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biology exam gr11
Unit 1: Diversity of Living Things
8 Levels of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Categories and Characteristics of Organisms in Each of the 3 Domains
Domain Archaea
Characteristics: Unicellular, prokaryotic organisms; often extremophiles (living in extreme environments); distinct biochemistry and genetics from bacteria.
Examples: Methanogens, Halophiles, Thermophiles.
Domain Bacteria
Characteristics: Unicellular, prokaryotic organisms; vary in shape, size, and metabolism; some are beneficial while others are pathogenic.
Examples: Escherichia coli, Streptococcus.
Domain Eukarya
Characteristics: Organisms with eukaryotic cells (membrane-bound organelles and nucleus); can be unicellular or multicellular.
Examples: Plants, Animals, Fungi, Protists.
Categories and Characteristics of Organisms in Each of the 6 Kingdoms
Kingdom Archaebacteria
Characteristics: Known for extreme habitats; no peptidoglycan in cell walls; unique lipid composition in cell membranes.
Kingdom Eubacteria
Characteristics: True bacteria with peptidoglycan in cell walls; diverse metabolic pathways; can be found in various environments.
Kingdom Protista
Characteristics: Mostly unicellular; eukaryotic; diverse group including algae, protozoa, and slime molds; capable of photosynthesis or heterotrophy.
Kingdom Fungi
Characteristics: Eukaryotic; multicellular (except yeasts); heterotrophic; cell walls made of chitin; decomposers.
Examples: Molds, Mushrooms.
Kingdom Plantae
Characteristics: Multicellular; eukaryotic; autotrophic (photosynthesis) with cell walls made of cellulose; essential for oxygen production.
Examples: Mosses, Ferns, Flowering plants.
Kingdom Animalia
Characteristics: Multicellular; eukaryotic; heterotrophic; no cell walls; diverse forms and behaviors, including locomotion.
Examples: Insects, Mammals, Birds.
Fundamental Differences Between the Different Kingdoms
Cell Structure: Bacteria and archaea are prokaryotic; eukaryotes (plants, animals, fungi, and protists) are eukaryotic.
Nutrition: Fungi are heterotrophs via absorption; plants are autotrophs with photosynthesis; animals are heterotrophs via ingestion.
Reproduction: Fungi and bacteria can reproduce asexually through spores and binary fission respectively, whereas plants and animals may have complex life cycles.
Viruses
Considered acellular; consist of genetic material (DNA or RNA) encapsulated in a protein coat; require a host cell for replication; not classified in any of the 3 domains.
Classification of Living Things
Viruses: Acellular entities; not classified as living organisms due to lack of cellular structure and metabolism.
Archaebacteria and Eubacteria: Both fall under prokaryotes but differ fundamentally in genetic and biochemical traits.
Protists: Highly diverse; include organisms that do not fit into the other kingdoms.
Fungi: Unique kingdom due to their decomposing role and cell wall composition.
Plant Classification: Includes non-vascular plants (mosses), vascular non-seed plants (ferns), seed plants (gymnosperms and angiosperms).
Animal Classification: Broad categories include invertebrates (e.g., insects, mollusks) and vertebrates (e.g., fish, amphibians, mammals).
Unit 2: Genetic Processes
Process, Outcome and Importance of Meiosis
Process: Meiosis is a two-stage cell division process that produces gametes (sperm and eggs) with half the number of chromosomes of the parent cell. It consists of two main divisions: meiosis I and meiosis II.
Meiosis I: Homologous chromosomes are separated into two cells.
Meiosis II: Sister chromatids are separated to form four haploid gametes.
Outcome: The result of meiosis is four genetically unique haploid cells. Each gamete contains one allele from each gene pair, ensuring genetic diversity.
Importance: Meiosis is crucial for sexual reproduction as it ensures the proper distribution of chromosomes, maintains chromosome number across generations, and contributes to genetic variation through processes such as crossing over and independent assortment.
Basic Structure of DNA
DNA (deoxyribonucleic acid) is a double helix composed of two strands of nucleotides. Each nucleotide consists of:
A phosphate group
A deoxyribose sugar
A nitrogenous base (Adenine [A], Thymine [T], Cytosine [C], Guanine [G])
The two strands are held together by hydrogen bonds between complementary base pairs: A with T and C with G.
