Final Exam Review - KEY Genetics & Heredity Vocab P, F1, F2 Generations: parental generation, and offspring generation Genotype: genetic makeup of an organism Phenotype: physical appearance of a trait Dominant: trait that can mask a recessive trait Recessive: trait that is not commonly seen and can be masked by a dominant trait Co-dominance: when the heterozygous individuals express both alleles (ex: a red flower crossed with a white flower will make red and white speckled flowers) Incomplete dominance: when the heterozygous individuals expressed a mixture of both traits (ex: a parent with curly hair and a parent with straight hair can result in offspring with wavy hair) Law of segregation: Law that states that alleles during gamete formation Pedigree: chart the shows the presence of absence of a trait according to the relationships within a family across several generations Allele: one of a number of different forms of a gene Homozygous: having two identical alleles for a particular gene Heterozygous: having two different alleles for a particular gene Law of independent assortment: law that states that genes for different traits can segregate independently during gamete formation Nondisjunction: error in meiosis in which the homologous chromosomes fail to separate properly Karyotype: graph of the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size Autosome: chromosomes that are not sex chromosomes; chromosomes # 1-22 Sex chromosome: one of the two chromosomes that determines an individual’s sex Crossing over: process in prophase I of meiosis when chromosomes exchange genetics information Questions 1. Who was Mendel and what he is best known for? Mendel was an Austrian scientist that is best known for his studies done on pea plants to explain genetics. Known as the father of genetics. 2. Why does crossing over create variation for future offspring? Crossing over allows for genetic variation because segments of DNA are exchanged during this time and recombinant DNA is made. 3. If an individual is homozygous recessive for attached earlobes and the other is heterozygous for detached earlobes, what is the probability that their offspring will have attached earlobes? The probability that their offspring will have attached earlobes is 50%. 4. How does meiosis I differ from meiosis II? Meiosis I is when tetrads line up, crossing over takes place, and tetrads split to chromosomes. Meiosis II is when chromosomes line up and then the cell splits into 4 genetically different haploid cells. 5. What is the difference between a diploid and a haploid cell? A diploid cell has 2 copies of each chromosome, a haploid cell has half the genetic information. 6. If the diploid number of a gorilla is 48, then what is the haploid number of its gametes? 24 7. What is the genotypic ratio for a cross between two heterozygous purple pea plants? (Purple is dominant over white) The ratio would be 1:2:1 (1 PP : 2 Pp : 1 pp) 8. What is the phenotypic ratio for a cross between a homozygous dominant individual and a heterozygous individual? The ratio would be 1. (100% purple) 9. What information can you attain just from looking at a pedigree? What can you see from a karyotype? A pedigree can determine what type of dominance the gene is over generations within a family, and possibly predict future offspring. A karyotype can tell you the sex of an individual and if there is any chromosomal disorders. 10. Why are X-linked disorders more commonly expressed in males? X-linked disorders are usually homozygous recessive. Males only have one X chromosomes therefore they cannot mask the trait like a female since their X chromosome is either affected or not. 11. How is it possible for one parent with A blood and the other with B blood to have a child with O blood? If both parents are heterozygous for A and B blood, they have a 25% chance of their offspring having O type blood. 12. What occurs in the cells during meiosis for an individual to have a child with Down syndrome? During meiosis, the chromosomes do not split evenly and the sex cell will have an extra copy of chromosome number 21. This occurrence is called nondisjunction. DNA, RNA, & Protein Synthesis Vocab Franklin: scientist that used X-ray diffraction to take photos of DNA Watson & Crick: scientists that are credited with discovering the structure of DNA Chargaff: scientist that discovered the arrangement of bonding nitrogenous bases (ex: adenine=thymine, guanine=cytosine) Avery: scientist that worked with bacteriophage and discovered that it is the DNA that causes infection DNA: nucleic acid that hold our genetic information and uses deoxyribose as the backbone RNA: nucleic acid that uses ribose as the sugar backbone mRNA: (messenger) recipe that codes for proteins tRNA: (transfer) brings amino acids to the ribosomes rRNA: (ribosomal) makes up ribosomes RNA Polymerase: enzyme that makes RNA from DNA template Transcription: synthesis of an RNA molecule from a DNA template Translation: process by which the sequence of bases of an mRNA is converted into the sequence of amino acids of a protein Exons: expressed sequence of DNA; codes for a protein Introns: sequence of DNA that is not involved in coding for a protein Nucleotide: monomer of a DNA or RNA Amino acid: monomer of a protein Questions 1. What are the three parts of a nucleotide? The three parts of a nucleotide are the sugar, phosphate group, and nitrogenous base. 2. What is the function of DNA in organisms? The function of DNA is to store all the genetic information for the organism. 3. List the 4 nitrogenous bases found in DNA. Adenine, guanine, thymine, cytosine 4. In DNA, which nitrogenous base bonds with adenine? Which base bonds to guanine? Adenine bonds to thymine. Guanine bonds to cytosine. 5. In what ways does DNA differ from RNA? RNA has ribose/DNA has dexoyribose, RNA uses uracil/DNA uses thymine, RNA is single stranded/DNA is double stranded 6. Where in the cell does transcription take place, and what is occurring during this step? Transcriptions takes place in the nucleus and the DNA is being copied into mRNA. 7. Where in the cell does translation take place, and what is occurring during this step? Translation takes place on a ribosome in the cytoplasm, and the mRNA is getting coded into a protein. 