| A | B |
|---|
| Karyotype | a diagrammatic representation of individual chromosomes cut out from a photograph and grouped together from large to small |
| Autosomes (autosomal chromosomes) | any chromosome other than a sex chromosome |
| Sex Chromosomes | X and Y chromosomes that determine the sex of an individual |
| Pedigree | diagram that tracks the inheritance of a single gene through several generations of a family |
| Multiple Allele | type of gene that is determined by more than two alleles for a single trait |
| Nondisjunction | failure of chromosome pair to separate correctly during meiosis |
| Trisomy | condition caused by cells that contain three copies of a chromosome rather than two |
| Chromosome Deletions | phenomenon in which a broken-off piece of chromosome is left out during meiosis, which usually results in a genetic disorder |
| Chromosome Translocations | phenomenon in which a broken-off piece of chromosome becomes reattached to another chromosome |
| Amniocentesis | prenatal technique that involves withdrawing a small amount of fluid from the sac surrounding the fetus |
| Chorionic Villus Sampling | The fluid contains cells from the fetus which can be examined for abnormalities. Cells from a fetus can also be obtained by another technique called ________________ |
| Selective Breeding | producing a new genaration by mating individuals with desired characteristics |
| Hybridization | mating of two organisms with dissimilar genetic characteristics |
| Inbreeding | mating of organisms with similar genetic characteristics |
| Mutations | abrupt aleration in the genetic information of a cell |
| Chromosomal Mutations | change in the number or structure of a cell's chromosomes; a mutation that afects the entire chromosome |
| Gene Mutation | mutation that involves only a single gene |
| Point Mutation | gene mutation that involves a single nucleotide |
| Frameshift Mutation | gene mutation that involves the insertion or deletion of a nucleotide, thus changing the grouping of codons |
| Restriction Enzymes | protein that cuts DNA at a specific sequence of nucleotides |
| Recombinant DNA | pieces of DNA from two or more sources that are reassembled to act as a single DNA molecule |
| Cell Transformation | the changing of a cell's genetic makeup by the insertion of DNA |
| Plasmids | small, circular DNA molecule in some bacteria that can be used for cell transformation |
| Genetic Engineering | manipulation and insertion of genes and DNA from different sources into an organism |
| Transgenic | description of an organism that has been transformed or altered with genes from another organism |
| RFLPs | dark band revealed when pieces of DNA are probed; can be used to identify and classify an individual's unique DNA pattern |
| DNA Fingerprinting | technique used to identify an individual from the unique pattern of DNA |
| Drosophila Melanogaster | name for a common fruit fly |
| 1st Reason for Using Fruit Flies | produces a new generation in just a few weeks, making it possible to conduct experiments in a reasonable amount of time |
| 2nd Reason for Using Fruit Flies | it is small and thus easy to maintain in large numbers in the laboratory |
| 3rd Reason for Using Fruit Flies | they has a relatively simple genetic system, with just 8 chromosomes in a diploid cell |
| Malaria | An infectious disease that causes severe chills and fevers, and may even cause death |
| Human Karyotype | 22 pairs of homologous chromosomes that are numbered from 1 to 22 in order of decreasing size--chromosome 1 being the largest |
| Male Sex Chromosomes | XY |
| Female Sex Chromosomes | XX |
| Sperm and eggs are both haploids containing ___ chromosomes | 23 chromosomes- half the total number of chromosomes in human body cells |
| During fertilization, a sperm and an egg unite to form a zygote that contains ___ chromosomes | 46 |
| Rh+/Rh+= | Rh+ |
| Rh+/Rh-= | Rh+ |
| Rh-/Rh-= | Rh- |
| Blood Type Groups | A, B, AB, O |
| Sex-Linked Genes | gene located on the sex chromosome |
| Colorblindness | Inability to see certain colors properly. As many as 10% of all males in the US suffer from at least one form of it |
| Hemophilia | Two other important genes carried on the X chromosome help to control blood clotting. Individuals with the recessive allele for one of these genes are unbale to produce one of the clotting factor proteins that normally help blood to clot. |
