Eukaryotic Biology

Flashcards covering key vocabulary and concepts related to the cytoskeleton, cell biology techniques, and related diseases.

Cytoskeleton

A fibrous network within the cell, composed of about 20% of the cell's proteins, crucial for cell shape and movement.

Cytoskeleton Structure

Microphil (actin), Myosin, Microtubles (tubulin), Intermediate Filaments (cytokeratins)

Microfilaments

Composed of actin, responsible for tension and cell motility, including muscle contraction. They consist of two intertwined strands. Tension load bearing

G-actin

Globular actin protein that polymerizes to form F-actin.

F-actin

Two intertwined chains of actin monomers, exhibiting +ve ends (polymerization) and -ve ends (actin loss). Double Helix

Microfilaments Role

resist deformation, stabilised, tissues, and connection, cell migration, endocytosis, chromosome segregation, muscle contraction

Tight Junctions

Plasma membranes tightly bound by proteins, creating a water-tight seal between cells.

Desmosomes

Protein rivets that anchor cells together, linking to sturdy keratin structures.

Myosin I

A ubiquitous cell protein with a globular head (ATP binding) and a short tail, involved in vesicle transport.

Intermediate Filaments

Composed of cytokeratins, resist deformation, stabilize tissues, and facilitate cell migration. Animals contain 6 types

Type I+II IF

The most diverse type, I (acidic) and II (basic), epithelial keratins and trichocytic keratins i.e hair

Type V IF

Used for structure and transcription regulation in the nucleus

Cytoskeleton Disease (DMD)

Duchenne Muscular Dystrophy, an X-linked disease caused by a mutation in the dystrophin gene on Xp21 locus.

Muscle Contraction

Mediated by conventional myosin II, involving actin and myosin interaction.

Microtubules

Composed of alpha (purple) and beta (blue) tubulin, involved in nerve impulse transmission and calcium signaling mediated by GTP hydrolysis

Centrioles

Consist of 27 microtubules and are involved in forming mitotic spindles during cell division surrounded by protein matrix

Microtuble Types

1. O - cytoplasm and mitotic spindles during cell

2. OO - cilia and flagella

3. OOO - centrioles and basal bodies

Mitotic Spindles

Organelles responsible for the partition of replicated chromosomes during mitosis. Formed during anaphase

Kinesin

Motor proteins involved in anterograde transport, cell cargo and depolymerising during anaphase

Cilia and Flagella Movement

Cilia move back-and-forth powered by dynein, while flagella undulate in snake-like movements. Core of microtubules and basal body anchor to

Dynein

Motor proteins involved in retrograde transport and cell cargo. Cytoplasmic for organelle function and Axonemal in cillia and flagella movement

Cytology

Microscopic examination of cells obtained from the body for diagnostic purposes. Painless and no anaesthetic needed

Homogenisation

Process used to break open cell membranes to extract cell contents, employing mechanical, chemical, physical, or enzymatic methods.

Fractionation

Centrifugation technique used to separate cell components based on size, density, and gradient medium.

Marker Enzymes

Enzymes localized exclusively to specific organelles, providing information on biochemical purity indicating levels of contamination

Mechanical Homogenisation

Bead mills using agitate beads, Ultra sonication using liquid shear with vibration, shock waves and titanium

Physical Homogenisation

Thermolysis using bacteria to heat to 50°C causing peri-plasmic proteins to release. 95°C for cell wall and cytoplasm

Microscopy

Techniques including bright field, phase contrast, fluorescence, confocal, and electron microscopy used to visualize cells.

Chemical Homogenisation

Detergents using chemicals to solubilise membrane proteins and causing lysis, anionic, cationic and non - ionic

Fluorescence Microscopy

Uses fluorochromes (dyes) for localization of specific molecules within cells. Slides can be fixed or living

Enzymatic Homogenisation

Enzymes that degrade cell walls

Plants - cellulase

Yeast - Zymolyases

Gram -/+ - Lysozomes

Animals - Proteinase K

Exfoliative Cytology

• microscopic of cells shed or mucous membrane

FNAC Cytology

Fine needle

• lumps or masses

Body Fluids Cytology

• thing needle in organ cavity i.e CSF

Immunocytochemistry

Technique for detecting cell markers via immuno-reactions, uses epitopes, useful for tumor diagnostics.

Isopycnic Phase

equal density between fraction and gradient

Organelle Movement

• vesicles along microtubules in nerve axon and motor proteins

• kin/dynein heads into ATP to bind

• systolic dynein mediates retrograde movement along singlet movements

Organelles

Membrane-bound living structures of a cell within cytoplasm, responsible for biosynthetic and metabolic activities

Staining

• Fixing (alcohol)

• Permeabilisation (mild detergents)

• Dehydration (cytoplasmic ie eosin)

• Clearing (xylene)

• Mounting (bonds and protects samples)

Diff-Quik

Romanowsky stain which is a modification of Wright-Glemsa for mucins and cytoplasm