Genetics PDF

Rheanna Maryen Tandog Molecular Genetics GENETICS Focuses on the chemical nature The scientific study of heredity. of genes. Genetics is essential for Studies the structure, organization,...

Rheanna Maryen Tandog Molecular Genetics GENETICS Focuses on the chemical nature The scientific study of heredity. of genes. Genetics is essential for Studies the structure, organization, understanding how traits and and function of genes. characteristics are passed from Major topics: one generation to the next, How genetic information is providing insights into disease encoded, replicated, and inheritance, biological diversity, processed. and evolution. The cellular processes of Divided into three major fields: replication, transcription, and Transmission Genetics (Classical translation. Genetics) Gene regulation: The process Molecular Genetics controlling the expression of Population Genetics genetic information. Why Genetics is Important? Population Genetics Medicine: Helps in understanding Explores the genetic composition the genetic basis of diseases, of groups of individuals, primarily enabling diagnosis, treatment, and within the same species. prevention of genetic disorders. Focuses on how the genetic Agriculture: Used to improve composition of a group changes crops and livestock by selecting for over time. beneficial traits. Evolutionary Genetics Livestocks (different breeds, Divided into five main categories: leaner beef, polled vs horned Phylogenetics cattle) Mutation and molecular population Transmission Genetics (Classical genetics Genetics) The genetics of speciation Studies the basic principles of Genome evolution genetics and how traits are Evolution and development passed from one generation to (Evo-Devo) the next. Mendel’s Peas Major topics: Mendel used peas in his experiments The relationship between because they were: chromosomes and heredity. Easy to grow. The arrangement of genes on Had easily identifiable traits. chromosomes. Allowed him to work with large Gene mapping: Determining numbers of samples where certain genes are located GENETICS P2 on chromosomes. Genetics Focuses on how individual The study of how traits are organisms inherit their genetic passed from parent to offspring. makeup and pass genes to their Traits are determined by genes, descendants. which are segments of DNA on chromosomes. Chromosomes come in homologous pairs, with one chromosome from each parent.  Gregor Mendel – The "Father of Probability of having a boy or girl: Genetics" 50% each. Developed the Principle of Incomplete Dominance and Independent Assortment: The Codominance inheritance of one trait has no Incomplete dominance: One effect on the inheritance of another allele is not completely dominant trait. over another, resulting in a blend. Dominant and Recessive Genes Example: Red carnations (R) crossed with Dominant gene: Prevents the white (W) produce pink (RW). expression of another gene. Codominance: Both alleles are Recessive gene: Does not show expressed equally. if a dominant gene is present. Example: In chickens, black and white Represented with letters: feathers are codominant, resulting in Uppercase for dominant (T), speckled feathers. lowercase for recessive (t). Sex-linked Traits Example: Genes for these traits are located Straight thumb (T) is dominant to on the X chromosome (not on the hitchhiker thumb (t). Y). These traits show up more Homozygous individuals: TT often in males because they (straight thumb), tt (hitchhiker only have one X chromosome. thumb). Examples: Heterozygous: Tt (straight thumb). Color Blindness: A recessive Genotype and Phenotype sex-linked trait where individuals Genotype: The genetic makeup cannot distinguish certain (e.g., TT, Tt, tt). colors. Phenotype: The physical Hemophilia: A disorder where expression of the trait (e.g., blood doesn’t clot properly. straight thumb or hitchhiker Mutations thumb). A mutation is a sudden genetic Punnett Squares change, specifically a change in Tool used to predict possible gene the base pair sequence of DNA. combinations in offspring. Mutations can be classified as: Example: Black fur (B) is dominant over Harmful mutations: organism white fur (b) in mice. Cross a less able to survive: genetic heterozygous male (Bb) with a disorders, cancer, death homozygous recessive female (bb): Beneficial mutations: allows Genotypic ratio: 50% Bb, 50% bb. organism to better survive: Phenotypic ratio: 50% black, 50% provides genetic variation white. Neutral mutations: neither Sex Determination harmful nor helpful to organism Humans have 23 pairs of chromosomes, with 22 pairs of Mutations can occur in two main forms: autosomes and 1 pair of sex Chromosomal Mutation chromosomes (XX for females, XY Less common than gene for males). mutations but more drastic. The father determines the sex of Affects entire chromosomes, the child. altering many genes.  