BIOPHYSICS MASTER

Who first observed cells under the microscope?

Robert Hooke (1665) coined “cell,” and Antonie van Leeuwenhoek observed single-celled organisms.

What did Galvani and Volta contribute?

Galvani studied “animal electricity”; Volta created the first battery.

What did Friedrich Miescher discover in 1869?

“Nuclein” (DNA) in white blood cells.

What did Rosalind Franklin’s X-ray diffraction data reveal?

DNA’s helical structure, critical for Watson & Crick’s model.

Hippocrates’ inheritance theory?

Pangenesis — all tissues produce “seeds” passed to offspring.

Lamarck’s theory?

Acquired traits can be inherited.

Darwin’s idea?

Natural selection + speculative “gemmules.”

Weismann’s germ-plasm theory?

Only germ cells transmit heritable info.

Why did Mendel use peas?

Clear traits, controlled crosses, large numbers.

Law of Segregation?

Gametes receive one allele randomly.

Law of Independent Assortment?

Genes on different chromosomes assort independently.

Role of Punnett squares?

Predict inheritance ratios.

Who observed cell division?

Remak & Virchow.

How does meiosis create diversity?

Crossing over + reduction of chromosome number.

What is linkage?

Genes on same chromosome often inherited together.

What is a karyogram?

Chromosome chart showing abnormalities.

Griffith’s experiment?

Harmless bacteria transformed by “principle.”

Avery’s work?

DNA is transforming principle.

Hershey–Chase phage experiment?

DNA is genetic material (not protein).

Chargaff’s rules?

A=T, C=G.

Key features of B-DNA?

Right-handed, ~10.5 bp/turn, bases perpendicular.

What stabilizes DNA?

Hydrogen bonds + base stacking.

Persistence length of DNA?

dsDNA ~50 nm, ssDNA ~2 nm.

DNA pol synthesis direction?

5′ → 3′.

Leading vs lagging strand?

Leading continuous, lagging Okazaki fragments.

End-replication problem?

Telomere shortening.

Telomere maintenance in different species?

Humans (telomerase in stem/germ cells), Drosophila (retrotransposons), Lobsters (persistent telomerase).

Tautomerism effect?

Causes mispairing.

UV damage?

Thymine dimers.

Beer–Lambert law?

A = εcl.

260/280 ratio meaning?

DNA purity (~1.8 = pure).

Why does DNA separate by size in gels?

Gel sieving effect.

What is Tm?

Temperature where 50% DNA is denatured.

What is persistence length?

Stiffness scale of polymer.

Why does stretching DNA require force?

Entropic elasticity.

What happens at ~60 pN force?

DNA overstretches to 1.6× contour length.

What do optical tweezers measure?

DNA elasticity at single-molecule level.

Who discovered nuclein?

Miescher.

Whose X-ray data showed DNA helix?

Franklin.

Griffith showed what?

Transformation.

Avery proved what?

DNA = hereditary material.

Hershey–Chase result?

DNA is genetic material.

Chargaff’s rules?

A=T, C=G.

Mendel’s laws?

Segregation & Independent Assortment.

Gene vs allele?

Trait vs variation.

Linkage?

Genes on same chromosome.

Karyogram use?

Detect chromosome abnormalities.

B-DNA bp/turn?

~10.5.

H-bonds: A–T vs G–C?

2 vs 3.

DNA pol direction?

5′ → 3′.

Leading vs lagging strand?

Continuous vs Okazaki.

End-replication problem solved by?

Telomerase.

Persistence length ds vs ssDNA?

50 nm vs 2 nm.

Tautomers cause?

Mutations.

UV light causes?

Thymine dimers.

Beer–Lambert law?

A = εcl.

260/280 ratio?

DNA purity (~1.8).

Gel electrophoresis separates DNA how?

Size sieving.

DNA Tm depends on?

GC content & length.

Overstretching DNA force?

~60 pN.

Optical tweezers measure?

DNA elasticity.