Bio Exam Review Summarized PDF

**Bio Exam Review** **Biodiversity:** **Decreasing biodiversity** can have many negative effects, including threatening the food supply, eliminating natural medicines, impacting tourism and forestry, and disrupting biogeochemical cycles like carbon uptake2. **Maintaining biodiversity** is cruci...

**Bio Exam Review** **Biodiversity:** **Decreasing biodiversity** can have many negative effects, including threatening the food supply, eliminating natural medicines, impacting tourism and forestry, and disrupting biogeochemical cycles like carbon uptake2. **Maintaining biodiversity** is crucial for the health and sustainability of ecosystems3. There is concern that the diversity of life is rapidly declining due to human activities like habitat fragmentation, pollution, and climate change3. **Species extinction** is a natural process, but human activity is causing a mass extinction with the loss of approximately 27,000 species per year2. The variety and number of species on Earth is referred to as **biodiversity**4. Scientists have identified and described about 1.8 million species, with estimates of up to 15 million4. **Taxonomy and Classification:** **Taxonomy** is the branch of biology that deals with identifying and classifying all organisms5. **Carolus Linnaeus** is known as the \"Father of Modern Taxonomy\" and developed a system for grouping species based on shared physical characteristics6. **Binomial nomenclature** is a naming system where each species is assigned a two-part name consisting of a genus name (capitalized) and a species name (lowercase)7. For example, *Felis silvestris* or *Felis silvestris*7. The **8 levels of taxa** in order from most inclusive to least inclusive are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species1\.... A mnemonic to remember the order is \"Did King Philip Come Over From Germany Swimming?\"8. Taxonomic lists can be used to identify the **relatedness, similarities, and differences** between organisms1. A **dichotomous key** is a tool used to classify unknown organisms based on the presence or absence of observable characteristics9. **Phylogeny:** **Phylogeny** is the study of evolutionary relationships among different groups of organisms9. Evidence for phylogeny includes: ◦Similar stages of **embryological development**10. ◦**Homologous structures**, which are similar in anatomy but may have different functions, indicating shared ancestry10. ◦**Genetic similarity**, where organisms that are genetically similar are more likely to share a common ancestor11. **Phylogenetic trees** are diagrams depicting the evolutionary relationships between different species or groups11. ◦Groups of descendant taxa are at the tips of the branches12. ◦Internal nodes represent common ancestors12. ◦Edges/branches show the evolutionary timeline12. ◦The root is the most recent common ancestor of all taxa on the tree12. ◦**Sister groups** are two descendants that split from the same node and are each other\'s closest relatives12. A **clade** is a taxonomic group that includes a single common ancestor and all of its descendants13. **Prokaryotes vs. Eukaryotes:** **Prokaryotic cells** do not contain membrane-bound organelles, and organisms with these cells are called prokaryotes13. **Eukaryotic cells** contain membrane-bound organelles, and organisms with these cells are called eukaryotes14. The three domains of life are Eubacteria (prokaryotes), Archaea (prokaryotes), and Eukarya (eukaryotes)15. Eukarya is divided into four kingdoms: Protista, Fungi, Plantae, and Animalia15. **Eubacteria** are \"true bacteria,\" diverse and widespread, and can be helpful or harmful to humans15. **Archaea** are \"ancient bacteria,\" often found in extreme environments, and do not infect humans15. **Eukarya** are more complex and contain a nucleus15. The main differences between prokaryotic and eukaryotic cells are summarized in the table below14: \| Characteristic \| Prokaryotic \| Eukaryotic \| \| \-\-\-\-\-\-\-\-\-\-- \| \-\-\-\-\-\-\-\-\-\-- \| \-\-\-\-\-\-\-\-\-\-- \| \| Nucleus \| No true nucleus \| True nucleus \| \| DNA \| Free in cytoplasm \| Inside the nucleus \| \| Organelles \| Not membrane bound \| Membrane bound \| \| Size \| Smaller \| Larger \| \| Cell Division \| Binary fission & conjugation \| Mitosis & meiosis \| **Bacteria:** Bacteria are classified by **shape and arrangement**1\.... ◦The three main shapes are coccus (round), bacillus (rod), and spirillum (spiral)16. ◦Arrangements include diplo- (pairs), strepto- (chains), and staphylo- (clusters)16\.... -Bacteria primarily reproduce asexually through **binary fission**1. Some bacteria can reproduce sexually through **conjugation**18. Bacteria can be autotrophic or heterotrophic17. They also have varying metabolisms19, and can be obligate aerobes, obligate anaerobes or facultative aerobes19. **Protists:** Protists are a diverse group of **eukaryotic** organisms20. Most protists are **unicellular,** but some are multicellular21. They can be **autotrophic or heterotrophic**21. Protists move using cilia, flagella, or pseudopods21. Protists can reproduce **asexually** through binary fission or **sexually** through conjugation22. Protists were the first eukaryotes23\.... **Infolding** is the process that led to the development of membrane bound organelles23. **Endosymbiosis** explains how mitochondria and chloroplasts developed in eukaryotes23. ◦Mitochondria and chloroplasts have two membranes25. ◦They have their own internal chromosomes25. ◦They reproduce independently within eukaryotic cells using binary fission25. **Viruses:** Viruses are **non-living**, infectious particles that contain genetic material (DNA or RNA) within a protein capsid26. Viruses are classified by shape, type of genetic material, size, and type of cell they invade27\.... Viruses cannot reproduce on their own29. They can become active when their genetic material enters and takes control of a living cell28. The **lytic cycle** involves the virus invading a living cell, assembling new viruses, and destroying the host cell through lysis30. The **lysogenic cycle** involves the viral DNA becoming part of the host DNA, remaining dormant until an environmental stimulus triggers the lytic cycle30\.... Some viruses have an envelope formed from part of the host cell membrane27\.... **Classification of Kingdoms:** The six kingdoms of life are Eubacteria, Archaea, Protista, Fungi, Plantae, and Animalia32. The kingdoms are organized within the three domains: Eubacteria, Archaea, and Eukarya32. The sources provide a chart summarizing the cell type, number of cells, cell structure, mode of nutrition, and reproduction methods for each kingdom26\.... **DNA Structure and Function** **DNA (deoxyribonucleic acid)** is the basic hereditary chemical of life and is the basis of inheritance2. **Chromosomes**, found in the nucleus of cells, are made of tightly packed chromatin and contain thousands of genes3\.... **Genes** are segments of DNA that code for the production of proteins and determine particular traits4. A **nucleotide** is the building block of DNA and consists of a phosphate, a deoxyribose sugar, and a nitrogenous base5\.... There are four nitrogenous bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T)5. **Complementary base pairing** dictates that A always binds with T, and G always binds with C6. DNA has a **double helix structure**5. The two DNA strands run antiparallel to one another5. **Chromosomes and Cell Division** **Haploid cells (n)** contain one set of chromosomes, while **diploid cells (2n)** contain two sets7\.... **Autosomes** are non-sex chromosomes, and **allosomes** are sex chromosomes9. Humans have 22 pairs of autosomes and 1 pair of allosomes9. **Mitosis** is a type of cell division that results in two identical daughter cells10. It is used for growth and repair of somatic (body) cells10\.... ◦Mitosis has four phases: prophase, metaphase, anaphase, and telophase10\.... ◦In **prophase**, chromatin condenses into chromosomes, the nuclear membrane disappears, and spindle fibers form10. ◦In **metaphase**, chromosomes align at the cell\'s equator12. ◦In **anaphase**, sister chromatids separate and move to opposite poles of the cell12. ◦In **telophase**, new nuclei form around the separated chromosomes13. ◦**Cytokinesis**, the division of the cytoplasm, occurs at the end of telophase, resulting in two new cells14. **Meiosis** is a type of cell division that results in four