Block: Science 10 Biology Biology Review Package. 1. What is the full name for DNA? Label the following diagram on the right. Deoxyriboucleic Acid

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1 Review Package 1. What is the full name for DNA? Label the following diagram on the right. Deoxyriboucleic Acid 2. What is the function of DNA? DNA provides the genetic code for organisms. It makes you the way you are. 3. Name the four nitrogenous bases that are present in DNA. Adenine, Guanine, Cytosine, Thymine 4. What would be the complimentary base pairing for the following DNA sequence: ACTGAATGGCATC TGACTTACCGTAG 5. What is the difference between the dominant and recessive forms of alleles? Dominant alleles will be expressed when the allele is present in the genotype. Recessive alleles will only be expressed if they are the only alleles present within the genotype. 6. In humans, the allele that codes for an ability to taste PTC (can taste bitter foods) is dominant (T), and the allele that codes for an inability to taste this chemical is recessive (t). A male who is heterozygous for this trait marries a female who cannot taste PTC. a. What are the genotypes of the male and female? Male Tt Female - tt b. Draw a Punnett square to show the possible genotypes of their offspring. Female Male t t T Tt Tt t tt tt c. What is the predicted percentage of their offspring that will be able to taste PTC? Offspring that is able to taste PTC 50% d. What is the percentage that will not be able to taste PTC? Offspring that is not able to taste PTC 50% 7. A purebred brown hamster was mated with a purebred female golden hamster. All of the offspring were brown. a. Which trait would be the dominant allele? Brown fur colour

2 b. Draw a punnet square for this problem. Brown Hamster Golden B B Hamster b Bb Bb b Bb Bb 8. A heterozygous, long-tailed cat is mated with a homozygous, short-tailed cat. If the two cats mate, what would be the probability of having Long-tailed Cat Shorttailed cat T t t Tt tt t Tt tt a. A long-tailed cat? 50% b. A short-tailed cat? 50% 9. Having a widow s peak (P) is dominant and having a straight hairline (p) is recessive. If there is a 100% chance that a particular individual will have a widow s peak, which of the following are the genotypes of the parents? a. PP and pp b. Pp and PP c. PP and PP 10. A woman who is heterozygous for colour blindness and a man with colour blindness (sex-linked recessive trait) are considering having children. What is the probability of having a child who is both male and colour-blind? Woman - X C X c Man - X c Y Woman Man X C X c X c X C X c X c X c Y X C Y X c Y Probability of having a child who is male and colour-blind 25% 11. Define and state the difference between complete dominance, co-dominance and incomplete dominance? Use examples of each. Complete dominance in a heterozygous genotype, when the dominant allele masks the phenotype of the homozygous genotype A yellow pea plant and a green pea plant cross and produce a green pea plant. Co-dominance - When both alleles in a heterozygous pair are expressed In humans, AB blood type is an example of codominance. In chickens, speckled feathers are an example of codominance. Incomplete dominance - where two traits blend together When a red coloured flower and a white coloured flower produce a pink coloured flower

3 12. Hemophilia is a genetic disorder caused by a gene found on the X chromosome. Therefore, it is referred to as a sex-linked disease. The recessive allele causes the genetic disorder. A man without this genetic disorder marries a woman that is heterozygous for the trait. Draw the Punnett square and give the genotypic and phenotypic ratios of the offspring. Woman X H X h Man - X H Y Woman Man X H X h X H X H X H X H X h Y X H Y X h Y Genotypes: X H X H ; X H X h ; X H Y ; X h Y Phenotypes: 50% female without hemophilia ; 25% male with hemophilia ; 25% male without hemophilia 13. Male-pattern baldness is a sex-linked recessive trait. Suppose a man with this trait marries a carrier woman. How many of their children will have male-pattern baldness? How many of their daughters will be carriers for male-pattern baldness? How many of their sons will have malepattern baldness? Woman X B X b Male - X b Y Woman Man X B X b X b X B X b X b X b Y X B Y X b Y 50% that their children will have male-pattern baldness 25% that daughter will be a carrier of the trait 25% that son will have male-pattern baldness 14. Use the following diagram to answer the question: a. How many females are in the pedigree? 8 b. How many males are in the pedigree? 7

4 c. List the individuals that are affected in the above pedigree. I-1, II-2, II-3, II-7, III-3 d. Is this trait dominant or recessive? Dominant 15. Use the following diagram to answer the question: a. Which characteristic is dominant? Black fur b. Which characteristic is recessive? White fur c. Determine the genotypes of all the individuals. Write the genotypes beneath each individual (use the letter A ). 16. Use the following diagram to answer the question: a. Which characteristic is dominant? The non-shaded one b. Which characteristic is recessive? The shaded one c. Determine the genotypes of all the individuals. Write the genotypes beneath each individual (use the letter A ). 17. List the 3 types of gene mutations and give an example for each. a. Insertion: sections of DNA get added b. Deletion: sections of DNA get deleted c. Substitution: new sections of DNA get substituted for existing sections 18. What is a frameshift mutation? Give an example using the following code: GAC TAT CAG CAT TTA Insertion and/or deletion can cause a frameshift where the genetic code is shifted over by one base this can result in a non-functional protein. Original: GAC TAT CAG CAT TTA Frameshift: GAC TAC AGC ATT TA

