Final Exam Review Grade 11 BIO

Unit 1: Diversity of Living Things

• Classification Key Concepts: Classification is essential for organizing biological diversity. The binomial nomenclature system uses a two-part Latin name (genus and species) to uniquely identify each organism. For example, the scientific name of humans is Homo sapiens. Understanding taxa levels is crucial:

• Kingdom: Broadest category (e.g., Animalia, Plantae).

  • Phylum: Groups organisms based on major body plans (e.g., Chordata for vertebrates).

  • Class: Subdivision of phylum (e.g., Mammalia for mammals).

  • Order: Further classification of class (e.g., Primates for primates).

  • Family: Groups of related genera (e.g., Hominidae for great apes).

  • Genus: Group of closely related species (e.g., Homo).

  • Species: Most specific level, representing individual organisms capable of interbreeding.

• Domains: Life is classified into three domains:

  • Archaea: Ancient, single-celled organisms without nuclei; often extremophiles that thrive in harsh environments, such as hot springs or salt lakes. They reproduce asexually.

  • Bacteria: Prokaryotic, unicellular organisms with a wide variety of metabolic pathways. They can be beneficial (e.g., gut bacteria) or harmful (pathogens). They reproduce mainly via binary fission.

  • Eukarya: Organisms with complex cells that include protists (e.g., amoeba, algae), fungi (e.g., mushrooms, molds), plants (e.g., flowering plants, conifers), and animals (e.g., mammals, birds).

  • Each domain has distinct characteristics in cell structure, metabolism, and reproduction methods.

• Kingdom Plantae: Plants exhibit unique adaptations enabling survival across varied environments. These adaptations include:

  • Mosses: Non-vascular plants that rely on water for reproduction (fertilization) and lack true roots, stems, and leaves.

  • Ferns: Vascular plants that reproduce via spores and have true roots, stems, and leaves. They are more advanced in structure than mosses.

  • Conifers: Gymnosperms that produce cones; they are adapted to dry climates with needle-like leaves to reduce water loss.

  • Flowering Plants: Aquatic or terrestrial plants reproduce via flowers and fruits, facilitating efficient seed dispersal. Their lifecycle alternates between two stages: the haploid gametophyte stage (producing gametes) and the diploid sporophyte stage (producing spores).

  • Kingdom Fungi: Fungi are heterotrophic organisms that absorb nutrients from their environment through external digestion. They possess cell walls made of chitin rather than cellulose. Reproduction occurs via spores, and they may reproduce sexually or asexually. Examples include:

  • Molds: Filamentous fungi that reproduce via spores. They play significant roles in decomposition.

  • Yeasts: Unicellular fungi commonly used in baking and fermentation processes (e.g., Saccharomyces cerevisiae).

  • Mushrooms: The fruiting bodies of certain fungi, important in nutrient cycling and as food sources.

• Kingdom Protista: This kingdom is highly diverse, containing both unicellular (e.g., amoeba, paramecium) and multicellular organisms (e.g., seaweeds). Protists can be:

  • Autotrophic: Such as algae, which perform photosynthesis and contribute significantly to oxygen production in aquatic ecosystems.

  • Heterotrophic: Such as protozoa, which consume organic material for energy. Protists are often classified based on movement mechanisms (flagella, cilia, or pseudopodia).

• Kingdom Animalia: This kingdom encompasses all animals, categorized into invertebrates (e.g., insects, jellyfish, mollusks) and vertebrates (e.g., fish, amphibians, reptiles, birds, mammals). Understanding the evolutionary relationships among these groups is explored through comparative anatomy, looking at homologous structures that indicate common ancestry.

• Bacteria Reproduction: Bacteria reproduce primarily through binary fission, a form of asexual reproduction, leading to two genetically identical cells. During conjugation, two bacteria can exchange genetic material through direct contact, which promotes genetic diversity. Common bacterial shapes include:

  • Cocci: Spherical bacteria (e.g., Staphylococcus).

  • Bacilli: Rod-shaped bacteria (e.g., Escherichia coli).

  • Spirilla: Spiral-shaped bacteria (e.g., Spirillum).

• Viruses Replication: Viruses replicate using the host's cellular machinery via two primary cycles:

  • Lytic Cycle: The virus attaches to the host, injects genetic material, replicates itself, and eventually causes the host cell to burst, releasing new viruses.

  • Lysogenic Cycle: The viral DNA integrates into the host genome, allowing it to replicate along with the host’s DNA without destroying the host immediately.

• Cellular Evolution: The transition from prokaryotic to eukaryotic cells involved key processes like infolding of the plasma membrane, leading to the development of organelles, and serial endosymbiosis, the theory that eukaryotes originated through a series of symbiotic relationships involving prokaryotes.

• Measurement: Understanding actual size in microscopy involves using the optical microscope to examine microorganisms and cells. Calculation of total magnification is done by multiplying the eyepiece magnification (typically 10x) by the objective lens magnification (e.g., 40x, 100x).