| Duchenne Muscular Dystrophy | A genetic disorder that causes a sudden weakness in muscles. The gene that is responsible for this disorder is also carried on the X chromosome. The recessive allele produces a defective protein that causes the muscles to weaken and break down, eventually causing death |
| Albinism | A genetic disorder caused by recessive allele on chromosome 11. Individuals who have two copies of this allele are unable to produce melanin, the pigment responsible for most human skin color. People with this disorder have no pigment in their hair or skin. They are sensitive to light and, therefore, must avoid excessive exposure to bright sunlight |
| Cystic Fibrosis | The most common fatal genetic disease. It is caused by a recessive allele on chromosome 7. Individuals with two copies of this allele make a defective cell membrane protein that interferes with the movement of chloride ions into and out of the cell. Soon chloride ions begin to build up inside the cells, causing water from the surrounding liquid to enter the cells. As a result, the surrounding liquid becomes thick and heavy,clogging the lungs and breathing passageways |
| Tay-Sachs Disease | A fatal genetic disorder caused by a recessive allele. It is most common in Jewish families of Eastern European ancestry. Children who are born with this disease suffer from a rapid breakdown of the nervous system beginning at age 2 or 3 |
| Sickle Cell Anemia | A blood disorder that is characterized by crescent, or sickle-shaped, red blood cells. It is caused by a recessive allele that produces an alternate form of hemoglobin--the red blood cell protein. It is common in those parts of the world where malaria is also common. Individuals with two copies of the allele suffer from it and have serious medical problems. People who are heterozygous for the allele are generally healthy. In addition, they have the important benefit of being resistant to malaria |
| PKU (Phenylketonuria) | A genetic disorder caused by a recessive allele. It can cause severe mental retardation. If an infant has this disorder, a special diet can help prevent damage to the nervous system |
| Huntington Disease | A rare genetic disorder caused by a dominant allele located on chromosome 4. Most individuals with this disorder have no symptoms until their late 30s or 40s, when they begin to lose control over their muscles. Later, as the disease progresses, the nervous system begins to break down, and most patients die within 15 years after symptoms of the disorder first appears. Most people who are at risk for the disorder have already had children by the time they find out that they carry the allele. Because the allele is dominant, a heterozygous person with Huntington disease has a 50-50 chance of passing the disorder along to one of his or her children |
| Turner Syndrome | One type of nondisjunction in which sex chromosomes fail to separate in meiosis. During meiosis, either a sperm or an egg is produced without a sex chromosome. When such a cell fuses with a sex cell carrying a single X chromosome, the zygote will be XO. The O indicates that a sex chromosome is missing. The karyotype for people who have this syndrome is written as 45XO. Only female can be afflicted because their sex organs do not fully develop and they can't have children. Most people with this syndrome are able to lead otherwise full and healthy lives |
| Klinefelter Syndrome | Nondisjunction can also produce males whose clls contain an extra chromosome. This abnormality is symbolized as 47 XXY. Mental retardation is often associated, although its extent varies from one person to the next. The extra X chromosome interferes with meiosis and prevents these individuals from reproducing. |
| Down Syndrome | There is an extra copy of chromosome 21. Its results in heart and circulatory problems, a weakened immune system, and mental retardation. The degree of retardation varies greatly. Although some people who have this syndrome are severely retarded, others are able to function quite well in society |
| Barr Body | a condensed turned-off X chromosome. They aren't found in male cells because their single X chromosome is still active |
| Thomas Hunt Morgan | an American geneticist who suggested the use of fruit flies as the perfect organism for genetic studies |
| Crossing over | exchange between homologous chromosomes |
