Honors Biology - Unit 1: The Nature of Life and Cycles of Matter

Comprehensive practice flashcards covering Unit 1: The Nature of Life, Abiotic and Biotic Factors, Properties of Water, Macromolecules, Dehydration Synthesis and Hydrolysis, and Biogeochemical Cycles (Water, Carbon, and Nitrogen).

Biology

The scientific study of life and living organisms.

Order (Property of Life)

A characteristic of life where organisms are composed of highly organized structures consisting of one or more cells.

Unicellular vs. Multicellular Organisms

Unicellular organisms are composed of only one single cell, whereas multicellular organisms are composed of many specialized cells.

Universal Genetic Code

The shared biological feature where all living things contain $DNA$, which carries the instructions for life and determines individual traits.

Sensitivity or Response to Stimuli

The ability of an organism to detect and respond to environmental changes, whether internal or external, by initiating a specific reaction.

Reproduction

The biological process by which living organisms produce offspring that resemble the parents, passing on genetic information through inheritance.

Asexual vs. Sexual Reproduction

Asexual reproduction involves only one parent producing offspring, whereas sexual reproduction requires two parents.

Adaptation

The evolutionary process where organisms exhibit a 'fit' to their environment over generations, enhancing individual survival and reproductive potential.

Growth and Development

The controlled change and maturation of an organism over time directed by genetic instructions, allowing young organisms to develop parental characteristics.

Regulation (Life Functions)

The coordination of complex internal checks and balances to maintain internal functions, such as nutrient transport, waste removal, and stress response.

Homeostasis

The maintenance of a constant, stable internal equilibrium ('steady state') despite fluctuating external environmental conditions.

Energy Processing

The utilization of energy sources for metabolic activities, such as capturing solar energy to produce food or metabolizing consumed organic molecules.

Biotic Factors

Any parts of an ecosystem that are currently living or were once living, including animals, plants, fungi, bacteria, and dead fallen logs.

Abiotic Factors

Non-living physical matter and environmental conditions that have never been alive, such as rocks, water, temperature, air quality, and sunlight.

Abiotic Nature of Water

Water is classified as an abiotic factor because it is an inorganic molecule that is not alive and has never been alive.

Biotic-Abiotic Ecological Interactions

Relationships within an ecosystem where living organisms interact with non-living factors, determining species behaviors, distributions, and habitats.

Human-Ecosystem Dependency

The direct reliance of humans on ecosystem resources for food, clean water, raw materials, and pleasure.

Anthropogenic Environmental Impacts

Negative changes inflicted on ecosystems by human activities, including pollution, land degradation, overpopulation, and overconsumption of resources.

Rotten Log (Ecological Classification)

A biotic factor within a forest or terrestrial ecosystem because it is organic matter derived from a once-living tree.

Primary Requirements for Life

Essential resources needed by organisms to survive, specifically water, food, and breathable oxygen ($O_2$).

Chemical Composition of Water

A molecule ($H_2O$) composed of two hydrogen atoms covalently bonded to one oxygen atom.

Polarity of Water

The uneven distribution of electrical charge where the oxygen atom has a partial negative charge ($\delta^-$) and the hydrogen atoms have partial positive charges ($\delta^+$).

Hydrogen Bonding in Water

The electrostatic attraction occurring between the partially negative ($\delta^-$) oxygen of one water molecule and the partially positive ($\delta^+$) hydrogen of an adjacent water molecule.

High Specific Heat of Water

The property requiring substantial amounts of heat energy to alter water temperature, which prevents large bodies of water from freezing solid or fluctuating wildly.

Cohesion (Water)

The attractive force that causes water molecules to stick to other water molecules via hydrogen bonding.

Adhesion (Water)

The intermolecular attraction that causes water molecules to cling to other polar surfaces or molecules.

Capillary Action

The upward movement of water against gravity inside narrow plant vessels, powered by cohesive and adhesive forces.

Universal Solvent

The property of water that enables it to dissolve and break down a wide range of polar and ionic solutes.