5 19. What is the difference between a gene mutation and a chromosomal mutation? Which do you think has the potential of being the most harmful? Gene mutation is a change in the nucleotide sequence, in a particular gene. Chromosomal mutation is a change in several genes Chromosomal mutations are more harmful. 20. What are the 4 types of chromosomal mutations? a. Deletion: segments of the chromosome are deleted b. Translocation: segments of the chromosome are rearranged c. Duplication: segments of the chromosome are replicated d. Inversion: segments of the chromosome are reversed (flipped) 21. What is the difference between a positive, neutral, and negative mutation? Provide an example for each. A positive mutation will enhance an organism s ability to survive and reproduce, whereas a negative mutative will impair an organism s ability to survive and reproduce. A neutral impact will have no impact on the individual. 22. Mutations will be passed onto future generations in which type of cell? Reproductive cells (gametes) 23. What are 3 reasons that mutations could occur within an individual? a. Random chance b. Mutagens i. Physical factors include: UV light and X-rays ii. Chemical factors include: tobacco and PCBs (polychlorobiphenyl) iii. Biological factors include viruses such as hepatitis B and AIDS c. Environmental factors 24. What should individuals take precautions when being exposed to a mutagen? Environmental factors (mutagens) can affect the genetic code of cells. This could cause cancer if the body cannot get rid of these cells. 25. Why are cancer cells harmful to an individual? What could be a cause for cancer cells to form? Cancer is uncontrolled cell division. If cells continue to divide without stopping, they can form tumors that can spread into nearby tissue. If tumors do not spread, they are considered benign.

6 26. Using the following Venn Diagram, compare and contrast Natural Selection and Artificial Selection. Natural Selection Change in the environment causes organisms best adapted to survive. Survival of the fittest Can lead to the evolution of a species Does not lead to be better adapted to the environment. Desirable traits are chosen by humans Artificial Selection 27. What would an adaptation a bird may have in order to reach a food source? Different types of beaks 28. How can camouflage be an adaptation? Can blend in with the environment so that these organisms are not seen by predators. 29. What best explains the fact that corn cobs today are approximately twice as long as they were 150 years ago? Through many years of artificial selection, humans were able to pick and choose the traits they wanted to see more of. As longer corn cobs were more favourable, humans chose these particular crops to plant and reproduce. 30. What is the bottleneck effect? Give an example. Explain why the bottleneck effect is an example of genetic drift and how it causes evolution to occur. When a population experiences a rapid reduction in population, the future generations will have a similar genetic make-up to the survivors only. Example: Cheetahs went through several bottlenecks where they had to mate with close relatives to survive. In addition to low genetic diversity, cheetah habitats are being destroyed to make way for human developments. Both factors put cheetahs at risk of extinction. Bottleneck effect changes the frequency of the population due to random sampling (the population is decreased in size due to random occurrences like floods, earthquakes, etc.). 31. Explain how a population bottleneck decreases variation within a population. Population bottleneck decreases variation within a population because the surviving individuals in the population will only be able to mate with a limited number of organisms in the population. Due to this, inbreeding could occur.

7 32. What is the founder effect? Give an example. Explain why the founder effect is an example of genetic drift and how it can cause evolution to occur. If a small number of individuals colonize a new area, the genetic diversity of the founders won t necessarily match the diversity of the original population. Founder effect is an example of genetic drift because if only a small number of individuals are present in the new population, there will only be a select number of genes within the population. The frequency of the population will be different from the original population. 33. Explain how the founder effect decreases variation within a population. Founder effect decreases variation within a population because there is only a limited number of organisms that are present within the population. Due to this, it could cause inbreeding to occur. 34. Define gene flow. Explain how gene flow can cause evolution to occur. New genes may be added to a population as organisms move locations. These new genes will be added into the gene pool of the existing population which could cause the population to change as these new genes could express new traits. 35. From the list below, indicate whether it will lead to a founder effect or a bottleneck effect. a. Hunting Bottleneck b. Immigration Founder c. Volcanic eruption Bottleneck d. River is created between a population Founder 36. Why is genetic variation important for the survival of a species? Genetic variation is important for the survival of a species as this will allow for more adaptations and evolution to occur within a population. For example, if a disease enters a population, this could affect all the individuals in the population if they are not adapted to fight off the disease. However, if there are adaptations present, some of the organisms may survive because they may have an adaptation that helps to fight off the disease. 37. What are some impacts on a population due to the loss of genetic diversity? Inbreeding, same genes expressed, same survival success for all organisms in the population, etc. Vocab: 1. Genes 2. Genome 3. Allele 4. Genotype 5. Phenotype 6. Homozygous 7. Heterozygous 8. Co-dominance 9. Incomplete dominance 10. Complete dominance 11. Pedigree 12. Mutation 13. Frameshift 14. Chromosomal mutation 15. Carcinogen 16. Benign 17. Mutagen 18. Natural Selection 19. Variation 20. Adaptation 21. Fitness 22. Artificial Selection 23. GMOs 24. Random mating 25. Gene flow 26. Genetic drift 27. Bottleneck effect 28. Founder effect 29. Genetic variation 30. Genetic diversity