The Cell in Action!!!

STATE UNIVERSITY OF SURABAYA

By: Ms. Dhita

Section 1 Objectives:

•Explain the process of diffusion

•Describe how osmosis occurs

•Compare passive transport with active transport

•Explain how large particles get into and out of cells

Exchange with the Environment

An organism must be able to obtain energy and

raw materials and get rid of waste.

Cell division allows organisms to grow and

repair injuries.

Exchange of materials between a cell and its

environment takes place at the cell’s

membrane.

Everything is made up of moving particles.

Particles travel from where they are crowded to

where they are less crowded.

This movement from areas of high concentration

(crowded) to areas of low concentration (less

crowded) is called DIFFUSION

Cells do not need energy to use energy for

diffusion

What is Diffusion?

Example of Diffusion

                             

Diffusion of Water

Cells of organisms are surrounded by and filled

with fluids that are made mostly of water.

OSMOSIS – the diffusion of water through cell

membranes

Water is made of up molecules

Pure water has the highest concentration of

water molecules, but when you mix something,

you lower the concentration of water molecules.

Osmosis Continued…

Semipermeable means only certain

substances can pass through

If certain substances pass through a

semipermeable membrane, over time the

water molecules move from the liquid with

the high concentration of water to the liquid

with low concentration of water molecules.

Osmosis Example

                        

The Cell and Osmosis

The Animal Cell

Plasma (surrounds red

blood cells) is made up

of water, salts, and

sugars.

Concentration of these

particles is kept in

balance by osmosis.

The Plant Cell

Osmosis occurs in

plant cells

When a wilted plant

is watered, osmosis

makes the plant firm

again!

Hypotonic, Isotonic, & Hypertonic Solution

If environment is: Hypertonic:

MORE SOLUTES outside cell MORE WATER IN CELL over time, cell loses water

Isotonic: “Iso-” means environment “=” cell No change in cell volume

Hypotonic: LESS SOLUTES outside cell LESS WATER IN CELL, more solutes in cell. over time, cell gains water

Comparison of 3 Types of Solutions

HYPHYPERERTONICTONICHYPHYPERERTONICTONIC ISOISOTONICTONICISOISOTONICTONIC HYPHYPOOTONICTONICHYPHYPOOTONICTONIC

Moving Small Particles

Small particles, such as sugars, cross the cell

membrane through passageways called CHANNELS.

Channels are made up of proteins in the cell

membrane.

Particles travel through the channels either through:

Passive Transport

Active Transport

Passive Transport

Movement of particles

across a cell membrane

without the use of energy

by the cell.

Particles move from an area

of high concentration to an

area of low concentration.

Diffusion and Osmosis are

examples of Passive

Transport!

Active Transport

Process of

transporting

particles that

requires the cell to

use energy.

Usually involves the

movement of

particles from an

area of low

concentration to an

area of high

concentration!

Moving Large Particles

Large particles move into and out of the cell

by processes called:

Endocytosis = “Within the Cell”

Exocytosis = “Outside the Cell”

Endocytosis

Active transport process that surrounds a large particle.

Encloses the particle in a vesicle.

Brings the particle into the cell.

2 types of endocytosis:

Fagocytosis

Pinocytosis

Receptor-Mediated Endocytosis

What are Vesicles?? Sacs formed from pieces of cell membrane

Receptor-Mediated Endocytosis

Exocytosis

Active transport which moves large particles

out of the cell.

A vesicle forms around a large particle within

the cell.

Vesicle carries the particle to the cell

membrane.

Vesicle fuses with the cell membrane and

releases the particle to the outside of the cell.

Quiz . . .

Describe Diffusion!

Describe Osmosis!

What is the difference between active

transport and passive transport!

Endocytosis means…?

Exocytosis means…?