Density Anomaly of Ice

The unique physical characteristic wherein solid water (ice) is less dense than liquid water, allowing ice to float on water bodies.

Ecological Functions of Water

Supporting plant growth, acting as permanent aquatic habitats, providing temporary breeding grounds for amphibians and insects, and transporting minerals.

Macromolecule

A large molecule formed by joining smaller molecular building blocks together.

Monomer

A small molecule that acts as a fundamental repeating subunit or building block for larger polymers.

Polymer

A long-chain molecule made up of a repeated pattern of bonded monomer units.

Organic Compound

A chemical compound that contains both carbon ($C$) and hydrogen ($H$) atoms.

Inorganic Compound

A chemical substance that does not contain both carbon ($C$) and hydrogen ($H$) atoms bonded together, such as water ($H_2O$).

Four Classes of Macromolecules

The four main types of biological macromolecules found in living systems: carbohydrates, lipids, proteins, and nucleic acids.

Five Finite Biological Elements

Carbon ($C$), hydrogen ($H$), oxygen ($O$), nitrogen ($N$), and phosphorus ($P$), which are finite on Earth and must be continuously recycled.

Carbohydrate

A biological macromolecule composed of carbon, hydrogen, and oxygen ($C, H, O$) arranged in ring-like structures, used for short-term energy and structure.

Monosaccharide (Simple Sugar)

The monomer building block of carbohydrates, such as glucose, that provides rapidly accessible energy.

Cellulose

A carbohydrate polymer of repeating sugars that forms the structural rigidity of plant cell walls.

Glycogen

A branched carbohydrate polymer used for short-term glucose storage in animals.

Chitin

A structural carbohydrate polymer found in fungal cell walls and arthropod exoskeletons.

Lipid

A nonpolar macromolecule composed of carbon, hydrogen, and oxygen ($C, H, O$) forming long hydrocarbon chains, used for long-term energy, insulation, and membranes.

Fatty Acid

A primary hydrocarbon monomer unit of lipids that can be saturated or unsaturated.

Glycerol

A three-carbon molecular backbone that bonds with fatty acids to form complex lipid structures.

Saturated Fatty Acid

A lipid chain with only single-bonded carbons that packs tightly, remaining solid at room temperature (e.g., butter).

Unsaturated Fatty Acid

A lipid chain with one or more double-bonded carbons that creates a kink, preventing close packing and remaining liquid at room temperature (e.g., olive oil).

Saturated vs. Unsaturated Fatty Acids

Saturated fatty acids possess straight chains of single-bonded carbons that pack closely together, while unsaturated fatty acids contain double bonds that bend the chain.

Protein

A biological macromolecule containing carbon, hydrogen, oxygen, and nitrogen ($C, H, O, N$) with four organizational levels, performing structural, catalytic, and transport functions.

Amino Acid

The monomer subunit of proteins, consisting of an amino group, a carboxyl group, a hydrogen atom, and a variable R-group.

R-Group (Side Chain)

The variable chemical portion of an amino acid that differs between types and dictates its chemical properties and identity.

Peptide Bond

The covalent chemical bond linking the amino group of one amino acid to the carboxyl group of another.

Polypeptide

A continuous polymer chain formed from multiple amino acids linked together by peptide bonds.

Enzyme (Biological Catalyst)

A protein that accelerates biochemical reaction rates without being permanently consumed in the process.

Nucleic Acid

A macromolecule composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus ($C, H, O, N, P$) that stores and transmits genetic information.

Nucleotide Structure

The monomer of nucleic acids composed of three distinct chemical components: a phosphate group, a five-carbon pentose sugar, and a nitrogenous base.

Deoxyribonucleic Acid ($DNA$)

A double-stranded nucleic acid containing deoxyribose sugar and the bases $A, T, C, G$, housed within eukaryotic nuclei.

Ribonucleic Acid ($RNA$)

A single-stranded nucleic acid containing ribose sugar and the bases $A, U, C, G$, found in the nucleus, ribosomes, and cytoplasm.

