Chapter 7Sections 3 and 4
Cell Boundaries and Transport
Cell Membrane
What are the yellow and blue structures located in the cell membrane?
Proteins and phospholipids
TransportIs the absorption and circulation within an
organismLook out!!
What is the structure all the way to the left?
Cell membrane
AbsorptionThe 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.
CirculationThe 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
DiffusionThe 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 solutionHypotonic: The solution has a lower concentration of solute particles than water compared with another solutionIsotonic: 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 TransportA 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 GradientThe 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 lipidsAlso known as :
- plasma membrane - selective membrane - semipermeable membrane
Water molecules are small enough to easily diffuse across the cell membrane
OsmosisThe 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 stomatesTranspiration 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
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