Eukaryotic cells notes

Eukaryotic cells

Cells found in animals, plants, fungi, and protists that contain a double-membrane bound nucleus with DNA chromosomes and membrane-bound organelles.

Prokaryotic cells

Cells found in bacteria and archaea that lack a nucleus or other membrane-bound organelles.

Flagella

Locomotor appendages in eukaryotic cells that are thicker and more complex than prokaryotic flagella and function in motility.

Cilia

Locomotor appendages in eukaryotic cells that are similar to flagella but shorter and more numerous, found only in certain protozoa and animal cells, and function in motility and as a feeding and filtering structure.

Glycocalyx

The outermost boundary of a eukaryotic cell that comes into direct contact with the environment, composed of polysaccharides, and functions in adherence and protection.

Cell wall

A rigid structure in eukaryotic cells that provides structural support and shape, with different chemical compositions in fungi, algae, and prokaryotic cells.

Cytoplasmic (plasma) membrane

The typical bilayer of phospholipids and proteins in eukaryotic cells that serves as a selectively permeable barrier in transport.

Nucleus

The most prominent organelle in eukaryotic cells that contains genetic material (chromosomes) and regulates the activity of the cell.

Rough endoplasmic reticulum (RER)

An organelle that originates from the outer membrane of the nuclear envelope, is rough due to the presence of ribosomes, and synthesizes proteins for transport to the Golgi apparatus.

Smooth endoplasmic reticulum (SER)

An organelle that is a closed tubular network without ribosomes, functions in nutrient processing, synthesis and storage of lipids, and detoxification of toxic products.

Golgi apparatus

An organelle consisting of a stack of flattened sacs called cisternae that modify, store, and package proteins, closely associated with the endoplasmic reticulum.

Lysosomes

Vesicles containing enzymes that originate from the Golgi apparatus and are involved in intracellular digestion of food particles and protection against invading microbes.

Mitochondria

Organelles consisting of an outer and inner membrane with folds called cristae, which hold the enzymes involved in aerobic respiration and function in energy production (ATP).

Chloroplast

Organelles found only in algae and plant cells that contain chlorophyll and convert the energy of sunlight into chemical energy through photosynthesis, producing oxygen and organic nutrients.

Ribosomes

Structures composed of rRNA and proteins that are free in the cytoplasm or attached to the endoplasmic reticulum, larger than prokaryotic ribosomes, and function in protein synthesis.

Cytoskeleton

A flexible framework of proteins that form a network throughout the cytoplasm, involved in movement, transport, and structural support.

Fungi

Organisms divided into macroscopic and microscopic groups, including molds and yeast, that are heterotrophic and can be harmless saprobes or parasites, with importance in medical microbiology.

Yeast

Unicellular fungi that grow in loose associations or colonies, have a round/oval shape, and reproduce through asexual budding.

Hyphae

Filamentous fungi organized into a mass called mycelium, with vegetative hyphae for nutrient absorption and reproductive hyphae for spore production.

Protozoa

Unicellular eukaryotes that lack tissues, vary in shape, and are microscopic and motile, with some being harmless free-living organisms and others being animal parasites.

Trophozoite

The motile feeding stage of protozoa that requires ample food and moisture to stay active.

Cyst

The dormant, resting stage of protozoa that forms when conditions in the environment become unfavorable, resistant to heat, drying, and chemicals, and important for the spread of disease.

Mastigophora

A group of medically relevant protozoa that are flagellated.

Sarcodina

A group of medically relevant protozoa that have pseudopods.

Ciliophora

A group of medically relevant protozoa that are ciliated.

Apicomplexa

A group of medically relevant protozoa that are non-motile.

Helminths

Multicellular animals that have organs for reproduction, digestion, movement, and protection, including tapeworms, flukes, and roundworms.

Pinworm

Enterobius vermicularis, a common infestation of the large intestine