Chapter 4 The Cell and Its Environment Standard 3: Students know and understand the characteristics and structure of living things, the processes of life,

Chapter 4The Cell and Its Environment

Standard 3: Students know and understand the characteristics and

structure of living things, the processes of life, and how living

things interact with each other and the environment.

Introduction to the Cell

Introduction and Evolution of the Cell (26:13)

Vocabulary

• Active transport Osmosis• Cell theory Passive transport• Cell wall Phagocytosis• Diffusion Pinocytosis• Dynamic equilibrium Plasma membrane• Endocytosis Exocytosis• Facilitated diffusion Transport protein• Fluid Mosaic model Vesicle• Middle Lamella• Selectively permeable membrane

4.1 Membrane Structure

• Key Terms:– Cell Theory– Plasma Membrane– Selective

Permeability– Lipid Bilayer– Membrane proteins– Fluid mosaic model

• Plasma Membrane animation

E-Coli

Kingdoms

• On Earth, there are five kingdoms that include specific organisms that fit into that kingdom based on similar characteristics. What are they?

Kingdoms

• On Earth, there are five kingdoms that include specific organisms that fit into that kingdom based on similar characteristics. They are:– Monera– Protista– Plantae– Fungi (There’s a fungus among us)– Animalia

Life Inside A Cell (3:10)

Animal Cell Plant Cell

Cell Theory

• What are the 3 components of the cell theory?

Cell Theory• All organisms are

composed of 1 or more cells or cell fragments.

• The cell is the basic unit of structure and function in organisms.

• All cells are produced from other cells.

• So, what are cells exactly? It’s alive!

Animal cell (Click on the picture)

Scientists and Cell Theory

• Who was the first scientist to see cells?• Who was the first scientist to declare that

plants are made up of cells?• Who was the first scientist to declare that

animals are made up of cells?

Scientists Behind Cell Theory

• Robert Hooke: 1665– First discovery of cells

• Matthias Schleiden: 1838– Concluded all plants are

made of cells and cells are the basis of a plant’s function

• Theodor Schwann: 1839– All animals are made of cells

• Rudolf Virchow: 1858– All cells come from other

cells. Robert Hooke and friendsClick on picture (3:32)

Pick me! Click me!

Plasma Membrane

• What are three properties of the plasma membrane?

Properties of Plasma Membrane• All cells live in a fluid environment• Each cell is a separate unit of life that

receives and releases substances from their environment through the plasma membrane.

• Plasma membrane is the cell’s gatekeeper.

Plasma Membrane(1:29)

Selective Permeability

• What is meant by selective permeability?• What kind of substances can easily pass

in and out of a cell?

Selective Permeability

• The cell’s membrane selectively lets things in and out in order to maintain organization.

• Substances that go in and out include:– Amino acids that make

polypeptides.– Glucose molecules used in

cellular respiration.– Oxygen in and Carbon Dioxide

out.

Substances go into and out of the cell membrane (1:01)

Lipid Bilayer

• Describe the lipid bilayer.– What is it made of?– What substances are most likely to pass

through it?

Lipid Bilayer

• Two layers of phospholipids form the plasma membrane.

• Each layer has a polar head and 2 nonpolar tails.

• Which layer would be more “friendly” to water molecules?

Phospholipids on the townClick on the picture (2:28)

4.2 Membrane Function

• Key Terms:– Diffusion

• Dynamic equilibrium

– Osmosis• Hypertonic solution• Hypotonic solution

– Facilitated diffusion• Transport proteins• Channel proteins• Carrier proteins

– Active Transport• Pumps

– Endocytosis• Phagocytosis• Pinocytosis• Receptor-aided

– Exocytosis– Cell Walls

• Middle lamella

Diffusion vs. Osmosis

• What is diffusion?• What is osmosis?• How are they different?• How are they similar?

Diffusion vs. Osmosis

Diffusion (:39)

Random movement of particles is called diffusion.

Particles go from a greater concentration to a lesser concentration to create a dynamic equilibrium.

What is dynamic equilibrium? (6:07)

Diffusion across a membrane (:53)

Osmosis• Diffusion across a cell

membrane is called osmosis.

• For any cell to survive, it must be in osmotic balance with its environment.

• Osmotic balance occurs when movement of water in and out of the cell is equal.

Isotonic, Hypotonic, Hypertonic

• Using the scenario where there is a red blood cell in the following solutions:

• What is isotonic?– What happens to the cell?

• What is hypotonic?– What happens to the cell?

• What is hypertonic?– What happens to the cell?

TONICITYIsotonic, Hypertonic and Hypotonic

Solutions (3:24)

Quick Checkup

• What is the difference between diffusion and osmosis?

• What is meant by selective permeability?• Explain dynamic equilibrium.• Explain what happens to a cell in a

– Hypertonic solution (:35)

– Hypotonic solution (:54)

Facilitated Diffusion

• What are two types of proteins that facilitate diffusion?

• Which of these uses energy?• What kind of transport is that called?• Which of these does not use energy?• What kind of transport is that called?

Facilitated DiffusionChannel Protein

Passive Transport System

Carrier Protein

Active Transport System

Carrier Protein ActionChannel Protein Action

Comparison of channel to carrier proteins

Active Transport• It takes ENERGY for

a cell to move substances from a region of lesser concentration to a region of greater concentration.

• Through active transport, cells use transport proteins called pumps.

Transport protein pump

Endocytosis

• What is endocytosis?• Name the three types of endocytosis and

specifically what type of substance is transported for each one.

Endocytosis

• Not all substances enter the cell through channels.

• A plasma membrane can enclose a substance, pinch it off from the rest of the membrane and deposit the material on the other side. Endocytosis (Click here 3:55)

Exocytosis

• What is exocytosis?• Describe how it works.

Exocytosis

• Exocytosis gets rid of unwanted particles and also distributes substances needed elsewhere, like hormones.

• The substance is enclosed in a vesicle that travels to the plasma membrane, breaks open, fuses with the membrane and expels the substance.

Endo and exocytosis review (1:23)

Plant Cells

• How are plant cells different than animal cells?

• How are plant cells similar to animal cells?• What is the carbohydrate in a plant cell

that provides structure to a plant?

Plants Have Cell Walls!!!• Unlike animal cells,

plants have cell walls made of cellulose.

• Cell walls are made up of dead cells that provide protection and support.

• The middle lamella, made of pectin, is sandwiched between the two primary cell walls.

Cell walls (1:53)

Eukaryotic Plant Cells