1. Human Heredity
How do biologists make a karyotype?
They photograph cells in Mitosis and cut out the chromosomes from the photographs and then group the chromosomes together in parts.

2. 2. The following is true about human chromosomes: A
2. The following is true about human chromosomes: A. The X and Y chromosomes are known as sex chromosomes because they determine an individual’s sex. C. All the chromosomes except the sex chromosomes are autosomes.

3. #3
4. Why is there a chance that half of the zygotes will be female and half will be male?
All the egg cells inherit an X chromosome from the Mother. Half of the sperm cells carry an X chromosome and the other half carry a Y chromosome.

4. 5. What does a pedigree chart show?
relationships within a family
A person who expresses the trait = a
A male = c
A person who does not express the trait = c
Represents a marriage = b
A female = a
Connects parts to their children = d

5. 13. Why is it difficult to study the genetics of humans?
Give two reasons why it is impossible to associate some of the most obvious human traits with single genes:
a. Many traits are polygenic
Many traits are strongly influenced by environmental factors
13. Why is it difficult to study the genetics of humans?
Humans have long generation times, a complex life cycle, and relatively few offspring.

6. 14. The following is true about human blood group genes: A
14. The following is true about human blood group genes: A. the Rh blood group is determined by a single gene. D. Individuals with type O blood are homozygous for the i allele (ii) and produce no antigen on the surface of red blood cells. 15. True or False: Many human genes have become known through the study of genetic disorders. TRUE

7. 16. PKU = c
17. Tay-Sachs Disease = A
Achondroplasia = B
Hungtington’s = D
What is the normal function of the protein that is affected by cystic fibrosis?
The protein allows chloride ions to pass across biological membranes.

8. 21. A change in just one DNA base for the gene that codes for the protein __________ causes sickle-shaped red blood cells. hemoglobin 22. What is the advantage of being heterozygous for the sickle cell allele? People who were heterozygous are generally healthy and are resistant to malaria. 23. What makes an allele dominant, recessive, or codominant? It depends on the nature of the gene’s protein product and its role in the cell.

9. Human Chromosomes
The following is true about human genes and chromosomes:
B. Chromosome 22 contains long stretches of repetitive DNA that do not code for proteins
D. Human genes located close together on the same chromosomes tend to be inherited together.
2. What are sex-linked genes?
They are genes that are located on the X or Y chromsome.

10. 3. True or False: The Y chromosome does not contain any genes at all
3. True or False: The Y chromosome does not contain any genes at all. False 4. Colorblindness - Inability to distinguish certain colors Defective version of any one of three genes associated with color vision Hemophilia- blood does not clot normally Duchenne Muscular Distrophy- progressive weakening and loss of skeletal muscle

11. 5. True or False: All X-linked alleles are expressed in males, even if they are recessive. True 6.

12. In female cells, one X chromosome is switched “off” What is Barr body?
7. How does the cell “adjust” to the extra X chromosome in female cells?
In female cells, one X chromosome is switched “off”
What is Barr body?
It is a dense region in the nucleus that is formed by the turned off X chromosome
True or False: Barr bodies are found only in males.
False

13. 10. If you see a white cat with orange and black spots, is it most likely a male or a female? Female. In cells in some parts of the body one X chromosome that has allele for orange spots is switched off, whereas in other parts of the body, the other X chromosome with the allele for black spots is switched off. 11. What occurs during nondisjunction? Homologous chromosomes fail to separate

14. 12. True or False: If nondisjunction occurs, gametes may have abnormal numbers of chromosomes. True 13. The condition in which an individual has three copies of a chromosome is known as ____________, which means “three bodies” trisomy 14. True or False: Down syndrome occurs when an individual has two copies of chromosome 21. False. Down syndrome = Trisomy 21

15. 15. Down syndrome is characterized by mental retardation 16
15. Down syndrome is characterized by mental retardation 16. Why does an extra copy of one chromosome cause so much trouble? scientists do not know 17. The following is true about sex chromosome disorders: A. A female with the karyotype 45,X has inherited only one X chromosome and is sterile. D. The Y chromosome contains a sex-determining region that is necessary for male sexual development.

16. Human Molecular Genetics 14-3
Biologists search volumes of the human genome using _______________.
sequences of DNA bases
2. Why might prospective parents decide to have genetic testing?
Genetic tests can determine whether parents risk passing alleles for genetic disorders to their children.

