Biology EOC Review Biological Molecules and Membranes/Cell Structure/Mitosis/Meiosis and Genetics/Evolution Part 5

If you recall… …we just discussed how living things such as plant cells can benefit from both asexual and sexual reproduction. …we just discussed how living things such as plant cells can benefit from both asexual and sexual reproduction. We discussed the structure of DNA and chromosomes. We discussed the structure of DNA and chromosomes. We also discussed that genes within the DNA of a cell have the means of potentially mutating which may help cells and organisms adapt to a changing environment. We also discussed that genes within the DNA of a cell have the means of potentially mutating which may help cells and organisms adapt to a changing environment. BioEOC Biomolecules & Membranes Part 5 2

How do we know? How do we know that genetic mutations in the DNA can actually help an organism survive? How do we know that genetic mutations in the DNA can actually help an organism survive?genetic mutations genetic mutations We need to simply look at something that is referred to as Mendelian Genetics to see this pattern. We need to simply look at something that is referred to as Mendelian Genetics to see this pattern.Mendelian Genetics Mendelian Genetics Mendelian Genetics, which is named afterGregor Mendel, is a pretty old concept that humans have been unknowingly utilizing for centuries as we have learned to domesticate plants and animals. Mendelian Genetics, which is named afterGregor Mendel, is a pretty old concept that humans have been unknowingly utilizing for centuries as we have learned to domesticate plants and animals.Gregor Mendeldomesticate plants and animalsGregor Mendeldomesticate plants and animals BioEOC Biomolecules & Membranes Part 5 3

??? Remember our little plant cells that have been growing asexually through the process of mitosis? Remember our little plant cells that have been growing asexually through the process of mitosis? The ones that are in a plant experiencing a major change in their environment so that they aren’t getting enough sunlight to use photosynthesis to make food for themselves? The ones that are in a plant experiencing a major change in their environment so that they aren’t getting enough sunlight to use photosynthesis to make food for themselves? How can Mendelian Genetics help? How can Mendelian Genetics help? BioEOC Biomolecules & Membranes Part 5 4

Grafting These plant cells may experience a genetic mutation that could change the sun-gathering pigment chlorophyll into a new pigment that absorbs different strengths or wavelengths of light. These plant cells may experience a genetic mutation that could change the sun-gathering pigment chlorophyll into a new pigment that absorbs different strengths or wavelengths of light. Maybe instead of absorbing red and blue light, which is what chlorophyll normally does, maybe this new mutated pigment absorbs green and yellow light. Maybe instead of absorbing red and blue light, which is what chlorophyll normally does, maybe this new mutated pigment absorbs green and yellow light. BioEOC Biomolecules & Membranes Part 5 5

Grafting This new mutated pigment will reflect red and blue light, so we see it as a purple pigment. This new mutated pigment will reflect red and blue light, so we see it as a purple pigment.purple pigmentpurple pigment If this purple pigment now helps our little plant cells grow by allowing it to photosynthesize, they will continue to multiply. If this purple pigment now helps our little plant cells grow by allowing it to photosynthesize, they will continue to multiply. If a farmer should see this new purple part of the plant, they could remove it, graft it on to a very strong stalk of a different plant, and grow it. If a farmer should see this new purple part of the plant, they could remove it, graft it on to a very strong stalk of a different plant, and grow it. BioEOC Biomolecules & Membranes Part 5 6

Grafting The farmer just grafted the purple part of our plant onto the healthy stem of another plant. The farmer just grafted the purple part of our plant onto the healthy stem of another plant.grafted That new plant does well and all new growth is now purple. That new plant does well and all new growth is now purple. The plant thrives and flowers. The plant thrives and flowers.flowers BioEOC Biomolecules & Membranes Part 5 7