genetically unique haploid gametes (sex cells)15\.... ◦Meiosis has two cycles: meiosis I and meiosis II16\.... ◦**Meiosis I** includes prophase I, metaphase I, anaphase I, and telophase I16\.... ▪In **prophase I,** homologous chromosomes pair up to form a tetrad, and crossing over occurs16\.... **Synapsis** is the pairing of homologous chromosomes18. ▪In **metaphase I,** tetrads line up randomly at the equator18. ▪In **anaphase I,** homologous chromosomes separate19. ◦**Meiosis II** includes prophase II, metaphase II, anaphase II, and telophase II20. ▪In **prophase II,** spindle fibers attach to centromeres20. ▪In **metaphase II,** double stranded chromosomes line up at the equator20. ▪In **anaphase II,** sister chromatids separate20. ▪**Telophase II** results in 4 haploid cells21. ◦**Crossing over**, during prophase I, involves the exchange of genetic material between non-sister chromatids of homologous chromosomes, which increases genetic variation18. ◦**Independent assortment** during metaphase I results in different combinations of maternal and paternal chromosomes in the gametes, also increasing genetic variation18\.... **Homologous chromosomes** are matching pairs of chromosomes, one from each parent15. **Sister chromatids** are two identical copies of the same chromosome, formed by DNA replication17. **Non-disjunction** is the failure of chromosomes to separate properly during meiosis, resulting in gametes with an abnormal number of chromosomes22. **Karyotypes and Genetic Disorders** A **karyotype** is an illustration or photograph of an organism\'s chromosomes, sorted by size and banding patterns2\.... Karyotypes are used to identify chromosome abnormalities9. **Aneuploidy** is the possession of an abnormal number of chromosomes22. ◦**Monosomy** is the presence of only one chromosome from a homologous pair23. ◦**Polysomy** is the presence of extra copies of a particular chromosome23. **Trisomy** is a type of polysomy where there are three copies of a chromosome23. ◦**Polyploidy** is the possession of more than two sets of chromosomes23. Examples of genetic disorders caused by chromosomal abnormalities include: ◦**Klinefelter syndrome** (XXY)24. ◦**Turner syndrome** (XO)25. ◦**Down syndrome** (trisomy 21)23\.... ◦**Patau syndrome** (trisomy 13)25\.... ◦**Edward\'s syndrome** (trisomy 18)26\.... ◦**Cri-du-chat syndrome** (deletion of part of chromosome 5)28\.... ◦**Fragile X syndrome** (duplication of CGG on the X chromosome)26\.... ◦**Supermale syndrome** (XYY)24\.... ◦**Triple X syndrome** (XXX)25\.... **Oogenesis and Spermatogenesis** **Spermatogenesis** is the process of sperm production, resulting in four viable sperm cells33\.... **Oogenesis** is the process of egg production, resulting in one viable egg cell and three non-functional polar bodies34. **Mendelian Genetics** **Gregor Mendel** is known as the \"father of genetics\"35. He studied patterns of inheritance in pea plants35. Mendel proposed three laws of inheritance: ◦**Law of Segregation**: Each trait is controlled by a pair of factors (genes), which separate during gamete formation36\.... ◦**Law of Independent Assortment**: Alleles of different genes are sorted into gametes independently of each other37\.... ◦**Principle of Dominance:** One allele (dominant) can mask the expression of another allele (recessive)38. A **gene** is a part of a chromosome that codes for a particular trait, and an **allele** is a different form of a gene39. **Homozygous** refers to having two identical alleles for a trait, while **heterozygous** refers to having two different alleles40\.... **Genotype** is the genetic makeup of an organism (e.g., TT, Tt, tt), while **phenotype** is the physical appearance of an organism (e.g., tall, short)41. A **monohybrid cross** involves the genetic crossing of only one trait41. A **Punnett square** is used to predict the possible genotypes and phenotypes of offspring42. A **dihybrid cross** involves the genetic crossing of two traits43. **Incomplete dominance** occurs when a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blending of the parental traits44. **Codominance** occurs when a cross between organisms with two different phenotypes produces offspring with a third phenotype in which