Chapter 6 - Genetics Flashcards
Who founded gene theory? Who discovered that genes sit on chromosomes, and that the Y chromosome is only present in males?
Gregor Mendel and Nettie Stevens
How many chromosomes do fruit flies have? What is their haploid and diploid number?
Fruit flies have 4 pairs of chromosomes, meaning that their diploid cells have 2n=8 chromosomes. Their diploid cells have n=4 chromosomes.
What is the locus?
The position of a particular gene on a chromosome.
What is albinism? Is it dominant or recessive?
Is the gene responsible for albinism on an autosome or on a sex chromosome?
Albinism is the lack of melanin pigmentation, it is recessive, and the gene is on an autosome.
What is red-green colorblindness? Is it dominant or recessive? Is it sex-linked or not?
Red-green coloblindness is the inability to distinguish red and green wavelengths of light. It is recessive and sits on the X chromosome.
What is cystic fibrosis? Is it sex-linked or autosomal?
Cystic fibrosis is a recessive disease that leads to abnoral gland secretions, it can result in liver degeneration and lung failure, which can lead to death. It is autosomal.
What is Duchenne musuclar dystrophy? Is it dominant or recessive?
Is it sex-linked?
Duchenne muscular dystrophy is a recessive disease which results in the wasting away of muscles during childhood. This is a lethal disease.
It is caused by a gene on the X chromosome.
What is Hemophilia? Is it dominant or recessive? Is it sex-linked?
Hemophilia is the inability for blood to clot properly. This is a recessive sex-linked disease. It is caused by a gene on the X chromosome.
What is sickle cell anemia? Is it dominant or recessive? Is it sex-linked?
Sickle cell anemia is a recessive disease which causes defective hemoglobin. This causes red blood cells to curve and stick together. This disease prevents blood from reaching the entire body, and can cause organ failure and death. It also causes the reduced efficiency of red blood cells, reducing the amount of oxygen that travels in the blood.
It is not sex linked. It is autosomal.
What is middigital hair? Is it dominant or recessive?
Middigital hair is a condition that makes hair grow on the middle segment of fingers. This is dominant.
What is Huntington’s disease? It is dominant or recessive? Is it sex-linked?
Huntington’s disease is a disease that causes degenration of the nervous system, starting in the middle ages. It is dominant and autosomal.
What is Phenylthiocarbamide sensitivity? (PCT) Is it dominant or recessive?
Phenylthiocarbamide sensitivity is the ability to taste PTC as bitter.
What is Hypercholesterolemia? Is it dominant or recessive?
Hypercholesterolemia is a dominant disease which causes elevated levels of cholesterol in the blood and a risk of heart attack.
What is the principle of segregation?
Teh principle of segregation states that each gamete carries only one allele of each type, as the alleles have separated during meiosis. For example, each gamete of an Rr parent can only have one R allele OR one r allele. The offspring will receive the second r or R allele from their mother.
How to tell if a plant is true breeding? Meaning that it is homozygous dominant, if all that is know is that the plant expresses the dominant phenotype?
If this plant is crossed with a homozygote recessive, the nature of the plant is revealed in the offspring. If some express the recessive phenotype, then the parent must have been heterozygote.
