Chapter 9 And 12 Note Guide
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Gregor Mendel was an Austrian monk who studied inheritance through pea plant experiments in his garden. He discovered the basic rules of genetics, including his laws of inheritance. Mendel studied seven traits in pea plants including plant height, flower position, and seed color. He used purebred plants to ensure each parent had the desired trait. Mendel's laws state that factors separate during meiosis and each offspring receives one factor from each parent which are passed on independently. Other forms of inheritance include incomplete dominance, codominance, sex-linked traits, and polygenic traits influenced by multiple genes. Mutations can also result in genetic disorders being passed down. Pedigrees are used to track the inheritance of traits through generations
Chapter 9 And 12 Note Guide
- 1. Chapter 9 and 12 Notes Name_____________________Mod___________ WHO WAS GREGOR MENDEL? _______________________monk that studied _________________. _____________________is the transmission of characteristics from ___________________________to ______________________. Experimented with ___________________________in his garden to determine what ___________________were passed along. He discovered the basic rules of ___________________. PEA PLANTS Mendel studied _____________________ traits. They were easily __________________________: plant height, flower position, pod color, pod appearance, seed texture, seed color and flower color. Mendel used _______________________________________ in his studies to make sure each parent was the correct one he wanted.
- 2. MENDEL’S LAWS • The ____________________________________________ states that paired factors separate during the formation of _________________________ (meiosis) • Each _____________________ only receives one factor or _______________________ from each parent. • The ________________________________ states that factors for different traits distribute to gametes independently regardless of the other trait. • ________________________________ means the organism has two of same _________________________ for a trait. • ___________________________________ means the organism has two __________________________ alleles for a trait. • Heterozygous would automatically have one _________________________ allele and one ___________________________ allele.
- 3. • Homozygous could have two __________________________ alleles or two ________________________ alleles. LET’S PRACTICE! Cross a homozygous plant with white flowers with a heterozygous plant with purple flowers. If there are 100 plants that grow, how many would you expect to be purple? How many would be white? Cross a two plants that are heterozygous for tall size. If 100 plants grow, how many would be tall? How many would be dwarf?
- 4. OTHER TYPES OF INHERITANCE Incomplete Dominance or Intermediate Inheritance • When two or more ___________________________ influence the phenotype, both are _____________________ so neither is completely dominant or recessive. • This results in a _________________ phenotype in addition to the originals. • The _________________________ genotype is always the new phenotype. LET’S PRACTICE! Cross a white flower with a red flower. What would be the phenotypes of the offspring? Cross a black mouse with a grey mouse. What would the phenotypes of the offspring be?
- 5. Codominance • This results when two or more _____________________ are equally dominant and both alleles are expressed in ____________________________ organisms • Both alleles are expressed ____________________. • This is different than incomplete dominance because it isn’t a _________________________ phenotype, both are expressed. • Human_________________ type is an example. LET’S PRACTICE! Cross a person that is heterozygous for blood type A with a person that is heterozygous for blood type B. What would be the percentages of phenotypes in the offspring? Sex-Linked • Some genes are found only on the ____________________________. • Many diseases are X-linked diseases and are more common in ____________________ than in __________________.
- 6. • Males need only ______________ copy of the bad gene while females need ________________ copies of the bad gene. • Hemophilia, colorblindness and Duchenne muscular dystrophy are human diseases associated with this inheritance. • A _________________________ is __________________________ for a disease but does not have the disease. It can be passed on to their children though. • Sex-influences traits like baldness are influenced by the sex of the person and are __________________________ differently even if the gene is the same. LET’S PRACTICE! Cross a woman that is a carrier for hemophilia with a man that is normal. What percentage of male children would have hemophilia? What percentage of female children would have hemophilia?
- 7. Cross a man who is colorblind with a normal woman. What percentage of the children (male or female) would be colorblind? What percentage of the children would be carriers for colorblindness? POLYGENIC TRAITS • _____________________________ traits are controlled by more than one gene. • ______________________ is controlled by at least __________________ genes which result is a different amount of pigment produced. • ____________________________ is also polygenic as well as height although _______________________ plays a part in that as well. MUTATIONS • ________________________________ results when the chromosomes don’t split evenly during meiosis resulting in three chromosomes under ____________________________. • ____________________________ also occurs this way and results in one less sex chromosome.
- 8. • Disorders can also be inherited ______________________or _________________________ or even as a result of chromosome pieces breaking off or “jumping” around. PEDIGREES Pedigrees show how a trait is passed along in a family through many generations. Circles are for females, squares are for males. Fill in the genotypes of each individual under each shape.
- 10. Sickle- cell anemia is a disease of the blood that causes blood cells which are normally round to become sickle shaped. It is a genetic disease that a person must be born with and inherit from BOTH parents! If sickle-cell is so bad, why is it around so much?
- 11. Why is sickle-cell anemia so prevalent in African and African American people? Write your explanation below and include a Punnett square!