Cell Structure and Function Flashcards

Comprehensive vocabulary flashcards covering cell structure and function, including microscopy techniques, organelle descriptions, and cytoskeletal components based on the lecture notes.

Light Microscope (LM)

An instrument where visible light passes through a specimen and glass lenses to magnify an image, effective up to approximately $1,000 \times$ the actual size of the specimen.

Resolution

A parameter of microscopy referring to the clarity of an image or the minimum distance required to distinguish two separate points; for the human eye, this threshold is about $0.1\text{ mm}$.

Contrast

The visible differences in brightness levels between various parts of a sample, often enhanced by staining or labeling components.

Scanning Electron Microscope (SEM)

A type of microscope that focuses an electron beam onto the surface of a specimen to provide detailed 3-D images.

Transmission Electron Microscope (TEM)

A type of microscope that passes an electron beam through a specimen, primarily used to study the internal ultrastructure of cells.

Cell Fractionation

A laboratory technique utilizing a centrifuge to break cells apart and separate major organelles based on size and density.

Nucleoid

An unbound region in a prokaryotic cell where the genetic material (DNA) is concentrated.

Eukaryotic Cells

Cells characterized by having DNA enclosed within a membranous nucleus and possessing various membrane-bound organelles.

Nuclear Envelope

A double membrane consisting of lipid bilayers that encloses the nucleus, separating its contents from the cytoplasm.

Nuclear Lamina

A netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus.

Chromatin

The complex of DNA and proteins that makes up eukaryotic chromosomes; it condenses into discrete structures during cell division.

Nucleolus

A specialized structure within the nucleus where ribosomal RNA ($rRNA$) synthesis occurs.

Ribosomes

Complexes made of $rRNA$ and protein that carry out protein synthesis; they can be free in the cytosol or bound to the endoplasmic reticulum.

Smooth Endoplasmic Reticulum

A region of the endoplasmic reticulum that lacks ribosomes and functions in lipid synthesis, carbohydrate metabolism, drug detoxification, and calcium ion ($Ca^{2+}$) storage.

Rough Endoplasmic Reticulum

A region of the endoplasmic reticulum studded with ribosomes that produces secretory proteins, such as glycoproteins, and acts as a membrane factory.

Golgi Apparatus

A stack of flattened membranous sacs called cisternae that modifies, sorts, and packages ER products into transport vesicles.

Lysosome

A membranous sac containing hydrolytic enzymes used by animal cells to digest macromolecules and recycle damaged organelles.

Phagocytosis

A process by which a cell engulfs another cell or food particle, forming a food vacuole that subsequently fuses with a lysosome for digestion.

Autophagy

The process where lysosomes use hydrolytic enzymes to recycle the cell's own organic material and damaged organelles.

Contractile Vacuoles

Specialized structures found in many freshwater protists that pump excess water out of the cell to maintain osmotic balance.

Central Vacuole

A large plant cell organelle that stores organic compounds and water while playing a role in cell growth.

Mitochondria

The sites of cellular respiration, which use oxygen to generate energy in the form of $ATP$. structures include an outer membrane and an inner membrane folded into cristae.

Chloroplasts

Plant and algal organelles that contain chlorophyll and are the sites of photosynthesis; they contain thylakoids stacked into grana and an internal fluid called stroma.

Peroxisomes

Metabolic compartments bounded by a single membrane that produce hydrogen peroxide ($H_2O_2$) as a byproduct and następnie convert it to water.

Microtubules

Hollow rods made of tubulin dimers, roughly $25\text{ nm}$ in diameter, that shape the cell, guide organelle movement, and separate chromosomes during division.

Microfilaments

Thin solid rods composed of actin subunits, about $7\text{ nm}$ in diameter, which function in muscle contraction, amoeboid movement, and maintaining cell shape.

Intermediate Filaments

Fibrous proteins coiled into cables, ranging from $8\text{--}12\text{ nm}$ in diameter, that specialize in bearing tension and anchoring the nucleus and other organelles.

Centrosome

A region near the nucleus in animal cells that functions as a microtubule-organizing center and contains a pair of centrioles.

Plasmodesmata

Open channels through plant cell walls that connect the cytoplasm of adjacent cells, allowing water and small solutes to pass through.