Bio 101- Module #4 (Questions and Answers A+ Graded 100% Verified)

Bio 101- Module #4 (Questions and Answers A+ Graded 100% Verified) Which parent determines the sex of a child in humans? CORRECT ANSWER: Father Which of the following human traits is NOT sex-linked? CORRECT ANSWER: pattern baldness Which of the following sex chromosome karyotype is NOT correctly matched with the sexual appearance of the individual? CORRECT ANSWER: XO: male Down syndrome is caused by what chromosome problem? CORRECT ANSWER: an extra copy of a chromosome A chances of a woman having a child with Down syndrome is highest for women CORRECT ANSWER: 40-50 When an organism acquires an entire extra SET of chromosomes it is called CORRECT ANSWER: polyploidy To find out if there are any chromosomal problems with a fetus, which type of test of fetal cells can be done? CORRECT ANSWER: amniocentesis or chorionic villi sampling Assume the gene for flower color (possible alleles: R,r) is on the SAME chromosome as the gene for plant height (possible alleles: T,t). A TTRR plant is crossed with a ttrr plant to produce a TtRr plant. What kinds of gametes will this TtRr plant make if there is NO CROSSING OVER when it does meiosis? CORRECT ANSWER: If we were to look at the chromosomes for the TtRr plant we would find that one chromosome had TR and the homologous chromosome tr. If there is no crossing over then chromosomes remain intact when they go into gametes. So some gametes will get the chromosome with TR and some will get the chromosome with tr. For the TtRr plant from the previous question, if there is crossing over in meiosis, what kinds of gametes will it produce? CORRECT ANSWER: Now it is possible to get all combinations of gametes because T can now be separated from R and t can be separated from r. So we get TR, Tr, tR, tr. For the TtRr plant from the previous question, if there is crossing over, what types of gametes will be the most commonly produced? CORRECT ANSWER: Because crossing over doesn't happen between the flower color gene and the plant height gene every time, we will tend to get more of the non-crossover gametes, TR and tr, than the crossover gametes, Tr and tR. This depends on how close the 2 genes are to each other. The farther apart they are the more likely that a crossover event will occur between them, producing more crossover gametes. Chromosomes other than sex chromosomes are called CORRECT ANSWER: autosomes Although the Y chromosome in humans has few genes, there is one gene that it does have that is very important. What is it? CORRECT ANSWER: the male-determining factor gene The ability to roll the tongue is caused by a dominant allele (R) (it is not sex-linked). Bob and his wife Alice can roll their tongues, but 2 of their children cannot. What are the genotypes of Bob and Alice? CORRECT ANSWER: Rr and Rr If a boy has a sex-linked trait, such as hemophilia, he inherited it from his CORRECT ANSWER: Mother Two carriers of an autosomal recessive genetic disease marry. What are the chances that their children will have the disease? CORRECT ANSWER: 1/4 For an autosomal dominant genetic disease, if a normal man marries an affected woman, what proportion of their children would be expected to have the disease? CORRECT ANSWER: 1/2 For an autosomal recessive genetic disease how many copies of the bad allele do you have to have to express the disease? CORRECT ANSWER: Two Are most mutations dominant or recessive? CORRECT ANSWER: Recessive A mutant allele can cause genetic disease because CORRECT ANSWER: a mutant allele is a botched recipe for a protein; a protein gets made but it is not the right one and so it can't perform its function as an enzyme properly In sickle-cell anemia, how is the hemoglobin different from normal hemoglobin? CORRECT ANSWER: one amino acid in the protein is wrong Name 2 autosomal recessive genetic diseases CORRECT ANSWER: albinism, Tay-Sachs, cystic fibrosis, PKU, sickle-cell anemia among others Name 2 autosomal dominant genetic diseases CORRECT ANSWER: Huntingtons disease and dwarfism How can a person who is a carrier for a particular genetic disease be detected? CORRECT ANSWER: Looking at chromosomes will not help, you need to look at the gene itself or the gene product. For some genetic diseases the gene has been located and so you can check the DNA to see if one copy is bad. For most genetic diseases the gene has not been located so you look at the gene product. A person who is a carrier of a genetic disease has one allele that makes the right protein and a second allele that makes the wrong protein. So you can look for the presence of the wrong protein to tell if the person is a carrier. The structure of DNA has been described as a twisted ladder. The rungs of this ladder consist of CORRECT ANSWER: Pairs of Bases The two scientists who came up with the structure of DNA were CORRECT ANSWER: Watson and Crick DNA polymerase is responsible for CORRECT ANSWER: Constructing a new DNA replica A mutation in which of the following can be passed on to offspring CORRECT ANSWER: Germ Cell In DNA replication, which statement about the 2 resulting DNA molecules is correct? CORRECT ANSWER: Each one has one original strand and one new strand