Cell Structures and Functions Flashcards
Basic and fundamental unit of life
Cell
4 Functions of the Cell
Cell Energy and Metabolism Use
Synthesis of New Molecules
Communication
Reproduction and Inheritance
regulates the
passage of substances
Encloses the cytoplasm and forms
the boundary between material
inside the cell and material outside it
Cell Membrane
substances outside of the cell are ____
Extracellular Substances
substances inside of the cell are ____
Intracellular substances
4 Components of the Cell Membrane Structure
- Phospholipids
- Cholesterol
- Carbohydrates
- Proteins
Lipid made of glycerol, two fatty acid tails, and a
phosphate-linked head group.
Phospholipids
_____ is arranged in a lipid bilayer that provides a ________
barrier to regulate the passage of substances into and out
of the cell.
Phospholipids
semi-permeable
Amphipathic in nature
Phospholipids
Polar head region is _____ while nonpolar tail region is _____$
hydrophilic
hydrophobic
Forms distinctive cellular markers that allow cells
to recognize each other.
found in the extracellular side attached to proteins or lipids
Carbohydrates
Gives added strength and stability by limiting the amount of
movement of the phospholipids.
Cholesterol
Cholesterol increases fluidity at _____ temperature
low
Cholesterol ____ fluidity at high temperature
reduces
“Floats” among phospholipid molecules
sometimes
extend from the inner to the outer surface of the cell
membrane
Protein
2 Main Types of Protein associated with the cell membrane
Integral Proteins
Peripheral Proteins
span the
entire plasma membrane
found in all types of biological
membranes
Transmembrane Proteins
proteins that are permanently attached to the
membrane from only one side.
Integral Membrane Protein
Not embedded in the lipid bilayer
associated with the
membrane surface, either on the extracellular or intracellular side.
often attached to integral
proteins or interact with the lipid head groups.
Peripheral Membrane Proteins
4 Functions of Membrane Protein
- Membrane Channel and Carrier Molecules
- Receptor Molecules
- Enzymes
- Structural support
involved with the
movement of substances through the cell membrane
Membrane channels and carrier molecules
part of an intercellular communication system
that enables cell recognition and communication of the activities of
the cell
Receptor molecules
Model that shows the arrangement of molecules in the cell membrane
Fluid Mosaic Model
It is selectively permeable.
Cell Membrane
Substances that are found at a higher concentration intracellularly
enzymes, glycogen, K+
Substances that are found at a higher concentration extracellularly
Na+, Ca2+, Cl-
Molecules that are lipid-soluble pass easily through the
phospholipid bilayer
Water-soluble substances can diffuse across the
cell membrane only by passing
through
Cell membrane channels
2 Cell Membrane Channels
Leak Channels
Gated Channels
Constantly allow ions to pass
through
Leak channels
Limits the movement of ions across the
membrane by opening and closing
Gated channels
Membrane transport that does not require the cell to expend
energy.
Passive Membrane Transport
Passive membrane transport
mechanisms include:
Diffusion
Facilitated Diffusion
Osmosis
Membrane transport that does require the cell to expend energy,
usually in the form of ATP
Active membrane transport
Active membrane transport mechanisms include:
Active transport
Secondary active transport
Endocytosis
Exocytosis
A process resulting from random motion of
molecules by which there is a net flow of matter
from a region of high concentration to a region
of low concentration.
Diffusion
gradual change in the
concentration of solutes in a solvent between
sides of a membrane
Concentration Gradient
diffusion of water (a solvent)
across a selectively permeable
membrane from a region of higher
water concentration to one of lower
water concentration
Osmosis
force required to prevent
movement of water across cell
membrane.
Osmotic Pressure
low osmotic pressure, cell swells, less solute and more water
Hypotonic
Equal osmotic pressure
The cell will neither shrink nor swell.
Same solute
concentrations inside
and outside the cell.
Isotonic
High osmotic pressure, cells shrink, more solute less water
Hypertonic
a transport process that combines a chemical
reaction with a diffusion process.
Carrier-mediated transport
a process that moves
substances across the cell
membrane from an area of higher
concentration to an area of lower
concentration of that substance.
ATP is not required
Facilitated Diffusion
A process that moves substances
across the cell membrane from
regions of lower concentration to
those of higher concentration
against a concentration gradient
requires
ATP
Active Transport
uses the energy provided by a concentration gradient established by
the active transport of one substance, such as Na+ to transport other
substances
Secondary Active Transport
2 Types of Secondary Active Transport
Cotransport
Countertransport
diffusing substance moves in the same direction as the initial
active transported substance
Cotransport
diffusing substance moves in a direction opposite to that
of the initial active transported substance
Countertransport
a process that brings materials into cells
using vesicles
Endocytosis
3 Types of Endocytosis Mechanisms
Receptor-mediated endocytosis
Phagocytosis
Pinocytosis
occurs
when a specific substance binds to the
receptor molecule and is transported into
the cell
Receptor-mediated endocytosis
used for
endocytosis when solid particles are
ingested
Phagocytosis