Solving Genetic Problems
Monohybrid Cross: A genetic cross involving one trait, where the inheritance pattern can be predicted using a Punnett square. Example: Cross between a homozygous dominant plant (AA) and a homozygous recessive plant (aa) yields all heterozygous offspring (Aa).
Dihybrid Cross: A genetic cross involving two traits. The inheritance of each trait follows the principle of independent assortment. Example: Crossing two heterozygous plants (AaBb x AaBb) gives a phenotypic ratio of 9:3:3:1.
Different Patterns of Inheritance
Dominant/Recessive: In dominant-recessive inheritance, the dominant allele masks the effect of the recessive allele (e.g., the allele for brown eyes is dominant over blue).
Incomplete Dominance: The heterozygous phenotype is a blend of both alleles (e.g., red and white flowers producing pink offspring).
Co-Dominance: Both alleles are fully expressed in the phenotype of heterozygous individuals (e.g., A and B alleles both expressed in AB blood type).
Sex-Linked Inheritance: Traits associated with genes located on sex chromosomes, often leading to different inheritance patterns in male and female offspring (e.g., color blindness).
Multiple Alleles: Involves more than two alleles for a single gene. An example is blood typing, with A, B, and O alleles.
Interpreting Karyotypes and Pedigrees
Karyotypes: A visual representation of an individual's chromosomes arranged in pairs. Karyotypes are used to identify chromosomal abnormalities (e.g., Down syndrome, Turner syndrome).
Pedigrees: Diagrams showing the inheritance of traits across generations. They are used to track genetic diseases within families and determine patterns of inheritance for specific traits.
Unit 3: Evolution
Various Evolutionary Theories
Natural Selection: Proposed by Charles Darwin; the process by which organisms that are better adapted to their environment tend to survive and reproduce.
Lamarckism: The idea that organisms can pass on traits acquired during their lifetime to their offspring (e.g., giraffes stretching their necks).
Mutation Theory: Emphasizes the role of mutations in creating genetic diversity that drives evolution.
Synthetic Theory of Evolution: Combines Darwin's theory of natural selection with genetics, explaining how evolution occurs at the genetic level.
Relationship Between Variation and Adaptation
Variation in traits among individuals in a population is essential for adaptation to environmental changes; those with advantageous traits are more likely to survive and pass these traits on to the next generation.
Hardy-Weinberg Principle
The Principle: This principle describes how allele frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.
Variables:
p: frequency of the dominant allele
q: frequency of the recessive allele
p²: frequency of homozygous dominant genotype
2pq: frequency of heterozygous genotype
q²: frequency of homozygous recessive genotype
Conditions for Hardy-Weinberg Equilibrium:
No mutations
Random mating
No natural selection
Large population size
No gene flow (immigration/emigration)
Solving Problems: Given p and q, or any of the genotypic frequencies, you can use the equations to calculate the others.
Evidence that Supports Evolution
Homologous Structures: Similar anatomical structures in different species indicate common ancestry (e.g., forelimbs of humans, whales, and bats).
Vestigial Structures: Remnants of organs or structures that had a function in early ancestors (e.g., human appendix, pelvic bones in whales).
Fossil Records: Provide chronological evidence of species evolution and extinction over time.
Macroevolution vs Microevolution
Macroevolution: Large-scale evolutionary changes that occur over long periods, leading to the emergence of new species and higher taxonomic groups.
Microevolution: Small-scale changes in allele frequencies within a population over a shorter period (e.g., changes in traits in a population due to environmental pressures).
Examples and Mechanisms
Examples of Evolutionary Change:
Darwin’s Finches: Variations in beak size among finches based on available food sources.
Insect Resistance: Development of resistance in pests to pesticides.
Mechanisms of Evolution:
Natural Selection
Mutation
Gene Flow
Genetic Drift
Types of Selection
Stabilizing Selection: Favors intermediate variants, reducing extremes (e.g., human birth weight).
Directional Selection: Favors one extreme phenotype over others (e.g., peppered moths during the industrial revolution).
Disruptive Selection: Favors individuals at both extremes of the phenotypic range (e.g., African seedcracker birds with either very large or small beaks).