8. Write the mRNA sequence for the following DNA strand: TAC-AAG-CGA-ACC-TTGATT AUG-UUC-GCU-UGG-AAC-UAA 9. What is the amino acid sequence for the mRNA strand you just transcribed? MetPhe-Ala-Trp-Asn-STOP Evolution Vocab Darwin: English naturalist that traveled to the Galapagos and constructed the theory of evolution by means of natural selection from his findings Natural selection: process by which organisms that are most suited to their environment survive and reproduce most successfully Artificial selection: process by which humans choose the organisms called selective breeding of plants and animals to promote desirable traits in offspring Adaptation: heritable characteristic that increases an organism’s ability to survive and reproduce in an environment Homologous: structures that are similar in species of common ancestry but have a different function Analogous: body parts that share a common function but not a common structure Common ancestry: explanation of how species now have many common structures derived from each other Vestigial organs: structure that is inherited from ancestors but has lost much or all of its original function Hutton & Lyell: scientists that helped Darwin understand his theory of evolution with geology Lamarck: scientist that came up with the theory of acquired traits and Darwin disproved that theory Questions 1. What is the driving force for evolution that Darwin highlighted in his book On the Origin of Species? Darwin explained that natural selection is the driving force for evolution. 2. How does an animal’s fitness determine whether it will survive in an environment? An animal’s fitness determines how well they will be able to adapt and survive in an environment and reproduce. 3. What were Darwin’s findings with the finches of the Galapagos? Darwin found that the finches of the Galapagos varied from island to island by their beaks. Depending on the food source on each island, the finches adapted to their surroundings and eventually became different species. 4. What are the conditions necessary for Hardy-Weinberg equilibrium? The conditions for Hardy-Weinberg equilibrium are: large population, no mutations, mating is random, no emigration/immigration, and no natural selection. 5. What are the four pieces of evidence to support the theory of evolution? DNA, biogeography, embryology, and fossils 6. If two organisms have very similar DNA sequences, but are of different species what can be inferred from this information? They must have shared a common ancestor. Ecology Vocab Ecosystem: all the organisms that live in a place, together with their non-living environment Organism: a single living thing Population: group of individuals of the same species that live in the same area Community: assemblage of different populations that live together in a defined area Biome: a group of ecosystems that share similar climates and typical organisms Biomass: total amount of living tissue within a given trophic level Niche: role that an organism plays in their environment Habitat: area where an organism lives Producers: first level of the trophic level (usually plants) that create energy from the sun Herbivores: organisms that only eat plants Omnivores: organisms that eat both plants and animals Carnivores: organisms that eat meat Decomposers: organism that breaks down and obtains energy from dead organic matter Autotroph: organisms that make their own food Heterotroph: organisms that need to eat food in order to get energy Scavengers: animal the consumes the carcasses of other animals Mutualism: relationship when both species benefit Commensalism: relationship when one species benefits and the other in unaffected Parasitism: relationship when one species benefits and the other is harmed Questions 1. What is the difference between a food chain and a food web? A food web is a more complex system that consists of many food chains. A food chain only follows just one path as animals find food. ex: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. A food web shows the many different paths plants and animals are connected. 2. Energy is transferred between trophic levels, what is the relationship between the two? The higher you go up a trophic level the energy decreases. 3. What is the ultimate source of energy on Earth? The sun. 4. What is the difference between an organism’s habitat and niche? An organism’s habitat is where it lives, and its niche is the role it plays in its environment. 5. How are nutrients put back into the Earth and allow the food web to be considered a cycle of life? Decomposers are organisms at the top of every food chain that break down dead and decaying organisms. They put nutrients back into the Earth for the producers. 6. Create a food chain starting with producers with the following organisms: rabbit, grass, bacteria, eagle grass rabbit eagle bacteria Bacteria/Viruses Vocab Coccus: spherical shaped prokaryote Bacillus: rod-shaped prokaryote Spirillum: spiral shaped prokaryote Virus: particle made of proteins, nucleic acids, and sometimes lipids that can replicate only by infecting living cells Binary fission: type of asexual reproduction in which bacteria reproduce Peptidoglycan: protein found in bacterial cell walls Questions 1. What are the differences between a prokaryotic cell and a eukaryotic cell? Prokaryotic cells are smaller and do not contain a nucleus or membrane bound organelles. Eukaryotic cells are more complex, larger, and contain a nucleus and organelles. 2. How are antibiotics used to kill bacteria in the body? Antibiotics target specific parts of a bacteria or bacterial processes like protein synthesis. Ex: some antibiotics target peptidoglycan which is only found in bacterial cell walls. 3. Where do phototrophic and chemoautotrophic bacteria get their energy from? Phototrophic bacteria get energy from the sun and chemoautotrophic bacteria get energy from chemicals. 4. What type of environments do bacteria typically grow in? Bacteria usually grow in warm, dark, and moist areas. 5. How was the bacteria lab done in class considered to be a controlled experiment? There was a control group (distilled) water and an experimental group (different places swabbed) that all went through the same treatment to maintain consistency. The experimental groups are compared to the control group for analysis. 6. Why are viruses considered to be non-living? Viruses do not carry out life process and do not have all the characteristics of life ex: cannot reproduce, no metabolism 7. What is the difference between the lytic cycle and the lysogenic cycle? The lytic cycle is the process when the viral DNA is using the living cell’s resources and creates new viruses and bursts the cell. The lysogenic cycle is the process when the viral DNA is inserted into the host’s genome and remains there with no symptoms until there is an activation of the genes and then the viral DNA will switch to the lytic cycle.