Chapter 12 ReviewName:Franco - KEY
Who did what?
Who proposed that heredity factors carried on chromosomes?______SUTTON______
Who hypothesized chromosomes responsible for heredity?_____WEISMANN______
Who called these small parts “genes”?______JOHANNSEN______
Who’s work was rediscovered?______MENDEL______
Who was the first to see chromosomes?______FLEMMING______
Who proposed the chromosome theory?______SUTTON______
Genetic Disorders: (match)
Turners syndrome- occurs mostly in African Americans
Klinefelter’s syndrome- contains an extra 21st chromosomes
Huntington’s disease- degeneration of muscles
PKU- excessive mucous produced in the lungs
Hemophilia- only one X chromosome
Sickle Cell Anemia- contains an XXY
Cystic fibrosis- failure of brain to develop in infancy
Tay Sachs- sex-linked blood clotting disorder
Down syndrome- destroys the central nervous system
Muscular Dystrophy- deterioration of brain tissue
Problems:
A man who is not bald marries a women who is heterozygous for baldness. What is the chance of having a bald child?
Bb (XX) / Bb (XY)bb (XX) / bb (XY)
bb x Bb
½ chance of having a bald child (including son and daughter)
A mother with Type AB blood marries a man with Type B blood. What are the genotypes of the parents if one child has Type AB and the other with Type A?IAIB x IBi
IAIB / IAiIBIB / IBi
In humans the gene from normal blood clotting, H, is dominate to the gene for hemophilia, h. This is a sex-linked trait found on the X chromosome. A woman with normal blood clotting has four children. They are a normal son, a hemophiliac son, and two normal daughters. The father has normal blood clotting. What is theprobable genotype for each member of the family?XHXh x XHY
XHXH / XHXhXHY / XhY
This is a sex-linked trait. A normal clotting female whose father was a hemophiliac, marries a man who has normal clotting blood. What are the expected genotypic and phenotypic ratios? XHXh x XHY
XHXH / XHXhXHY / XhY
Genotypic ratio = 1 XHXH : 1 XHXh : 1 XHY : 1 XhY
Phenotypic ratio = 2 normal females : 1 normal male : 1 hemophiliac male
Windows peak (W) is dominant to the No widows peak (w). A science class wanted to find the frequency of the 2 alleles in their school’s population. A survey showed the following results: 388 non widows peak and 812 who had a widows peak. Find the following information, show the math you have to do - you may use a calculator to actually do the math.
Use these equations: p2 + 2pq + q2 = 1 and p + q = 1 (answers to nearest .001)
frequency of homozygous recessive ______
388 non = w = q
812 with peak = W = p
q2 = 388/1200 = .322
frequency of gene (w) ______frequency of gene (W) ______
q = (.322)1/2 = .5671 - .567 = .433
frequency of heterozygous genotype ______
2 x p x q = 2 x .433 x .567 = .491
number of students that are heterozygous ______(nearest whole student)
.491 x 1200 = 589
A.
B.
------
C.
______Homologous______What is the name of the area marked C?
______Holandric______What is the name of the area marked B?
Sex-linked (non-homologous) What is the name of the area marked A?
Night/total colorblindness Name a trait found in humans that the gene for it would be located in area C?
TDF/hairy pinnae Name a trait found in humans that the gene for it would be located in area B?
Defective tooth enamel, hemophilia, muscular dystrophy, R/G colorblindness Name a trait found in humans that the gene for it would be located in area A?
The chromosome on the right is called the ______Y______chromosome.
The chromosome on the left is called the ______X______chromosome.
A scientist wishes to find out how many people in the United States have attached earlobes. Will the scientist check the ears of every person in the country? Explain what he would do.
No, the scientist could take a sample from a population and use the Hardy-Weinburg theory.
A set of fraternal twins separated at birth and reared in different environments was studied to determine to what extent environmental factors shape development. What problem do you see in the reliability of such a study?
They are fraternal twins, not identical twins. Due to this, they have different DNA so there are too many variables to account for.
Define multiple alleles. What alleles are present for blood types? Name the blood types.
Multiple alleles are a variety of alleles of the same gene that affect traits. Multiple allele traits are controlled by 3 or more alleles of the same gene. The alleles present for blood types are IA, IB, and i. The blood types possible are A, B, AB, and O.
Explain why skin color is considered a polygenic trait?
Skin color is a polygenic trait because there is a continuous variation in the trait. Each gene has a small additive effect.
Explain why baldness is a sex-influenced trait and describe the inheritance pattern.
Baldness is a sex-influenced trait because testosterone causes an increased expression in the trait. Inheritance pattern:
Pattern baldnessPhenotypes / Male / Female
Bald / BB and Bb / BB
Normal hair / bb / bb and Bb
Define nondisjunction
The failure of homologous chromosomes to separate properly in the formation of gametes
Give the name of the following disorders:
XXY = Klinefelter syndrometrisomy #21 = Down syndrome
XXX = Super femaleXO = Turner syndrome
What are the following:
- amniocentesis Removal of some amniotic fluid at 14-16 weeks in order to analyze fetal cells and proteins or make a karyotype
- chorionic villi biopsy Sample of tissue between uterus and placenta at 8-10 weeks to make a karyotype (from chorion)
- ultra sound Sonogram (use sound waves)
- genetic screening Used for those with a history of genetic disorders. Make a karyotype, examine blood for presence or absence of certain proteins
- genetic counseling Medical guidance informing parents of potential problems for offspring
- erythroblastosis fetalis Destruction of the fetus’ RBC due to the mother being Rh – and the first and second babies being Rh +.
- Rhogam shot (When mother is Rh – and first and second child are Rh +) Injection given to mother within 72 hours of childbirth in order to destroy any Rh + blood antigens the mother may have gotten from the child (contains anti Rh antibodies)
Classify each of these genetic disorders under its proper heading.
PKUDown syndromepolydactaly
hemophiliasickle-cell anemia Turner’s syndrome
Klinefelter’s syndromebaldnesscolor blindness
Genetic Disorders on autosomes / Nondisjunction / Sex linked or Sex influenced traitsPKU / Down syndrome / Baldness
Sickle-cell anemia / Turner syndrome / Color blindness
polydactaly / Klinefelter’s syndrome / hemophilia
Explain fully why type A blood cannot be transfused into a type B person.
Type A blood has A antigens on its surface. Due to this, when it is introduced to a type B person (who has antibodies towards type A), the type B person will begin to fight off and agglutinate the type A blood.
For erythroblastosis fetalis to occur, what is the Rh factor for the mom, dad and baby?
Mom _____-_____Dad ____+______Baby _____+______
Can Rh positive blood be transfused into an Rh negative person? Not multiple times. There is little problem on the first transfusion, but the subsequent transfusion could be fatal due to the production of Rh antibodies.