Sexual Selection: Favors traits that increase an individual’s chance of mating (e.g., peacock tail feathers).
Convergent vs Divergent Evolution
Convergent Evolution: Different species evolve similar traits independently due to similar environmental pressures (e.g., wings of birds and insects).
Divergent Evolution: Related species evolve different traits or behaviors due to different environments (e.g., common ancestors of mammals evolving into various species).
Unit 4: Plants - Anatomy, Growth and Development
The details on this unit will continue on anatomy, growth processes, and the overall development of plants, focusing on structures such as roots, stems, leaves, and reproductive systems, alongside their physiological processes and growth patterns.
Structure: Overview of plant tissues: meristematic (growth), permanent (mature tissues), vascular (transport), and dermal (protection).
Growth Processes: Understanding how plants grow through primary and secondary growth modes, including factors affecting growth like light, water, and nutrients.
Development: Examination of how environmental and genetic factors influence the phases of plant development from seed germination to maturity and reproduction.
Unit 4: Plants - Anatomy, Growth and Function
Types of Plant Cells and Plant Tissues
Types of Plant Cells:
Parenchyma Cells: Involved in storage, photosynthesis, and tissue repair.
Collenchyma Cells: Provide flexible support in young stems and leaves.
Sclerenchyma Cells: Provide rigid support, often dead at maturity with thick cell walls.
Xylem Cells: Conduct water and minerals from roots to leaves.
Phloem Cells: Transport sugars and nutrients throughout the plant.
Types of Plant Tissues:
Meristematic Tissue: Responsible for growth through cell division.
Permanent Tissue: Mature tissue that does not change; can be simple (consisting of one cell type) or complex (composed of various cell types).
Vascular Tissue: Includes xylem and phloem, involved in transportation.
Dermal Tissue: Covers and protects plant surfaces.
Differences Between Monocots and Dicots
Monocots:
One cotyledon in the seed.
Parallel leaf venation.
Vascular bundles scattered in stems.
Fibrous root system.
Examples: Grasses, lilies.
Dicots:
Two cotyledons in the seed.
Netlike leaf venation.
Vascular bundles arranged in a ring.
Taproot system.
Examples: Beans, sunflowers.
Structure and Functions of: Roots, Stems, Leaves, Flowers, Seeds (Embryo)
Roots: Anchor the plant, absorb water and nutrients, store food.
Stems: Support for leaves and flowers, transport nutrients and water between roots and leaves.
Leaves: Main site of photosynthesis, gas exchange through stomata.
Flowers: Reproductive structures, facilitate pollination and seed production.
Seeds (Embryo): Contains the embryo, provides food reserves, and is involved in plant reproduction and dispersal.
Transportation in Xylem and Phloem
Xylem: Transports water and dissolved minerals from roots to other parts of the plant through capillary action and transpiration.
Phloem: Transports organic nutrients (sugars) produced during photosynthesis from leaves to non-photosynthetic parts of the plant.
Plant Growth
Growth occurs at meristems and is influenced by genetic and environmental factors.
Primary growth: increase in length; Secondary growth: increase in thickness.
Nutrition
Plants require essential nutrients such as nitrogen, phosphorus, potassium, magnesium, and others for growth and development.
Nutrients are absorbed from the soil through roots.
Hormones
Plant hormones (auxins, gibberellins, cytokinins, abscisic acid, ethylene) regulate growth, development, and responses to environmental stimuli.
Tropisms
Tropisms are growth responses to environmental stimuli:
Phototropism: Growth towards light.
Gravitropism: Growth in response to gravity.
Thigmotropism: Growth in response to touch.
Environmental Adaptations
Plants adapt to their environment through modifications such as drought resistance (e.g., succulents), salt tolerance (e.g., mangroves), and temperature resilience.
Unit 5: Animals - Structure and Function
Digestive System
Label Diagram: (Diagram to be included in actual notes)
Function of Each Structure/Organ:
Mouth: Mechanical digestion (chewing), secretion of saliva (contains enzymes).
Esophagus: Transports food from the mouth to the stomach using peristalsis.
Stomach: Chemical digestion of food using gastric juices (acidic environment) and mechanical churning.