| Haploid | description of a cell that contains a single set of chromosomes; often represented by the letter n |
| Diploid | description of a cell that contains a double set of chromosomes; represented by the term 2n |
| Triploid | three sex chromosomes -- sex disorder? |
| Tetraploidy | Three sex chromosomes-- unable to reproduce -- take good eggs of woman and husbands sperm and fertilize the good egg and after that they take the two and inject into an egg with a normal child-- 50-50 chance(XXY)? |
| Polyploidy | Fatal in animals, but tolerated in pants (bananas, wheat, citrus) |
| How Many Chromosomes Are There in the Human Body Cells? | 46 Chromosomes |
| How Many Chromosomes Are There in the Human Gametes? | 23 Chromosomes |
| Examples of Sex-Linked Genetic Disorders | Colorblind, Hemophilia, and Duchenne Muscular Dystrophy |
| What factors can increase the rate of mutation? | X-rays, Ultra Violet Rays, and Chemicals |
| Tool #1- Cutting DNA | DNA can be cut at specific places by proteins known as restriction enzymes. More than 100 restriction enzymes are known, and each one cuts DNA at a specific sequence of nucleotides. Like a key that fits only one lock, a restriction enzyme will cut a DNA sequence only if it matches the sequence perfectly. Restrction enzymes make it possible to cut enormous DNA molecules into smaller, precisely sized fragments. Biologists can then work on pieces of DNA that contain a few hundred nucleotides, instead of many millions. |
| Tool #2- Separating DNA | DNA fragments are placed at one end of the gel. Then the gel is placed in an electric field. Because DNA fragments carry negative charges, they move toward the positively charged electrode. This separates the fragments because the smaller fragments slip through the gel faster than the larger fragments. The DNA fragments can be separated by a technique known as electrophoresis. The DNA fragments separate as they move through a special gel-- a water solid with a consistency similar to dessert gelatin |
| Tool #3- Reading DNA | Researchers developed a way to read the sequence of small, single-stranged pieces of DNA--typically fewer than 200 nucleoties. First, the pieces are placed in test tubes with the enzyme DNA polymerase. The enzyme is then allowed to make a new complementary strand, occasionally using chemically modified nucleotides that halt the assembly of the new strand at certain places. The new strands are then separated from each other by electrophoresis, producing a pattern of bands. This pattern reveals the base sequence of the original strand.Automated machines now carry out the sequencing reactions, and computers analyze the sequencing gell |
| Tool #4- Splicing DNA | When some restriction enzymes cut DNA, they leave a short, single-stranded region on each side of the cut, and these regions act like the sticky side of a piece of tape. So by mixing two DNA fragments cut with the same enzyme, the single-stranged regions hold the ends of the fragments together. Other enzymes can then be used to permanently join the fragments. The joined pieces of DNA act like a single DNA molecule. This kind of DNA is known as recombinant DNA because it is made by combining DNA from two different sources. Two genes could be fused into one, the control region of one gene coudl be placed next to another, and several genea from different sources that could be assembled into the same DNA molecule. |
| Why is inbreeding a bad idea? | Crossing individuals of the same breed may bring together two recessive alleles for a genetic defect. Excessive inbreeding has caused several problems in many dog breeds, including blindness and joint deformities in both shepherds and retrievers. |
| Antigen | molecule that stimulates the production of an antibody |
| Blood Type A | Antigen on Red Blood Cell is A. Its alleles are IAIA or IAi. Safe Transfusions To: A, AB; Safe Transfusions From: A, O |
| Blood Type AB | Antigen on Red Blood Cell is B. Its alleles are IBIB or IBi. Safe Transfusions To: B, AB; Safe Transfusions From: B, O |
| Blood Type B | Antigen on Red Blood Cell are A and B. Its alleles is IAIB. Safe Transfusions To: AB; Safe Transfusions From: A, B, AB, O |
| Blood Type O | There are no antigen on Red Blood Cell. Its alleles is ii. Safe Transfusions To: A, B, AB, O; Safe Transfusions From: O |
| Electropheresis | a technique that can separate DNA fragments |