both parental traits appear together45. The **ABO blood grouping system** is an example of codominance and multiple alleles46. ◦There are three alleles: IA, IB, and i. ◦IA and IB are codominant, while i is recessive47. ◦Four phenotypes are possible: A, B, AB, and O47. ◦Six genotypes are possible: IAIA, IAi, IBIB, IBi, IAIB, and ii47. **Sex-Linked Inheritance** **Sex-linked genes** are found on the X or Y chromosomes48. **X-linked dominant disorders** are caused by a dominant allele on the X chromosome48. **X-linked recessive disorders** are caused by a recessive allele on the X chromosome49. Examples of X-linked recessive disorders include hemophilia, color blindness, and muscular dystrophy49\... **Theories of Evolution** **Lamarck\'s Theory of Evolution** proposed that evolution occurs due to the inheritance of acquired characteristics and the law of use and disuse2\.... ◦The **law of use and disuse** suggests that body parts that are used more become stronger, while those not used become weaker2. ◦**Inheritance of acquired characteristics** suggests that traits acquired during an organism\'s lifetime can be passed to offspring, which was proven incorrect3\.... ◦For example, Lamarck would suggest that giraffes developed long necks by stretching to reach high leaves, and passing that longer neck trait to their offspring4\.... **Darwin\'s Theory of Evolution** (also called the Darwin-Wallace Theory of Evolution) proposes that species evolve through natural selection6. ◦**Natural selection** is the process where organisms with favorable variations are more likely to survive and reproduce7. ◦For example, Darwin would say that giraffes with longer necks were naturally selected, because they were able to reach food that giraffes with shorter necks could not reach. Thus, longer neck giraffes survived and reproduced more frequently7. **Alfred Russel Wallace** is a scientist also credited for developing a theory of evolution similar to Darwin's8. **Charles Darwin** made many of his discoveries during his voyage on the HMS Beagle, particularly in the Galapagos Islands9. **Natural Selection** **Natural selection** acts most directly on a **population**, not an individual1\.... **Survival of the fittest** is a phrase used to describe natural selection, where \"fitness\" refers to the ability to survive, find a mate, and produce offspring6. **Evidence of Evolution** The sources describe four types of evidence for evolution1: 1.**Biogeography** is the study of the geographical distribution of species, suggesting species evolve in one location and spread to others11\.... 2.**The fossil record** provides evidence of past life and shows a chronological collection of life's remains in rock layers, indicating species have changed over time and some have gone extinct13. ▪**Relative dating**, such as stratigraphy (rock layers), is used to determine the approximate age of fossils by comparing them to other known fossils13. ▪**Absolute dating**, such as radiocarbon dating, is used to determine the actual age of a fossil in years14. 3.**Comparative anatomy** involves the study of structural similarities between different organisms15. ▪**Homologous structures** are similar in anatomy but may have different functions, indicating common ancestry16\.... ▪**Analogous structures** have similar functions but different anatomical structures, indicating convergent evolution16\.... ▪**Vestigial structures** are functional in one species but not in another15\.... 4.**Molecular biology** uses DNA sequences to determine the relatedness of different species15\.... ▪Organisms with similar DNA sequences are likely to be more closely related17. **Mechanisms of Evolution** There are six mechanisms of evolution1\...: 1.**Genetic drift** is a random change in allele frequencies within a population, which can occur due to the bottleneck effect or the founder effect20. 2.**Gene flow** is the movement of genes between populations through migration20\.... 3.**Mutations** are changes in the DNA sequence that introduce new variations into a population10\.... 4.**Sexual selection** is a form of natural selection where individuals with certain traits are more likely to find mates1\.... ▪**Sexual dimorphism** is a difference in appearance between males and females of the same species1\.... 