TedTest

From the Ted Talk by Hortensia Jiménez Díaz: How Mendel's pea plants helped us understand genetics

Unscramble the Blue Letters

These days stestnciis know how you inherit characteristics from your parents. They're able to calculate probabilities of having a sicpfeic trait or getting a genetic disease according to the inamfrotoin from the parents and the fmaily history. But how is this possible? To understand how traits pass from one linivg being to its descendants, we need to go back in time to the 19th century and a man named Gregor Mendel. Mendel was an Austrian monk and biologist who loved to work with plants. By breeding the pea plants he was goniwrg in the monastery's garden, he discovered the principles that rule heredity. In one of most classic examples, Mendel combined a purebred yellow-seeded plant with a perrbued green-seeded plnat, and he got only yellow seeds. He called the yellow-colored tairt the dmaonint one, because it was expressed in all the new seeds. Then he let the new yellow-seeded hybrid plants self-fertilize. And in this second generation, he got both yellow and green seeds, which meant the green trait had been hidden by the dominant yellow. He called this hidden trait the recessive trait. From those results, Mendel inferred that each trait depends on a pair of factors, one of them cmnoig from the mother and the other from the fehtar. Now we know that these factors are called alleles and represent the different variations of a gene. Depending on which type of allele Mendel found in each seed, we can have what we call a huzoomogys pea, where both alleles are identical, and what we call a hzogyetuores pea, when the two alleles are different. This combination of alleles is known as gneopyte and its result, being yoellw or green, is called phenotype. To clearly visualize how aeellls are distributed amongst descendants, we can a diagram called the pnutnet square. You place the different alleles on both axes and then figure out the possible coiioanbtnms. Let's look at Mendel's peas, for example. Let's write the dominant yellow allele as an uppercase "Y" and the recessive green allele as a lowercase "y." The uppercase Y always overpowers his leaswcroe friend, so the only time you get green bebais is if you have lowercase Y's. In Mendel's first generation, the yellow homozygous pea mom will give each pea kid a yellow-dominant alllee, and the green homozygous pea dad will give a green-recessive allele. So all the pea kids will be yellow heterozygous. Then, in the second generation, where the two heterozygous kids marry, their babies could have any of the three possible genotypes, showing the two possible phenotypes in a three-to-one proportion. But even peas have a lot of characteristics. For example, besides being yellow or green, peas may be round or wnielrkd. So we could have all these possible combinations: round yellow peas, round green peas, wrinkled yellow peas, wrinkled geren peas. To clcultaae the proirtoopns for each genotype and phenotype, we can use a Punnett square too. Of course, this will make it a little more complex. And lots of things are more complicated than peas, like, say, people. These days, scientists know a lot more about genetics and heredity. And there are many other ways in which some characteristics are inherited. But, it all started with mdneel and his peas.

Open Cloze

These days __________ know how you inherit characteristics from your parents. They're able to calculate probabilities of having a ________ trait or getting a genetic disease according to the ___________ from the parents and the ______ history. But how is this possible? To understand how traits pass from one ______ being to its descendants, we need to go back in time to the 19th century and a man named Gregor Mendel. Mendel was an Austrian monk and biologist who loved to work with plants. By breeding the pea plants he was _______ in the monastery's garden, he discovered the principles that rule heredity. In one of most classic examples, Mendel combined a purebred yellow-seeded plant with a ________ green-seeded _____, and he got only yellow seeds. He called the yellow-colored _____ the ________ one, because it was expressed in all the new seeds. Then he let the new yellow-seeded hybrid plants self-fertilize. And in this second generation, he got both yellow and green seeds, which meant the green trait had been hidden by the dominant yellow. He called this hidden trait the recessive trait. From those results, Mendel inferred that each trait depends on a pair of factors, one of them ______ from the mother and the other from the ______. Now we know that these factors are called alleles and represent the different variations of a gene. Depending on which type of allele Mendel found in each seed, we can have what we call a __________ pea, where both alleles are identical, and what we call a ____________ pea, when the two alleles are different. This combination of alleles is known as ________ and its result, being ______ or green, is called phenotype. To clearly visualize how _______ are distributed amongst descendants, we can a diagram called the _______ square. You place the different alleles on both axes and then figure out the possible ____________. Let's look at Mendel's peas, for example. Let's write the dominant yellow allele as an uppercase "Y" and the recessive green allele as a lowercase "y." The uppercase Y always overpowers his _________ friend, so the only time you get green ______ is if you have lowercase Y's. In Mendel's first generation, the yellow homozygous pea mom will give each pea kid a yellow-dominant ______, and the green homozygous pea dad will give a green-recessive allele. So all the pea kids will be yellow heterozygous. Then, in the second generation, where the two heterozygous kids marry, their babies could have any of the three possible genotypes, showing the two possible phenotypes in a three-to-one proportion. But even peas have a lot of characteristics. For example, besides being yellow or green, peas may be round or ________. So we could have all these possible combinations: round yellow peas, round green peas, wrinkled yellow peas, wrinkled _____ peas. To _________ the ___________ for each genotype and phenotype, we can use a Punnett square too. Of course, this will make it a little more complex. And lots of things are more complicated than peas, like, say, people. These days, scientists know a lot more about genetics and heredity. And there are many other ways in which some characteristics are inherited. But, it all started with ______ and his peas.

