Essential Concepts in Biology: From Cells to Ecosystems
Biology
The science of living organisms and their interactions.
Growth and Development
Organisms grow according to DNA instructions.
Molecule
The smallest unit of life, such as DNA.
Cell
The basic unit of structure and function in organisms.
Organism
An individual living entity capable of life processes.
Population
A group of the same species in a specific area.
DNA
Carries genetic information in a double-helix structure.
Natural Selection
A mechanism where favorable traits enhance survival.
Ecosystems
Living organisms and non-living components interacting.
Food Chains
Show energy flow from producers to consumers.
Food Webs
Complex networks of interrelated food chains.
Biomes
Large areas with distinct climates and ecosystems.
Scientific Method
Steps include question, research, hypothesis, experiment, data analysis, conclusion, and communication.
Independent Variable
The changed or manipulated variable in an experiment.
Dependent Variable
The measured variable affected by the independent variable.
Control Group
A group not receiving treatment for comparison.
Commensalism
One species benefits, the other is unaffected.
Niche
An organism’s role and interactions in its ecosystem.
Keystone Species
A species with a large impact on ecosystem dynamics.
Abiotic Factors
Non-living components like temperature and water.
Biotic Factors
Living components including plants and animals.
Trophic Levels
Hierarchical levels in a food chain.
Marine Biomes
Oceanic ecosystems with saltwater and high biodiversity.
Cell Organization
Living things are unicellular or multicellular.
Metabolism
Chemical reactions maintaining life within organisms.
Homeostasis
Stable internal conditions maintained by organisms.
Reproduction
Passing on genetic material through reproduction.
Cell Structure
The basic unit of life, defining organism functions.
Cell Theory
All organisms consist of cells, the basic unit of life.
Plant Cells
Have cell walls, chloroplasts, and large vacuoles.
Animal Cells
Lack cell walls and chloroplasts; smaller vacuoles.
Atoms
Basic units of matter consisting of protons, neutrons, and electrons.
Elements
Substances made of only one type of atom.
Atomic Number
The number of protons in an element’s nucleus.
Molecules
Combinations of two or more bonded atoms.
Compounds
Molecules formed from different elements.
Covalent Bonds
Strong bonds formed by sharing electrons.
Ionic Bonds
Formed by electron transfer between atoms.
Organic Molecules
Include carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates
Energy sources composed of C, H, and O.
Protein
Made of amino acids, serves various functions.
Lipids
Hydrophobic molecules that store energy.
Cells
Basic structural and functional units of life.
Cytology
The study of cells and their structures.
Prokaryotic Cells
Cells without a nucleus or membrane-bound organelles.
Nucleus
Contains DNA and controls cell activities.
Cytoplasm
Gel-like substance supporting organelles in cells.
Cell Membrane
Lipid bilayer regulating substance movement in cells.
Mitochondria
The powerhouse of the cell, producing ATP.
Endoplasmic Reticulum (ER)
Network involved in protein and lipid synthesis.
Rough ER
Studded with ribosomes for protein synthesis.
Smooth ER
Involved in lipid synthesis and detoxification.
Golgi Apparatus
Modifies and packages proteins and lipids.
Lysosomes
Digest worn-out organelles and foreign invaders.
Ribosomes
Sites of protein synthesis from mRNA.
Centriole
Organizes the mitotic spindle during cell division.
Chloroplasts
Sites of photosynthesis in plant cells.
Vacuoles
Storage organelles for water and nutrients.
ATP
Primary energy carrier produced in the mitochondria.
Eukaryotic Cells
Cells with specialized structures like the nucleus and mitochondria.
Photosynthesis Formula
6CO2 + 6H2O + light –> C6H12O6 + 6O2
Cellular Respiration
Process converting glucose into ATP in mitochondria.
Cellular Respiration Formula
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
Glycolysis
The first step of cellular respiration, occurs in the cytoplasm.
Krebs Cycle
The second step of cellular respiration, occurs in the mitochondria.
Electron Transport Chain
The final step of cellular respiration, produces ATP.
Diffusion
Movement of molecules from high to low concentration.
Osmosis
Diffusion of water across a selectively permeable membrane.
Passive Transport
Movement of substances without energy use.
Active Transport
Movement of substances requiring energy input.
Cellular Reproduction
The process of cell division to produce new cells.
Phases of Mitosis
Includes prophase, metaphase, anaphase, telophase, and cytokinesis.
Interphase
Preparation phase before mitosis, includes G1, S, and G2.
G1 Phase
Cell growth and normal function before DNA replication.
S Phase
DNA replication occurs, forming sister chromatids.
G2 Phase
Cell prepares for division, synthesizes proteins.
Crossing Over
Exchange of genetic material between homologous chromatids.
Nuclear Membrane
Membrane surrounding the nucleus, dissolves during mitosis.
Spindle Fibers
Structures that pull chromosomes apart during cell division.
Cytokinesis
Division of the cytoplasm, resulting in two daughter cells.
Genetic Diversity
Variation in offspring due to meiosis processes.
Mitosis
One division producing two identical diploid cells.
Sexual Reproduction
Process involving meiosis to form gametes.
Genetic Variation
Differences in genetic makeup among individuals.
Haploid
A cell with half the chromosome number.
Diploid
A cell with two sets of chromosomes.
Meiosis I
First division separating homologous chromosomes.
Prophase I
Crossing over occurs.
Metaphase I
Homologous chromosome pairs align at the metaphase plate.
Anaphase I
Homologous chromosomes move to opposite poles.
Telophase I
Formation of two haploid daughter cells.
Meiosis II
Second division separating sister chromatids.
Prophase II
Chromosomes condense in haploid cells.
Metaphase II
Chromosomes align at the metaphase plate.
Anaphase II
Sister chromatids are separated to opposite poles.
Telophase II
Formation of four unique haploid cells.
Genetics
The study of trait inheritance across generations.
Mendel’s Laws
Principles governing genetic inheritance patterns.
Law of Independent Assortment
Different traits segregate independently during gamete formation.
Genes
DNA sections coding for specific traits.
Gametes
Reproductive cells that carry genetic information.
Punnett Square
A tool for predicting offspring genotype and phenotype.
Genotype
The genetic makeup of an organism.
Phenotype
The physical expression of a genotype.
Mendelian Inheritance
Principles of inheritance described by Gregor Mendel.
Alleles
Different forms of a gene.
Dominant Allele
An allele that masks the expression of another allele.
Recessive Allele
An allele masked by a dominant allele.
Genetic Disorders
Conditions caused by mutations in genes.
Meiosis
Cell division that produces gametes with genetic variation.
Genetic Variation
Differences in DNA among individuals.
Ecology
The study of organisms and their environment interactions.
Biotic Components
Living factors in an ecosystem, like plants and animals.
Abiotic Components
Nonliving factors like climate and soil.
Levels of Organization
Hierarchy from individual to biosphere in ecology.
Predation
One organism kills and eats another.
Symbiosis
Close interactions between different species.
Energy Flow
Movement of energy from producers to consumers.
Producers
Organisms that produce their own food.
Consumers
Organisms that obtain energy by consuming others.
Decomposers
Break down dead organic matter.
Food Chain
A linear sequence of energy transfer.
Food Web
A complex system of interconnected food chains.
Infiltration
Water soaks into the soil from the surface.
Carbon Cycle
Movement of carbon through ecosystems.
Photosynthesis
Plants convert CO2 into organic compounds.
Respiration
Organisms release CO2 through cellular respiration.
Fossil Fuels
Burning releases stored carbon.