Unit 1 and 2: The Building Blocks of Life and Cell Biology Flashcards

A comprehensive set of 60 vocabulary flashcards covering the building blocks of life, macromolecules, photosynthesis, and cellular respiration based on the lecture notes provided lecture notes.

Water Cycle

A solar-driven system that continuously moves water through the atmosphere, land, and living organisms as a dynamic exchange of energy and matter.

Evaporation

The process where water changes from liquid to gas when it absorbs heat energy from the Sun, causing the fastest-moving molecules to leave and cooling the remaining water.

Transpiration

The process where plants release water vapor through stomata in leaves, powered by evaporation, cohesion, and a continuous water column pulled from roots.

Condensation

The process where water vapor cools and becomes liquid droplets, clustering around particles in the air to form clouds.

Infiltration

The process where water enters soil and rock layers to form groundwater stored in aquifers.

Aquifers

Major freshwater reservoirs composed of soil and rock layers where groundwater is stored.

Homeostasis

The maintenance of internal stability within an organism; water helps maintain this by stabilizing temperature.

Turgor pressure

The mechanical pressure created by water-filled vacuoles that keeps plant cells rigid and prevents structures from collapsing.

Polarity

A property of water where oxygen is more electronegative than hydrogen, creating a partial negative charge near oxygen and partial positive charges near hydrogen.

Hydrogen bond

A weak attraction between the opposite partial charges of water molecules, creating a dynamic network and enabling emergent properties.

Cohesion

The attraction between water molecules due to hydrogen bonding, creating surface tension and continuous water columns in plants.

Adhesion

The attraction between water and other polar surfaces, enabling capillary action and movement through narrow tubes like xylem.

Specific heat capacity

The resistance of a substance to temperature change; water has a high capacity because energy is used to break hydrogen bonds before the temperature increases.

Hydration shells

The structures formed when water molecules surround ions to dissolve ionic and polar substances as a universal solvent.

Catenation

The self-linking ability of carbon to bond with itself to form long chains, branched structures, and rings, enabling biological complexity.

Carbon cycle

A biogeochemical cycle that moves carbon between the atmosphere, biosphere, hydrosphere, and geosphere.

Photosynthesis

The process where plants, algae, and some bacteria convert $CO_2$ and water into glucose and oxygen using sunlight.

Cellular Respiration

The controlled breakdown of glucose ($C_{6}H_{12}O_{6}$) to release energy ($ATP$) and $CO_2$ back into the atmosphere.

Decomposition

The process where bacteria and fungi break down dead organisms and waste, releasing carbon back into the soil and atmosphere as $CO_2$.

Combustion

The burning of organic matter, such as wood or fossil fuels, which accelerates the release of stored carbon as $CO_2$ into the atmosphere.

Greenhouse gas

A gas, such as carbon dioxide ($CO_2$), that traps heat in Earth’s atmosphere and is regulated by the carbon cycle.

Macromolecules

Large, carbon-based biological molecules, including carbohydrates, lipids, proteins, and nucleic acids, built from smaller subunits called monomers.

Monomers

The individual subunits that join together to form polymers through covalent bonds.

Polymers

Large molecules formed by linking many monomers together; examples include polysaccharides, polypeptides, and nucleic acids.

Dehydration synthesis

A chemical reaction where monomers join by removing a water molecule ($H_{2}O$), forming a covalent bond and storing energy.

Hydrolysis

A chemical reaction where water is added to break polymers into monomers by splitting the covalent bonds.

Monosaccharide

A single sugar molecule, such as glucose, with a $1:2:1$ ratio of $C:H:O$; it serves as a primary cellular fuel.

Glycosidic bond

The covalent bond formed between two monosaccharides through dehydration synthesis.

Starch

A branched or coiled glucose polysaccharide used by plants for energy storage, containing alpha ($α$) linkages.

Glycogen

A highly branched glucose polymer used for rapid energy storage and release in animal liver and muscle cells.

