Bio-ch.14 assessments
How can you use karyotypes to identify a species?
A karyotype shows the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size. A haploid sperm, carrying just 23 chromosomes, fertilizes a haploid egg, also with 23 chromosomes. The resulting diploid cell develops into a new individual and carries the full complement of 46 chromosomes---two sets of 23
What is the relationship between the environment and phenotype?
An individual's actual phenotype is determined by its environment as well as its genes.
Explain how sex-linked traits are inherited?
Becuase the X and Y chromosomes determine sex, the genes located on them show a pattern of inheritance called sex-linkage.
What techniques are used to study human DNA?
By using tools that cut, separate, and then replicate DNA base by base, scientists can now read the base sequences in DNA from any cell
How do small changes in DNA molecules affect human traits?
Changes in a gene's DNA sequence can change proteins by altering their amino acid sequences, which may directly affect one's phenotype
What are the effects of errors in meiosis?
If nondisjunction occurs during meiosis, gametes with an abnormal number of chromosomes may result, leading to a disorder of chromosomes numbers
what does incomplete dominance mean? Give an example
Incomplete dominance means that an allele is neither dominant nor recessive. An example would be the alleles for the genes that decide the color trait of a Mirabilis plant.
How can a small change in a person's DNA cause a genetic disorder?
It can affect the structure and function of a protein, which may cause a disorder.
How do molecular biologists identify genes in sequences of DNA?
Molecular biologists identify genes in sequences of DNA by using tools to cut, separate, and then replicate the base sequences so they can be able to read them.
How does nondisjunction cause chromosomal disorders?
Nondisjunction is when chromosomes fail to separate, causing gametes to have abnormal numbers of chromosomes.
How do genetic disorders such as CF support the theory of evolution?
People with one CF allele have an advantage of being less likely to contract typhoid. This helped them survived and pass their trait to their offspring.
Design an experiment to determine whether the pink flowers of petunia plants result from incomplete dominance.
Separate different plants and test the different colors and cross pollination
How is shotgun sequencing similar to doing a jigsaw puzzle?
Shotgun sequencing is similar to doing a jigsaw puzzle because the sequence is cut into random fragments and then pieced back together after determining the pieces's base sequence.
What does a pedigree show?
Shows the presence or absence of a trait according to the relationships between parents, siblings, and offspring.
What is The Human Genome Project
The Human Genome Project is a multibillion, international project where mankind undertook the challenge of sequencing all 3 billion genes in the human body.
Why would the Y chromosome be unlikely to contain any of the genes that are absolutely necessary for survival?
The Y chromosome is much smaller than the X chromosome and contains only about 140 genes, most of which are associated with male sex determination and sperm development.
Judge the potential impact of the Human Genome Project on both scientific thought and society. How might the project be used to benefit humankind? What potential problems might it create?
The impact of the Human Genome Project is unimaginable. For the first time in human history, scientists have learned every single gene that a human can get (so far). This can benefit mankind by allowing tests to screen for genetic illnesses, allowing the person to be treated earlier so they may live a longer life. The problems with this can also be that insurance agencies can deny people if their genome turns out to be unhealthy, even though that is illegal at the moment.
What types of human chromosomes in a karyotype
The normal human karyotypes contain 22 pairs of autosomal chromosomes and 1 pair of sex chromosomes (allosomes). Normal karyotypes for females contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY.
If a woman with type O blood and a man with type AB blood have children, what are the possible genotypes?
The possible genotypes are: A, B, AB, and O.
What might be the result of an exceptionally hot spring on wing pigmentation in the western white butterfly?
The wings would have less pigmentation
multiple alleles
a gene that has more than two alleles
What are autosomes ?
chromosomes that are not a sex chromosome" also called autosomal
What were the goals of the Human Genome Project, and what have we learned so far
it was a 13 year, international effort with the main goals of sequencing all 3 billion base pairs of human DNA and identifying all human genes, it pinpointed genes and associated particular sequences in those genes with numerous disease and disorders. It also identified about three million locations where single-based DNA differences occur in humans
What patterns of inheritance do human traits follow
many human traits follow a pattern of simple dominance, alleles for many human genes display codominant inheritance, because the x and y chromosomes determine sex, the genes located on them show a pattern of inheritance called sex-linkage
What determines whether a person is male or female?
sex chromosomes, X and Y chromosomes; Females have two X chromosomes; males have one X and one Y chromosome
incomplete dominance
situation in which one allele is not completely dominant over another allele
codominance
situation in which the phenotypes produced by both alleles are completely expressed
what are some exceptions to Mendel's
some alleles are neither dominant nor recessive, many genes exist in several different forms and are therefore said to have multiple alleles, many traits are produced by the interaction of several genes
how can pedigrees be used to analyze human inheritance?
the information gained from pedigree analysis makes it possible to determine the nature of genes and alleles associated with inherited human traits
polygenic trait
trait controlled by two or more genes
