Cell Biology and Genetics Foundations

These flashcards cover cellular architecture, bacterial morphology, eukaryotic organelles, motility mechanics, and the fundamental principles of genetics as described in the lecture notes.

Coccus

Spherical-shaped bacterial cells.

Sarcina

Cubical packets of $8$ or more cocci.

Bacillus

Cylindrical or rod-shaped bacterial cells.

Palisades

Bacterial arrangement consisting of side-by-side rows of cells.

Vibrio

Comma-shaped bacterial cells.

Spirillum

Rigid corkscrew-shaped bacterial cells, occasionally found in short chains.

Spirochete

A flexible helix-shaped bacterial cell.

Pleomorphism

High variation in size and shape among cells of a single species due to nutritional or genetic factors.

Positive Chemotaxis

Cellular movement toward a favorable chemical stimulus, such as nutrients.

Negative Chemotaxis

Cellular movement away from a harmful chemical compound, such as toxins.

Run

Counterclockwise flagellar rotation resulting in a smooth, linear trajectory toward a stimulus.

Tumble

Clockwise flagellar rotation that halts forward progress, causing the cell to stop and randomly redirect course.

Pilus (Pili)

Rigid structures utilized for genetic transfer (conjugation) and occasionally adhesion, but not general locomotion.

Fimbria (Fimbriae)

Small, hair-like fibers that provide surface adhesion but lack locomotory function.

Nanowires (Nanotubes)

Tubular cytoplasmic extensions used for cell-to-cell adhesion and the transfer of nutrients, electrons, or signals.

Biofilms

Complex microbial communities anchored to surfaces that protect organisms from environmental threats and share access to resources.

Last Common Ancestor (LCA)

The primitive ancestral cell line from which Bacteria, Archaea, and Eukaryotes all diverged.

Nucleolus

An intensely staining region rich in RNA that serves as the primary site for ribosomal RNA (rRNA) synthesis.

Chromatin

Linear eukaryotic DNA strands tightly bound to basic histone proteins.

$$80S$$

The full functional size of eukaryotic ribosomes.

Polyribosomes

Short, functional chains consisting of multiple ribosomes actively translating a single mRNA strand simultaneously.

Rough ER (RER)

A region of the endoplasmic reticulum studded with ribosomes that handles protein synthesis, folding, and packaging.

Smooth ER (SER)

A region of the endoplasmic reticulum devoid of ribosomes responsible for lipid synthesis and toxin detoxification.

Cristae

Inner membrane folds of the mitochondria which embed respiratory enzymes and electron carriers.

Cytoskeleton

An internal structural matrix consisting of actin filaments, intermediate filaments, and microtubules.

Genomics

The formal study of an organism's entire structural and functional genome.

Genome

The sum total of all genetic material within an organism.

Genotype

The sum of all types of genes constituting an organism's distinctive genetic makeup.

Phenotype

The physical expression of genes creating observable structures or functional traits.

Semiconservative Replication

Replication where each daughter DNA molecule contains one original parental template strand and one newly synthesized identical strand.

The Central Dogma

The unidirectional pathway of genetic information flow: DNA is transcribed into RNA, and RNA is translated into proteins.

Proteomics

The comprehensive study of an organism's entire complement of actively expressed proteins.

Codon

A series of triplet bases read by ribosomes that dictates which amino acids are added to a growing peptide chain.

Redundancy

The representation of certain amino acids by multiple distinct codons to prevent dangerous phenotypic mutations.

Wobble Effect

A phenomenon where only the first two nucleotides of a codon are strictly required to encode the correct amino acid.