Cellulose

A structural polysaccharide made of beta ($β$) glucose that forms straight, strong fibers via hydrogen bonding in plant cell walls.

Lipids

Diverse, hydrophobic biological molecules made of glycerol and fatty acids; they are not true polymers and are used for long-term energy storage and membranes.

Triglyceride

A lipid molecule consisting of one glycerol molecule and three fatty acid chains, used for energy storage and thermal insulation.

Saturated fatty acids

Lipids containing only single bonds between carbon atoms, resulting in straight chains that are solid at room temperature.

Unsaturated fatty acids

Lipids containing one or more $C=C$ double bonds, resulting in kinked structures that are liquid at room temperature.

Phospholipid

A molecule with a hydrophilic phosphate head and two hydrophobic fatty acid tails that spontaneously forms bilayers in cell membranes.

Steroids

Lipids characterized by a carbon skeleton consisting of four fused rings, functioning as signaling molecules or membrane stabilizers like cholesterol.

Amino acid

The monomer of proteins, containing an amino group ($-NH_{2}$), a carboxyl group ($-COOH$), and a specific R group.

Peptide bond

The covalent bond formed between amino acids through dehydration synthesis.

Denaturation

The loss of a protein’s physical structure and biological function due to extreme heat or changes in pH.

Nucleotide

The monomer of nucleic acids, composed of a phosphate group, a $5$-carbon sugar, and a nitrogenous base.

DNA (Deoxyribonucleic acid)

A double-stranded helix that stores long-term genetic instructions using the sugar deoxyribose and bases A, T, C, and G.

RNA (Ribonucleic acid)

A single-stranded molecule involved in protein synthesis that uses the sugar ribose and the base uracil ($U$) instead of thymine.

Transcription

The process in the central biological flow where information is transferred from $DNA \rightarrow RNA$.

Translation

The process in the central biological flow where RNA instructions are used to build a protein ($RNA \rightarrow \text{protein}$).

ATP (Adenosine Triphosphate)

The universal energy currency of life, composed of adenine, ribose, and three phosphate groups.

Phosphorylation

The process of transferring a phosphate group to another molecule, which changes its shape or activates it to drive cellular work.

Energy coupling

The cellular strategy of using energy-releasing reactions (like ATP breakdown) to drive energy-requiring reactions.

Chloroplast

The organelle where photosynthesis occurs, consisting of thylakoid membranes for light reactions and stroma for the Calvin cycle.

Thylakoid

The membrane-bound compartment inside a chloroplast where light-dependent reactions convert sunlight into ATP and NADPH.

Stroma

The fluid-filled space surrounding thylakoids in a chloroplast where the light-independent reactions (Calvin cycle) occur.

Photolysis

The process where water molecules are split using light energy ($H_{2}O \rightarrow 2H^{+} + 2e^{-} + \frac{1}{2}O_{2}$) to replace electrons in chlorophyll.

RuBisCO

The key enzyme in the Calvin cycle responsible for carbon fixation by attaching $CO_{2}$ to a $5$-carbon RuBP molecule.

Carbon fixation

The initial step of the Calvin cycle where inorganic $CO_{2}$ is converted into organic molecules.

Glycolysis

The first stage of cellular respiration occurring in the cytoplasm, where glucose is split into two molecules of pyruvate with a net gain of $2$ ATP.

Acetyl-CoA

The $2$-carbon molecule formed from pyruvate that enters the Krebs cycle in the mitochondrial matrix.

Krebs Cycle

The mitochondrial process that fully breaks down carbon from Acetyl-CoA, releasing $CO_{2}$ and generating electron carriers like NADH and $FADH_{2}$.

Electron Transport Chain (ETC)

A system of protein complexes in the inner mitochondrial membrane that use high-energy electrons to build a proton gradient for ATP production.

ATP synthase

The enzyme that uses the flow of hydrogen ions (proton gradient) to convert $ADP$ and $Pi$ into $ATP$.

Fermentation

An anaerobic process used to regenerate $NAD^{+}$ so that glycolysis can continue producing ATP when oxygen is not available.