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Biology Accel
Patterns of Inheritance Notes
| Question | Answer |
|---|---|
| heredity: | the passing of genetic traits from parent to offspring |
| the scientific study of heredity is known as: | genetics |
| blending inheritance: | where both parents contributed factors that were blended in offspring |
| gregor mendel (1800's): | austrian monk |
| gregor mendel worked with garden peas: flowers ____ ______ | self-fertilized (pollen fertilized egg before flower opened) |
| all peas were true-breeding: | seeds had same characteristic as single parent plant |
| mendel cross-pollinated the plants: | he selected plants with different traits to breed together |
| mendel studied traits: | 7 unique traits were studied |
| trait: | a specific characteristic that varies from one to another |
| mendel crossed plants with 7 contrasting characteristics and studied offspring. example: | round x wrinkled, yellow x green, tall x short |
| original pair of plants were called P ___ offspring were called F1 ___ | parental; first filial |
| hybrids: | the results of crosses between parents with different traits |
| when crossing two different parents what were the offspring like? P: tall x short F1: | all were tall |
| inherited traits are determined by: today these factors are called ____ | factors that are passed from one generation to the next; genes |
| alleles: (example gene for tall plant, gene for short plant) | different forms of gene - each is given a letter |
| the principle of dominance: | some alleles are dominant, other are recessive |
| if an organism had a ___ of an allele for a trait, _______. (dominant alleles are written with a capital letter) | dominant form; the organism will always have form |
| if an organism has a ___ of a trait, it will only show if ______. (recessive alleles are written with a lower-case letter) | recessive form; the dominant allele is present |
| principle of segregation: during _____, alleles are ___ from each other so that each gamete carries only a ____. | gamete formation; segregated; single copy of each gene |
| the alleles are ______. | paired up again when gametes fuse during fertilization |
| probability: | the likelihood that a particular event will occur |
| what is the probability of flipping heads twice? | 1/2*1/2 or 1/4 |
| the principles of probability can be used to predict the ____. | outcomes of genetic crosses |
| we can determine the probable results of a genetic cross by drawing a _____. | punnett square |
| homozygous: | having two of the same allele |
| heterozygous: | having two different alleles |
| phenotype: | physical characteristics of an organism |
| genotype: | genetic makeup of an individual EX: TT or tt- the letters |
| if a plant has a tall ____ it can have one of two ____ EX: phenotype: genotype: | phenotype; genotype; tall plant; TT or Tt |
| the larger the number of individuals in the sample, ______. | the more accurate the ratios come out |
| the two-factor cross: | two traits |
| principle of independent assortment: | genes for different traits can be segregated independently during the formation of gametes |
| incomplete dominance: the heterozygous phenotype is in between ______. | one allele isn't completely dominant over another; 2 homozygous phenotypes |
| co-dominance: example: in cattle read hair and white hair are codominant. _______ | both alleles contribute to the phenotype; cattle with both are roan |
| multiple alleles: | some genes have more than just 2 alleles. EX: human blood has 3; ABO |
| polygenic traits: | many traits are controlled by 2 or more genes EX: human height, skin, color |
| sex-linkage: | the pair of sex chromosomes x and y determine the gender of an individual |
| autosome: | the chromosomes that are the same in males and femals |
| sex chromosome: | the 'mismatched' chromosomes that determine the gender of the organism |
| how is the sex of the offspring determined? in animals such as fruit flies and humans, _______. | the pair of sex chromosomes x and y determine the gender of an individual |
| genes on sex chromosomes: | a gene is located on one of the sex chromosomes is said to be sex-linked |
| where in the cell are the factors that control heredity? where are the genes? | genes; DNA in nucleus |
| chromosomal theory of heredity: | genes occupy specific positions on chromosomes; chromosomes undergo independent assortment and segregation |
| linked genes: | genes are linked together in chromosomes |
| linkage groups: | genes close together are likely to be inherited together |
| thomas hunt morgan: worked with _____ | drosophila melanogaster-fruit flies |
| why don't all of the offspring have the same genotypes as their parents? | because of crossing over |
| crossing over: | during meiosis- exchange of information between homologous chromosomes |
| crossing over breaks _______. | linkages on genes |
| gene map: | a diagram of chromosomes showing relative locations of genes |
| genes close together are ______. | likely to be inherited together |
| genes far apart separated by ________. | crossing over |