Lecture: Cellular Elements Flashcards
Basic structural and functional unit, and the smallest living part of the body
Cell
Has nucleus surrounded by cytoplasm, a system of membranous organelles, non-membranous molecular
assemblies, and a cytoskeleton
Eukaryotic
Has a cell wall, lacks nuclei and membranous cytoplasmic structures
Prokaryotic
2 Basic Parts of Eukaryotic Cell
Cytoplasm
Nucleus
Outermost component of the cell, separating the cytoplasm from its extracellular environment
Plasma Membrane
Fluid component of cytoplasm. Contains hundreds of enzymes that produce building blocks for
larger molecules and break down small molecules to liberate energy
Cytosol
Functions of Plasma Membrane
Physical Barrier
Selective Permeability
Electrochemical Gradient
Communication
Head part of Membrane Phospholipids
Carbohydrate and Hydrophilic
Tail part of Membrane Phospholipids
UFA, SFA, and Hydrophobic
Directly incorporated within the lipid bilayer itself
Integral Proteins
Exhibit a looser association with one of the two membrane surfaces, particularly the inner
Peripheral Proteins
Unassisted net movement of small, nonpolar substances down their concentration gradient across a selectively permeable membrane
Simple Diffusion
Movement of ions and small, polar molecules down their concentration gradient
Facilitated Diffusion
Movement of ion down its concentration gradient through a protein channel
Channel-mediated
Movement of small, polar molecule down its concentration gradient by a carrier protein
Carrier-mediated
Diffusion of water across a selectively permeable membrane; continues until equilibrium is reached
Osmosis
Transport of ions or small molecules across the membrane against a concentration gradient by transmembrane protein pumps
Active Transport
Movement of substances down a concentration gradient due to kinetic energy of the substance
Passive Processes
Movement of substances requires expenditure of cellular energy
Active Processes
Movement of substance up its concentration gradient; powered directly by ATP
Primary
Movement of substance up its concentration gradient is powered by harnessing is the movement of a second substance down its concentration gradient
Secondary
Movement of substance up its concentration in the same direction as Na+
Symport
Movement of substance up its concentration gradient in the opposite direction from Na+
Antiport
Vesicle formed or lost as material is brought into a cell or released from a cell
Vesicular Transport
Bulk movement of a substance out of the cell by fusion of secretory vesicles with the plasma membrane
Exocytosis
Bulk movement of substances into the cell by vesicles forming at the plasma membrane
Endocytosis
Type of endocytosis in which vesicles are formed as particulate materials external to the cell are engulfed by pseudopodia
Phagocytosis
Type of endocytosis in which vesicles are formed as interstitial fluid is taken up by the cell
Pinocytosis
Type of endocytosis in which plasma membrane receptors first bind specific substances
Receptor-mediated endocytosis
Small electron-dense particles, about 20 × 30 nm
in size
Ribosomes
Multiple ribosomes on the same mRNA make up
Polyribosome (polysome)
An abundance of these polysome produces
Basophilic Cytoplasm
Convoluted membranous network that extends from the surface of the nucleus to the cell membrane and encloses a series of intercommunicating channels and sacs
Endoplasmic Reticulum
Series of intercommunicating channels and sacs
Cisternae
ER for synthesis and segregation of proteins not destined for the cytosol (for secretion)
Rough ER
ER for glycogen and lipid metabolism
Smooth ER
Dynamic organelle consisting of stacked membranous cisternae in which proteins made in RER are processed further and packaged for secretion or other roles
Golgi Apparatus
Small membrane enclosed carriers that move materials from RER cisternae to the Golgi apparatus
Transport Vesicles
Sites of intracellular digestion and turnover of cellular components
Lysosomes
Hydrolytic Enzymes examples
Proteases
Nucleases
Phosphatase
Phospholipases
Sulfatases
β-glucuronidase
Membrane-enclosed organelles with arrays of enzymes specialized for aerobic respiration and production of adenosine
triphosphate
Mitochondria
An inner membrane with many folds enclosing a gel-like matrix
Cristae
Cell death
Apoptosis
Spherical organelles enclosed by a single membrane. Named for their enzymes producing and degrading hydrogen
peroxide
Peroxisomes
Complex array of protein polymers
Cytoskeleton
Components of Cytoskeleton
Microtubules
Microfilaments (actin filaments)
Intermediate filaments
Contains the code for all of a cell’s enzymes and other proteins
Nucleus
Double set of membranes with a narrow perinuclear space that separates the cytoplasm from the nucleoplasm
Nuclear Envelope
Combination of DNA and its associated proteins in a largely uncoiled state
Chromatin
Chromatin with DNA that is active in transcription stains lightly
Euchromatin
Inactive chromatin stains more darkly
Heterochromatin
DNA molecule + histone
Nucleosome
Very basophilic or electron-dense area of chromatin localized where rRNA transcription and ribosomal subunits assembly occur
Nucleolus
Specialized cellular subunits that carry out essential functions
Organelles
Large, membrane bound organelle present in all cells except mature erythrocytes
Nucleus
Encloses the whole mitochondria
Outer Membrane
A portion of its cisternae is continuous with the nuclear envelope
RER
Site of most intracellular activity
Cytosol
Collection of fused, flattened sacs which received protein from the RER
Golgi Apparatus
Controls which molecules enter and leave the cell
Plasma Membrane
Site of lipid and steroid synthesis
SER
Small membrane enclosed carriers that move materials from RER cisternae to the Golgi apparatus
Transport Vesicle
Membrane-limited vesicles that contain about 40 different hydrolytic enzymes
Lysosome