5.**Artificial selection** is the process where humans select for certain traits in organisms, which can have both advantages and disadvantages20\.... 6.**Natural selection** is the process where individuals with certain traits are more likely to survive and reproduce6\.... ▪there are three types of natural selection: **Directional selection** favors one extreme phenotype24. **Stabilizing selection** favors intermediate phenotypes24. **Disruptive selection** favors both extreme phenotypes, but not intermediate ones24. **Allele frequency calculations** measure the proportion of each allele in a population23\.... **Speciation** **Speciation** is the process by which new species arise from existing ones23\.... ◦**Allopatric speciation** occurs when populations are geographically separated, leading to reproductive isolation and genetic divergence28. ◦**Sympatric speciation** occurs when populations become reproductively isolated without physical separation29\.... New species are likely to form when populations become reproductively isolated23\.... **Adaptation** **Adaptation** is the process by which organisms become better suited to their environment32. ◦**Structural adaptations** involve physical parts of an organism's body, such as wings on a bird32. ◦**Physiological adaptations** involve the chemicals needed for an organism to perform a function, such as the production of spider webs32\.... ◦**Behavioral adaptations** involve reactions to the environment, such as the migration of birds33. **Mimicry** **Mimicry** is when one species changes to resemble another33. ◦**Batesian mimicry** is when a harmless species mimics a harmful one34. ◦**Mullerian mimicry** is when a harmful species mimics another harmful species34. **Reproductive Isolating Mechanisms** **Reproductive isolating mechanisms** prevent different species from interbreeding31. ◦**Pre-zygotic mechanisms** prevent fertilization and zygote formation35. ▪**Behavioral isolation** occurs when different species use different courtship rituals36. ▪**Temporal isolation** occurs when different species breed at different times36. ▪**Habitat isolation** occurs when different species occupy different habitats in the same region37. ▪**Mechanical isolation** occurs when differences in physical features make mating incompatible37. ◦**Post-zygotic mechanisms** prevent a fertilized egg from growing into a viable, reproducing adult35. ▪**Hybrid inviability** occurs when offspring from two species does not survive38. ▪**Hybrid infertility** occurs when the offspring of two species is sterile38. ▪**Hybrid breakdown** occurs when the first generation of hybrids are viable and fertile, but later generations are not38. **Rate of Evolution** There are two theories for the rate of evolution39: ◦**Gradualism** suggests that species evolve gradually through the accumulation of small variations over long periods of time39\.... ◦**Punctuated equilibrium** suggests that species remain relatively unchanged for long periods, but evolve rapidly in short bursts40 **Digestive System** The digestive system is responsible for breaking down food into smaller components that the body can absorb3. **Structures of the digestive system**: ◦The **alimentary canal** is a 7-9 meter long canal that includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus4\.... ◦**Accessory organs** such as the salivary glands, liver, gallbladder, and pancreas, are connected to the alimentary canal by ducts and secrete substances needed for digestion4\.... **Peristalsis** is the muscular contraction that pushes food through the digestive tract2\.... **Macromolecules (biomolecules)** are large molecules necessary for life including carbohydrates, proteins, and lipids (fats)2\.... ◦**Carbohydrates** are broken down into **monosaccharides**, such as glucose, fructose, and galactose8\.... ◦**Proteins** are broken down into **amino acids**8\.... ◦**Lipids (fats)** are broken down into **fatty acids** and **glycerol**10\.... **Enzymatic reactions** are chemical reactions that are sped up by enzymes2\.... ◦**Amylase** breaks down starches into maltose2\.... ◦**Pepsin** breaks down proteins into polypeptides2\.... ◦**Lipase** breaks