Genetic disorders
Down Syndrome got its name from who?
John Langdon Down
Used to predict the probability of offspring traits
Punnett squares
What is meiosis?
The process in which new gametes are formed.
Define the term trait
A trait is a characteristic or feature of an organism, such as eye color or height, that can be inherited.
Types of reproduction
Sexual and Asexual
What is a physical effect of Down Syndrome?
Flattened facial profile, upward slanting eyes, low muscle tone, shorter stature, and a single crease across the palm, heart defects, etc.
Monohybrid cross of two heterozygous, chances of phenotype recessive?
25%
How many daughter cells are created as a result of Meiosis?
4
What is the difference between genotype and phenotype?
Genotype is the genetic makeup (alleles) of an organism; phenotype is the observable physical or behavioral expression of those genes.
What kinds of organisms use vegetative reproduction?
Plants
What is the cause of Turner Syndrome?
It is caused by the complete or partial absence of one X chromosome.
In a Punnett square, what letters represent alleles inherited from each parent?
Capital and lowercase letters
What are some things that happen in prophase I?
During this phase of meiosis I, homologous chromosomes pair up to form tetrads and crossing over occurs between non-sister chromatids.
Explain the difference between dominant and recessive traits.
A dominant trait is expressed when at least one dominant allele is present, while a recessive trait is only expressed when both alleles are recessive.
What is budding?
A new organism grows from the side of the parent and may detach.
What causes tall stature and reduced testosterone production in males?
Klinefelter Syndrome
What type of cross involves two traits at once?
A Dihybrid cross
Does the S phase happen during Meiosis?
False
What is a homozygous organism?
An organism with two identical alleles for a trait (e.g., AA or aa).
Why does sexual reproduction require meiosis?
Meiosis creates gametes with half the number of chromosomes, allowing fertilization to restore the full set.
What is Nondisjunction?
Nondisjunction is the failure of chromosomes to separate properly during cell division.
In a monohybrid cross, a homozygous dominant parent is crossed with a homozygous recessive parent. What percent of offspring will be heterozygous?
100%
During this phase of meiosis II, sister chromatids are pulled apart to opposite poles of the cell by spindle fibers.
Anaphase II
What is a heterozygous organism?
An organism with two different alleles for a trait (e.g., Aa).
Why do organisms that regenerate often also reproduce using fragmentation?
Their ability to regrow lost parts allows those parts to form new individuals.