Caused by the failure of carry enough oxygen to body homologous chromosomes to tissues, but being heterozygous for separate properly during meiosis this condition offers protection from (cell division that produces malaria. gametes). Cystic Fibrosis: Caused by a Chromosome pairs may not look recessive gene mutation that leads the same after the mutation, to the buildup of mucus in the leading to too few or too many lungs, causing respiratory and genes, or changes in chromosome digestive problems. shape. Tay-Sachs Disease: A recessive Examples of Chromosomal Mutations: gene mutation that leads to the Down’s Syndrome (Trisomy 21): deterioration of the nervous An individual has an extra system, often resulting in early chromosome at pair #21, death. Mutated genes produce resulting in 47 chromosomes enzymes that cannot break down instead of 46. fatty substances (gangliosides), Turner’s Syndrome: Affects causing them to accumulate in females who have only 45 cells. chromosomes, missing one sex Phenylketonuria (PKU): A chromosome (X). Symptoms recessive gene mutation where the include short stature, slow growth, amino acid phenylalanine cannot and heart problems. be broken down, leading to its Klinefelter’s Syndrome: Affects buildup, which causes mental males with 47 chromosomes due retardation. Newborns are tested to an extra X chromosome (XXY). for this condition so it can be Boys with this condition may have managed early. low testosterone levels, Dominant Gene Mutations: underdeveloped muscles, and Huntington’s Disease: A sparse facial hair. dominant mutation causing the Polyploidy: Having an extra set gradual deterioration of brain of chromosomes, which is tissue, usually manifesting in typically fatal in animals but can middle age and ultimately leading make plants larger and more to death. resilient. Dwarfism: A dominant mutation Gene or Point Mutation that results in various skeletal The most common type of abnormalities​ mutation. Detecting Genetic Disorders Less drastic because it only picture of an individual’s chromosomes – affects a single gene. karyotype This mutation alters just one base amniotic fluid surrounding the embryo is pair in the DNA sequence of a removed for gene. analysis – amniocentesis BASIC GENETICS Examples of Gene Mutations: Mendelian Genetics: The study of Sickle Cell Anemia: A recessive heredity, initiated by Gregor gene mutation where red blood Mendel, who is known as the cells become sickle-shaped "father of genetics". He observed instead of round. These cells can't  how traits are passed from parents Charles Darwin is considered the to offspring. Father of Evolution, known for his Pea Plant Experiments: Mendel theory of Natural Selection. chose pea plants because they Charles Darwin: The Father of grew quickly, allowed control over Evolution reproduction, and had easily Charles Darwin (1809-1882): observable traits such as seed Born in Shrewsbury, England. shape, seed color, pod shape, and Studied medicine and later earned stem height. a degree in theology. Generation Naturalist who developed the P Generation: Purebred parent theory of evolution by natural plants. selection. F1 Generation: Hybrid offspring Buried in Westminster Abbey. from cross-pollination of purebred Darwin’s Theory of Evolution: plants. Evolution refers to how modern F2 Generation: Offspring from organisms have descended from crossing F1 plants, showing a 3:1 ancient organisms through ratio of dominant to recessive changes over time. traits. A scientific theory is a Genes and Alleles: well-supported, testable Traits are controlled by genes, explanation of natural world which exist in pairs called alleles. phenomena. Homozygous means having two Ideas That Shaped Darwin’s Thinking identical alleles, while James Hutton: heterozygous means having two Introduced the Theory of different alleles. Geological Change (1795), Mendel’s Laws: stating that Earth's surface is Law of Segregation: Alleles are shaped slowly over time. separated during the formation of The Earth is much older than sex cells. thousands of years, which Principle of Dominance: Some supports the long process of alleles are dominant, others are evolution. recessive, and the dominant allele Charles Lyell: will be expressed if present. Wrote Principles of Geography, Punnett Square: A tool used to proposing that geographical predict the probability of features are built up or torn down offspring inheriting specific over time. combinations of alleles.This is a Darwin applied this to life, grid designed by Reginald reasoning that if Earth could Punnett to keep track of the change over time, so could alleles. species. Jean-Baptiste Lamarck’s Theory of EVOLUTION Evolution: Evolution is the process by which Tendency Toward Perfection: species change over time to adapt Organisms strive for perfection to their environments. (e.g., giraffe necks becoming longer to reach high leaves).  