Chapter 3: Cell Structure and Functions Flashcards
basic living unit of all organisms
Cell
The simplest organisms consist of ____ cells
single
humans are composed of ___ cells
multiple
4 Cell Structures
- Plasma Membrane
- Nucleus
- Cytoplasm
- Organelles
control center of the cell
Nucleus
specialized structures within the cell that perform specific functions
Organelles
forms the boundary of the cell through which the cell interacts with its environment
Plasma membrane
living material surrounding the nucleus where most activities take place
Cytoplasm
4 Functions of Cell
- Cell Metabolism and Energy
- Synthesis of molecules
- Communication
- Reproduction and inheritance
outermost component of a cell and serves as the boundary between its inside and outside
Cell Membrane
Cell membrane is also known as ___
plasma membrane
Cell membrane encloses the cytoplasm and forms the boundary between: ___ and ____
- intracellular
- extracellular
Cell membrane’s primary role lies in regulating the ____, including nutrients and waste materials
passage of substances
Cell membrane’s structure is described by the ___
fluid-mosaic model
In Phospholipid Structure, phospholipids form a ___
double layer of molecules.
In the phospholipid, the ___ ___ (water-loving) head face the extracellular and intracellular fluids.
polar hydrophilic (water-loving)
head
The nonpolar hydrophobic (water-fearing) tail face away from the ___
fluid, towards the center of the double layer.
Cell membranes are ___ ____, allowing some substances to pass into or out of cells while restricting others.
selectively permeable
Movement through the cell membrane can be either ___ or___
- passive
- active
require the cell to expend energy, usually in the form of ATP
Active Transport Mechanisms
Active Transport Mechanisms includes
(1) active transport
(2) secondary active transport
(3) endocytosis
(4) exocytosis
do not require the cell to use energy
Passive Transport Mechanisms
Passive Transport Mechanisms includes
(1) diffusion
(2) osmosis
(3) facilitated diffusion
process where solutes, such as ions or molecules, move from an area of higher concentration to an area of lower concentration.
Diffusion
Diffusion generally involves the movement of substances in a solution down a ___ ___
concentration gradient
a difference in solute concentration between two points divided by the distance between them.
Concentration Gradient
acts as a barrier to most water-soluble substances
phospholipid bilayer
2 Cell Membrane Channels
- Leak Channels
- Gated Channels
open and close to limit the movement of ions across the membrane
Gated Channels
constantly allow ions to pass through
Leak Channels
diffusion of water across a selectively permeable membrane, such as the cell membrane, from a region of higher water concentration to one of lower water concentration.
Osmosis
force required to prevent water movement across a selectively permeable membrane.
Osmotic Pressure
pushing force on water due to the presence of more fluid in one region than another.
Hydrostatic Pressure
A cell may be placed in solutions that are either:
- hypotonic
- isotonic
- hypertonic
equal solute and water concentration
Isotonic
lower solute concentration, higher water concentration
Hypotonic
higher solute concentration, lower water concentration
Hypertonic
transport of molecules from the region of higher concentration to the region of lower concentration with the help of carriers.
Facilitated Diffusion
Exhibits the properties of specificity, competition, and saturation.
Carrier-Mediated Transport
3 Types of Carrier-Mediated Transport
- Facilitated Diffusion
- Active Transport
- Secondary Active Transport
___ ____ does not require ATP for energy
Facilitated Diffusion
__ ___ does require ATP for transport.
Active Transport