17. 3. The following is true about genetic testing: B
3. The following is true about genetic testing: B. Labeled DNA probes can be used to detect specific sequences found in disease-causing alleles. C. Some genetic tests use changes in restriction enzyme cutting sites to identify disease-causing alleles. D. DNA testing makes it possible to develop more effective therapy and treatment for individuals affected by genetic disease.

18. 4. What is DNA fingerprinting?
It is the identification of individuals by a method that analyzes sections of DNA that have little or no known function but vary widely from one individual to another.
Small sample of DNA is cut with a __restriction______ enzyme.
The fragments are separated by size using __gel_electrophoresis__.
Fragments with highly variable regions are detected with a __DNA_probe__, revealing a series of DNA bands of various sizes.
The pattern of bands produced is the _DNA_fingerprint_, which can be distinguished statistically from the pattern of any other individual in the world.

19. 6. The following are sources of DNA samples: A. blood B. sperm D
6. The following are sources of DNA samples: A. blood B. sperm D. hair 7. True or False: DNA evidence is not reliable enough to be used to convict criminals. False 8. What is the Human Genome Project? It is an ongoing effort to analyze the human DNA sequence.

20. 9. The following is true about the Human Genome Project: C
9. The following is true about the Human Genome Project: C. Researchers completed the genomes of yeast and fruit flies during the same time they sequenced the human genome. D. a working copy of the human genome was completed in June 2000.

21. 10. What were the three major steps in the process of sequencing the human genome?
Widely separated regions of DNA on each chromosome were sequenced
Random fragments of DNA were sequenced
Computers found overlapping regions between the fragments and positioned them relative to the known markers.
11. What is an open reading frame, and what is it used for?
A series of DNA bases that will produce an mRNA sequence. Scientists use it to locate genes.

22. 12. The mRNA coding regions of most genes are interrupted by __________. introns 13. List three other parts of the gene that researchers look for a. promoter b. “start” site for transcription c. “stop” site for transcription

23. 14. Why are biotechnology companies interested in genetic information
14. Why are biotechnology companies interested in genetic information? They are trying to use this information to develop new medicines and treatments for diseases. 15. True or False: Human genome data are top secret and can be accessed only by certain people. False

24. 16. What is gene therapy? The process of changing the gene that causes a genetic disorder. 17. The following is true about gene therapy: A. When the normal copy of the gene is inserted, the body can make the correct protein, which eliminates the disorder. C. Viruses are often used to carry the normal genes into cells.

25. 18. True or False: All gene therapy experiments have been successful
18. True or False: All gene therapy experiments have been successful. False 19. What other changes could be made to the human genome by manipulating human cells? Biologists could try to engineer taller people, change eye color, appearance, etc. They could even clone human beings.

26. 20. What is the responsibility of society in biology
20. What is the responsibility of society in biology? Society will have to learn to wisely use the tools that science has given it. It will have to develop an ethical consensus of what should and should not be done with the human genome. 21. True or False: Scientists should be expected to make all ethical decisions regarding advances in human genetics. False

27. 2. Autosomes
1. Karyotype
3. Sex chromosome

28. 4. Karyotype = c 5. Sex chromosome = e 6. Autosomes = g 7
4. Karyotype = c 5. Sex chromosome = e 6. Autosomes = g 7. Pedigree = a 8. sex-linked gene = f 9. Nondisjunction = b 10. DNA fingerprinting = d

29. Pedigree Practice
1. Given the following genotypes, describe the phenotypes (normal or albino) AA = _______normal______ Aa = ______normal_______ aa = _____albino_________

30. Pedigree Practice aa x Aa Aa, Aa, aa
3. How many children does this family have? __3____ What are the sexes of the children? ___female____

31. Pedigree Practice
4. Aa x aa aa , Aa, Aa - Aa aa 5. How many children does the original couple have? _3_ 6. How many grandchildren does the original couple have? _1__ What is the sex of the grandchild? __male__

32. Pedigree Practice
7. Aa x Aa aa, Aa - Aa aa - Aa, aa, Aa or AA * aa *When two hetorzygotes are crossed (Aa x Aa) offspring may be unknown and can be either AA or Aa.

33. Pedigree Practice
8. How many children does the original couple have? _2__ 9. How many grandchildren? ____3__ 10. Rats can produce a lot more offspring than humans, making a pedigree more difficult to manage. A researcher has four female white rats named April, May, June, and July. One night, the cage was left open in the lab and a brown rat got into the female's cage. Six weeks later, the rats had litters of babies of varying colors. Two of the offspring managed to reproduce before the researcher was able to sort out the mess. Determine genotypes of the rats in this pedigree.

34. Pedigree Practice #10
For Homework