Peas show easily observed variations in a number of characters, such as pea shape and flower color.
Many of the observable characters that vary in pea plants are controlled by single genes.
Peas have an unusually long generation time.
It is possible to control matings between different pea plants.
It is possible to obtain large numbers of progeny from any given cross.
A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations
A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents.
A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.
A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only for one.
The blending model of genetics
The mistakes made by Mendel
A dihybrid cross
No genes interacted to produce the parental phenotype
One phenotype was completely dominant over another
Different genes interacted to produce the parental phenotype
Each allele affected phenotypic expression
The traits blended together during fertilisation
Genes are composed of DNA
Traits are inherited in discrete units, and are not the results of blending
An organism that is homozygous for many recessive traitsis at a disadvantage
There is considerable genetic variation in garen peas
Recessive genes occur more frequently in the F1 than do dominant ones.
That the parents were both heterozygous.
That each offspring has the same alleles.
That the parents were true-breeding for contrasting traits.
That a blending of traits has occurred.
Each of the traits is controlled by single genes.
The genes controlling the characters obey the law of independent assortment.
Four genes are involved.
Sixteen different phenotypes are possible.
Each of the genes controlling the characters has two alleles.
Parental traits that were not observed in the F1 reappeared in the F2.
He obtained very few F1 progeny, making statistical analysis difficult.
Analysis of the F1 progeny would have allowed him to discover the law of segregation, but in the law of independent assortment.
The dominant phenotypes were visible in the F2 generation, but not in the F1.
Many of the F1 progeny died.
Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.
The traits were lost in the F1 due to blending of the parental traits.
Members of the F1 generation had only one allele for each character, but members of the F2 had two alleles for each character.
New mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1.
The mechanism controlling the appearance of traits was different between the F1 and the F2 plants.
It is a method that can be used to determine the number of chromosomes in a plant.
It states that each of two alleles for a given trait segregate into different gametes.
It can account for the 3:1 ratio seen in the F2 generation of Mendel's crosses.
It can be used to predict the likelihood of transmission of certain genetic diseases within families.
It can be explained by the segregation of homologous chromosomes during meiosis.
The diploid number of chromosomes in the pea plants was 7.
None of the traits obeyed the law of segregation.
All of the genes controlling the traits were located on the same chromosome.
All of the genes controlling the traits behaved as if they were on different chromosomes.
The formation of gametes in plants occurs by mitosis only.
His experiments with the breeding of plants such as peas
The understanding of particulate inheritance he learned from renowned scientists of his time
His discussions of heredity with his colleagues at major universities
His reading of the scientific literature current in the field
His reading and discussion of Darwin's Origin of Species
Anaphase of mitosis
Prophase I of meiosis
Anaphase I of meiosis
Metaphase I of meiosis
Prophase II of meiosis
Alignment of tetrads at the equator
Synapsis of homologous chromosomes
Separation of cells at telophase
separation of homologs at anaphase
TtRr–dwarf and pink
TTRR–tall and red
Ttrr–dwarf and white
TtRr–tall and red
TtRr–tall and pink
Both genetic and environmental factors contribute to the disease.
It has many different symptoms.
It is caused by a gene with a large number of alleles.
It tends to skip a generation.
It affects a large number of people.
Have increased resistance to malaria.
Produce normal and abnormal hemoglobin.
Are usually healthy.
Are heterozygous for the sickle-cell allele.
All of the above
A procedure that could test for the carrier status of the foetus
Lowest risk procedure that would provide the most reliable information
The procedure that can test for the greatest number of traits at once
A procedure that provides a 3D image of the foetus
The procedure that can be performed at the earliest time in the pregnancy
To follow the segregation of the allele during meiosis
To introduce a normal allele into deficient newborns
To design a test for identifying heterozygous carriers of the allele
To test school-age children for the disorder
To screen all newborns of an at-risk population
The malarial parasite changing the allele
Mendel's law of segregation
Darwin's observations of competition
Mendel's law of independent assortment
Darwin's explanation of natural selection
Feed them the substrate that can be metabolised into this amino acid.
Transfuse the patients with blood from unaffected donors.
Feed the patients the missing enzymes in a regular cycle, i.e., twice per week.
Regulate the diet of the affected persons to severely limit the uptake of the amino acid.
All cases must occur in relatives; therefore, there must be only one mutant allele.
Each patient will have had at least one affected family member in a previous generation.
Successive generations of a family will continue to have more and more cases over time.
The disorder may be due to mutation in a single protein-coding gene.
The disease is autosomal dominant.
A new mutation
The child has a different allele of the gene than the parents.
The condition skipped a generation in the family.
One of the parents has very mild expression of the gene.
The mother carries the gene but does not express it at all.