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48 Cards in this Set
- Front
- Back
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What is inheritance (heredity)? |
The genetic transmission of characteristics from parent to offspring, such as hair, eye, and skin color |
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What is genotype? |
The genes present in the DNA of an organism (always 2 letters [result from sexual reproduction]; 1 gene from each parent = 2 genes [2 letters] for offspring) |
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What is homozygous? |
Genotype has 2 capital or 2 lowercase letters (aka purebred) |
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What is heterozygous? |
Genotype has 1 capital and 1 lowercase letter (aka hybrid) |
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What is phenotype? |
How the trait physically shows up in the organism; the observable traits present in an organism; what the organism looks like |
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What are alleles? |
Alternative forms of the same gene |
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What is dominant? |
When one allele masks the effect of another |
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What is recessive? |
The hidden/masked allele |
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What is genetics? |
The scientific study of heredity |
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Who was Gregor Mendel? |
An Austrian monk who studied genetics/heredity |
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What type of organism did Gregor Medel work with? |
Garden peas |
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Mendel knew that male flower parts produced ____________ and female flower parts produced ____________. |
Pollen; egg cells |
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What is fertilization? |
When sperm and egg cells join during sexual reproduction |
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What does it mean to say that pea plants are self-pollinating? |
They produce offspring identical to themselves |
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How did the offspring produced by self-pollinating plants relate to the parents? |
They are identical |
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What is cross pollination? |
Seeds with 2 different parents |
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What is a trait? |
A specific characteristic that varies between individuals |
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What is the P generation? |
Parental generation |
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What is the F1 generation? |
First filial generation |
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What was Mendel's first conclusion from his experiments with the 7 traits of the pea plants? |
biological inheritance is determined by factors that are passed from one generation to the next |
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What was Mendel's second conclusion? (2) |
Principle of dominance; some alleles are dominant and others are recessive |
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What did the reappearance of the recessive allele in the second generation suggest about the alleles? |
At some point the allele for shortness had been separated, or segregated, from the allele for tallness |
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What are Mendel's 3 Laws? |
1. Genes are passed from parents to their offspring 2. If two or more alleles of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive 3. In most sexually reproducing organisms, each adult has two copies of each gene. These genes are segregated from each other when gametes are segregated from each other when gametes are formed |
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While working with peas, Mendel questioned whether ______________________? |
The segregation of one pair of alleles affected the segregation of another pair of alleles (Does the gene that determined gene shape have anything to do with the gene for seed color? Are all round seeds yellow? Are all wrinkled seeds green?) |
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To answer the question of whether or not the segregation of one pair of alleles affects the segregation of another pair, Mendel performed a cross that followed two different genes as they passed from one generation to the next. What is this known as? |
Dihybrid cross |
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If the genotypes Rr and Yy were crossed, what would be the possible alleles? |
FOIL; (Rr)(Yy) RY Ry rY ry |
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In Mendel's experiment, the alleles for seed shape segregated (DEPENDENTLY/INDEPENDENTLY) of those for seed color. |
INdependently |
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Mendel's Principle of Independent Assortment states that... |
genes for different traits can segregate independently during the formation of gametes and do not influence each other's inheritance. This accounts for the many genetic variations observed in nature. |
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Incomplete dominance occurs when... |
one allele is not completely dominant over another allele |
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What is the heterozygous phenotype usually between? |
Between the 2 homozygous phenotypes |
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Codominance occurs when... |
both alleles are equally dominant |
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The heterozygous phenotype results from |
both alleles |
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Blood type (phenotype) A or B:
I^AI^A is (dominant/recessive) I^Ai is (dominant/recessive) |
Dominant; recessive |
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What are sex-linked genes? |
Genes located on the sex chromosomes X and Y; many sex-linked disorders are found on the X chromosome |
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Sex-linked genes are represented using _____ for females and _____ for males. |
XX; XY |
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Hemophilia is a(n)... |
X-linked recessive disorder; shown by X^hX^h for females and X^hY for males; if any X chromosome has a capital H, that individual does not have the disorder. |
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(Males/females) are most likely to be affected by a sex-linked disorder. Why? |
Males; because they only have one X chromosome; females must have both of their X chromosomes be affected, while males only need the one |
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What does Mendel's Law of Dominance state? |
That if 2 or more alleles of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive |
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What does Mendel's Law of Segregation state? |
Allele pairs segregate from each other during gamete formation |
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What is a gene? |
a sequence of DNA that codes for a protein
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Describe Mendel's experiment with pea plants. |
Questioned whether the segregation of one pair of alleles affected the segregation of another; performed a dihybrid cross; crossed true-breeding (homozygous) round, yellow peas (RRYY) with recessive wrinkled, green peas (rryy) |
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What is the purpose of Punnett Squares? |
To determine the probability of offspring having a particular genotype/phenotype |
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What is meant by multiple alleles? |
Genes are controlled by more than 2 alleles |
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What are polygenic traits? |
Traits controlled by more than one gene Ex. Skin color |
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What does Mendel's Law of Independent Assortment state? |
The alleles for different genes usually segregate independently from one another |
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What is a pedigree? |
A chart that can help trace the genotypes and phenotypes in a family; like a family tree |
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Pedigrees: What gender are squares? What gender are circles? What is a half circle/square? What is a shaded circle/square? |
Males; females; male/female carrier; affected male/female |
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What is the difference between an autosomal and a sex-linked pedigree? |
Autosomal pedigrees show that females are about just as affected as the males; sex-linked show that males are much more affected |
