Kinetic energy
energy of motion
Potential energy
stored energy
Chemical energy
potential energy stored in chemical bonds (C-H)
Metabolism
all the chemical reactions in our body
Reactants
substrates (substances present at the start of a chemical reaction)
Products
substances formed by chemical reaction
Oxidation
losing an electron
Reduction
gaining an electron (molecule's charge is reduced)
Exergonic
produces/releases energy
Endergonic
requires/consumes energy
Reaction rate
how quickly a chemical reaction takes place
Activation energy (Ea)
amount of energy required to break chemical bonds
Cytology
study of cells
Plasma membrane
barrier between inside of cell and outside environment (phospholipid bilayer)
Interstitial fluid
fluid in the spaces between cells
Nucleus
largest organalle that contains DNA
Cytoplasm
all of the contents besides the nucleus
Cytosol
fluid inside cell
Organelles
complex organized structures with unique functions
Functions of Cells
Maintain cellular integrity and structure/shape, 2. Obtain nutrients and form chemical building blocks, 3. Dispose of waste products
Phospholipids
Form phospholipid bilayer (Hydrophilic head & Hydrophobic tails)
Cholesterol
Scattered in hydrophobic region, Increases strength of bilayer, & Provides stability during temperature extremes
Glycolipids
Lipids + carbohydrate, Outer surface of bilayer, Form glycocalyx
Glycocalyx
identity markers and cell adhesion
3 Lipid Components
phospholipids, cholesterol, glycolipids
2 Protein Components
Integral: embedded within and extend across plasma membrane(Includes glycoproteins) & Peripheral: loosely attached to internal or external surface
Glycoproteins
help compose glycocalyx
6 Categories of Membrane Proteins
Transport proteins: regulate motion of substance across membrane(Channels, carriers, pumps), Cell surface receptors: bind ligands(Molecules released from one cell that bind to receptors of another cell), Identify markers: identify cell as belonging to body(glycoproteins), Enzymes: catalyze reactions, Anchoring sites: secure cytoskeleton to plasma membrane, Cell-adhesion proteins: allow cell-to-cell attachments and connections
Passive processes
No required energy from cell & rely on chemical gradients, Substances use their own kinetic energy, Substances move DOWN their concentration gradient
Active Processes
Require energy from cell, Substances moved AGAINST their concentration gradient, Release/formation of vesicles
Diffusion
net movement of substance from area of high à low concentration; Passive Process
equilibrium
even distribution of substance
Diffusion rate varies on ...
Steepness of gradient: how extreme the difference is(More extreme = faster rate) & Temperature: higher temperature = faster movement(More heat = more kinetic energy)
Simple diffusion
Doesn't require transport proteins, Only works for small nonpolar substances, & Follow concentration gradient through membrane
Facilitated diffusion
Requires specialized transport proteins, Required for small charged or polar substances, Broken into two categories(Channel-mediated/Carrier-mediated)
Channel-mediated diffusion
The movement of ions through highly specific channels(Leak channels: always open & Gated channels: usually closed and open only in response to a set stimulus)
Carrier-mediated diffusion
The movement of substances is assisted by specialized carrier proteins(Small polar substances binded to carrier)
Uniporter
Carrier with only one substance binded to it
Osmosis
passive movement of water through a selectively permeable (semipermeable) membrane
Permeable
can pass through membrane(In cells: small nonpolar substances)
Nonpermeable
cannot pass through membrane(Charged, polar, or large substances)
Aquaporins
channel proteins that facilitate the passage of water
Vesicles
small membrane sacs that specialize in moving products into, out of, and within a cell
Tonicity
the ability of a solution to change the volume/pressure of a cell(Isotonic, hypotonic, hypertonic)
Isotonic solution
cell cytosol and surrounding solution have the SAME relative concentration of solutes (No net movement of water into or out of cell)
Hypotonic Solution
Solution has lower concentration of solutes, Within cell: more solutes & less water, Outside of cell: less solutes & more water, Result: water ENTERS cell (Cell may swell or lyse)
