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Module 11 in the Syllabus

The Eukaryotic Cell Images
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Question Drill for The Eukaryotic Cell
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
EukaryoteAnimals, plants, fungi, and protists are eukaryotes, which are organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton.
CytoskeletonThe cytoskeleton is a cellular scaffolding or skeleton contained within the cytoplasm.
CytoplasmCytoplasm is a gelatinous, semi-transparent fluid that fills most cells.
Cell nucleusThe nucleus is a membrane-enclosed organelle found in most eukaryotic cells which contains the cell's genetic material.
Golgi apparatusThe Golgi apparatus is an organelle found in most eukaryotic cells the primary function of which is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell.
MitochondrionA mitochondrion is a membrane-enclosed organelle that is found in most eukaryotic cells that. In addition to supplying cellular energy, they are involved in a range of other processes.
OrganelleAn organelle is a specialized subunit within a cell, having a specific function, and separately enclosed within its own lipid membrane.
Nuclear envelopeThe nuclear envelope or membrane is the double membrane of the nucleus that encloses genetic material in eukaryotic cells.
Nuclear poreNuclear pores are large protein complexes that cross the nuclear envelope, which is the double membrane surrounding the eukaryotic cell nucleus.
ChloroplastChloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. They are generally considered to have originated as endosymbiotic cyanobacteria.
LysosomeLysosomes are organelles that contain digestive enzymes to digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.
CentrioleA centriole is a barrel shaped organelle found in most eukaryotic cells with walls usually composed of nine triplets of microtubules.
NucleolusThe nucleolus is a sub-organelle of the cell nucleus. Its main function is the production and assembly of ribosome components.
Endomembrane systemThe endomembrane system is the system of internal membranes within eukaryotic cells that divide the cell into functional and structural compartments, or organelles.
VesicleA vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid bilayer.
CiliumA cilium is an organelle found in eukaryotic cells. It is a thin, tail-like projection extending approximately 5-10 micrometers outwards from the cell body.
MicrofilamentMicrofilaments are the thinnest filaments of the cytoskeleton found in the cytoplasm of all eukaryotic cells. These linear polymers of actin subunits are flexible and relatively strong.
Spindle apparatusThe spindle apparatus is a structure of the eukaryotic cytoskeleton involved in mitosis and meiosis, often referred to as the mitotic spindle during mitosis and the meiotic spindle during meiosis.
CisternaA cisterna comprises a flattened membrane disk which makes up the Golgi apparatus.
Vesicular-tubular clusterVesicular-tubular cluster is an intermediate compartment mediating trafficking between the endoplasmic reticulum and Golgi complex.
PeroxisomePeroxisomes are ubiquitous organelles in eukaryotes that participate in the metabolism of fatty acids and other metabolites. They have enzymes that rid the cell of toxic peroxides.
Basal bodyA basal body is an organelle formed from a centriole, a short cylindrical array of microtubules. It is found at the base of a eukaryotic undulipodium (cilium or flagellum) and serves as a nucleation site for the growth of the axoneme microtubules.
Endosymbiotic theoryThe endosymbiotic theory concerns the origins of mitochondria and plastids, according to which these organelles originated as separate prokaryotic organisms which were taken inside the cell as endosymbionts.
ActinActin is the protein which serves as the monomeric subunit of microfilaments, one of the three major components of the cytoskeleton, and of thin filaments which are part of the contractile apparatus in muscle cells.
Intermediate filamentIntermediate filaments are cytoskeletal structures formed by members of a family of related proteins. These filaments have a diameter between that of actin microfilaments and microtubules.
PlastidPlastids are major organelles found in plants and algae responsible for photosynthesis, storage of products like starch and for the synthesis of many classes of molecules such as fatty acids and terpenes.
CentrosomeThe centrosome is the main microtubule organizing center of the cell as well as a regulator of cell-cycle progression.
