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Biology EOC Vocabulary Review + Study Session (25 min)
Lasseter’s Lab
Overview
This video provides a comprehensive vocabulary review for biology EOC exams, covering essential terms across cell biology, genetics, ecology, and evolution. It explains key concepts such as cell types (prokaryotic vs. eukaryotic), macromolecules, enzyme function, cell transport mechanisms, ecological relationships, cellular organelles, DNA structure and protein synthesis, the cell cycle and division (mitosis vs. meiosis), photosynthesis and cellular respiration, biogeochemical cycles, genetics (genotype, phenotype, inheritance patterns), evolution, and biotechnology. The goal is to equip students with the foundational vocabulary needed to understand biological content and succeed on their exams.
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Chapters
- Prokaryotic cells lack a nucleus and membrane-bound organelles.
- Eukaryotic cells have their DNA within a nucleus and possess membrane-bound organelles like mitochondria.
- Examples of eukaryotic organisms include plants, animals, protists, and humans.
Understanding the fundamental differences between prokaryotic and eukaryotic cells is crucial as it forms the basis for comprehending cellular structure, function, and the diversity of life.
Humans are eukaryotic, possessing a nucleus and specialized organelles within their cells, unlike bacteria which are prokaryotic.
- Organic compounds, or biological macromolecules, are essential for life and include nucleic acids, proteins, carbohydrates, and lipids.
- Enzymes are proteins that act as biological catalysts, speeding up reactions by lowering activation energy.
- Enzymes are specific to their substrates, have an active site, and can be denatured (unfolded) by environmental changes like heat or pH, losing their function.
These macromolecules are the building blocks and functional units of cells, and enzymes are critical for virtually all biological processes.
When an enzyme like lactase breaks down lactose (a sugar), it binds to lactose at its active site, facilitating the reaction and remaining unchanged afterward.
- The cell membrane is primarily composed of a phospholipid bilayer, which is selectively permeable.
- Concentration gradients describe the difference in substance concentration between two areas, driving natural movement from high to low concentration.
- Cell transport includes diffusion (high to low, no energy), facilitated diffusion (high to low, with protein help), and active transport (low to high, requires energy like ATP).
The cell membrane regulates what enters and exits the cell, maintaining homeostasis, while various transport mechanisms are vital for nutrient uptake, waste removal, and cellular communication.
Oxygen moves into cells via simple diffusion because its concentration is higher outside the cell than inside, requiring no energy or transport proteins.
- Autotrophs (like plants) produce their own food, while heterotrophs (like humans) must consume other organisms.
- Energy pyramids illustrate trophic levels, showing energy loss as it moves from producers to consumers (primary, secondary, tertiary).
- Symbiotic relationships describe close interactions between different species, including mutualism (both benefit), parasitism (one benefits, one harmed), and commensalism (one benefits, one unaffected).
These concepts explain how energy flows through ecosystems and how different organisms interact, forming the basis of ecological community structure.
A lion (tertiary consumer) eating a zebra (primary consumer) illustrates the flow of energy and the heterotrophic nature of consumers in an ecosystem.
- Key organelles include the vacuole (storage), lysosome (waste breakdown), Golgi apparatus (packaging), endoplasmic reticulum (transport), ribosomes (protein synthesis), cell wall (structure in plants), chloroplasts (photosynthesis), and mitochondria (energy production).
- DNA, or deoxyribonucleic acid, is genetic material made of nucleotides (phosphate, sugar, base A, T, G, or C).
- Protein synthesis involves transcription (DNA to RNA) and translation (RNA to protein), with mRNA carrying the message from the nucleus to ribosomes.
Organelles perform specific functions within eukaryotic cells, and DNA holds the genetic blueprint for life, directing protein synthesis and inheritance.
Ribosomes are responsible for building proteins by linking amino acids together, using instructions transcribed from DNA onto messenger RNA.
- The cell cycle includes growth (G1, G2), DNA replication (S phase), and cell division (M phase/mitosis).
- Mitosis produces two genetically identical diploid daughter cells for growth and repair.
- Meiosis produces four genetically unique haploid gametes (sperm/egg) for sexual reproduction, involving processes like crossing over to increase genetic variation.
Understanding cell division is fundamental to growth, development, reproduction, and the repair of tissues, as well as understanding diseases like cancer.
When you get a cut, mitosis is the process that creates new skin cells to heal the wound, ensuring the new cells are genetically identical to the old ones.
- Photosynthesis uses sunlight, water, and carbon dioxide in chloroplasts to produce glucose (food) and oxygen.
- Cellular respiration breaks down glucose and oxygen to release energy (ATP), carbon dioxide, and water, occurring in mitochondria.
- Anaerobic respiration (fermentation) occurs without oxygen, yielding much less ATP than aerobic respiration.
