Cell structure Flashcards
Chapters 5
Golgi apparatus description
Stack of flattened sacs (cisternae) surrounded by vesicles
Nucleus
Largest cell structures and located in central area. Not part of cytoplasm
Cytoplasm
Gel-like substance made of organelles and molecules suspended in watery fluid called cytosol (intracellular fluid)
Plasma membrane
Separates intracellular from extracellular environments. Two back to back layers of lipids in a chain
Chromatin
Formed from DNA, RNA, and proteins. Take form of chromosomes in dividing cells.
Golgi apparatus functions
Synthesizes carbohydrate, combines it with protein, and packages the product as globules of glycoproteins
Microvilli function
Tiny fingerlike extensions that increase a cell’s abosorptive surface area
Amphipatic (plasma membrane)
Lipids in the bilayer have both polar and non-polar parts. Hydrophilic heads and hydrophobic tails. This allows lipid soluble molecules to pass through the membrane
Microvilli description
Short, fingerlike extensions of plasma membrane and supported internally by microfiliments
Centrioles
Barrial shaped organelles comprised of microtubules. Form bases for cilia and flagella
Vesicles description
Tiny membranous sacs
Cytoskeleton function
Supporting framework of the cell and its organelles - functions in cell movement using molecular motors - forms cell extensions (microvilli, cilia, flagella)
Lipid rafts
Stiff groupings of membrane molecules (cholesterol) that travel along surface and organize/create cell depressions that get pulled into the cell
Composite cell
Exhibits most important characteristics of many different cells
Cell connections
Integrins. Hold cells in place, anchored into matrix. Help with cell to cell connections and allow direct communication between cells
Centrosome function
Acts as the microtublues-organizing center of the cell - centrioles assist in forming and organizing microtubules
Main cell structures
- Plasma membrane
- Cytoplasm (includes organelles0
- Nucleus
ER function
ER folds and shines he’s polypeptides - synthesizes integral membrane proteins (IMPS) and membrane lipids incorporated in cell membranes, steroid hormaones, detoxification enzymes, glycogen-regulating enzymes, and carbohydrates - removes and stores Ca2++ from cell’s interior
Cilia and flagella description
Moderate (cilia) to long (flagella) hairlike extensions of plasma membrane - supported internally by cylindrical formation of microtubules, sometimes with attached molecular motors
Desmosomes
Hold adjacent cells together.
- Spot desmosomes: fibers interlock like Velcro. Anchored internally by cytoskeleton intermediate filaments
- Belt desmosomes: completely encircles the cell. Adhesive belt
Tight junctions
Created by fusion of similar integral membrane proteins to limit permeability (plastic around a sixer). Molecules must go through controlled channel or use carrier molecules to get through.
Plasma membrane components percentage
Phospholipids 75%, cholesterol 20%, and glycolipids (phospholipids with carb groups attached) 5%
Centrosome description
Region of cytoskeleton that includes two cylindrical groupings of microtubules called centrioles
Lysosomes description
Tiny membranous bags containing enzymes
Plasma membrane structure model
-Fluid mosaic model: fluid sea of lipids (always moving) and mosaic of proteins on surface or embedded through membrane
Centrosome components
Centrioles and pericentriolar material
Ovum
Largest cell, female sex cell
Peroxisomes description
Tiny membranous bags confining enzymes
Lysosomes functions
Digestive enzymes break down defective cell parts (autophagy) and ingested particles - a cell’s “digestive system” - some lysosomes involved in membrane repair or secretion
Ribosomes description
Small particles assembled from two tiny subunits of rRNA and protein
Nucleus contents
DNA, RNA, cluster of proteins
Vesicles functions
Temporarily contain molecules for transport or later use
Endoplasmic reticulum description
Network of canals and space extending from the nuclear envelope; may have ribosomes attached
Mitochondria description
Tiny membranous capsule surrounding an inner nightly folded membrane embedded with enzymes. Has small, ring like chromosomes (DNA)
Proteasomes function
Destroys misfolded or their wise abnormal proteins manufactured by the cell - quality control for protein synthesis
Membranous organelles
Sacs/canals made of cell membrane
Organelles
Little, non-living organs.
Cytoskeleton description
Network of inter connecting flexible filaments, still tubules, and molecular motors within the cell
Proteasomes discriptions
Hollow protein cylinders with embedded enzymes
Integral membrane proteins
Firmly embedded in membrane.
- Transport: gates can be specific or closed/open
- Identification: distinguish between “self” and “non-self” cells, attacking non-self
- Signaling: receptors signal transduction. React to hormones/chemicals
- Connection: connect cell membrane to another membrane to another membrane (tissues)
Peroxisomes function
Enzymes detoxify harmful substances in the cell
Cilia and flagella function
Cilia move substances over the cell surface or detect changes outside the cell - flagella propel sperm cells
Gap junctions
Membrane channels of adjacent plasma membranes connect and form gaps or tunnels that join cytoplasm of two cells.
- fuse 2 plasma membranes into single structure to allow for easy passage of molecules and fast electrical impulse propagation
Peripheral proteins
Wally attached to polar heads or integral preteins on inner or outer surface
Ribosomes function
Site of protein synthesis
Mitochondria function
Catabolsim - ATP synthesis - power house of the cell
Spermatozoa
Smallest cell, male sex cell
Nucleus structure
Enclosed by 2 membranes (nuclear envelope) with many pores/openings (NPComplex are gate keepers). Inside enclosure are nucleoplasm, nucleolus, and chromatin
Nonmembranous organelles
Made of microscope filaments or there particles, not membranes
