AnswersDrive11th December 2019
sciencedaily
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What is an organism that has two different alleles for a trait?
An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous.
What is an allele whose trait always shows up in the organism when the allele is present?
the set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait. an allele whose trait always shows up in the organism when the allele is present. an allele that is masked when a dominant allele is present.
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What trait will be expressed if an organism has one dominant allele and one recessive allele?
Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait. One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin.
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What is the physical expression of a combination of alleles called?
Therefore, each fly will carry two alleles for the body color gene. Within an individual organism, the specific combination of alleles for a gene is known as the genotype of the organism, and (as mentioned above) the physical trait associated with that genotype is called the phenotype of the organism.
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What is not expressed when the dominant form of the trait is present?
letter is lowercase; the trait was not expressed when the dominant form of the trait was present. two alleles of a gene are the same. only the dominant allele is expressed; the recessive allele is present but unexpressed.
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What is a trait called when it is controlled by more than one gene?
A trait that is controlled by more than one gene is called polygenic which translates to "multiple genes". The genes work together to make one trait. Examples are skin, eye and hair color. In that case one gene has more than two alleles. An example of multiple alleles is blood type.
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What is an organism that has two identical alleles for a particular trait?
Organisms that have two identical alleles for a particular trait are said to be homozygous (AA) or (aa). 6. Organisms that have two different alleles for the same trait are heterozygous (Aa).
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When gametes are produced 2 alleles separate is called?
Ch 8 Vocabulary - Mendel & Heredity
| A | B |
|---|---|
| law of independent assortment (8-2) | the alleles of different genes separate independently of one another during gamete formation |
| law of segregation (8-2) | the two alleles for a trait separate when gametes are formed |
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What are the factors that control a trait?
Mendel reasoned that individual factors, or sets of genetic information, must control the inheritance of traits in peas. The factors that control each trait exist in pairs. The female parent contributes one factor, while the male parent contributes the other factor. Geneticists use letters to represent alleles.
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How many alleles do you have for a single trait?
When the gene for one trait exists as only two alleles & the alleles play according to Mendel's Law of Dominance, there are 3 possible genotypes (combination of alleles) & 2 possible phenotypes (the dominant one or the recessive one).
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What does it mean to say that an allele is dominant?
Recessive and dominant alleles. You will recall that genes have different forms called alleles. An allele can be recessive or dominant. A recessive allele only shows if the individual has two copies of the recessive allele.
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What does it mean when an organism is heterozygous?
An organism can be homozygous dominant, if it carries two copies of the same dominant allele, or homozygous recessive, if it carries two copies of the same recessive allele. Heterozygous means that an organism has two different alleles of a gene.
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What does the word allele mean?
An allele is one of the possible forms of a gene. Most genes have two alleles, a dominant allele and a recessive allele. If an organism is heterozygous for that trait, or possesses one of each allele, then the dominant trait is expressed.
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What is meant by a dominant trait?
Note. In humans, dark hair is a dominant trait; if one parent contributes a gene for dark hair and the other contributes a gene for light hair, the child will have dark hair.
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What are the alleles?
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
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What are the physical characteristics of an organism?
The physical appearance of an organism as distinguished from its genetic makeup. The phenotype of an organism depends on which genes are dominant and on the interaction between genes and environment. Compare genotype.
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Why did Thomas Hunt use fruit flies in his study?
Morgan wanted to understand heredity and mutation, which is genetic change. The Drosophila melanogaster, or fruit fly, is a good genetic research subject because it can be bred cheaply and reproduces quickly. Morgan was not the first to use the fruit fly as a subject, but his innovation and success popularized its use.
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What is an organism genetic makeup or allele combinations?
Genetics Vocabulary Quiz
| A | B |
|---|---|
| phenotype | An organism's physical appearance, or visible traits |
| genotype | An organism's genetic makeup, or allele combinations |
| heterozygous | Describes an organism that has two different alleles for a trait |
| homozygous | Describes an organism with two identical alleles for a trait |
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What is the dominant and recessive alleles?
The terms dominant and recessive describe the inheritance patterns of certain traits. For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent. An individual with one dominant and one recessive allele for a gene will have the dominant phenotype.
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What is an allele whose trait always shows up in the organism when the allele is present?
the set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait. an allele whose trait always shows up in the organism when the allele is present. an allele that is masked when a dominant allele is present.
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What is the genetic makeup of an organism?
The genotype is the part of the genetic makeup of a cell, and therefore of an organism or individual, which determines one of its characteristics (phenotype). The term was coined by the Danish botanist, plant physiologist and geneticist Wilhelm Johannsen in 1903.