Exam 1 Study Guide Extra Credit Biology PDF

Section 1: General Biology and Evolution 1. Which domains contain unicellular life? o The three domains that contain unicellular life are:  Bacteria: Consists entirely of unicellular organisms.  Archaea: Also consists entirely of unicellular organisms...

Section 1: General Biology and Evolution 1. Which domains contain unicellular life? o The three domains that contain unicellular life are:  Bacteria: Consists entirely of unicellular organisms.  Archaea: Also consists entirely of unicellular organisms.  Eukarya: Includes unicellular organisms (e.g., Protists) as well as multicellular organisms. 2. What are the 7 properties of life? o Order: Organized structure in cells, tissues, organs, and systems. o Reproduction: The ability to produce new organisms. o Growth and Development: Organisms grow and develop following specific genetic instructions. o Energy Processing: All living things acquire energy from their environment and convert it to a usable form. o Regulation (Homeostasis): The ability to maintain internal stability. o Response to Stimuli: Organisms can respond to environmental changes. o Adaptation (Evolution): Populations evolve over time through natural selection. 3. Use a Venn Diagram to compare and contrast eukaryote cells and prokaryote cells using at least 5 distinct bullet points. o Prokaryote Cells:  Lack a nucleus.  DNA is circular and located in a nucleoid region.  Generally smaller (0.1-5 µm in diameter).  Lack membrane-bound organelles.  Example: Bacteria and Archaea. o Eukaryote Cells:  Contain a nucleus that houses DNA.  DNA is linear and associated with histones.  Generally larger (10-100 µm in diameter).  Contain membrane-bound organelles (e.g., mitochondria, ER, Golgi apparatus).  Example: Plants, Animals, Fungi, Protists. o Similarities:  Both have a plasma membrane.  Both contain ribosomes.  Both have cytoplasm.  Both carry genetic material (DNA). 4. What is the core theme in biology? o Evolution is considered the core theme of biology, as it explains the diversity and unity of life. 5. What accounts for the unity and diversity of life on Earth? o Unity: All life forms share common ancestry and genetic codes (DNA). o Diversity: Life has diversified through evolution, with different species adapting to various environments. 6. What is the scientific method?  o The scientific method is a systematic process used to test hypotheses and theories through observation, experimentation, and analysis. The steps include:  Observation.  Question.  Hypothesis formation.  Experimentation.  Data collection and analysis.  Conclusion.  Reporting results. 7. What is an independent variable and a dependent variable? o Independent Variable: The variable that is manipulated or controlled by the experimenter. o Dependent Variable: The variable that is measured and observed; it depends on the independent variable. 8. What is the main requirement for a scientific hypothesis? o A scientific hypothesis must be testable and falsifiable. 9. What is the purpose of an experimental control? o An experimental control is used to provide a baseline for comparison to see the effect of the independent variable on the dependent variable. 10. Where does genetic variation come from? o Genetic variation arises from:  Mutations: Changes in DNA sequences.  Sexual reproduction: The combination of genes from two parents.  Gene flow: The transfer of genetic material between populations. Section 2: Evolution and Natural Selection 11. Give an example of artificial selection. How did the population change over time? o Example: The breeding of domestic dogs. Over time, through selective breeding for specific traits (e.g., size, coat color, behavior), different dog breeds with varying characteristics have been developed. 12. Give an example of natural selection. How did the population change over time? o Example: Peppered moths during the Industrial Revolution. The population of dark-colored moths increased due to their better camouflage in polluted environments, while the light-colored moths were more likely to be preyed upon. 13. Which part of natural selection is random? Which part of natural selection is not random? o Random: The occurrence of mutations that lead to genetic variation. o Not Random: The selection process where advantageous traits become more common in a population because they confer survival or reproductive benefits. 14. Circle the most recent common ancestor of snakes and chickens. o The most recent common ancestor of snakes and chickens would be located on a phylogenetic tree where the lineages of reptiles (including snakes) and birds (including chickens) diverge from a shared ancestor. 15. Circle the most recent common ancestor of chickens and frogs.  o The most recent common ancestor of chickens and frogs would be located where the lineages of amphibians (frogs) and reptiles (leading to birds) diverge on the phylogenetic tree. 16. Circle the most recent common ancestor of all these species on the diagram below. o The most recent common ancestor of all species on a phylogenetic tree would be the point from which all lineages diverge, representing the most ancient ancestor. 17. Which of the following two pictures is an example of convergent evolution? o Convergent evolution occurs when different species develop similar traits independently due to similar environmental pressures, not because of shared ancestry. o Which is an example of divergent evolution? o Divergent evolution occurs when related species develop different traits due to adaptation to different environments. 