down fats into fatty acids and glycerol2\.... **Nutrient absorption** primarily occurs in the small intestine2\.... ◦**Capillaries** absorb all digested nutrients except lipids18. ◦**Lacteals** absorb digested lipids18. The pancreas produces **insulin and glucagon**, which regulate blood glucose levels19\.... ◦**Insulin** lowers blood glucose by allowing glucose to enter cells21\.... ◦**Glucagon** raises blood glucose levels13\.... **Increased surface area** is important in the digestive system for absorption, particularly in the small intestine, and in the stomach, to allow for expansion and better mixing of food6\.... Disease: Constipation: Large intestine. Bowel movements as food is difficult to pass Stomach ulcers: open bacterial sores in a stomach Jaundice: Liver. Yellow eyes Gallbladder stones: Hardened deposits in gall bladder Acid reflux: Esophagus. Stomach acid flows back into esophagus Chrons disease: Gastrointestinal track infection. Causes diarrhea and weight loss Celiac disease: Autoimmune disorder in small intestine. Gluten damages small intestine Diarrhea: Small intestine or colon **Respiratory System** The respiratory system facilitates gas exchange between the body and the environment25. **Structures of the respiratory system**: ◦**Trachea** (windpipe) is a hollow tube that connects the pharynx to the bronchi, and is made of cartilage to prevent it from collapsing19\.... ◦**Bronchi** are two tubes that carry air from the trachea into the lungs19\.... ◦**Bronchioles** are smaller branches of the bronchi inside the lungs19\.... ◦**Alveoli** are tiny air sacs in the lungs where gas exchange occurs19\.... **Filtering** in the respiratory system is accomplished by the cilia and mucus lining the respiratory tract, which trap and remove foreign particles19\.... **Inhalation** involves the diaphragm contracting and moving down, while the intercostal muscles contract and expand the rib cage19\.... This causes the lungs to expand, drawing air in31. **Exhalation** involves the diaphragm and intercostal muscles relaxing, which decreases the volume of the thoracic cavity and forces air out of the lungs19\.... **Breathing rate control** is regulated by the concentration of carbon dioxide in the blood19\.... **Increased surface area** is important in the respiratory system, particularly in the alveoli, to allow for efficient gas exchange24\.... **Circulatory System** The circulatory system transports materials throughout the body34. **Structures of the circulatory system**: ◦**Arteries** carry oxygenated blood away from the heart, except for the pulmonary artery, which carries deoxygenated blood to the lungs19\.... ◦**Veins** carry deoxygenated blood back to the heart, except for the pulmonary vein, which carries oxygenated blood from the lungs to the heart19\.... ◦**Capillaries** are small blood vessels where the exchange of gases, nutrients, and waste occurs between the blood and the body cells19\.... **Hemoglobin** is a protein in red blood cells that carries oxygen19\.... The circulatory system has **two circuits**: ◦The **pulmonary circuit** moves blood between the heart and the lungs19\.... ◦The **systemic circuit** moves blood between the heart and the rest of the body19\.... **Homeostasis** is the maintenance of a stable internal environment19\.... **Blood pressure** is the force of blood against the walls of the blood vessels19\.... ◦**Systole** is the contraction phase of the heart, where blood pressure is higher19\.... ◦**Diastole** is the relaxation phase of the heart, where blood pressure is lower19\.... ◦A normal blood pressure reading is around 120/80 mmHg19\.... **Increased surface area** is important in the circulatory system, such as in the capillaries, for efficient exchange of nutrients and waste24. **Diseases** Bronchitis: Inflammation of bronchiole tubes. In Bronchi Pneumonia: Infection inflaming air sacs in lungs. Lungs Tuberculosis(TB): Bacteerial infection in lungs Emphysema: Chronic damage to alveoli Asthma: Chronic causing airway inflammation Cystic fibrosis: Genetic. Cuses thick mucus. Lungs and digestive system Chronic obstructive pulmonary disease (COPD): Group of lung disease Pneumothorax: Collapsed lung due to air leaking from lung