DAT Biology Practice Flashcards (2026 Edition)

These practice flashcards cover essential vocabulary and concepts from the DAT Biology comprehensive lecture notes, encompassing biochemistry, cell biology, genetics, anatomy, and ecology.

Element

A pure substance that has specific physical/chemical properties and can’t be broken down into a simpler substance.

Intramolecular forces

Attractive forces that act on atoms within a molecule.

Polymers

Substances made up of many monomers joined together in chains.

Dehydration (condensation) reaction

A chemical process that creates a covalent bond between monomers and releases water.

Hydrolysis

A reaction that breaks a covalent bond by using water.

Ribose

A five-carbon monosaccharide.

Isomers

Molecules that have the same chemical formula but a different arrangement of atoms, such as glucose and fructose.

Chitin

A structural polysaccharide found in fungal cell walls and the exoskeletons of arthropods.

Secondary structure

Intermolecular forces between the polypeptide backbone due to hydrogen bonding, forming $\alpha$-helices or $\beta$-pleated sheets.

Protein denaturation

The loss of protein function and higher order structures, leaving only the primary structure unaffected; caused by temperature, $pH$, or salt changes.

Induced fit theory

Describes how an enzyme's active site molds itself and changes shape to fit the substrate when it binds.

Ribozyme

An $RNA$ molecule that can act as a non-protein enzyme.

Coenzyme

An organic cofactor, such as a vitamin, that helps enzymes perform reactions.

Kinase

An enzyme that indirectly adds a phosphate group to a substrate molecule by transferring a phosphate group from an $ATP$ molecule.

KM (Michaelis Constant)

The substrate concentration $[X]$ at which the velocity $(V)$ is $50\%$ of the maximum reaction velocity $(V_{max})$.

Amphipathic

Molecules that possess both hydrophobic and hydrophilic properties, such as phospholipids and cholesterol.

Phosphodiester bonds

Bonds formed through a condensation reaction where the phosphate group of one nucleotide connects to the hydroxyl group of another.

RNA world hypothesis

The theory that early life forms relied on self-replicating $RNA$ both to store genetic information and to catalyze chemical reactions.

Fluid mosaic model

Describes the cell membrane as a collection of different kinds of structures that can move freely within the membrane.

Clathrin

A protein that aids in receptor-mediated endocytosis by forming a pit in the membrane that pinches off as a coated vesicle.

Secondary active transport

Uses energy from one molecule moving down its electrochemical gradient to drive the transport of another molecule against its gradient.

Nucleolus

A dense area within the nucleus responsible for producing components of ribosomal subunits, including $rRNA$.

Endomembrane system

A group of organelles, including the nucleus, $ER$, Golgi, and lysosomes, that work together to modify, package, and transport proteins and lipids.

Microfilaments

The smallest cytoskeleton structures, composed of a double helix of actin, involved in cell movement, cyclosis, and muscle contraction.

Integrin

A transmembrane protein that facilitates $ECM$ adhesion and signaling to cells regarding growth or apoptosis.

Desmosomes

Cell-cell junctions that provide support against mechanical stress by connecting neighboring cells via intermediate filaments.

Plasmolysis

The process of a cell's cytoplasm shrinking away from the cell wall when placed in a hypertonic solution.

Exergonic

A spontaneous chemical reaction that releases energy and has a negative Gibbs free energy $(-\Delta G)$, such as cellular respiration.

Substrate-level phosphorylation

The process of generating $ATP$ in glycolysis by transferring a phosphate group to $ADP$ directly from a phosphorylated compound.

Fermentation

An anaerobic pathway that relies on glycolysis and the conversion of pyruvate into other molecules to oxidize $NADH$ back to $NAD^+$.

Photolysis

The process of splitting water molecules using light energy to release electrons during photosynthesis.

RuBisCo

The enzyme that catalyzes the reaction of $CO_2$ with $RuBP$ to form three-carbon phosphoglycerates during the Calvin cycle.

Kinetochores

Proteins on the sides of centromeres that help microtubules pull sister chromatids apart during cell division.

Somatic cells

All body cells excluding gametes; in humans, these cells are diploid.

Synapsis

The pairing up of homologous chromosomes to form tetrads during prophase I of meiosis.

Purines

Double-ringed nitrogenous bases including Adenine and Guanine.

Topoisomerase

An enzyme that nicks the $DNA$ double helix ahead of helicase to relieve built-up tension and supercoiling during replication.

Telomerase

An enzyme that extends the noncoding, repeated nucleotide sequences at the ends of linear chromosomes to prevent information loss.

Operon

A group of genes in prokaryotes that function as a single unit controlled by one promoter.

Codon

A group of three $mRNA$ bases that code for an amino acid or signal the termination of translation.

Capsid

A viral protein coat made of subunits called capsomeres.

Hemizygous

A state where only one allele is present for a gene, such as in human males for genes located on the $X$ and $Y$ chromosomes.

Epistasis

Occurs when one gene affects the expression of a different, independent gene.

Proto-oncogenes

Genes normally involved in cell cycle control that can cause cancer if they undergo a gain-of-function mutation and become oncogenes.

Scanning electron microscopy (SEM)

Microscopy technique providing high resolution $3D$ images of the surface of a dehydrated sample.

Sanger sequencing

A $DNA$ sequencing method that uses deoxynucleotides $(dNTPs)$ and chain-terminating dideoxynucleotides $(ddNTPs)$.

Radicle

The first part of a seed embryo to emerge, developing into the root and anchoring the plant.

Auxins

Plant hormones responsible for cell growth and tropisms, including phototropism and gravitropism.

Systole

The phase of the cardiac cycle where blood pressure is highest in the arteries, occurring when ventricles eject blood.

Foramen ovale

A hole in the fetal heart that allows blood in the right atrium to flow into the left atrium, bypassing pulmonary circulation.

Bohr effect

The phenomenon where hemoglobin has decreased oxygen affinity when $CO_2$ is high due to lowered $pH$.

Nodes of Ranvier

Gaps between myelin sheaths where ion exchange occurs, enabling saltatory conduction of action potentials.

Sarcomere

The functional unit of skeletal muscle that shortens during contraction, composed of actin and myosin filaments.

Osteoblast

Cells that build bone by secreting proteins and utilizing blood calcium.

G cells

Cells in the stomach lining that release gastrin in response to food entry.

Iteroparity

A mating strategy where an organism mates many times in its lifetime, typically producing fewer offspring with higher survival rates.