18. Use natural selection to explain how the sickle cell allele is more frequently found in humans of Africa and the Arabian Peninsula but not as much in the Americas. o The sickle cell allele is more common in regions where malaria is prevalent (Africa and the Arabian Peninsula) because individuals with one sickle cell allele (heterozygotes) have a survival advantage against malaria. This is an example of natural selection where the allele frequency is higher in malaria-endemic areas, whereas it is less common in regions like the Americas where malaria is not widespread. 19. How are genes expressed? o Genes are expressed through the process of transcription (DNA to mRNA) and translation (mRNA to protein), resulting in the production of proteins that perform various functions in the cell. 20. What are the key components of a nucleotide? o A nucleotide consists of:  A nitrogenous base (adenine, thymine, cytosine, guanine, or uracil).  A pentose sugar (deoxyribose in DNA, ribose in RNA).  A phosphate group. 21. Draw the structure of a nucleotide. Label the three parts. o (Here, an illustration of a nucleotide would be provided, showing the phosphate group, pentose sugar, and nitrogenous base.) 22. What is the primary structure of DNA? How is it related to its function? o The primary structure of DNA is the linear sequence of nucleotides (A, T, C, G) along a DNA strand. This sequence encodes genetic information and determines the structure and function of the resulting proteins. 23. What is the secondary structure of DNA? o The secondary structure of DNA is the double helix, formed by two complementary strands of DNA winding around each other, with base pairs (A-T, C-G) connected by hydrogen bonds. 24. What are the key differences between RNA and DNA? o DNA:  Double-stranded.  Contains the sugar deoxyribose.  Uses thymine (T) as one of the bases.   Primarily functions to store genetic information. o RNA:  Single-stranded.  Contains the sugar ribose.  Uses uracil (U) instead of thymine.  Functions in protein synthesis (e.g., mRNA, tRNA, rRNA). 25. What is the central dogma of molecular biology? o The central dogma describes the flow of genetic information:  DNA → RNA → Protein. 26. What are the three types of RNA, and what are their roles in protein synthesis? o mRNA (Messenger RNA): Carries the genetic code from DNA to the ribosome. o tRNA (Transfer RNA): Brings amino acids to the ribosome during translation. o rRNA (Ribosomal RNA): A component of ribosomes, where protein synthesis occurs. 27. What is the relationship between DNA, genes, and chromosomes? o DNA is the molecule that contains genetic information. o Genes are segments of DNA that code for proteins. o Chromosomes are structures within cells that contain tightly packed DNA. 28. What is the difference between a gene and an allele? o Gene: A segment of DNA that codes for a specific trait. o Allele: A variant form of a gene. Section 3: Biomolecules, Genetics, and Cell Biology 29. Explain the process of DNA replication. o DNA replication is the process by which a DNA molecule makes an exact copy of itself. It involves:  Initiation: Helicase unwinds the DNA double helix.  Elongation: DNA polymerase adds complementary nucleotides to each original strand.  Termination: The process concludes when two identical DNA molecules are formed. 30. What are the differences between mitosis and meiosis? o Mitosis:  Results in two genetically identical daughter cells.  Involves one division cycle.  Occurs in somatic cells. o Meiosis:  Results in four genetically diverse daughter cells (gametes).  Involves two division cycles.  Occurs in germ cells for sexual reproduction. 31. Describe the stages of the cell cycle. o Interphase:  G1 Phase: Cell growth.  S Phase: DNA replication.  G2 Phase: Preparation for mitosis.  o M Phase (Mitosis):  Prophase, Metaphase, Anaphase, Telophase. o Cytokinesis: Division of the cytoplasm to form two daughter cells. 32. What are the key differences between plant and animal cells? o Plant Cells:  Have a cell wall.  Contain chloroplasts for photosynthesis.  Large central vacuole. o Animal Cells:  Lack a cell wall.  No chloroplasts.  Small vacuoles, if present. 33. Explain how photosynthesis and cellular respiration are complementary processes. o Photosynthesis: Converts light energy into chemical energy (glucose) in plants. o Cellular Respiration: Converts chemical energy (glucose) into usable energy (ATP) in both plants and animals. o The products of photosynthesis (glucose and oxygen) are the reactants for cellular respiration, and vice versa. 34. Describe the structure and function of the plasma membrane. o The plasma membrane is a phospholipid bilayer with embedded proteins. It controls the movement of substances in and out of the cell and facilitates communication and signaling. 35. What are enzymes, and how do they function? o Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy. They bind to specific substrates at their active sites. Section 4: Genetics and Molecular Biology 36. Define genotype and phenotype. o Genotype: The genetic makeup of an organism (e.g., AA, Aa, aa). o Phenotype: The observable traits or characteristics of an organism. 37. What is a Punnett square, and how is it used? o A Punnett square is a diagram used to predict the genotype and phenotype of offspring from a genetic cross. 38. Explain the law of segregation and the law of independent assortment. o Law of Segregation: Each individual has two alleles for a trait, which segregate during gamete formation, so each gamete carries only one allele for each trait. o Law of Independent Assortment: Alleles of different genes assort independently during gamete formation, leading to genetic variation. 