Use and Disuse: Parts of the body adapted to specific diets on each that are used frequently grow island (e.g., seeds, insects, stronger, while unused parts nectar). weaken (e.g., birds using forelimbs Darwin concluded that species on for flight). these islands had adapted to their Inheritance of Acquired Traits: environments over time, a key Traits acquired during an observation for his theory of organism's lifetime are passed to natural selection. offspring, although this idea was Animals found in the Galapagos later disproved. – Land Tortoises Thomas Malthus: – Darwin Finches Malthus was a 19th-century – Blue-Footed Booby economist who proposed that – Marine Iguanas population growth would outpace Types of Evolution resources, leading to competition Convergent Evolution: for food, shelter, and space. Unrelated species evolve similar Darwin applied this theory to traits as they adapt to similar animals, seeing competition as a environments (e.g., wings of birds driving force for natural selection. and bats are similar in function but Alfred Russel Wallace have different origins). An English naturalist who Divergent Evolution: independently developed a A single species evolves into theory of evolution by natural multiple distinct species due to selection. adapting to different environments Wallace's essay on evolutionary (e.g., Darwin’s finches in the change from his work in Malaysia Galapagos). prompted Darwin to publish his Natural Selection and Artificial own findings. Selection Voyage of the H.M.S. Beagle Natural Selection: Dates: February 12, 1831, to 1836. The process where organisms with Captain: Charles Darwin. beneficial traits survive longer, Ship: H.M.S. Beagle. reproduce more, and pass on Destination: Voyage around the those traits to their offspring. world, especially the Galapagos Also known as Survival of the Islands. Fittest, where the "fittest" are those Findings: Darwin observed best suited to their environment. variations in species, collecting Artificial Selection: evidence to support the idea of Humans select specific traits in natural selection. plants and animals to breed for those traits, such as breeding dogs Discoveries in the Galapagos Islands for size or cattle for milk Darwin studied plants, animals, production. and fossils during the voyage. Darwin realized this process was He noticed variations in species similar to natural selection, except from island to island, especially in driven by human choice. finches. Finch Beaks: Different species of finches had different beak shapes Key Components of Natural Selection Fossil Evidence Genetic Variation: Fossils provide a record of Species show differences among species that lived in the past, individuals (e.g., no two zebras showing how organisms have have the same stripe pattern). changed over time. Struggle for Existence: Fossil Record: A collection of Organisms must compete for fossils used to show the limited resources such as food, progression of species. water, and shelter. Relative-Age Dating: Determines Survival of the Fittest: the age of fossils by comparing the Individuals with traits best suited to rock layers in which they are their environment are more likely to found. survive and reproduce (e.g., Absolute-Age Dating: Uses giraffes with longer necks are radioactive decay to determine the better able to reach food during exact age of fossils. droughts). Biological Evidence of Evolution Descent with Modification: Comparative Anatomy: Over generations, beneficial traits Homologous Structures: Similar become more common in the structures in different species that population, leading to the evolution indicate a common ancestor (e.g., of new species. the forelimbs of humans, bats, and Adaptations whales). Adaptation: An inherited trait that Analogous Structures: Structures increases an organism's chance of that serve similar functions but survival and reproduction in its have different evolutionary origins environment. (e.g., wings of birds and insects). Types of Adaptations: Vestigial Structures: Body parts Structural: Physical that no longer serve a function but characteristics (e.g., the thick fur of were useful in an ancestor (e.g., polar bears for insulation in cold human appendix). climates). Embryology: Behavioral: Changes in the way The study of the development of an organism acts (e.g., birds embryos shows that many species migrating to warmer climates share similar early development during winter). stages, suggesting a common Functional: Internal processes ancestry. (e.g., snake venom production for Molecular Biology: defense and hunting). Comparing DNA and proteins Camouflage: Allows species to among species shows genetic blend into their surroundings (e.g., similarities, indicating evolutionary a chameleon changing color to relationships. match its environment). Example: Molecular data indicate that Mimicry: One species evolves to whales and porpoises are more closely resemble another for protection related to hippopotamuses than to other (e.g., a harmless butterfly marine mammals. mimicking a poisonous one to Speciation avoid predators). Speciation is the process by which new species form as populations of  the same species become data with a significant emphasis on reproductively isolated and adapt DNA sequence data in to different environments. contemporary studies. Phylogenetic Tree: A diagram that Key Concepts and Terminology shows the evolutionary history of a Phylogenetics - The study of species or group of species. ancestor descendant relationships. Darwin’s Contributions Phylogeny - A hypothesis of Provided evidence that species ancestor descendant relationship. evolve over time. Phylogenetic tree - A graphical Proposed the theory of Natural representation summarizing Selection to explain how evolution phylogenetic relationships occurs. Taxa - Groups of organisms at Demonstrated that new species various levels of classification evolve by replacing less successful Internal nodes - Represent species. common ancestors in a Fossils show that species have phylogenetic tree evolved from ancestors that are Sister groups - Two taxa that now extinct. arise from the same node Key Points to Remember indicating close evolutionary Evolution by Natural Selection relationship. Descendants from the explains how species change over same node (e.g., species A & B). time by adapting to their Edges - Sometimes represent environments. evolutionary time. Adaptations are inherited traits that Outgroup - A taxon outside the improve an organism’s survival group of interest providing context and reproductive success. for the relationships within the Fossils, comparative anatomy, ingroup embryology, and molecular biology Clades - groups of organisms that all provide evidence supporting include an ancestor and all its evolution. descendants clades are depicted Natural Selection is an ongoing as branches on the tree of life process, and species continue to Clades are nested within one evolve as they adapt to changing another - they form a nested environments. hierarchy. Types of Phylogenetic Trees PHYLOGENY Rooted trees - Directed trees with Introduction a unique root node indicating the Phylogeny is the study of the most recent common ancestor. evolutionary relationships among Unrooted trees - Illustrate various biological species or taxa relationships without assumptions which are believed to have about common ancestry common ancestors. Understanding Dendogram - The genetic term phylogeny is crucial as it explains applied to any type of digrammatic the diversity of life forms on Earth. representation. The construction of phylogenetic Cladograms - Trees where trees uses various data types branch lengths do not represent including morphological, evolutionary time physiological and molecular  Phylograms Trees - where from a common ancestor (e.g., branch lengths do represent vertebrate limbs). evolutionary time Homoplasy - State that look similar but arose independently Construction of Phylogenetic Trees due to convergent or parallel Data Collection - Biologists collect evolution (e.g., fins in sharks and data on heritable traits such as whales). morphology genetic sequences and behavioral traits Why can Homoplasy Occur? Character States - In molecular phylogenetics characters are Convergent Evolution - When typically nucleotide positions in a different species develop similar gene sequence with four possible adaptations to the same states A C G T environment. Parallel Evolution - When closely Cladistic character state definitions: related species evolve similar traits independently due to similar Plesiomorphy - An ancestral selection pressures. character state. Secondary loss - reversion to Apomorphy - A derived state ancestral condition different from the ancestral state. Synapomorphy - A shared Methods of Phylogenetic Analysis derived state, indicating common ancestry. Parsimony - A principle stating Autapomorphy - A uniquely that simpler explanations are derived state. preferred the tree with the least Homoplasy - Similar state arising evolutionary changes is considered independently (e.g., through most parsimonious convergent evolution). Parsimony (Cladistics): The simplest More Synapomorphies explanation, or the tree with the fewest evolutionary changes, is Monophyletic Group - A true preferred. clade, includes all descendants of Example: In whale evolution, fewer a common ancestor. changes suggest that whales are Non Monophyletic - Any case that part of the Artiodactyla (which does not satisfy the above such as includes hoofed mammals like Paraphyletic Group - Includes deer, pigs, and camels.), a group some but not all descendants (e.g., of even-toed ungulates. reptiles). Outgroup - A taxon outside the Polyphyletic Group- Erroneously group of interest, used to root the grouped taxa due to homoplasy phylogenetic tree and determine (e.g., vultures). the direction of evolutionary changes. Homology vs. Homoplasy Bootstrap Method - A computational technique used to Homology - A State shared by two estimate the confidence level of or more taxa due to inheritance phylogenetic hypotheses by generating new datasets and  analyzing the frequency of 1. Dewey Decimal System: Used in groupings libraries. 