These processes are the primary ways energy enters and is utilized by living organisms, forming a critical link in the flow of energy through ecosystems.
Plants perform photosynthesis to create glucose, and then both plants and animals perform cellular respiration to break down that glucose for energy.
- Biogeochemical cycles, like the carbon and nitrogen cycles, describe the movement of essential elements through the environment, involving biological, geological, and chemical processes.
- Ecosystem stability is enhanced by biodiversity, making ecosystems more resilient to disturbances.
- Key ecological phenomena include invasive species, biomagnification (toxins accumulating up the food chain), ocean acidification, and habitat loss (a major cause of extinction).
These cycles and concepts explain how matter is conserved and recycled within ecosystems and the environmental challenges facing biodiversity.
The carbon cycle involves plants removing CO2 through photosynthesis and animals releasing CO2 through respiration, demonstrating the interconnectedness of life and the atmosphere.
- Genotype refers to an organism's genetic makeup (allele combination), while phenotype is the observable physical trait.
- Alleles can be dominant (masking recessive alleles) or recessive, leading to concepts like homozygous (two same alleles) and heterozygous (two different alleles).
- Inheritance patterns include codominance (both alleles expressed) and incomplete dominance (blending of traits), and gene expression can be influenced by environmental factors.
Understanding genetics explains how traits are passed from parents to offspring and how variations arise, forming the basis of heredity.
A heterozygous genotype for a trait (e.g., Bb) might result in a phenotype where only the dominant 'B' trait is expressed, while 'bb' would express the recessive trait.
- Evolution is the change in a population's genetic makeup over time, driven by mechanisms like natural selection.
- Natural selection favors individuals with higher evolutionary fitness (reproductive success), leading to adaptation.
- Evidence for evolution includes fossils, comparative anatomy, embryology, and molecular data; genetic drift and gene flow also alter allele frequencies.
Evolution explains the diversity of life on Earth and how species change and adapt over vast periods, driven by environmental pressures and genetic variation.
Over generations, finches with beaks better suited to available food sources in their environment are more likely to survive and reproduce, passing on those advantageous beak traits.
- Biotechnology involves modifying organisms for human use, employing techniques like gel electrophoresis and creating genetically modified organisms (GMOs).
- Bioethics addresses the ethical considerations arising from biotechnology.
- Binomial nomenclature is the scientific system for naming organisms using their genus and species (e.g., Homo sapiens).
These fields represent the application of biological knowledge to solve problems and the standardized way scientists communicate about the organisms they study.
Genetically modified crops, like pest-resistant corn, are an example of biotechnology used to improve agricultural yields and reduce pesticide use.
Key takeaways
- Cellular structure and function are defined by the presence or absence of a nucleus and membrane-bound organelles.
- Enzymes are crucial protein catalysts that facilitate biological reactions but are sensitive to environmental conditions.
- The cell membrane's selective permeability and various transport mechanisms are essential for maintaining cellular integrity and homeostasis.
- Ecosystems function through the flow of energy and the cycling of matter, with biodiversity playing a key role in stability.
- DNA carries genetic information that dictates protein synthesis, and this information is passed down through cell division and reproduction.
- Mitosis is for growth and repair, producing identical cells, while meiosis is for sexual reproduction, creating genetically diverse gametes.
- Photosynthesis and cellular respiration are complementary processes that drive energy flow in ecosystems.
- Evolution explains the adaptation and diversification of life through mechanisms like natural selection, altering populations over time.
- Genetics explains inheritance patterns, showing how traits are passed on and how variations arise, influenced by both genes and environment.
- Biotechnology offers powerful tools for modifying organisms and addressing human needs, raising important ethical questions.
Key terms
ProkaryoticEukaryoticEnzymePhospholipid bilayerActive transportAutotrophHeterotrophOrganelleDNAProtein synthesisMitosisMeiosisPhotosynthesisCellular respirationGenotypePhenotypeEvolutionNatural selectionBiotechnologyBinomial nomenclature
Test your understanding
- What is the primary structural difference between prokaryotic and eukaryotic cells, and why is this distinction important?
- How do enzymes function to speed up chemical reactions, and what factors can cause them to lose their function?
- Compare and contrast diffusion, facilitated diffusion, and active transport across the cell membrane in terms of energy requirements and protein involvement.
- Explain the roles of autotrophs and heterotrophs in an ecosystem's energy flow.
- What are the key differences between mitosis and meiosis in terms of their purpose, the number of daughter cells produced, and their genetic makeup?
- How do photosynthesis and cellular respiration relate to each other in terms of their inputs and outputs?
- What is the difference between genotype and phenotype, and how can environmental factors influence phenotype?
- Describe the concept of natural selection and how it drives the process of evolution.