39. What are the differences between codominance, incomplete dominance, and complete dominance? o Codominance: Both alleles are fully expressed in the phenotype (e.g., AB blood type). o Incomplete Dominance: The heterozygous phenotype is a blend of the two alleles (e.g., red and white flowers producing pink offspring). o Complete Dominance: One allele completely masks the expression of the other.  40. Describe the process of transcription and translation. o Transcription: The process by which a DNA sequence is copied into mRNA. o Translation: The process by which mRNA is decoded by a ribosome to produce a polypeptide chain (protein). 41. What is a mutation, and how can it affect an organism? o A mutation is a change in the DNA sequence. It can have various effects, including:  Silent: No effect on the protein.  Missense: Changes one amino acid in the protein.  Nonsense: Introduces a premature stop codon.  Frameshift: Alters the reading frame of the gene. 42. What are the stages of meiosis, and how do they contribute to genetic diversity? o Meiosis I:  Prophase I: Homologous chromosomes pair up and exchange genetic material (crossing over).  Metaphase I: Homologous pairs align at the equator.  Anaphase I: Homologous chromosomes separate.  Telophase I: Two haploid cells are formed. o Meiosis II: Similar to mitosis, resulting in four genetically diverse haploid gametes. 43. Explain the concept of genetic linkage. o Genetic linkage occurs when genes are located close together on the same chromosome and tend to be inherited together. This can violate the law of independent assortment. 44. Describe the structure of a chromosome and its role in heredity. o A chromosome is a long DNA molecule wrapped around histone proteins. It carries genes that determine an organism's traits. During cell division, chromosomes ensure accurate distribution of genetic material to daughter cells. 45. How does crossing over during meiosis contribute to genetic variation? o Crossing over occurs during Prophase I of meiosis, where homologous chromosomes exchange genetic material, leading to new combinations of alleles and increased genetic diversity. Section 5: Advanced Genetics and Biotechnology 46. What is the polymerase chain reaction (PCR), and how is it used in molecular biology? o PCR is a technique used to amplify small segments of DNA. It involves repeated cycles of denaturation, annealing, and extension to generate millions of copies of a specific DNA sequence. 47. Describe the concept of gene cloning. o Gene cloning involves the isolation and replication of a specific gene sequence. This is done by inserting the gene into a plasmid vector, which is then introduced into a host cell for replication. 48. What are CRISPR-Cas9 and its applications in gene editing?  o CRISPR-Cas9 is a powerful gene-editing tool that allows for precise modifications to DNA. It has applications in genetic research, medicine, and agriculture, such as correcting genetic mutations or creating genetically modified organisms. 49. Explain the role of genetic engineering in agriculture. o Genetic engineering in agriculture involves modifying the DNA of crops to enhance traits such as pest resistance, drought tolerance, or nutritional content, leading to improved yields and food security. 50. What is a genetic map, and how is it constructed? o A genetic map shows the relative positions of genes on a chromosome. It is constructed using data from genetic crosses or molecular markers, indicating how often genes are inherited together. Section 6: Evolutionary Biology 51. What is natural selection, and how does it drive evolution? o Natural selection is the process by which organisms with advantageous traits are more likely to survive and reproduce, passing those traits on to the next generation. Over time, this leads to the evolution of species. 52. Describe the different types of speciation. o Allopatric Speciation: Occurs when populations are geographically isolated. o Sympatric Speciation: Occurs within the same geographic area, often due to genetic differences or niche specialization. o Parapatric Speciation: Occurs when populations are partially isolated and experience some gene flow. 53. What is genetic drift, and how does it affect populations? o Genetic drift is the random change in allele frequencies within a population, which can lead to reduced genetic diversity, especially in small populations. 54. Explain the concept of adaptive radiation. o Adaptive radiation is the rapid evolution of a single ancestral species into multiple species, each adapted to a different ecological niche. This often occurs after a mass extinction or when a species colonizes a new environment. 55. What is the significance of the fossil record in understanding evolution? o The fossil record provides evidence of the history of life on Earth, showing how species have changed over time and providing insight into evolutionary processes. 56. How do homologous and analogous structures provide evidence for evolution? o Homologous structures are anatomical features that are similar due to shared ancestry, while analogous structures are similar due to convergent evolution. Both provide evidence for the process of evolution. Section 7: Ecology and Environmental Biology 57. What are the different levels of ecological organization? o Levels of ecological organization include individual, population, community, ecosystem, biome, and biosphere. 58. Explain the concept of an ecological niche.  o An ecological niche is the role and position a species has in its environment, including its interactions with other species, its habitat, and its contribution to the ecosystem. 59. Describe the process of ecological succession. o Ecological succession is the gradual process by which ecosystems change and develop over time. It can be primary succession (starting from bare rock) or secondary succession (following a disturbance that leaves soil intact).