Small Intestine: Main site for digestion and absorption of nutrients; bile (emulsification of fats) and pancreatic enzymes (carbohydrates, proteins, and lipids) act here.
Large Intestine: Absorbs water and electrolytes; compacts waste for excretion.
Rectum: Stores feces until excretion.
Anus: Exit point for waste.
Function of Each Secretion & Organ That Produces It:
Saliva: Produced by salivary glands; contains amylase to begin starch digestion.
Gastric Juice: Produced by the stomach, containing hydrochloric acid and pepsin for protein digestion.
Bile: Produced by the liver, stored in the gallbladder; emulsifies fats for easier digestion.
Pancreatic Juice: Produced by the pancreas; contains enzymes (amylase, lipase, proteases) that digest carbohydrates, fats, and proteins.
Basic Structure and Function of Carbohydrates, Proteins & Lipids:
Carbohydrates: Composed of carbon, hydrogen, and oxygen; primary energy source for the body.
Proteins: Made of amino acids; essential for growth, repair, and enzymes.
Lipids: Include fats and oils; used for energy storage, insulation, and cellular membrane structure.
Disorders:
Gastritis: Inflammation of the stomach lining.
Gastroesophageal Reflux Disease (GERD): Backflow of stomach acid into the esophagus.
Celiac Disease: Autoimmune disorder triggered by gluten.
Irritable Bowel Syndrome (IBS): Disorder affecting the large intestine leading to pain and irregular bowel movements.
Respiratory System
Label Diagram: (Diagram to be included in actual notes)
Function of Each Structure/Organ:
Nasal Cavity: Filters, warms, and moistens air; contains olfactory receptors.
Pharynx: Passageway for air and food; aids in swallowing.
Larynx: Voice box; contains vocal cords; protects the trachea against food aspiration.
Trachea: Windpipe; passage for air to the lungs; lined with cilia and mucus for trapping particles.
Bronchi: Main passageways into the lungs; branch into smaller bronchioles.
Lungs: Organs for gas exchange; contain alveoli where oxygen and carbon dioxide are exchanged.
Lung Volumes:
Tidal Volume: Volume of air inhaled or exhaled during normal breathing.
Inspiratory Reserve Volume: Extra volume of air that can be inhaled after a normal breath.
Expiratory Reserve Volume: Extra volume of air that can be forcefully exhaled after a normal breath.
Vital Capacity: Maximum amount of air that can be exhaled after maximum inhalation.
Total Lung Capacity: Total volume of the lungs, including all volumes.
Disorders:
Asthma: Inflammation and narrowing of airways; causes difficulty in breathing.
Chronic Obstructive Pulmonary Disease (COPD): Chronic condition that obstructs airflow; includes emphysema and chronic bronchitis.
Pneumonia: Infection causing inflammation of the air sacs in the lungs.
Circulatory System
Label Diagram of Heart: (Diagram to be included in actual notes)
Function of Each Structure/Organ of the Heart:
Atria: Upper chambers; receive blood (right atrium from body, left atrium from lungs).
Ventricles: Lower chambers; pump blood (right ventricle to lungs, left ventricle to body).
Valves: Ensure unidirectional blood flow; include tricuspid, pulmonary, mitral, and aortic valves.
Septum: Divides left and right sides of the heart.
Coronary Arteries: Supply blood to the heart muscle.
Differences Between Arteries, Veins & Capillaries:
Arteries: Carry oxygen-rich blood away from the heart; thick, elastic walls.
Veins: Carry oxygen-poor blood back to the heart; thinner walls; contain valves to prevent backflow.
Capillaries: Microscopic vessels where gas and nutrient exchange occurs; walls are one cell thick.
Components of Blood:
Red Blood Cells (RBC): Carry oxygen via hemoglobin.
White Blood Cells (WBC): Part of the immune system; fight infections.
Platelets: Cell fragments involved in blood clotting.
Plasma: Liquid component of blood; carries cells, nutrients, hormones, and waste products.
Disorders:
Anemia: Low red blood cell count or hemoglobin; leads to fatigue and weakness.
Atherosclerosis: Build-up of plaque in arteries; can lead to heart disease.
Hypertension: High blood pressure; increases risk of heart disease and stroke.