Question | Answer |
When is a recessive genetic trait expressed | recessive genetic traits are expressed when individual is homozygous recessive |
If C= normal and c= cystic fibrosis...someone with cystic fibrosis would have the genotype ___ | little c , little c |
An individual that is heterozygous for a recessive disorder ( and do not show the recessive disorder) are called a/an | carrier |
What does it mean to be homozygous | to have two of the same alleles for a particular trait |
What does it mean to be heterozygous | to have two different alleles for a particular trait |
What trait is observed when an individual is heterozygous | the dominant trait |
What is the only way a person can show a recessive trait | to have two recessive genes for the trait of be homozygous |
What is the cause and effect of someone with the genetic disorder known as cystic fibrosis | they have a defective transport protein in the cell membrane and make excess mucus causing respiratory failure and digestive problems |
You will need to know 3 recessive disorders in humans... Name them | Cystic fibrosis, Albinism, and Tay-Sachs disease |
One of the most common recessive genetic disorders among Caucasians is ? | Cystic fibrosis |
Which recessive disorder is caused when the genes have an absence of the pigment melanine in the skin, hair and eyes | Albinism |
Describe the effect of Albinism | white hair, pale skin, and pink pupils.. the skin is very susceptible to UV damage and vision problems result from the lack of pigment |
What recessive disorder affects people of Jewish descent ( mostly eastern european jewish people) | Tay-Sachs |
Which genetic recessive disorder has no cure and Death usually occurs by age five from the accumulation of fatty substances in the brain causing mental deterioration | Tay-Sachs |
If a person has a dominant genetic disorder , what is true about their parents | one of the parents must have a dominant gene and had the disorder |
what are two genotypes that would give someone a dominant genetic disease (use( A) or( a) for an example) | AA or Aa |
What genotype would mean that you do not have a dominant genetic disorder ( use( A) or( a) for an example | aa |
What dominant disorder first appears in affected individuals between the ages of 30 and 50 | Huntington's disease |
What is true about preventive treatment or cure for Huntington's.? Are Genetic Tests available to detect the dominant gene? | * there is no preventive treatment or cure
* there is a genetic test to detect the dominant allele |
What happens to a person with Huntington's disease | they have gradual loss of brain function, uncontrollable movements, and emotional disturbance leading to death |
A person with this genetic disorder has a small body size and limbs that are comparatively short. the head is larger .... it is the most common form of dwarfism | Achondroplasia |
Name two dominant disorders that you should know | Huntington's disease and Achondroplasia |
Many times it seems that achondroplasia is because of ________because 75% of people with achondroplasia are born to parent of average size | a new mutation or genetic change |
A diagram that traces the inheritance of a particular trait through several generations | pedigree |
Symbol for a male in a pedigree | a square |
Symbol for a female in a pedigree | a circle |
If the person in a pedigree has the trait being studied it is shown as_____ | a dark or filled in square or circle depending on the gender |
How do you show a mating or a marriage in a pedigree | the circle and square are joined by a horizontal line |
what type of line shows the children of a set of parents | a vertical line connects the parent to the children |
Roman numbers show _____ and arabic numerals going from left to right show ______ | * generations ( I or II)
* individuals in a certain generation 1,2,3, |
How a carrier is shown for a particular trait | a circle or square that is half shaded |
One major clue to a pedigree showing a recessive trait would be | two unaffected parents can have an affected child |
If a pedigree shows a dominant trait than an unaffected person would have to have a genotype that is | homozygous recessive |
One major use of pedigrees is to infer ____ from the observation of the families physical trait | infer genotypes from the observation of phenotypes |