Cell Structure And Function Flashcards
Cell Theory
All living things are made of cells
Smallest living unit of structure and function of all organisms is the cell
All cells arise from preexisting cells
Cell structure: what is a cell
Building blocks of living systems: self-contained systems, surrounded by a membrane and plasma membrane PM
Self-sustained systems, multiple functions -Organelles
Plasma membrane
Surrounds cell and most organelles
Phospholipids
Bipolar = hydrophilic
And hydrophobic
Fluid mosaic model
Phospholipids
Proteins: integral membrane proteins and peripheral membrane proteins ( CH2O often attached to outside proteins)
Cholesterol
Purpose of PM
Separate the inside living part of cell from outside environment
PM is semi-permeable
Regulate transport of molecules (Molecular Transport)
Building materials, nutrients, waste products, signals, et.
Small, uncharged molecules are allowed to go through phospholipid bilayer
EX. Water, O2, CO2
Molecular Transport: Passive Transport
Diffusion
Osmosis
Facilitated Diffusion
Passive transport
Involves the movement of material ALONG a concentration gradient
From HIGH TO LOW
Because materials are moving down a concentration gradient, it does not require energy
Active Transport
Involves the movement of materials AGAINST a concentration gradient (LOW TO HIGH)
Because materials are moving AGAINST the gradient, it requires to use ENERGY
Molecular Transport: Active transport
Direct
Indirect
Large scale transport
Dynamic equilibrium
Molecules are still moving in both directions, but the net movement is ZERO
DIFFUSION
Movement of molecules across PM from HIGH to LOW in order to establish a dynamic equilibrium
NO ENERGY REQUIRED
EX. Perfume and CO2
Osmosis
Diffusion of water through a semi-permeable membrane from LOW - HIGH in order to establish a dynamic equilibrium
NO ENERGY REQUIRED
Remember water can flow through semi-permeable PM, while large, or charged molecules can’t (sugars, proteins, H+
Osmosis is also called
The diffusion of water
CELLULAR ENVIRONMENTS
Isotonic
Hypotonic
Hypertonic
Isotonic
Same (solute) concentration inside and outside cell
hypotonic
Solute outside is LOWER than inside
Hypertonic
Solute outside is HIGHER than inside
Isotonic
Same solute concentration inside and outside cell
Hypotonic
Solute inside is higher than outside
Cell will take on water and may burst
CYTOLYSIS (OSMOTIC LYSIS)
Hypertonic
Solute inside is lower than outside
Cell will LOSE water and may shrink
CRENATION (PLASMOLYSIS)
FACILITATED DIFFUSION
DIFFUSION OF LARGE OR CHARGED MOLECULES through a protein carrier that can open and close
HIGH - LOW in order to establish an equilibrium
No extra energy required
EX. Glucose into cells to break down for food
EX. NA+/K+ pump: pumps Na+ out and K+ in
ACTIVE TRANSPORT: movement from LOW to HIGH against the concentration gradient, against equilibrium
Up the concentration gradient
Energy is REQUIRED
ATP ( direct and Primary)
Gradient-based (indirect, Secondary)
Large scale transport: Whole cell event: requires large quantities of ENERGY and PROTEINS to proceed
Endocytosis
Phagocytosis
Pinocytosis
Receptor - mediated
Exocytosis
Endocytosis: - Phagocytosis
Cell wraps the PM around the object to be taken in and engulfs it
EX: macrophages - white blood cell (leukocytes, lymphocytes) that engulf and digest bacteria as part of the immune system
