lec 2 Flashcards
A membrane-enclosed structure capable of
performing all of the basic functions of life
independently
cell
The fundamental unit of structure and
function of all organisms
cell
Cell Theory
- All living organisms are composed of one
or more cells - The cell is the basic unit of life
- All cells come only from pre-existing cells
by cell division
The Proponents of Cell Theory:
- Matthias Schleiden
○ German botanist - Theodor Schwann
○ German zoologist - Rudolf Virchow
○ German pathologist
Two types of cells
Prokaryotes
● Bacteria
● Archaea
Eukaryotes
● Animals
● Plants
● Fungi
● Protozoa
● A semipermeable membrane separating the cell from its external environment
cell membrane
● Regulates the substances that go in an out of the cell based on various factors
such as size, lipid solubility and interaction with specific receptors
and/chemicals
cell membrane
● Functions to protect the cell, maintain its shape, cell transport and intercellular
transport
cell membrane
Contains a gel-like matrix consisting of mostly water and various soluble
substances such as minerals
cytoplasm
The genetic blueprint of the cell/organism containing its hereditary traits
DNA
■ Molecules move from an area of high concentration to an area of low
concentration
■ Movement stops when molecules are evenly distributed or achieve
equilibrium
simple diffusion
Molecules temporarily bind to carrier roteins and are then transported from an area of high concentration to an area of low
concentration
1.
2.
faciliated diffusion
1. protein channels (aquaporin)
2. carrier proteins
Diffusion of water (solvent) from an area of high concentration to an area of low concentration through a semipermeable membrane
osmosis
Relative concentration of all solutes in the water found inside and outside of the cell
tonicity
■ Solute concentration is the same inside and outside of the cell
■ e.g. normal saline solution (NSS, 0.85% NaCl)
isotonic solution
■ Solute concentration is higher outside the cell than inside
■ e.g. seawater
hypertonic solution
■ Solute concentration is higher inside the cell than outside
■ e.g. distilled water
hypotonic solution
Movement of molecules through a selective membrane against a concentration gradient (i.e. from an area of low concentration to an area of high concentration)
Adenosine triphosphate (ATP) and carrier molecules are needed
active transport
○ Bulk transport of materials
across the membrane
○ Results in loss of membrane
due to membrane invagination
and eventual detachment to
form vesicles, containing the
engulfed material in the cell
endocytosis
3 smth of endocytosis
■ Pinocytosis (cell drinking)
■ Phagocytosis (cell eating)
■ Receptor-mediated endocytosis
○ Bulk movement of materials out of a cell
○ A vesicle fuses with the plasma membrane and expels particles or fluids from the cell
exocytosis
Cellular material located between the plasma membrane and the nuclear membrane
cytoplasm
■ Semifluid portion of the cytoplasm
■ Where organelles are suspended in
cytosol
■ Consists of well-defined structures (i.e. endoplasmic reticulum, vacuole, vesicle)
cytomembrane / endomembrane system
Control center of the cell
nucleus
Semifluid material in the nucleus
nucleoplasm
● Carry multiple copies of DNA information to synthesize ribosomal RNA
● Composed of specialized parts of certain chromosomes that stain in a characteristically dark manner
nucleolus
double-layered structure
nuclear envelope
Provide a direct passageway through the nuclear envelope for the exchange of
materials between the nucleus and the cytoplasm
nuclear pores
Non-membrane bound structures that are the sites for protein synthesis
Contains: ___ & ___
Some ribosome ____
ribosome
protein & rRNA
attach to the endoplasmic reticulum and some float freely
A complex, membrane-bound series
of channels that helps various materials to circulate throughout the cytoplasm
Endoplasmic Reticulum
Function: Site for protein synthesis
Structure: flattened sacs
Rough ER
● Function: Site for lipid production,
detoxification, and storage of calcium
ions in muscles
● Structure: Tubules
Smooth ER
Function in modification and packaging of polypeptide and protein products
produced by the endoplasmic reticulum
GOLGI COMPLEX / APPARATUS
Powerhouses of cells
Where most of a cell’s ATP is produced
Mitochondria
● Capable of causing lysis, or disintegration
○ Involved in the breakdown of foreign material
● Destroy injured or diseased cells and worn-out cellular components
● Act by fusing with other membrane-bound vesicles and pouring their enzymes
into the larger membrane-bound body
Lysosome
● System of tubules and filaments
● Provide support and maintain the form of cells
● Provide means of cellular locomotion and movement of macromolecules and
organelles within a cell
cytoskeleton
Thin, linear structures
microfilaments
● Larger than microfilament
● Hollow tubular structures
microtubules
● Larger than microfilaments but smaller than microtubules
● Resist stretching, and help to hold adjacent cells together
intermediate filaments
