Comprehensive Biology and Human Physiology Practice Flashcards

This set of vocabulary flashcards covers essential biological principles including biochemistry, molecular genetics, microbiology, cell biology, and major human physiological systems as described in the lecture transcripts.

Amino acids

Building blocks of proteins consisting of a carbonyl, amino group, and a variable R group.

Disulfide Bonds

A bond formed when two Cysteine amino acids undergo a covalent interaction, resulting in a cystine.

Secondary Structure

The protein structure characterized by $\alpha$-helices and $\beta$-sheets, involving H-bonds.

Glycosidic linkage

The bond that connects monosaccharides to form disaccharides, oligosaccharides, or polysaccharides.

Triglycerides

A type of lipid used for energy storage in adipose cells, composed of glycerol and 3 fatty acids.

Phospholipids

Lipid molecules composed of glycerol, 2 fatty acids, and 1 phosphate, which spontaneously form micelles and bilayers.

Terpenes

Lipid compounds made of isoprene units with the general formula $(C_5H_8)_n$.

Anhydride linkage

The process that binds two orthophosphates together to create pyrophosphate.

Watson-Crick Model

States that DNA is antiparallel, double-stranded, and corkscrews in a clockwise manner as a right-handed double helix.

DNA Gyrase

An enzyme used by prokaryotes to twist circular DNA into a supercoil for packing.

Heterochromatin

Denser, more tightly wound areas of chromatin that are usually transcriptionally inactive.

Degenerate

A term for the genetic code because multiple codons can indicate the same amino acid.

Topoisomerases

Enzymes that cut DNA strands to help unravel the helix and relieve strain during replication.

Okazaki fragments

Short fragments of DNA synthesized on the lagging strand in the $5'$ to $3'$ direction away from the replication fork.

Telomerase

An enzyme that adds repetitive sequences to telomeres to prevent the loss of genetic information during replication.

Missense Mutation

A point mutation in which a single base pair substitution leads to a change in the encoded amino acid.

Transposase

An enzyme coded by transposons that allows them to cut and paste themselves within the genome.

Haploinsufficiency

A condition in which having only one working copy of a gene is insufficient for normal cellular function.

Mismatch Repair Pathway (MMR)

A post-replication repair mechanism that identifies and replaces mismatched nucleotides.

Homologous Recombination

A double-strand break repair process that relies on a sister chromatid as a template to repair the damaged DNA.

Monocistronic

Eukaryotic mRNA that codes for only one polypeptide or gene.

Spliceosome

A complex containing proteins and 5 snRNAs that removes introns from hnRNA to produce mature mRNA.

Wobble Hypothesis

Crick's hypothesis stating that the third base of a tRNA anticodon can have flexible pairing with the mRNA codon.

Shine-Dalgarno sequence

A specific ribosomal binding site in prokaryotic mRNA located at $-10$.

IRESs (Internal Ribosome Entry Sites)

Specialized sequences in mRNA that allow for cap-independent translation, typically during cell stress.

X Chromosome Inactivation

The random process in female mammals where one X chromosome (Xi) is inactivated and heavily methylated.

Lac Operon

An inducible, catabolic system in prokaryotes that is activated to break down lactose when glucose levels are low.

Zymogens

Also called proenzymes, these are precursor proteins that must be cleaved to become functional enzymes.

Bacteriophage

A virus that infects bacteria, typically injecting its genome via a tail sheath.

Prions

Self-replicating, misfolded proteins that violate the Central Dogma by causing other proteins to misfold.

Gram-negative Bacteria

Bacteria that stain pale pink and have a thin peptidoglycan layer encapsulated by an outer phospholipid membrane.

Chemotaxis

The movement of bacteria toward or away from chemical attractants using chemoreceptors.

Auxotrophs

Bacteria that cannot survive on minimal media because they lack the ability to synthesize a necessary molecule.

Conjugation

A method of bacterial genetic exchange involving a sex pilus and the unidirectional transfer of the F factor.

Endosymbiotic Theory

The theory that mitochondria originated as separate prokaryotic organisms that were engulfed by a host cell.

Crinophagy

The process by which lysosomes degrade excess or unneeded secretory proteins.

Fluid Mosaic Model

A model describing the plasma membrane as a structure where lipids and proteins move laterally but cannot flip-flop.

Van’t Hoff factor ($i$)

A measure of how many particles a solute dissociates into when placed in a solution.

Osmotic pressure ($\Pi$)

The amount of pressure required to stop the flow of osmosis, calculated as $\Pi = MiRT$.

Na+/K+ ATPase

A primary active transporter that pumps 3 Na+ out and 2 K+ into the cell per 1 ATP molecule.

G-protein linked receptor

A cell surface receptor that activates internal signal cascades, often involving cAMP, for signal amplification.

9+2 arrangement

The structural organization of eukaryotic cilia and flagella, consisting of 9 pairs of microtubules around 2 central ones.

Desmosomes

Cell junctions that anchor cells together at specific points, providing mechanical stability.

p53

A tumor suppressor protein responsible for monitoring DNA integrity and inducing apoptosis if damage is irreparable.

Caspases

Proteases that regulate and carry out the process of apoptosis.

Parenchyma

The functional parts of an organ, often composed of epithelial cells.

Law of Segregation

Mendel's law stating that alleles for a gene are separated and passed to the next generation singly.

Crossing Over

The exchange of genetic material between homologous chromosomes during synapsis in Prophase I of meiosis.

Hardy-Weinberg Equilibrium

A theoretical state where allele frequencies in a population remain constant due to lack of mutation, migration, or selection.

Nodes of Ranvier

Periodic gaps in the myelin sheath of an axon where depolarization and ion exchange occur.

Saltatory Conduction

The rapid jumping of an action potential from one node of Ranvier to the next in myelinated axons.

Absolute Refractory Period

The time after an action potential when a neuron cannot fire again because voltage-gated Na+ channels are inactivated.

Vagus Nerve

A cranial nerve that decreases heart rate and increases GI activity as part of the parasympathetic system.

Pacinian corpuscles

Mechanoreceptors located deep in the dermis that respond to deep pressure and vibration.

Weber’s Law

States that two stimuli must differ by a constant proportion for the difference to be noticeable.

Tropic Hormones

Hormones that act as control mechanisms by regulating the release of other hormones.

Frank-Starling Mechanism

States that increasing the stretch of heart muscle (via venous return) leads to more forceful contractions and higher stroke volume.

Bohr Effect

The phenomenon where low pH, high binary $CO_2$, and increased temperature stabilize the tense state of hemoglobin, reducing its oxygen affinity.

Enterokinase

Also called enteropeptidase, it is a brush border enzyme that activates trypsinogen into trypsin.

Sarcomere

The fundamental contractile unit of a myofibril, bounded by Z lines and containing actin and myosin.

Osteoclasts

Cells responsible for breaking down bone tissue to release calcium into the bloodstream.