TubulinA tubulin is one of several members of a small family of globular proteins. The most common members this family are the proteins which makes up microtubules.
Nuclear localization signalA nuclear localization signal is an amino acid sequence which acts like a 'tag' on the exposed surface of a protein to target the protein to the cell nucleus through the nuclear pore complex and to direct it into the nucleus via its recognition by cytosolic nuclear transport receptors.
AxonemeThe axoneme is the inner cytoskeletal structure of eukaryotic cilia or flagella.
Microtubule organizing centerThe microtubule-organizing center is a structure found in all plant and animal cells from which microtubules emerge.
KinesinKinesins are a class of motor proteins found in cells which move on the much larger microtubule cables powerered by the hydrolysis of ATP. They are dimers reminiscent of feet on a rod.
DyneinDynein is a motor protein in cells which converts the chemical energy contained in ATP into the mechanical energy of movement, transporting various cellular cargo by walking along cytoskeletal microtubules towards the minus-end of the microtubule, ie. toward the center of the cell..
UndulipodiumAn undulipodium is a general term for a 9+2 organelle containing a microtubule array such as eukaryotic flagella and cilia.
NucleoporinA nucleoporin is a type of porin which facilitates transport through nuclear pores in the nuclear envelope.
Nuclear laminaThe nuclear lamina is a dense fibrillar network composed of intermediate filaments made of lamin that lines the inner surface of the nuclear envelope in animal cells.
Nuclear export signalA nuclear export signal is a short amino acid sequence of 5-6 hydrophobic residues in a protein that targets it for transport from the cell nucleus to the cytoplasm through the nuclear pore complex.
AutophagyAutophagy, or autophagocytosis, is a catabolic process involving the degradation of a cell's own components through the lysosomal machinery.
ChromoplastFound in coloured organs of plants, chromoplasts are plastids responsible for pigment synthesis and storage.
HydrogenosomeA hydrogenosome is a membrane-bound organelle of ciliates, trichomonads and fungi which produces molecular hydrogen and ATP. This organelle is thought to have most likely evolved from mitochondria.
LaminLamins are fibrous proteins having structural function in the cell nucleus.
Advanced terms that may appear in context in MCAT passages
Intraflagellar transportIntraflagellar transport refers to the cellular process essential for the formation and maintenance of eukaryotic cilia and flagella.
Cajal bodyCajal bodies are spherical sub-organelles found in the nucleus of proliferative cells like tumor cells, or metabolically active cells like neurons. In such cells they are bound to the nucleolus by coilin proteins.
LeucoplastLeucoplasts are a category of plastid and as such are organelles found in plant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast.
MelanosomeA melanosome is an organelle containing melanin, the most common light-absorbing pigment found in the animal kingdom.
ImportinImportin is a type of karyopherin which moves molecules into the nucleus by binding to the nuclear localization signal present on the molecules.
KaryopherinKaryopherins are a group of proteins involved in transporting molecules through the pores of the nuclear envelope.
ParaspeckleParaspeckles are irregularly shaped sub-cellular compartments, approximately 0.2-1 micrometers in size, found in the nucleus' interchromatin space. Although the likely protein components have RNA recognition motifs, the function of these structures is not well understood.
Topogenic sequenceA topogenic sequence is a segment of a protein that ensures it acquires the proper orientation during its insertion into the endoplasmic reticulum.
Ergastic substanceErgastic substances are non-protoplasm materials found in cells.
AmyloplastAmyloplasts, a specialized form of leucoplasts, are non-pigmented organelles found in plant cells responsible for the storage of amylopectin
StatolithStatoliths are a specialised form of amyloplasts involved in gravity perception by plants.
ElaioplastElaioplasts are a type of leucoplast which is specialized for the storage of lipids.
ProteinoplastProteinoplasts are sometimes called proteoplasts, aleuroplasts, or aleuronaplasts. They are specialized organelles found only in plant cells, containing crystalline bodies of protein.

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