chapter 7 sections 3 and 4 cell boundaries and transport

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