Parenting The flower produces male gametes or sex cells, which we call pollen (In humans, male gametes are called sperm.). The flower produces male gametes or sex cells, which we call pollen (In humans, male gametes are called sperm.).gametes or sex cellspollenspermgametes or sex cellspollensperm The flower also produces female gametes or sex cells, which we call oocytes, ova (ovum), or eggs (We use the same term in humans.). The flower also produces female gametes or sex cells, which we call oocytes, ova (ovum), or eggs (We use the same term in humans.).gametes or sex cellsoocytes, ova (ovum), or eggsgametes or sex cellsoocytes, ova (ovum), or eggs BioEOC Biomolecules & Membranes Part 5 8

Parenting Each parent (Mom = egg and Dad = sperm/pollen) has genetic information that they will share, through meiosis, with their offspring. Each parent (Mom = egg and Dad = sperm/pollen) has genetic information that they will share, through meiosis, with their offspring. This process is called fertilization. This process is called fertilization.fertilization Quick recap – Remember that in meiosis, a.k.a. sexual reproduction, that one cell produces four completely different cells. Quick recap – Remember that in meiosis, a.k.a. sexual reproduction, that one cell produces four completely different cells. BioEOC Biomolecules & Membranes Part 5 9

Punnett Squares BioEOC Biomolecules & Membranes Part 5 10 We can show this Mom v. Dad DNA genetics sharing by using something called a Punnett Square. We can show this Mom v. Dad DNA genetics sharing by using something called a Punnett Square.Punnett SquarePunnett Square

Punnett Square In a Punnett square, we look at each parent’s gene and give it an abbreviation. In a Punnett square, we look at each parent’s gene and give it an abbreviation. For example, let’s say that, in our purple plant, a gene in the DNA codes for a yellow flower. We could use Y to describe that yellow flower. For example, let’s say that, in our purple plant, a gene in the DNA codes for a yellow flower. We could use Y to describe that yellow flower. However, we notice that sometimes these same plants produce a red flower. We could use y to describe that red flower. However, we notice that sometimes these same plants produce a red flower. We could use y to describe that red flower. BioEOC Biomolecules & Membranes Part 5 11

Punnett Square BTW, Y and y are called alleles. BTW, Y and y are called alleles.alleles Since you only need one copy of the Y allele to have a yellow flower, we can call it the dominant trait. Since you only need one copy of the Y allele to have a yellow flower, we can call it the dominant trait.dominant trait.dominant trait. While red flowers needs two y alleles, which is why we call it a recessive trait. While red flowers needs two y alleles, which is why we call it a recessive trait.recessive trait.recessive trait. BioEOC Biomolecules & Membranes Part 5 12

Punnett Square The combination of alleles is known as a genotype. The combination of alleles is known as a genotype.genotype You could have either YY or Yy or yy. You could have either YY or Yy or yy. YY can also be called a homozygous dominant genotype. YY can also be called a homozygous dominant genotype.homozygous dominant genotypehomozygous dominant genotype Yy can also be called a heterozygous genotype. Yy can also be called a heterozygous genotype.heterozygous genotypeheterozygous genotype yy can also be called a homozygous recessive genotype. yy can also be called a homozygous recessive genotype.homozygous recessive genotypehomozygous recessive genotype BioEOC Biomolecules & Membranes Part 5 13

Punnett Square If Mom’s egg carries a Y and Dad’s sperm carries a Y, the zygote or baby produced will have a YY allele/gene combination. If Mom’s egg carries a Y and Dad’s sperm carries a Y, the zygote or baby produced will have a YY allele/gene combination. Their seed or future little baby plant will have a homozygous dominant genotype. Their seed or future little baby plant will have a homozygous dominant genotype. What color flower will the baby plant produce? What color flower will the baby plant produce? The physical characteristic of flower color is called the phenotype. The physical characteristic of flower color is called the phenotype. BioEOC Biomolecules & Membranes Part 5 14