2. Sections of Stores: Such as a CLASSIFICATION AND music store. CHARACTERISTICS OF SPECIES 3. Periodic Table of Elements: Used 1.Characteristics of Living Things in chemistry. Made of Cells - Unicellular vs 4. Others: Various other examples of multicellular organisms classification systems. Examples: Red blood cells onion skin epidermal cells D. Binomial Nomenclature Growth and Development - Increase in cell size, number, 1. A system of scientific naming. development, aging and death 2. Developed by Carolus Linnaeus Obtains & Uses Energy - (Swedish botanist) in the 1750s. Metabolism (Anabolism - builds up, 3. The scientific name consists of two Catabolism - breaks down) parts: Genus and species. Examples: Heterotrophic - other feeding 4. The name must be underlined or (animals) vs autotrophic - self feeding in italics. (plants) 5. The names are in Latin (the dead Reproduction - Asexual (one language of scholars). parent) vs sexual (two parents) Example: Response to Environment - Movement: Internal or external E. Homo sapiens: motion. Irritability: Ability to respond to ○ Homo = Genus (capitalized stimuli like touch or light. and underlined/italicized). Adaptability: Ability to adjust to ○ sapiens = Species (not the environment. capitalized, but underlined/italicized). 2. Taxonomy F. Definition of Species: Taxonomy: The science of naming 1. Can breed successfully, producing things and assigning them to viable, fertile offspring. groups. 2. Unique features similar to others of the same species. B. Why Have a Classification 3. Have similar DNA to other System? members of the species. G. 7 Taxa of Living Things (taxon = 1. To provide a single, universal group): name. 1. Kingdom (kings) 2. To avoid confusion. 2. Phylum (play) 3. To understand how living things 3. Class (chess) are related to one another. 4. Order (on) 5. Family (fine) C. Examples of Classification 6. Genus (green) Systems: 7. Species (silk) H. Kingdom: Plantae: Plants. Kingdom is the least specific and Animalia: Animals, including the largest group. humans. I. Species: 3. Species Species is the most specific and Definition - The smallest contains only one kind of classification unit where individuals organism. can interbreed and produce fertile J. Example of Classification: offspring Kingdom: Animalia Example: Mountain lion Felis concolor Phylum: Chordata Reproductive Isolation - Class: Mammalia Mechanisms that prevent species Order: Primates from interbreeding Family: Hominidae Prezygotic Barriers - Prevent Genus: Homo fertilization Species: sapiens Habitat Isolation - Species live in K. Other Systems of Classification: different areas Cladograms: Diagrams showing Example: Polar bears and brown bears relationships among organisms. Temporal Isolation - Species Three-Domain System: breed at different times Archaea Example: American toads and Fowlers Bacteria toads Eukarya Behavioral Isolation - Species L. What Determines How Something is use different mating signals Classified?: Example: Magnificent Riflebirds unique DNA mating dance Structure Mechanical Isolation - Physical Embryology and development differences prevent mating M. Definitions: Example: Mallard ducks have Prokaryotic: Does not have a incompatible reproductive organs nucleus to contain its DNA. Gametic Isolation - Gametes Eukaryotic: Has a sperm and eggs cannot fuse membrane-bound nucleus. Example: Red and purple sea urchins Taxonomy of Unicellular and Postzygotic Barriers - Hybrids do Multicellular Organisms: not survive or are sterile Unicellular: Organisms that consist of a Example: Liger sterile offspring of a lion single cell. and tiger Examples: 4. Patterns of Speciation Archaebacteria: Ancient bacteria. Punctuated Equilibrium - Species Eubacteria: Most bacteria. remain unchanged for long periods Protista: Mostly single-celled followed by sudden changes eukaryotes like algae and Gradualism Species - change protozoa. slowly and continuously over time 5. Species Identification Concepts Multicellular: Organisms made up of Biological Species - Concept multiple cells. Species are defined by their ability Examples: to reproduce and produce fertile Fungi: Multicellular organisms like offspring mushrooms.  