Molecular Biology Lecture Notes

Flashcards covering key vocabulary and concepts from a molecular biology lecture.

Information Processing in the Cell

The complex activities of cells are controlled by genes in chromosomes, containing information for protein synthesis, which determines structural and functional characteristics

Molecular Biology Focus

Focuses on: (1) information encoding in chromosomes, (2) information processing, (3) blueprint replication during cell division, and (4) information modification for new messages.

DNA

A macromolecule that explains information encoding, processing, replication, and mutability; it directs the cell's destiny and maintains genetic continuity between generations

Transcription

The production of a messenger molecule (mRNA) from a DNA template.

Translation

The process where mRNA joins with ribosomes and other molecules to synthesize a protein.

Mutations

Physical alterations in DNA that lead to changes in the coded sequence, providing new genetic sequences for evolutionary modifications.

Friedrich Miescher

Isolated nuclein (nucleic acid) from cell nuclei, which later was identified as DNA.

C.B. Bridges

Showed chromosomes are the physical basis of inheritance, carrying the genes.

Robert Feulgen

Developed a method for staining DNA and showed it is found in chromosomes.

P.A. Levene

Determined the chemical properties of DNA, identifying the nucleotide as its basic unit (phosphate group, deoxyribose sugar, and nitrogenous base).

Erwin Chargaff

Showed that DNA bases are not present in equal parts but vary, with the rule that A=T and G=C.

Watson and Crick

Developed the double helix model for DNA structure using x-ray diffraction photographs by Rosalind Franklin.

DNA Forms

B-DNA (Watson-Crick model), A-DNA (partially unwound), C-DNA (tightly coiled), and Z-DNA (helix wound opposite to B-DNA).

Complementary Bases

Adenine (A) pairs with Thymine (T) via two hydrogen bonds; Guanine (G) pairs with Cytosine (C) via three hydrogen bonds.

Codons

A sequence of three bases that code for assembling amino acids into proteins

Genetic Code

A linear sequence of three bases that appears to be universal for all living forms.

RNA

Resembles DNA but is single-stranded, has ribose sugar, and uses uracil instead of thymine.

RNA Polymerase

An enzyme that attaches to the promoter region of DNA and catalyzes the attachment of nucleotides to form an RNA strand during transcription.

Introns

Long sequences of bases in DNA that do not contain meaningful information for protein synthesis but are transcribed into hnRNA and later excised.

Exons

DNA sections that are translated and remain in mRNA after introns are excised.

hnRNA

Heterogeneous nuclear RNA, a slurry of primary transcripts in the nucleus including both introns and exons.

tRNA

Transfer RNA, responsible for carrying amino acids to mRNA for incorporation into the protein chain, contains an anticodon complementary to mRNA codons.

Svedberg Unit

Specific measure of sedimentation in a gravitational field, used to describe ribosomal subunits (e.g., 30 S, 50 S).

DNA Replication

Each DNA strand serves as a template for a complementary strand, creating two identical double helices consisting of one parent strand and one newly synthesized strand.

Semiconservative Replication

Each newly created DNA double helix consists of one original “parent” strand and one newly synthesized strand.

Mutations

Changes in the sequence of triplet codons in DNA, including insertions, deletions, and substitutions.

Transposition

Jumping genes phenomenon where DNA stretches move from one chromosome to another.

Mutagens

Agents that cause mutations, including chemicals, ionizing radiation (x-rays, cosmic rays; alpha, beta, gamma rays), and ultraviolet light.

Genetic Engineering

Procedures to intentionally alter genetic information machinery, like DNA recombinant procedures (gene splicing).

Restriction Enzymes

Enzymes that act like scissors to cut DNA at precise regions, used in recombinant DNA studies.

Plasmids

Small circular DNA outside the chromosome in bacteria, used in recombinant techniques to incorporate foreign DNA.

Cloning

A technique to produce many copies of a single gene, chromosome, or whole individual without sexual recombination.