7th Science Genetics Outline Flashcards
_______ is the passing of traits from parents to offspring.
Heredity
In the 1850s, _______, an Austrian friar, performed experiments that helped answer questions about how traits are inherited.
Gregor Mendel
_______ is the study of how traits pass from parents to offspring.
Genetics
Pea plants were ideal for genetic studies because they ________ quickly; they have easily observed traits; and the experimenter can control which pairs of plants ______ .
reproduce,reproduced
Mendel controlled which plants ________ other plants.
Pollinated
When a(n) ________ plant self-pollinates, it always produces offspring with traits that match the parent.
True breeding
By _________ plants himself, Mendel was able to select which plants pollinated other plants.
Cross pollinating
With each cross-pollination Mendel did, he recorded the traits that appeared in the __________
Offspring
Mendel’s crosses between true-breeding plants with purple flowers produced plants with only _______ flowers. Crosses between true-reeding plants, with white flowers produced plants with only ______ flowers.
purple;white
Crosses between true-breeding plants with purple flowers and true-breeding plants with white flowers produced plants with only _______ flowers.
purple
The first generation purple-flowering plants are called ______ plants.
hybrid
When Mendel cross pollinated two hybrid plants, the trait that had disappeared in the first generation always _________ in the second generation.
reappeared
Mendel analyzed the data from many experiments on seven different __________. he always noted a 3:1 _________; for example, purple flowers grew from hybrid crosses ________ times more often than white flowers.
traits;ratio;three
After analyzing the results of his experiments, Mendel concluded that two _________ control each trait.
genetic factors
Mendel also proposed that, when organisms reproduce, each _________, sperm or egg, contributes one factor for each trait.
reproductive cell
A genetic factor that blocks another genetic factor is ______.
dominant trait
A genetic factor that is blocked by the presence of a dominant factor is called ________.
recessive trait
For the second generation, Mendel cross-pollinated two hybrids with purple flowers. About _______ percent of the second generation plants had purple flowers. These plants had at least one ________ factor. _________ percent of the second-generation plants had white flowers. These plants had the same two ______ factors.
75%;dominant; 25%;recessive
Inside each cell is a nucleus that contains threadlike structures called ________.
chromosomes
Mendel’s factors are parts of chromosomes, and each cell in the offspring contains chromosomes from both ______.
parents
A(n) __________ is a section on a chromosomes that has genetic information for one trait.
gene
The different forms of a gene are called ______.
alleles
Geneticists refer to how a trait appears, or is expressed, as the trait’s ______.
phenotype
The two alleles that control the phenotype of a trait are called the trait’s _______.
genotype
In genetics, _________ letters represent dominant alleles, and _________ letters represent recessive alleles.
upper case; lower case
When two alleles of a gene are the same, ins genotype is _________.
homozygous
If two alleles of a gene are different, its genotype is _______.
Hetrosyzgus
In a situation based on chance, such as flipping a coin, the chance of getting a certain outcome can be represented by a(n) __________ such as 50:50, or 1:1.
ratio
A(n) __________ is a model that is used to predict possible genotypes and phenotypes of offspring.
Punnett Square
To create a Punnett square, you need to know the _______ of both parents.
genotypes
If you count large numbers of ________ from a particular cross, the overall ratio will be close to the ratio predicted by the Punnett square.
offspring
A(n) _________ is a diagram that shows phenotypes of genetically related family members. It also gives class about their ________.
pedigree, heredity
Alleles show _______ when the offspring’s phenotype is a bland of the parents’ phenotype.
incomplete dominance
Alleles show _________ when both alleles can be observed in a phenotype.
codominance
Unlike the genes in Mendel’s pea plants, some genes have _________ alleles.
multiple
ABO ________ type is a trait that is determined by multiple alleles.
blood
___________ occurs when multiple genes determine the phenotype of a trait.
Polygenic inheritance
Human eye _______ is an example of polygenic inheritance.
color
________ are not the only factor that can affect phenotypes. An organism’s ____________ can also affect its phenotype.
Genes; environment
The flower color of one type of hydrangea is determined by the ________ in which the hydrangea grows.
soil
________ choices can affect a person’s phenotype.
Healthful
How a trait appears or is expressed?
phenotype
Name some examples of phenotypes.
blue eyes, brown hair, red flowers, horns
The two alleles that control the phenotype of a trait?
genotype
What are genotypes represented by?
one uppercase and one lowercase letter
For example what does BB, Bb and bb represent?
brown or blue eye color
Uppercase letters represent what type of alleles?
Dominant traits
For example, what does BB and Bb represent?
Dominant brown eye color
Lowercase letters represent what type of alleles?
Recessive traits
For example, what doe bb represent?
Recessive blue eye color
What does home mean?
the same
What is it called when two alleles of a gene are the same, for example BB or bb?
homozygous genotypes
What does heater mean?
different
What is it called when two alleles of a gene are different, for example Bb?
heterozygous genotypes
What is a way to model inheritance to determine possible genotypes and phenotypes of an organism based on the genotype of the parent organisms?
punnett square