Morphological Species - Concept Kingdom (Animalia) - Multicellular Species are identified by their and unable to produce their own physical traits like size and shape food heterotrophic Phylogenetic Species - Concept Phylum (Chordata) - Presence of Species are classified based on a nerve cord along the back DNA similarities Class (Mammalia) - Warm 6. Binomial Nomenclature Blooded gives birth to live young Definition - A twopart naming system for and has hair organisms Genus and species Order (Primates) - Forwardfacing Example: Redbreasted parakeet eyes enlarged brains and vertical Psittacula alexandri named after posture Alexander the Great Family (Hominidae) - Capacity for Polynomial Nomenclature - language culture and empathy Multiple word naming system Scientific Naming 10. Five Kingdoms Developed by Carolus Linnaeus Monera (Swedish botanist) in the 1750s. Includes archaebacteria and The scientific name consists of two eubacteria parts: Genus and species. All monerans are prokaryotic The name must be underlined or meaning they lack a nucleus in italics. Prokaryotic cells are simple and The names are in Latin (the dead their genetic material is not language of scholars). enclosed in a nuclear membrane Protista 7. Three Domain System - A higher Includes mostly single - celled classification that divides life into eukaryotic organisms Archaea Ancient - prokaryotes Some are autotrophic able to that separates from other form of make their own food like algae bacteria. (extremophiles - live in while others are heterotrophic harsh environment) cannot make their own food like Bacteria - Modern prokaryotes protozoa (Cuase infectious human disease) Protists may move using Eukarya - Eukaryotic organisms structures like cilia, flagella, or with a nucleus and organelles. amoeboid movement Protozoa are animal - like protists 8.Classification System that are heterotrophic and can The most common system of classification move independently is the five kingdom system It organizes Algae are plant - like protists that living things into a hierarchy of groups have chlorophyll and carry out Kingdom photosynthesis Phylum Slime molds are fungus - like Class protists that absorb nutrients from Order dead or decaying matter Family Fungi Genus Includes both single - celled and Species multicellular organisms that are heterotrophic 9. Human Classification  Fungi obtain their nutrients through Circulation, Distribution of absorption nutrients and gases throughout the Saprophytes live on dead or body decaying matter while parasites Nervous, system For sensing and feed on living organisms. responding to the environment Symbionts will live in close Animal Phyla relationship with another (fungi and Porifera The most primitive algae in lichens) animals They have no distinct Fungi have cell walls made of tissues or organs, they are sessile chitin a polysaccharide (different (permanently attached to solid from the cellulose in plant cell sureface) and exhibit asymmetry walls) (no distinct body pattern) Fungi reproduce through spores are filter feeders (they strain their which are small singlecelled food from water) reproductive structures Example: Sponges Fungi are usually non-motile. Cnidaria - Radial symmetry Examples Mushrooms mold (appendages originate from a central point) stinging cells Plantae cnidocytes and a simple nervous Includes all multicellular, system. May be sessile or autotrophic organisms plants freeliving that are non-motile Example: Jellyfish anemones Plants have cell walls made of Platyhelminthes Also known as cellulose flatworms they have bilateral They also have a higher degree symmetry, parasitic or of organization than protists and free-living, and lack an anus fungi with specialized organs like having an incomplete digestive roots stems and leaves system Plants carry out photosynthesis Example: Tapeworms to make their own food using Nematoda Also known as chlorophyll roundworms, they have a complete digestive system and Animalia exhibit sexual dimorphism Includes all eukaryotic, physically different males and multicellular, heterotrophic females. organisms animals Example: Ascaris Most animals have a high degree Annelida Segmented worms with of motility compared to other multiple organ systems such as kingdoms digestive, circulatory and Animals range from simple to complex and respiratory systems include organisms with intricate organ Example: Leeches earthworms systems such as: Arthropoda Characterized by Respiration, gas exchange of jointed appendages and a sturdy oxygen and carbon dioxide exoskeleton made of chitin This is Digestion, Breaking down the most diverse phylum complex molecules using enzymes Example: Insects spiders Mollusca phylum soft-bodied species with radical symmetry that  may be aquatic or land-dwelling. Features Bilaterally symmetrical animals many of which have hard animals have external shells. They possess a Anterior (front), Posterior (back) mantle which secretes calcium Dorsal (upper) Ventral (lower) carbonate to form the shell. sides Example: Snails octopuses Differentiation of Germ layers: Echinodermata Radial symmetry Endoderm (innermost germ layer) in adults spiny covering and found - Develops into the linings of the exclusively in marine organisms. digestive and respiratory They also have complete digestive systems and reproductive systems Example: Gut lining Example: Starfish sea urchins Mesoderm (Middle Layer) - Forms Chordata All members possess a muscles and systems like hollow, tubular nerve cord along circulatory reproductive and the back Some develop a vertebral excretory column backbone Example: Heart muscles Example: Humans fish reptiles Ectoderm (outermost layer) - Develops into the skin nerves and ANIMAL - BODY - PLANTS and sensory organs EVOLUTION Example: Nervous system skin Levels of Organization Body Cavities Tissues - Groups of specialized Coelom - True body cavity fully cells performing similar lined with mesoderm functions Example: Annelids earthworms Examples Acoelomates - Animals without a Epithelial tissue - Covers body cavity surfaces like the lungs allowing Example: Flatworms easy gas diffusion Pseudocoelomates - Body cavity Muscle tissue - Enables only partially lined with movement mesoderm Nervous tissue - Conducts nerve Example: Roundworms impulses Patterns of Embryological Organs and Systems Tissues - Development combine to form organs and organ Begins as a zygote fertilized egg systems forming a blastula hollow ball of Example: Digestive system Includes the cells mouth stomach intestines and anus Protostomes - The blastopore Body Symmetry develops into the mouth Radial Symmetry - Body parts Example: Mollusks arthropods eg insects arranged around a central point Deuterostomes - The blastopore Example: Sea anemones develops into the anus Bilateral Symmetry - Body can Example: Chordates, echinoderms (eg be divided into mirror image left starfish) and right sides Segmentation Examples: Humans, insects and most Body divided into repeated parts animals or segments Example: Centipedes earthworms  Found in many bilaterally symmetrical animals like insects and vertebrates. Cephalization Concentration of sense organs and nerve cells at the head Examples: Insects, vertebrates Insect and vertebrate embryos Heads form through fusion and specialization of body segments The Cladogram of Animals Limb Formation Bilaterally symmetrical animals typically have external appendages Examples Worms Simple bristles Spiders Jointed legs Dragonflies Wings Birds Wings Dolphins Flippers Represents evolutionary Frogs Legs relationships among animal phyla based on traits fossil records and Body Plans and Evolution genetics Body plans of modern Example: The cladogram shows the invertebrates and chordates evolutionary history of animals and suggest evolution from a common highlights the sequence in which key traits ancestor evolved like bilateral symmetry and cephalization Evolutionary Experiments Each phylum represents an evolutionary experiment where a body structure adapts to an environment Example: Fish brains are simpler than monkey brains but fish have survived and thrived in aquatic environments for millions of years Invertebrates Have simpler systems but function well enough to survive (eg jellyfish) Chordates More complex body systems (eg mammals) Lesson 5: Chromosome and (e.g., Cri du Chat Syndrome - deletion in Chromosomal Aberrations chromosome 5). Inversions: Flipped Key Concepts segments; classified as Chromosome: Thread-like pericentric (involving structure in the nucleus composed centromere) or paracentric. of DNA and proteins; carries Translocations: Exchange genetic information. between non-homologous Chromosomal Number: chromosomes. Humans: 46 chromosomes (23 pairs); 22 pairs of autosomes, 1 pair of sex chromosomes. Lesson 6: DNA Structure and Function Male: 46, XY; Female: 46, XX. Key Concepts Karyotype: Visual representation of chromosomes in an organism. DNA: Structure: Double helix, Chromosomal Aberrations composed of nucleotides (sugar, phosphate, 1. Aneuploidy: Gain or loss of nitrogenous bases - A, T, individual chromosomes. G, C). Caused by Nondisjunction: Function: Stores, copies, Failure of chromosomes to and transmits genetic separate during meiosis. information. Examples: Replication: Trisomy: Extra Semi-conservative process chromosome (e.g., involving: Down Syndrome - Helicase: Unwinds Trisomy 21). DNA. Monosomy: Missing DNA Polymerase: chromosome (e.g., Adds Turner Syndrome - complementary 45, X). bases. Effects: Developmental, Okazaki Fragments: physical, and mental Formed on the abnormalities. lagging strand. 