Punnett Square DIY Videos In order to prove this, which is what scientists do, you need to show the data, a.k.a. complete a Punnett Square. In order to prove this, which is what scientists do, you need to show the data, a.k.a. complete a Punnett Square. If you need to review how to fill out a Punnett Square please view this link before going to the next slide. If you need to review how to fill out a Punnett Square please view this link before going to the next slide. ‪ Monohybrids and the Punnett Square Guinea Pigs ‬ ‪ Monohybrids and the Punnett Square Guinea Pigs ‬ Monohybrids and the Punnett Square Guinea Pigs ‬ Monohybrids and the Punnett Square Guinea Pigs ‬ BioEOC Biomolecules & Membranes Part 5 15

Punnett Square Note that all of the future seeds or baby plants will be YY. Note that all of the future seeds or baby plants will be YY. The genotypic ratio or mathematical way to say this is 100% of the next generation will be YY. The genotypic ratio or mathematical way to say this is 100% of the next generation will be YY. BioEOC Biomolecules & Membranes Part 5 16

Punnett Square Note that all of the future seeds or baby plants will also be homozygous dominant. 100% will be homozygous dominant, which is another way to say the genotypic ratio. Note that all of the future seeds or baby plants will also be homozygous dominant. 100% will be homozygous dominant, which is another way to say the genotypic ratio. BioEOC Biomolecules & Membranes Part 5 17

Punnett Square The phenotypic ratio for all of the seeds or baby plants is 100% yellow. The phenotypic ratio for all of the seeds or baby plants is 100% yellow. You will need to know how to provide all of this information on any Punnett Square. You will need to know how to provide all of this information on any Punnett Square. BioEOC Biomolecules & Membranes Part 5 18

Punnett Square What if Mom provides a yy allele and Dad provides a yy allele? What if Mom provides a yy allele and Dad provides a yy allele? Can you predict the genotypic ratio for all of their seeds? Can you predict the genotypic ratio for all of their seeds? Can you predict the phenotypic ratio for all of their seeds? Can you predict the phenotypic ratio for all of their seeds? BioEOC Biomolecules & Membranes Part 5 19

Punnett Square 100% Homozygous recessive or yy for the genotypic ratio. 100% Homozygous recessive or yy for the genotypic ratio. 100% Red Flowers for the phenotypic ratio. 100% Red Flowers for the phenotypic ratio. BioEOC Biomolecules & Membranes Part 5 20

Punnett Square What if Mom is Yy and Dad is YY? What if Mom is Yy and Dad is YY? What is the genotypic ratio? What is the genotypic ratio? What is the phenotypic ratio? What is the phenotypic ratio? BioEOC Biomolecules & Membranes Part 5 21

Punnett Square 50% YY or homozygous dominant and 50% Yy or heterozygous for the genotypic ratio. 50% YY or homozygous dominant and 50% Yy or heterozygous for the genotypic ratio. What about the phenotypic ratio? What about the phenotypic ratio? BioEOC Biomolecules & Membranes Part 5 22

Punnett Square You need to know if it is a complete or incomplete dominant trait. You need to know if it is a complete or incomplete dominant trait.complete or incomplete dominant complete or incomplete dominant If there is no other color of flower other than yellow or red, it probably is complete dominance. If there is no other color of flower other than yellow or red, it probably is complete dominance. BioEOC Biomolecules & Membranes Part 5 23

Punnett Square For a complete dominant trait in which only yellow or red flowers are possible, this shows 50% yellow and 50% red flowers as the phenotypic ratio. For a complete dominant trait in which only yellow or red flowers are possible, this shows 50% yellow and 50% red flowers as the phenotypic ratio. BioEOC Biomolecules & Membranes Part 5 24

Punnett Square Mom is YY and Dad is yy. Mom is YY and Dad is yy. You know what to do. You know what to do. Go! Go! BioEOC Biomolecules & Membranes Part 5 25

Punnett Square 100% heterozygous or Yy for the genotypic ratio. 100% heterozygous or Yy for the genotypic ratio. 100% Yellow Flowers for the phenotypic ratio assuming complete dominance. 100% Yellow Flowers for the phenotypic ratio assuming complete dominance. BioEOC Biomolecules & Membranes Part 5 26

Punnett Square Mom is Yy and Dad is Yy. Mom is Yy and Dad is Yy. You know what to do. You know what to do. Go! Go! BioEOC Biomolecules & Membranes Part 5 27

