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By New England Biolabs.

Publisher: New England Biolabs.

This source is credited to an organization.

Online text: www.neb.com/faqs/why-do-i-see-amplification-curves-in-my-ntc-samples

Cited passages: FAQ: primer structures as DNA-polymerase substrates, and carryover PCR-product contamination.

By Addgene.

Publisher: Addgene.

This source is credited to an organization.

Online text: www.addgene.org/protocols/primer-design/

Cited passages: Primer Design for PCR: specificity, paired melting temperatures and complementary primer sequences.

By Thermo Fisher Scientific.

Publisher: Thermo Fisher Scientific.

This source is credited to an organization.

Online text: www.thermofisher.com/us/en/home/life-science/cloning/cloning-learning-center/invitrogen-school-of-molecular-biology/pcr-education/pcr-reagents-enzymes/pcr-cycling-considerations.html

Cited passages: PCR cycle number determination and Figure 7: lowered efficiency and plateau from reaction-component depletion and by-products.

Additional cited passages: Template DNA denaturation assessment, paragraphs 1 and 3–6; DNA denaturation considerations, paragraph 1; Primer annealing optimization, opening, calculated-setting and nonspecific-product paragraphs; Primer extension considerations, paragraphs 1 and 3. No human byline or publication or revision date was verified.

By Thermo Fisher Scientific.

Publisher: Thermo Fisher Scientific.

This source is credited to an organization.

Online text: videos.thermofisher.com/detail/video/4896138740001/principles-of-pcr

Cited passages: Principles of PCR, accompanying description: denaturation, annealing, primer-dependent extension and dNTP incorporation.

Additional cited passages: accompanying Description, first three paragraphs, strand separation, complementary primer binding, enzyme-dependent extension temperature, dNTP incorporation and two-step cycling. Accompanying text was inspected; frame-by-frame video viewing is not asserted. No human byline or publication or revision date was verified.

By Addgene.

Publisher: Addgene.

This source is credited to an organization.

Online text: www.addgene.org/protocols/pcr/

Cited passages: Background Information: two primers, template-directed copying and product verification; Basic PCR Program, steps 1–6; Materials List: Taq buffer with magnesium chloride.

Additional cited passages: Background Information; Basic PCR Program, steps 1–6; Procedure, Primer Design and PCR step 13, gel readout. Basic PCR Program and Procedure give different extension durations; no unified duration is attributed to the source. No human byline or publication or revision date was verified.

Publisher: Brigham Young University-Idaho.

Online text: content.byui.edu/file/a236934c-3c60-4fe9-90aa-d343b3e3a640/1/module5/readings/osmosis.html

Cited passages: Cell Membranes—Structure and Transport, Osmosis: paragraphs beginning Earlier this semester and Osmolarity is a useful term; total particle counting; Cell Membranes—Structure and Transport, Osmosis: paragraphs beginning Here is another way and final Note; permeating solutes and transient effects.

By University of Toronto Department of Physics.

Publisher: University of Toronto Department of Physics.

This source is credited to an organization.

Online text: ugdemos.physics.utoronto.ca/db/demos/osmosis-brine

Cited passages: Osmosis (Brine), Description steps 1–14, water-filled comparison and Old Description A.2: apparatus, readout and leak check.

A cell line comprises descendants after a primary cell culture's first subculture. Further division can be finite or continuous; one founder biological cell is not required.^[ref]

The useful continuity is ancestry across successive subcultures: descendants supply the next experiment. Individual biological cells can divide or die while their cell line persists. A common origin helps compare experiments, but does not imply that every descendant has identical DNA, gene expression or cell state.

A biochemist investigates the molecular chemistry of living systems, including the structure, reactions, and regulation of proteins, nucleic acids, lipids, and metabolites. The subject links chemistry with biology through experimentally testable mechanisms.

For example, measuring how an enzyme's reaction rate changes after a targeted amino-acid substitution can test a proposed catalytic role. Structural, kinetic, and cellular measurements answer complementary questions; a molecular interaction observed in isolation need not establish its importance in a living organism.

Energy metabolism comprises reactions that capture, transfer, and use energy to support cellular processes. Oxidation of nutrients can reduce electron carriers and support synthesis of ATP, which then couples favorable chemical change to otherwise unfavorable work.

ATP is a transferable chemical intermediate, not a substance that creates energy. In oxidative phosphorylation, electron transfer helps establish an electrochemical gradient across a membrane, and ATP synthase uses that gradient. Conservation of energy and the direction of free-energy changes constrain the whole process.