Unit 2: Genetics

• Punnet Squares: Used to predict offspring ratios from genetic crosses, distinguishing between monohybrid (one trait) and dihybrid crosses (two traits). Recognize patterns of: incomplete dominance (blended traits, e.g., red and white flowers producing pink), codominance (both traits expressed, e.g., AB blood type), and sex-linked traits (traits linked to sex chromosomes, primarily X, such as color blindness).

• Law of Independent Assortment: Mendel's law states that alleles for different traits segregate independently during gamete formation, leading to genetic variation. This law means that the inheritance of one trait generally does not affect the inheritance of another, unless genes are located close together on the same chromosome.

• Cell Division: Mitosis results in two identical diploid cells for growth and repair (PMAT: Prophase, Metaphase, Anaphase, Telophase), while meiosis produces four genetically diverse haploid gametes for sexual reproduction (two rounds of division). Mitosis is essential for somatic cell division, whereas meiosis is critical for producing gametes (sperm and eggs).

• Genetics Terminology: Familiarize with key terms:

  • Genes: Units of heredity located on chromosomes.

  • Alleles: Variants of a gene that can produce different traits.

  • Heterozygous: Having different alleles for a gene (e.g., Aa).

  • Homozygous: Having the same alleles for a gene (e.g., AA or aa).

  • Phenotype: The observable traits resulting from the genotype.

  • Genotype: The genetic makeup of an organism.

  • Pedigree Analysis: A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and how they are passed through generations.

• Non-disjunction Disorders: Non-disjunction occurs when chromosomes fail to separate correctly during meiosis, leading to disorders such as:

  • Down syndrome: Caused by an extra copy of chromosome 21 (trisomy 21).

  • Turner syndrome: Occurs when all or part of one X chromosome is missing in females (monosomy X).

• Genetic Engineering: Techniques used to modify organisms include creating GMOs (genetically modified organisms), using gel electrophoresis for DNA separation during forensic analysis and research, utilizing restriction enzymes to cut DNA at specific sequences, employing recombinant DNA technology to combine genes from different organisms, and applying gene therapy to treat genetic disorders by correcting faulty genes.

• DNA Structure: DNA consists of four nucleotide bases:

  • Adenine (A) pairs with Thymine (T), while Cytosine (C) pairs with Guanine (G). Each base is part of a nucleotide that includes a sugar (deoxyribose) and phosphate group, forming a double helix structure that encodes genetic information.

Unit 3: Evolution

• Proofs of Evolution: Evidence supporting evolution includes:

  • Fossils: Remnants of past organisms found in sedimentary rock layers that show a progression of life forms over time.

  • Geographic Distribution: Observation of similar species in different environments suggesting common ancestry influenced by geography (e.g., finches on the Galápagos Islands).

  • Comparative Anatomy: Study of structures (e.g., bones and limbs) that are similar across various species (homologous structures indicate common ancestry, while analogous structures serve similar functions but arise independently).

  • Embryology: Examination of embryonic development stages showing similarities between different species (e.g., vertebrate embryos).

  • Molecular Biology: Comparison of DNA and protein sequences among species reveals similarities and differences indicative of evolutionary relationships.

• Evolutionary Terminology: Key concepts to understand include:

  • Homozygosity: Individuals with identical alleles (e.g., AA or aa).

  • Divergent Evolution: The process whereby related species develop different traits, often due to different environmental conditions.

  • Natural Selection: The process where organisms better adapted to their environment tend to survive and produce more offspring.

  • Genetic Drift: Random changes in allele frequencies within a population, particularly in small populations, which can lead to significant evolutionary changes over time.

• Key Scientists Contributions: Focus on Charles Darwin, who formulated the theory of natural selection, emphasizing that variations within species are selected for or against by environmental pressures. Also study Alfred Russel Wallace’s similar ideas concerning biogeography.

• Selection Types: Types of selection include:

  • Stabilizing Selection: Favors average traits, reducing variance (e.g., birth weight).

  • Directional Selection: Favors one extreme phenotype (e.g., peppered moth color change during the Industrial Revolution).

  • Disruptive Selection: Favors extremes over the average, leading to speciation (e.g., Darwin’s finches with varied beak sizes).

• Species Concepts: Different ways to define species include:

  • Morphological Species Concept: Based on structural features.

  • Biological Species Concept: Based on the ability to interbreed and produce viable offspring.

  • Genetic Species Concept: Based on DNA similarities and differences.

• Extinction and Earth Eras: Significant geological eras in Earth's history include:

  • Cenozoic: Age of mammals, characterized by diversification following the mass extinction event at the end of the Mesozoic.

  • Mesozoic: Age of reptiles, notably the era of dinosaurs.

  • Precambrian: The earliest part of Earth's history, where simple life forms began to evolve.

  • Paleozoic: Characterized by the Cambrian explosion and the rise of diverse marine and terrestrial life forms. Understand factors (commercial, geological, climate) contributing to mass extinction events.

