Monohybrid practice problems for each of the following show...

Monohybrid Practice Problems. For each of the following, show the Punnett Square and give the Genotype AND Phenotype for each on your own paper. In humans, brown eyes are dominant over blue eyes. What type of offspring would you expect if you crossed a heterozygous brown-eyed person to a heterozygous brown-eyed person? 2. A widow's peak hairline is dominant to a straight hairline. Cross a heterozygous widow's peak hairline person to a straight hairline person. In humans, premature gray hair is dominant over normal hair coloring. Cross a homozygous premature gray-haired person to a homozygous normal-haired person. In humans, tongue rolling is dominant to non-tongue rolling. What would be the expected type of offspring if a homozygous tongue roller was crossed to a heterozygous tongue roller? Brown hair is dominant over light-colored hair. Cross two light-haired people. In a certain plant, yellow fruit is dominant to white fruit. A heterozygous plant with yellow fruit is crossed with a plant with white fruit. Determine the probable offspring. In a certain animal, black fur is dominant to white fur. Determine the possible offspring from crosses between: a. Homozygous black x white b. Heterozygous black x heterozygous black In garden peas, round peas are dominant to wrinkled peas. If you crossed a homozygous dominant and homozygous recessive, what would be the genotype and phenotype of the offspring? 9. In corn, normal kernels are dominant to waxy kernels. If you crossed a waxy kernel plant to a heterozygous normal plant, what type of seeds would be produced? 10. Tall plants are dominant to short plants in the garden pea plant. Cross a heterozygous tall plant to a heterozygous tall plant.

Transcript

00:01 Hello students, today will be solving a question in biology.

00:03 As you can see from the question, they've given us that for each of the following monohybred crosses, show the punet square and give it a genotype and phenotype for each of your own.

00:13 Okay, so this question is about monohybrid cross and they're asking us using pannets square, using pannets square, we have to demonstrate the expression of genes and give them the genotype as well as the phenotype of the progeny of date.

00:41 So this question is about monohybrid cross.

00:46 Now the first question they've given us is human eye color, okay? human eye color and the cross they've given us is between a heterozygous brown person, okay? a heterozygous brown eye which means that person, has brown eyes but the condition the genotype of that brown eye is hetrozygous and the other person is also the same who is heterozygous for brown eyes so we can see that both parents is genotype can be written at b so this b represents the dominant ala capital represents the dominant and the small b represents the recessive the capital b represents the dominant and the small represents the resistive.

01:44 So now we have to construct upon its square words.

01:49 So b b crossing with b b b we'd be getting the following outcomes in this generation which would be b b b b b and b b so here we can see that there is one dominant homozygous okay that is one homozygous dominant we have two heterozygous and then there is also a homozygous recessive okay so in this cross we've obtained one homozygous dominant and one homozygous resistive and then we've also obtained normal two heterozygous we've obtained two hetrozygous which has a similar genotype as similar to path.

02:47 So the genotypic percentages are genotypic percentages.

02:59 The genotypic percentages are different for each and every genotype.

03:04 As we can see here, there are three types of genotype here.

03:07 The first one is bb.

03:09 Since there is only one bb in the given cross, we can say that there is 1 by 4.

03:14 Of bb which is 25 percentage.

03:18 This second genotype that we can identify is the heterozygous one.

03:23 Okay.

03:25 Since that is two heterozygous one in our cross, we can say that we can say this two by four which accounts to 50 percentage.

03:34 Similarly, the third genotype given to us is the homozygous receptor and an amount of homozygous versus have in our cross is again just one.

03:42 So, it is 1 by 4 giving us 25 percentages.

03:47 So, this is the genotypic percentages of all the genotype obtained in the f1 generation of this cross.

03:54 Now we have to find the phenotypic percentages.

03:58 Next is our phenotypic percentages.

04:07 As we can see here, when dominant and recessive alleles are present together, the dominant allel will suppress and will mask the expression of the recessive allele.

04:17 Therefore, we'll be only seeing the dominant character in all the heterogeneous one.

04:22 Only dominant is expressed in all heterozygous species.

04:33 This is because the dominant allel masks the recessive alleles.

04:38 The dominant allel mask the recessive allele.

04:43 That's why the recessive genes are.

04:45 Are not expressed in the final outcome.

04:49 So now we have to find our phenotypic percentages.

04:53 So the dominant character here is the brown eye.

04:58 The dominant trait here is our presence of brown eyes.

05:06 But if the dominance is brown, then the recessive character is nothing but are blue eyes.

05:15 Brown eyes and brunette hair is dominant where the blue eyes and blonde hair is recessive in human beings so therefore there is three organisms the tree offspring have brown eyes okay therefore it is three by four seventy five percentage but on the other hand there is only one organism or only one member of in this generation that has blue eyes and which is 1 by 4 giving us 25 percentage...

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