Punnett Square 25% YY, 50% Yy, and 25% yy is the genotypic ratio. 25% YY, 50% Yy, and 25% yy is the genotypic ratio. 75% Yellow and 25% Red is the phenotypic ratio. 75% Yellow and 25% Red is the phenotypic ratio. BioEOC Biomolecules & Membranes Part 5 28

Incomplete Dominance This incomplete dominance pattern can be identified when three different phenotypes are apparent. This incomplete dominance pattern can be identified when three different phenotypes are apparent.incomplete dominance incomplete dominance This occurs when RR produces a red flower. This occurs when RR produces a red flower. RW produces a pink flower. RW produces a pink flower. WW produces a white flower. WW produces a white flower. BioEOC Biomolecules & Membranes Part 5 29

Incomplete Dominance The genotypic ratio is 1 RR to 2 RW to 1 WW. The genotypic ratio is 1 RR to 2 RW to 1 WW. The phenotypic ratio is 1 red flower, 2 pink flowers, and 1 white flower. The phenotypic ratio is 1 red flower, 2 pink flowers, and 1 white flower. Animal fur patterns can also be explained using incomplete dominance patterns. Animal fur patterns can also be explained using incomplete dominance patterns. BioEOC Biomolecules & Membranes Part 5 30

Codominant Patterns Codominance patterns occur when each allele codes for a specific phenotype. Codominance patterns occur when each allele codes for a specific phenotype. Codominance Human Blood Types are the most common example. Human Blood Types are the most common example. Human Blood Types Human Blood Types I A I A and I A I O would have Blood Type A. I A I A and I A I O would have Blood Type A. I A I B would have Blood Type AB. I A I B would have Blood Type AB. I B I B and I B I O would have Blood Type B. I B I B and I B I O would have Blood Type B. I O I O would have Blood Type O. I O I O would have Blood Type O. BioEOC Biomolecules & Membranes Part 5 31

Codominance Patterns Blood Type A = I A I A and I A I O Blood Type A = I A I A and I A I O Blood Type AB = I A I B Blood Type AB = I A I B Blood Type B = I B I B and I B I O Blood Type B = I B I B and I B I O Blood Type O = I O I O Blood Type O = I O I O Phenotypic Ratio for this cross is 1 Blood Type AB, 1 Blood Type A, 1 Blood Type B, and 1 Blood Type O. Phenotypic Ratio for this cross is 1 Blood Type AB, 1 Blood Type A, 1 Blood Type B, and 1 Blood Type O. BioEOC Biomolecules & Membranes Part 5 32

Sex-Linked Traits Genes/alleles can also be found on the sex chromosomes, which is why they are sex-linked. Genes/alleles can also be found on the sex chromosomes, which is why they are sex-linked.sex-linked Males have XY in which the X chromosome contains much more genes than the Y chromosome. Males have XY in which the X chromosome contains much more genes than the Y chromosome. Females have XX in which both X chromosomes contain several genes. Females have XX in which both X chromosomes contain several genes. This means that some genetic traits are passed down to only certain sexes and not others. This means that some genetic traits are passed down to only certain sexes and not others. BioEOC Biomolecules & Membranes Part 5 33

Sex-Linked Traits A common example of a sex-linked trait is red-green color blindness. A common example of a sex-linked trait is red-green color blindness.red-green color blindnessred-green color blindness Male with normal vision = X R Y Male with normal vision = X R Y Male with red-green color blindness = X r Y Male with red-green color blindness = X r Y Female with normal vision = X R X R Female with normal vision = X R X R Female carrier with normal vision = X R X r Female carrier with normal vision = X R X r Female with red-green color blindness = X r X r Female with red-green color blindness = X r X r BioEOC Biomolecules & Membranes Part 5 34