• Adaptation Examples: Various adaptations enhance survival, such as:

  • Camouflage: Blending in with the environment (e.g., chameleons).

  • Mimicry: Imitating other species for protection or hunting (e.g., viceroy butterflies mimicking monarchs).

Unit 4: Internal Systems

• Digestive System: Study nutrient categories:

  • Carbohydrates: Provide energy; complex carbs (e.g., grains) vs. simple sugars (e.g., glucose).

  • Proteins: Build and repair tissues; consist of amino acids, some of which are essential and must be obtained from diet.

  • Fats: Important for storing energy and insulating the body.Understand digestion processes including:

  • Peristalsis: Coordinated muscle contractions that move food along the digestive tract.

  • Enzymatic Breakdown: The chemical breakdown of food by enzymes (e.g., amylase for carbohydrates).

  • Nutrient Absorption: Occurs primarily in the intestines, where nutrients enter the bloodstream.

• Circulatory System: Learn about:

  • Blood Types: A, B, AB, O; determine compatibility for transfusions based on antigens present in red blood cells.

  • Heart Structure: Composed of four chambers (left/right atria and left/right ventricles) and valves (to prevent backflow of blood).

  • Role of the Pacemaker: Synapses electrical impulses to coordinate heartbeats, thus regulating heart rate.

• Respiratory System: Identify key parts and their roles:

  • Lungs: Main organs for gas exchange, containing alveoli where oxygen and carbon dioxide are exchanged.

  • Trachea: Windpipe leading air to lungs, lined with cilia and mucus for protection.

  • Alveoli: Tiny air sacs that increase surface area for gas exchange.Understand mechanisms of

  • gas exchange: oxygen and carbon dioxide diffusion through alveolar walls and into bloodstream. Common respiratory disorders include asthma (inflammation of airways) and pneumonia (infection causing fluid buildup in lungs).

Unit 5: Plants

• Plant Structures and Functions: Plants have specialized structures that perform various functions essential for their survival:

  • Roots: Anchor the plant in the soil, absorb water and nutrients, and store food.

  • Stems: Support the plant, transport nutrients and water between roots and leaves, and sometimes store food.

  • Leaves: The primary site of photosynthesis; they capture sunlight and convert it into energy. The leaf structure is optimized to maximize light absorption and gas exchange.

• Plant Tissues: Plants are composed of various tissues that perform different functions:

  • Meristematic Tissue: Regions of continuous cell division responsible for plant growth. Apical meristems at the tips of roots and stems lead to vertical growth, while lateral meristems lead to thickness.

  • Ground Tissue: Provides support, storage, and photosynthesis. Includes parenchyma (photosynthesis and storage), collenchyma (support), and sclerenchyma (strength).

  • Vascular Tissue: Comprises xylem (transports water and minerals) and phloem (transports sugars and nutrients); allows efficient transport throughout the plant.

• Photosynthesis: The process by which plants convert light energy into chemical energy:

  • Chloroplasts: Organelles that contain chlorophyll, where photosynthesis takes place. The general equation for photosynthesis is: [ \text{6CO}_2 + \text{6H}_2\text{O} + \text{light energy} \rightarrow \text{C}6\text{H}{12}\text{O}_6 + \text{6O}_2 ]

  • Light Reactions and Dark Reactions (Calvin Cycle): Light reactions capture sunlight to produce ATP and NADPH, while the Calvin Cycle uses these energy carriers to synthesize glucose from carbon dioxide.

• Plant Reproduction: Plants can reproduce both sexually and asexually:

  • Asexual Reproduction: Includes vegetative propagation (e.g., cuttings, bulbs), which allows rapid reproduction without seed formation.

  • Sexual Reproduction: Involves flowers, where pollination occurs, leading to fertilization, seed formation, and dispersal. Different mechanisms enhance flowering and seed dispersal, such as wind, water, and animals.

• Plant Responses to Environment: Plants respond to environmental factors in significant ways:

  • Tropisms: Growth responses toward or away from stimuli (e.g., phototropism - growth toward light, gravitropism - response to gravity).

  • Plant Hormones: Chemicals that regulate growth and development; examples include auxins (promote cell elongation), gibberellins (promote seed germination and growth), and abscisic acid (inhibits growth during stress conditions).

• Ecological Concepts: Understand processes that contribute to ecosystem structure and function:

  • Primary Succession: The colonization of barren land by pioneer species (e.g., lichens and mosses), leading to a gradual increase in biodiversity over time.

  • Secondary Succession: Occurs in areas that have been disturbed but still retain soil and some organisms, allowing quicker recovery compared to primary succession.

• Importance of Plants: Plants are crucial for life on Earth:

  • Oxygen Production: They are responsible for producing oxygen during photosynthesis.

  • Food Source: Serve as the base of food chains; primary producers support herbivores and higher trophic levels.

  • Ecosystem Services: Contribute to habitat creation, soil formation, and water regulation, maintaining ecosystem balance.