Cytology Flashcards
What are the main components of a cell?
Plasma membrane, Cytoplasm, Organelles
Plasma Membrane is…
Semi-permeable barrier forming the outer border of a cell
Cytoplasm is…
The contents of a cell including organelles and a liquid called cytosol
Cytosol is…
Intracellular fluid containing ions, proteins and nutrients
Organelles are…
cellular structures that perform a function (i.e. Nucleus)
What is the function of the plasma membrane?
Separates extracellular fluid from intracellular fluid, controls what enters and exits the cell, cell markers and receptors ( cell recognition, binds hormones, cell communication)
What is extracellular matrix?
Fluid betwen other cell membranes or extracellular materials
What does the plasma membrane consist of?
Phospholipid bilayers, proteins, Glycocalyx
What makes up the phospholipid bilayer?
hydrophilic heads (water loving) face extracellular and intrecelllar fluid and hydrophobic tails (water fearing ) face inward away from fluid
What are the different proteins found in the plasma membrane?
Peripheral membrane proteins, integral membrane proteins and channel proteins
Peripheral membrane proteins
located on inside or outside of the membrane
Integral membrane proteins
embedded in the membrane
Channel proteins
Allow ions in/out of cell
Glycocalyx
Coating that covers the outside of cell used for recognition of cell and protection of cell surface
What is passive transport?
Movement of solutes across the plasma membrane not requiring ATP
Diffusion
solutes move from region of high concetration to a region of low concentration until evenly distributed
Osmosis
diffusion of water across the membrane from region of higher concentration to region of lower concentration
What is active transport?
Movement of solutes across the plasma membrane requiring ATP
Solute Pumping
Proteins use ATP to move solutes against concentration gradient (i.e sodium-potassium pump)
Endocytosis
moves material from extracellular space to interior of cell
Phagocytosis
Cell takes in a large particle
Pinocytosis
Cell takes in sample of extracellular fluid and small particles
Receptor mediated endocytosis
cell takes in particles with specific structures
Exocytosis
Moves material from interior of cell to extracellular space. Vesicles fuse with plasma membrane expelling the contents out of the cell
What are come of the major organelles?
Nucleus, nucleolus, ribosomes, endoplasmic reticulum, golgi apparatus, lysosome, peroxisome, mitochondria, centrosome
Nucleus
control center of the cell, contains chromosomes made of chromatin (strands of DNA bound to proteins)
Nuclear envelope or nuclear membrane
double membrane separating the nucleus from the cytoplasm
Nucleolus
Dark stained body, site of ribosome production
Ribosome
Small dark bodies made of protein and RNA, site of protein synthesis (translation), found free in the cytoplasm and attached to rough ER
Endoplasmic Reticulum or ER
fluid-filled coiled tubules, serve as a channel for transporting substances within the cell
Rough ER
studded with ribosomes, manufactures all secreted proteins
Smooth ER
Functions in lipid metabolism and cell signaling
Golgi Apparatus
Stack of flat membranous sacs, packages proteins for transport depending on their final destination
Vesicles
Small membranous compartments bud off of the cell membrane, nucleus, ER and golgi apparatus, secretory vesicles release content by exocytosis, membrane renewal vesicles fuse with the cell membrane or they become lysosomes or peroxisomes and remain in cytoplasm
Lysosome
specialized vesicles containing digestive enzymes- digest proteins from non-usable or damaged organelles, destroy bacteria and other foreign materials within the cell
Peroxisome
specialized vesicles containing oxidase enzymes- Detoxify harmful substances like alcohol and formaldehyde, break down free radicals (highly reactive chemicals)
Mitochondria
Double membrane structures- the “powerhouse” of the cell that provides ATP for cellular energy, infoldings of inner membrane are called cristae, inner fluid called the matrix, contains it’s own circular DNA for reproduction and protein synthesis
Centrosome
Directs the formation of microtubules, located near the nucleus, important role in enabling the movement of chromosomes during cell division, consists of a pair of centrioles (Rod-shaped bodies composed of short microtubules and other proteins arranged in a cylindrical structure)
Cytoskeleton
Provides the cell with an internal framework, supports organelles and facilitates intracellular motility
Microtubules
Hollow tubes made of protein, radiate out from a region near the nucleus, anchor and move organelles, form mitotic spindles during cell division, largest diameter of cytoskelton elements
Microfilaments
Concentrated under the plasma membrane, function in cell mobility and shape, braces plasma membrane and strengthens cell surface, smallest diameter of cytoskeleton elements
Intermediate filaments
Composed of proteins with high tensile strength, resist pulling forces on the cell
Cilia
Whip-like extensions that occur on the free surface of the cell, Move substances along the cell surface, found in epithelial cells lining most of the respiratory tract
Flagella
much longer whip-like extensions, functions to propel the cell itself, only human anatomy example is sperm
Microvilli
Small finger-like extensions that increase the surface area, found on epithelial cells lining the intestines and tubules of the kidney
Tight Junctions
Form an impermeable barrier between cells by interlocking proteins encircling the cell, found at the apical surface of epithelial cells, keeps out enzymes, acids and microorganisms
Desmosome
Anchor intermediate filaments of adjacent cells together, prevent cells that are subjected to mechanical stress from being pulled apart
Gap Junctions
Cells are connected by hollow cylinders. allow chemical communication between cells, found in smooth and cardiac muscle
What is transcription?
The sequence of nucleotides in the DNA coding for a gene are read and used to guide the synthesis of a messenger RNA copy of the gene with a corresponding nucleotide sequence, occurs in the nucleus
What is translation?
Sequence of messenger RNA is read and used to guide the synthesis of a protein, occurs at ribosome