2. Polyploidy: Possessing more than DNA Ligase: Seals two sets of chromosomes (e.g., gaps. triploid, tetraploid). RNA: Common in plants and Types: some amphibians. mRNA: Carries 3. Structural Changes: genetic code from Duplications: Extra DNA to ribosomes. chromosome segments. Deletions: Loss of chromosome segments  tRNA: Transfers Prokaryotic cells: Occurs amino acids to without a nucleus but ribosomes. follows a similar process rRNA: Structural with some differences. component of When It Occurs: During interphase, ribosomes. before mitosis or meiosis. Key Players (Enzymes) Classic Experiments Helicase: Unzips the DNA by 1. Griffith's Experiment: breaking hydrogen bonds between Demonstrated complementary bases. transformation, where DNA Polymerase: The builder; genetic material from dead replicates DNA molecules to build bacteria altered live new strands. bacteria. Primase: The initializer; creates 2. Hershey-Chase Experiment: RNA primers to indicate where Proved DNA, not protein, is DNA polymerase should start. the genetic material. Ligase: The gluer; seals gaps between Okazaki fragments on the Gene Expression lagging strand. Single-Strand Binding Proteins 1. Transcription: DNA → mRNA. (SSBs): Prevent DNA strands from Enzyme: RNA Polymerase. re-annealing after separation. Product: Complementary Topoisomerase: Prevents mRNA strand. supercoiling by managing the 2. Translation: mRNA → Protein. overwinding of DNA strands. Codons: Triplets of nucleotides coding for Steps of DNA Replication amino acids. Ribosomes facilitate 1. Initiation: assembly of amino acids Begins at the origin into proteins. (specific DNA sequences recognized for replication). Helicase unwinds the DNA, Summary of DNA Replication - Amoeba creating replication forks. Sisters SSBs bind to strands to keep them apart. Key Points About DNA Replication Topoisomerase prevents supercoiling near the Definition: DNA replication is the replication fork. process of creating an identical 2. Primer Placement: copy of DNA, necessary before cell Primase synthesizes RNA division to ensure daughter cells primers on both strands to receive DNA. guide DNA polymerase. Where It Occurs: 3. Elongation: Eukaryotic cells: In the Leading Strand: nucleus.  DNA polymerase DNA polymerase has proofreading builds continuously capabilities to correct errors, in the 5’ to 3’ ensuring accurate DNA replication. direction. Lagging Strand: Summary of Protein Synthesis - DNA polymerase Amoeba Sisters builds discontinuously in the 5’ to 3’ direction, General Overview forming Okazaki Protein Synthesis: The process by fragments. which DNA leads to protein Multiple primers are production, resulting in traits like placed due to the eye color. opposite orientation Two Major Steps: (3’ to 5’). Transcription: DNA Primers are later → mRNA. replaced with DNA Translation: mRNA bases. → Protein. Ligase joins Okazaki Purpose of Proteins: fragments, sealing the Essential for various strand. functions (transport, 4. Completion: enzymes, structural roles, Two identical DNA protection, etc.). molecules are formed. Each consists of one original (parent) strand and Step 1: Transcription one newly synthesized Occurs in the nucleus (for strand (semi-conservative eukaryotic cells). replication). Process: RNA Polymerase: Additional Notes Binds to DNA and connects Base Pairing Rules: complementary Adenine (A) pairs with RNA bases to DNA Thymine (T) via 2 hydrogen bases. bonds. Creates a Guanine (G) pairs with single-stranded Cytosine (C) via 3 mRNA (messenger hydrogen bonds. RNA) molecule Anti-Parallel Strands: based on the DNA DNA strands run in template. opposite directions: one 5’ Resulting mRNA leaves the to 3’, the other 3’ to 5’. nucleus and enters the cytoplasm. mRNA Role: Carries the genetic message from DNA to the Proofreading:  ribosome for protein to become a functional synthesis. protein. Step 2: Translation Key Components of Protein Synthesis Occurs in the cytoplasm, at the DNA: Original genetic material ribosome (composed of rRNA - directing protein synthesis. ribosomal RNA). mRNA: Messenger carrying the Process: code from DNA to ribosome. tRNA (transfer RNA): rRNA: Structural component of the Carries specific ribosome, aiding translation. amino acids. tRNA: Adapter molecule that Has an anticodon brings specific amino acids to the that pairs with the ribosome. complementary Codon Chart: Used to determine codon on the which amino acid each mRNA mRNA. codon specifies. Codons: Groups of three Important Notes nucleotides on the mRNA. Start Codon: AUG (codes for Each codon methionine, the first amino acid). corresponds to a Stop Codons: Signal the end of specific amino acid translation; do not code for any (e.g., AUG codes amino acid. for methionine, the Degeneracy of Genetic Code: start codon). Multiple codons can code for the Building Proteins: same amino acid (e.g., leucine). Ribosome reads Protein Folding: After translation, mRNA codons in proteins may undergo folding, sequence. modification, and transport based tRNAs bring the on their function. corresponding amino acids. Amino acids are linked by peptide bonds to form a chain. The process continues until a stop codon is reached, which signals the end of translation. Result: A polypeptide chain (sequence of amino acids), which will fold and modify