Sex-Linked Trait Phenotypic ratio would be: 50 % female carrier with normal vision, 50 % male with normal vision even though Dad is a red-green color blind male. Phenotypic ratio would be: 50 % female carrier with normal vision, 50 % male with normal vision even though Dad is a red-green color blind male. If you need to, feel free to view the videos using the links on the next slide and practice doing more of these Punnett Squares. If you need to, feel free to view the videos using the links on the next slide and practice doing more of these Punnett Squares. BioEOC Biomolecules & Membranes Part 5 35

Punnett Square DIY Videos For more complex Punnett Squares view these: For more complex Punnett Squares view these: ‪ Dihybrid Crosses and a Cat Called "Moo” ‬ ‪ Dihybrid Crosses and a Cat Called "Moo” ‬ Dihybrid Crosses and a Cat Called "Moo” ‬ Dihybrid Crosses and a Cat Called "Moo” ‬ Multiple Alleles (ABO Blood Types) and Punnett Squares ‬ Multiple Alleles (ABO Blood Types) and Punnett Squares ‬ Multiple Alleles (ABO Blood Types) and Punnett Squares ‬ Multiple Alleles (ABO Blood Types) and Punnett Squares ‬ Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis! ‬ Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis! ‬ Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis! ‬ Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis! ‬ ‪ Punnett Squares and Sex-Linked Traits ‬ ‪ Punnett Squares and Sex-Linked Traits ‬ Punnett Squares and Sex-Linked Traits ‬ Punnett Squares and Sex-Linked Traits ‬ BioEOC Biomolecules & Membranes Part 5 36

So, what about… …our purple plant? …our purple plant? Let’s imagine that it blooms in the Spring. Let’s imagine that it blooms in the Spring. You manage to collect the pollen from some of the flowers and you pollinate some of the other flowers in a process called cross-pollination. You manage to collect the pollen from some of the flowers and you pollinate some of the other flowers in a process called cross-pollination. If purple is a recessive trait, make predictions on genotypic and phenotypic ratios for the seedlings. If purple is a recessive trait, make predictions on genotypic and phenotypic ratios for the seedlings. BioEOC Biomolecules & Membranes Part 5 37

BTW By the way, we call the parent generation = P1. By the way, we call the parent generation = P1. The grandparent generation = P2. The grandparent generation = P2. The kids/seedlings = F1. The kids/seedlings = F1. The grandkids/grand-seedlings = F2. The grandkids/grand-seedlings = F2. BioEOC Biomolecules & Membranes Part 5 38

Did you solve the cross- pollination question? If the pollen came from a flower that had the recessive purple trait and it was used to cross- pollinate another flower that had the recessive purple trait, you are dealing with a pp X pp Punnett square. If the pollen came from a flower that had the recessive purple trait and it was used to cross- pollinate another flower that had the recessive purple trait, you are dealing with a pp X pp Punnett square. Both parents (male = pollen from the stamen; female = stigma of the flower) are purple, which is a recessive trait. (Assume complete dominance) Both parents (male = pollen from the stamen; female = stigma of the flower) are purple, which is a recessive trait. (Assume complete dominance) BioEOC Biomolecules & Membranes Part 5 39

Result This means that all seedlings from this cross- pollination event will have purple parts. This means that all seedlings from this cross- pollination event will have purple parts. Now, what if that did not happen and, yet, you would like to somehow have purple plant parts? Now, what if that did not happen and, yet, you would like to somehow have purple plant parts? Well, that’s a molecular biology thing, which we will cover next time. Well, that’s a molecular biology thing, which we will cover next time. BioEOC Biomolecules & Membranes Part 5 40

Review We discussed at Mendelian Genetics and how to complete a variety of Punnett Squares. We discussed at Mendelian Genetics and how to complete a variety of Punnett Squares. We discussed genotype, phenotype, ratios, and other little details that will hopefully let you understand how humans have been able to domesticate a wide variety of different species throughout history. We discussed genotype, phenotype, ratios, and other little details that will hopefully let you understand how humans have been able to domesticate a wide variety of different species throughout history. BioEOC Biomolecules & Membranes Part 5 41

The End BioEOC Biomolecules & Membranes Part 5 42