Dehydration Synthesis

A chemical reaction where monomers combine to form polymers by creating bonds and releasing a molecule of water ($H_2O$).

Hydrolysis

A chemical reaction that breaks the bonds of a polymer into individual monomers using a molecule of water ($H_2O$).

Identification of Synthesis vs. Hydrolysis Reactions

Dehydration synthesis starts with monomers and yields water on the product side, while hydrolysis starts with a polymer and features water on the reactant side.

Importance of Macromolecule Cycling

Organisms consume macromolecules in food and break them down into monomers, allowing cells to rebuild the specific polymers needed for survival.

Suffix "-lysis"

A scientific word part meaning to split, break apart, or release.

Root "Hydro-"

A scientific word root referring to water or gaining water.

Prefix "Dehydrate"

A scientific term meaning to lose or remove water.

Term "Synthesis"

A scientific term meaning to make, combine, or build something.

The Water Cycle

The continuous biogeochemical movement of water through the atmosphere, land, and oceans via processes driven by solar heat and gravity.

Evaporation

The phase change where liquid water absorbs thermal energy and turns into gaseous water vapor, entering the atmosphere.

Condensation

The cooling of water vapor in the atmosphere into liquid droplets that gather around dust particles to form clouds.

Precipitation

Water that has condensed in the atmosphere falling back to Earth's surface as rain, snow, sleet, or hail.

Infiltration

The hydrological process where surface water soaks and moves downward into the soil.

Transpiration

The process by which plants absorb water through their roots and release water vapor into the air via leaf pores.

Surface Runoff

The flow of excess precipitation across land surfaces, soils, and pavements into nearby bodies of water.

Driving Force of the Water Cycle

Heat energy from the Sun that breaks hydrogen bonds between water molecules to cause evaporation, paired with gravity pulling precipitation back down.

The Carbon Cycle

The continuous movement and recycling of carbon atoms throughout Earth's atmosphere, oceans, soil, and living organisms.

Photosynthesis in the Carbon Cycle

The biological process in which autotrophs capture solar energy to convert atmospheric carbon dioxide ($CO_2$) into glucose ($C_6H_{12}O_6$).

Cellular Respiration in the Carbon Cycle

The metabolic pathway in plants and animals that breaks down glucose ($C_6H_{12}O_6$) to harvest energy, releasing carbon dioxide ($CO_2$) as waste.

Decomposition in the Carbon Cycle

The breakdown of dead organic matter by decomposers, returning trapped carbon biomolecules back to the soil.

Combustion in the Carbon Cycle

The burning of organic matter and fossil fuels by cars and factories, releasing carbon dioxide ($CO_2$) into the atmosphere.

The Nitrogen Cycle

The biogeochemical cycle where nitrogen is converted into multiple chemical states as it circulates among atmospheric, terrestrial, and marine systems.

Atmospheric Nitrogen ($N_2$)

A stable diatomic gas with a strong triple bond making up approximately $78\%$ to $80\%$ of the atmosphere, largely inaccessible to organisms until fixed.

Nitrogen Fixation

The conversion of atmospheric nitrogen gas ($N_2$) into biologically usable ammonia ($NH_4^+$) by specialized soil and plant-associated bacteria.

Nitrification

The process where nitrifying bacteria alter ammonia ($NH_4^+$) into nitrites ($NO_2^-$) and nitrates ($NO_3^-$), the ideal forms for plant absorption.

Nitrogen Assimilation

The biological process in which plants absorb soil nitrates ($NO_3^-$) and incorporate nitrogen into proteins and $DNA$, which animals obtain by feeding.

Ammonification

The decomposition process wherein decomposers break down dead organic matter and nitrogenous waste back into ammonia ($NH_4^+$).

Denitrification

The process carried out by denitrifying bacteria where soil nitrates ($NO_3^-$) are reduced back into nitrogen gas ($N_2$), returning to the atmosphere.

Law of Conservation of Matter and Energy

A scientific law stating that matter and energy cannot be created or destroyed, but instead cycle and transform between abiotic and biotic components of an ecosystem.