pollinating Hybrid- the mating or crossing of 2 different true-breeding varieties P gen- the true-breeding parents, the white flowered plants, and the purple flowered plants F1- the hybrids offspring F2- the offspring from the self-pollination of the F1 hybrids 4. What is a locus and what is an allele? On a homologous pair of chromosomes (that are not duplicated) how many loci and alleles would there be for one gene? 2 5. Describe the following terms: dominant allele, recessive allele, homozygous, heterozygous, phenotype, genotype? Dominant allele determines organism’s appearance Recessive Allele has no noticeable effect on the organism’s appearance Homozygous having 2 identical alleles for the given gene (AA) (aa) Heterozygous having 2 different alleles for a given gene (Aa) Phenotype the observable physical and physiological traits of an organism, determined by its genetic make up Genotype the genetic makeup, or set of alleles of an organism

6. The results of Mendel’s experiment established that alleles for a heritable character segregate during gamete formation and end up in different gametes. Describe the independent variable,

dependant variable, control group, and treatment group. Describe how the genotypes (results) of the first and second filial generation supported Mendel’s hypothesis. Independent variable producing hybridized offspring vs. true-breed offspring Dependent variable observable offspring trait Control group true-breeding plants Results- Hypothesized plants in P gen were homozygous, F1: 100% purple; F2: 75% purple, 25% white; the test cross revealed the genotype of the F1 generation 7. In which phase of meiosis do alleles for a heritable character segregate during gamete formation and end up in different gametes? Metaphase I 8. Describe Mendel’s law of independent assortment, how did he use a dihybrid cross to provide evidence that supported his hypothesis? At what point in meiosis does independent assortment of homologous chromosomes occur? Law of Independent Assortment each pair of alleles segregates independent of each other pair of alleles during gametes formation based on how homologous chromosomes line up based on Metaphase 1 Dihybrid cross evidence- the F1 were dihybrids which were individual heterozygous for the 2 characters being followed in the cross (YyRr)

9. How does incomplete dominance and codominance differ from complete dominance? Incomplete dominance in which the phenotypes of heterozygotes is intermediate between the phenotype of the individuals homozygous on either allele (mixed) Codominance in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate distinguishable ways (not mixed) Difference- In complete dominance there is no distinguished effect because the dominance allele masks the recessive allele and incomplete/ codominance show effect of the dominance 10. What is pleiotropy? The ability of a single gene to have multiple effects Responsible for multiple symptoms associated with certain hereditary diseases

11. How are the A, B, O and AB blood types determined? How many alleles are involved in determining these blood types? Is this an example of incomplete dominance or codominance?

By the three alleles of a single gene that refer to the A and B carbohydrates 12. What does the term epistasis refer to? The phenotype expression of a gene at one locus alters that of a gene in the second locus 13. Are traits always determined by single genes? If a character is determined by many genes (polygenic) what kind of phenotypes are observed in the population? No Many genes are quantitative characters i.e. skin color 14. What is a multifactorial character and what is the norm of reaction for a multifactorial character? Describe the effect the environment can have on a multifactorial genetic disorder. When many factors (genetic/ environmental) collectively influence phenotype Norm of reaction the range of phenotypes produced by a single genotype, due to environmental influences 15. Why do humans use pedigrees and what are they useful in determining? Pedigree is a diagram of a family tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over many generations Used because when geneticists are unable to manipulate the mating patterns of people Determines traits through generations of the same family 16. Compare and contrast inheritance patterns of recessive and dominantly inherited disorders. What is a carrier? Carrier is an individual that has inherited a gene/ mutation but doesn’t show symptoms but passes the gene to their offspring who may express the gene Recessively inherited disorders show up only on the homozygous individual who inherit 1 recessive allele from each parent Dominantly inherited disorders found in a heterozygous indviduals...