Solution

growing
mendel
combinations
allele
wrinkled
yellow
proportions
scientists
heterozygous
purebred
living
homozygous
calculate
information
dominant
coming
genotype
father
green
plant
specific
trait
punnett
family
alleles
lowercase
babies

Original Text

These days scientists know how you inherit characteristics from your parents. They're able to calculate probabilities of having a specific trait or getting a genetic disease according to the information from the parents and the family history. But how is this possible? To understand how traits pass from one living being to its descendants, we need to go back in time to the 19th century and a man named Gregor Mendel. Mendel was an Austrian monk and biologist who loved to work with plants. By breeding the pea plants he was growing in the monastery's garden, he discovered the principles that rule heredity. In one of most classic examples, Mendel combined a purebred yellow-seeded plant with a purebred green-seeded plant, and he got only yellow seeds. He called the yellow-colored trait the dominant one, because it was expressed in all the new seeds. Then he let the new yellow-seeded hybrid plants self-fertilize. And in this second generation, he got both yellow and green seeds, which meant the green trait had been hidden by the dominant yellow. He called this hidden trait the recessive trait. From those results, Mendel inferred that each trait depends on a pair of factors, one of them coming from the mother and the other from the father. Now we know that these factors are called alleles and represent the different variations of a gene. Depending on which type of allele Mendel found in each seed, we can have what we call a homozygous pea, where both alleles are identical, and what we call a heterozygous pea, when the two alleles are different. This combination of alleles is known as genotype and its result, being yellow or green, is called phenotype. To clearly visualize how alleles are distributed amongst descendants, we can a diagram called the Punnett square. You place the different alleles on both axes and then figure out the possible combinations. Let's look at Mendel's peas, for example. Let's write the dominant yellow allele as an uppercase "Y" and the recessive green allele as a lowercase "y." The uppercase Y always overpowers his lowercase friend, so the only time you get green babies is if you have lowercase Y's. In Mendel's first generation, the yellow homozygous pea mom will give each pea kid a yellow-dominant allele, and the green homozygous pea dad will give a green-recessive allele. So all the pea kids will be yellow heterozygous. Then, in the second generation, where the two heterozygous kids marry, their babies could have any of the three possible genotypes, showing the two possible phenotypes in a three-to-one proportion. But even peas have a lot of characteristics. For example, besides being yellow or green, peas may be round or wrinkled. So we could have all these possible combinations: round yellow peas, round green peas, wrinkled yellow peas, wrinkled green peas. To calculate the proportions for each genotype and phenotype, we can use a Punnett square too. Of course, this will make it a little more complex. And lots of things are more complicated than peas, like, say, people. These days, scientists know a lot more about genetics and heredity. And there are many other ways in which some characteristics are inherited. But, it all started with Mendel and his peas.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
dominant yellow	2
punnett square	2
homozygous pea	2

Important Words

allele
alleles
austrian
axes
babies
biologist
breeding
calculate
call
called
century
characteristics
classic
combination
combinations
combined
coming
complex
complicated
dad
days
depending
depends
descendants
diagram
discovered
disease
distributed
dominant
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expressed
factors
family
father
figure
friend
garden
gene
generation
genetic
genetics
genotype
genotypes
give
green
gregor
growing
heredity
heterozygous
hidden
history
homozygous
hybrid
identical
inferred
information
inherit
inherited
kid
kids
living
lot
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loved
lowercase
man
marry
meant
mendel
mom
monk
mother
named
overpowers
pair
parents
pass
pea
peas
people
phenotype
phenotypes
place
plant
plants
principles
probabilities
proportion
proportions
punnett
purebred
recessive
represent
result
results
rule
scientists
seed
seeds
showing
specific
square
started
time
trait
traits
type
understand
uppercase
variations
visualize
ways
work
wrinkled
write
yellow