Hypertonic solution
Solution has higher concentration of solutes, Within cell: less solutes & more water, Outside of cell: more solutes & less water, Result: water EXITS cell (Cell may crenate:shrivel)
Phosphorylation
The metabolic process of introducing a phosphate group into an organic molecule changing the protein shape
Ion Pump
used to move substances against concentration gradient
Symport
both substances are moving in the same direction
Antiport
substances moving in opposite directions
Exocytosis
movement of substance out of the cell
invagination
the folding in of a membrane or layer of tissue so that an outer surface becomes an inner surface
Phagocytosis
cells form pseudopods to capture material
Pinocytosis
cell engulfs droplets of interstitial fluid
Receptor-mediated endocytosis
substances bind to receptors inside vesicle
Direct contact
two cells physically touch (Important in immune system (glycocalx) & tissue repair)
Ligand-receptor signaling
molecules released from one cell bind to a receptor on another(3 forms: Channel-linked, Enzymatic, G Protein-Coupled)
Channel-linked receptors
chemically gated channel that allow ion passage
Enzymatic receptors
serve as protein kinase enzymes (Phosphorylate other enzymes, Turns them on or off, & Alters activity of cell)
G protein-coupled receptors
Receptor activates G protein, G protein activates another enzyme or ion channel and produces second messenger substance, Second messenger activates protein kinase enzyme, Alters activity of cell
membrane-bound organelles
possess their own membrane(Similar to plasma membrane)
Endomembrane system
A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
Non-membrane-bound organelles
lack a membrane, exposed to cytosol, composed of proteins with or without RNA
Rough ER
ribosomes attached; Modifies, transports, and stores proteins produced by the ribosomes; Produces peroxisomes
Smooth ER
no ribosomes; Synthesizes, transports, and stores lipids; Metabolizes carbohydrates; Detoxifies drugs, alcohol, and poisons
Functional groups
the components of organic molecules that are most commonly involved in chemical reactions
Golgi apparatus
A system of membranes 4-5 sets of cisternae that modifies and packages proteins for export by the cell via transport/secretory vesicles; produce lysosomes
Peroxisomes
Small sacs lined with membrane that contain oxidative enzymes
Cis-face
closer to the ER, larger diameter
Trans-face
further from ER, smaller diameter
Lysosomes
Small sacs lined with membrane that contain digestive enzymes; Autophagy: self-eating, break down damaged organelles & Autolysis: upon extreme cell damage or death, the digestive enzymes are released into the entire cell, destroying it
Detoxification
remove hydrogen atoms from molecules and produces hydrogen peroxide as a byproduct
Beta oxidation
breaks down fatty acid molecules and forms Acetyl CoA
Mitochondria
Possess a double membrane(divided into outer compartment and matrix & Inner folds called cristae), Produce ATP for cell
Translation
RNA to protein
Bound ribosomes
attached to rough ER (Proteins that leave cell, become enzymes, join plasma membrane)
Free ribosomes
suspended in cytosol (proteins that function within cell)
Cytoskeleton
Structural support and organization(provides cell framework), Cell division(pulls the chromosomes apart in mitosis), Movement(move structures around the cell and aids in muscle contraction); 3 Types(Microfilaments, intermediate filaments, and Microtubules)
Microfilaments
Composed of actin protein(2 intertwined thin strands); Line the inner side of the plasma membrane; Maintain cell shape & Support microvilli & Separate cells during mitosis/meiosis & Move cytoplasm & Muscle contraction
Intermediate Filaments
Structural support for cells & Stabilize junctions between cells
Microtubules
Hollow and composed of tubulin protein; Maintain cell shape & Organize/move organelles & Contribute to structure of cilia/flagella & Contribute to vesicle transport & Separate chromosomes during mitosis/meiosis
Centrioles
Located near the nucleus and help to organize cell division
Ubiquitin
Proteasomes tag unwanted proteins with this protein
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