Chapter 7
Sections 3 and 4
Cell Boundaries and
Transport
Cell Membrane
What are the yellow
and blue structures
located in the cell
membrane?
Proteins and
phospholipids
Transport
Is the absorption and
circulation within an
organism
Look
out!!
What is the
structure
all the way
to the left?
Cell membrane
Absorption
The passage of materials
across the cell membrane
and into the cell
Materials are absorbed into
the small intestine of a
human through the villi,
small fingerlike projections
on the inside tube of the
intestine.
Circulation
The movement of materials
within a cell and/or throughout
an organism
a) blood circulation
- throughout the body
b) intracellular circulation
- within the cell (cyclosis)
I. Absorption
Processes of
Diffusion
The movement of particles from
an area of high concentration to
an area of low concentration
Passive Transport
A type of transport in which
materials move across the cell
membrane without using
energy
( high concentration to low concentration)
Is diffusion a type of passive transport?
Yes
Types of Solutions
Hypertonic: The solution has a higher
concentration of solute particles than water
compared with another solution
Hypotonic: The solution has a lower
concentration of solute particles than water
compared with another solution
Isotonic: The solution has a lower
concentration of solute particles than water
compared with another solution
External vs. Internal Solutions
hypertonic, hypotonic or isotonic?
Hypotonic
Does water move into
or out of the cell?
Into the cell
By what process does the water move into the cell? Osmosis/Diffusion
Active Transport
A type of transport requiring
energy to move materials across
the cell membrane
(low concentration to high concentration)
If the diagram on the left represents
active transport, which side has the
higher concentration of molecules?
Side 2
Active Transport (cont.)
What is the source of energy for this
process?
ATP
What process provided the energy
for active transport?
Cell Respiration
In a cell, what would the yellow line represent?
The phospholipids of a membrane
What would the green rectangle represent?
A transport protein
Concentration Gradient
The difference in concentration between
a region of high concentration and a
region of low concentration
If substances flow with the
concentration gradient, it is known as
passive transport.
If they flow against the concentration
gradient, it is active transport.
Concentration Gradient (cont.)
Diagram A
Diagram B
Does a concentration gradient exist in either diagram?
Diagram B
What kind of solution exists in diagram B: hyper, hypo or isotonic?
hypertonic
Cell membrane
Made up of proteins and lipids
Also known as :
- plasma membrane
- selective membrane
- semipermeable membrane
Water molecules are small enough to
easily diffuse across the cell
membrane
Osmosis
The diffusion of water across a
semipermeable membrane from
a region of high concentration to
a region of low concentration
Example of Passive transport
II. Circulation
Intracellular Circulation
Circulation within the
cell
To see cyclosis in an elodea cell, click on the
hyperlink and scroll down to Measurement of
cyclosis in the elodea.
Cyclosis, the
streaming of
cytoplasm,
also occurs in
ameba when
they are
performing
phagocytosis
Extracellular Circulation
Circulation outside of
the cell
Transport in Vascular Plants
Plants have vascular (conducting)
tissue known as xylem and phloem
1. Xylem- carries water and dissolved
materials upward from the roots to the
stems and leaves.
2. Phloem- carries food (glucose) and
other organic compounds from the leaves
throughout the rest of the plant.
Roots
Roots are structures that specialize
in the absorption of water and
minerals from the soil, and the
movement of these materials upward
to the stem
Root Hairs
Found on roots
Increase surface
area for water
absorption
Stems
Structure is more complex than
roots
The xylem and phloem tubes are
continuous with the xylem and
phloem of the roots
Leaves
The xylem and phloem tubes in the
leaves are in vascular bundles called
veins
The xylem and phloem tubes are
continuous with the xylem and
phloem of the roots and stems
Bryophytes
vs.
Tracheophytes
Bryophytes
Are simple, multicellular
organisms that lack vascular
tissue (xylem and phloem)
Therefore, transport is done
by diffusion through cell
membrane
Bryophytes
- The Bryophytes
have
- no true roots,
stems or leaves.
- No vascular tissue
(no tubes)
Ex: moss
-
Tracheophytes
Are higher, more complex
multicellular organisms that
have vascular tissue for
transport
Tracheophytes
- 2. Tracheophytes-
Have true roots,
stems, and leaves.
- Have vascular tissue
- Ex: trees and
flowering plants
Plant Processes
Movement of nutrients and
water from the ground and
into the root hairs involve the
following:
1. Diffusion (nutrients in)
2. Osmosis (water in)
Transpiration
The evaporation of water from
the leaves through the stomates
Transpiration calls for the need
of more water in the leaves, and
as a result, water is pulled
upward to replace the water that
has evaporated
Transpirational Pull
The upward pull of water
through the xylem due to
transpiration