Chapters 1-3

Vocabulary flashcards covering key terms from ecology, cellular biology, and nutrition in the video.

Ecosystem

A defined space containing biotic (living) and abiotic (nonliving) components that interact and depend on one another.

Abiotic

Nonliving components of an ecosystem, such as water, gases, and minerals.

Biotic

Living components of an ecosystem and their interactions.

Cell

The basic unit of life; a membrane‑bound compartment that can be single or multicellular.

Cell Membrane

Selective barrier surrounding a cell that controls what enters and leaves.

DNA

Deoxyribonucleic acid; the molecule of inheritance that carries genetic information.

Sexual Reproduction

Reproduction involving two parents; offspring have mixed DNA.

Asexual Reproduction

Reproduction without a mate, producing genetically identical offspring (clones).

Evolution

The change in a population over time due to variation and differential survival/reproduction.

Prokaryote

Single‑celled organism lacking a nucleus (e.g., bacteria and archaea); DNA is in the cytoplasm.

Eukaryote

Organisms with complex cells that have a nucleus and organelles.

Microbes

Very small organisms (often invisible to the eye), including bacteria, that live on and in organisms.

Bacteria

Prokaryotic microbes; can be decomposers, nitrogen fixers, or pathogens; many are beneficial.

Archaea

Prokaryotes often found in extreme environments; less commonly encountered in daily life.

Ribosome

Molecular machines that synthesize proteins from genetic information.

Proteins

Large biomolecules made of amino acids; perform structural, enzymatic, signaling, and transport roles.

Amino Acids

Monomers of proteins; 20 standard types; eight are essential for humans.

Enzymes

Proteins that speed up chemical reactions in the body.

Carbohydrates

Nutrients used for energy; include monosaccharides, disaccharides, and polysaccharides.

Monosaccharide

Single sugar unit (e.g., glucose, fructose).

Disaccharide

Two monosaccharides linked together (e.g., sucrose).

Polysaccharide

Long chains of monosaccharides (e.g., starch, glycogen, cellulose).

Glycogen

Stored form of glucose in animals, mainly in liver and muscles.

Starch

Plant storage carbohydrate; a polysaccharide stored in endosperm or other tissues.

Fiber

Indigestible polysaccharides (e.g., cellulose) that aid digestion and health.

Lipids

Hydrophobic fats and related molecules; storage, membranes, and insulation.

Fats

Hydrophobic energy‑rich molecules; include saturated, unsaturated, and trans fats.

Saturated Fats

Fats that are solid at room temperature; typically from animal sources; can raise LDL.

Unsaturated Fats

Fats that are bendable (monounsaturated and polyunsaturated); generally healthier.

Trans Fats

Hydrogenated unsaturated fats; tend to be solid at room temperature and raise cardiovascular risk.

Phospholipid

Lipid with a phosphate group; forms the cell membrane bilayer with hydrophilic heads and hydrophobic tails.

Cholesterol

Hydrophobic molecule in membranes; precursor to steroid hormones; transported by LDL/HDL.

LDL (Low‑Density Lipoprotein)

Cholesterol‑rich particle often termed 'bad' cholesterol because it can deposit in arteries.

HDL (High‑Density Lipoprotein)

Cholesterol‑carrying particle often termed 'good' cholesterol because it returns cholesterol to the liver.

Sodium

Electrolyte ion essential for nerve signaling, muscle contraction, and water balance.

ATP

Adenosine triphosphate; universal energy carrier that stores/releases energy via phosphate groups.

NADPH

Energy carrier that donates electrons in biosynthetic reactions and energy transfers.

Photosynthesis

Process by which light energy is converted into chemical energy, producing organic molecules from CO2 and water; oxygen is released as a byproduct.

Chloroplast

Plant cell organelle where photosynthesis occurs; contains chlorophyll and the photosystems.

Chlorophyll a

Primary pigment that captures light energy and drives electron transfer in photosynthesis.

Pigment

Substance that absorbs light; chlorophyll is a key pigment in photosynthesis.

Photosystem

Functional unit in chloroplasts comprising pigments and an electron transport chain; captures light energy.

Electron Transport Chain

Series of proteins in the chloroplast thylakoid membrane that transfers electrons to generate ATP and NADPH.

Carbon Fixation

Incorporation of carbon dioxide into an organic molecule during photosynthesis (Calvin cycle).

Calvin Cycle (Dark Reactions)

Set of reactions that assemble carbon from CO2 into sugars using ATP and NADPH.

Light Reactions

First stage of photosynthesis; uses light to create ATP and NADPH and releases O2.

Organic

Substance that contains carbon and hydrogen; carbon‑based molecules.

Autotroph

Organism that can produce its own organic molecules from inorganic sources.

Photoautotroph

Autotroph that uses light energy to synthesize organic molecules (e.g., plants, cyanobacteria).

Chemoautotroph

Autotroph that uses chemical energy from inorganic reactions to synthesize organic molecules.

Heterotroph

Organism that must ingest other organisms to obtain organic molecules for energy and growth.

Photoheterotroph

Heterotroph that uses light energy to assist in metabolism; common mainly in microbes.

Chemoheterotroph

Organism that uses chemical energy and consumes organic molecules (e.g., humans).

Producers

Autotrophs that create organic compounds used by other organisms in a food web.

Consumers

Heterotrophs that obtain energy by consuming other organisms.

Decomposers

Organisms that break down dead matter, recycling nutrients (e.g., fungi and many bacteria).

Food Web

Diagram of all feeding relationships in an ecosystem showing who eats whom.

Food Chain

Linear sequence of who eats whom; a simplified version of a food web.

Energy

Capacity to cause change; exists as kinetic (doing work) or potential (stored) energy.

Calorie (kilocalorie, kcal)

Unit of energy; on food labels, 'calorie' equals 1 kcal (1000 calories).