CELLS

Animal vs. Plant Cells

Open to pg. 206 – 207 of your textbook. On your

notes, record 3 major differences between plant

and animal cells.

Characteristics of Life……

1. Made of cells

2. Ability to reproduce (leave offspring)

3. Metabolism (need energy)

4. Grow and develop

5. Respond to environment

6. Homeostasis (internal balance)

7. Genetic code (traits and variations)

8. Evolve (change over time)

Important steps to cell study

Robert Hooke – looking at cork termed

the word “cell” not really seeing a cell

but the cell walls

Anton van Leeuwenhoek – first to

view single cell organisms (cells)

Researchers….

Schwann (German) – 1839

Studied animal cells

Schleiden (German) - 1838

Studied plant cells

Virchow (German) - 1855

Physician – studied human cells

Their research collectively lead to the Cell Theory

Cell Theory

All living things are composed of cells

Cells are the basic units of structure

and function in living things

New cells are produced from existing

cells

Cellular Structure and Function

Light Microscopes

Utilizes a series of

glass lenses and

visible light to

magnify an image

Magnifies images

up to 1,000 times

the actual size

7.1 Cell Discovery and Theory

Chapter 7

Electron Microscopes

Cellular Structure and Function

Utilizes magnets to aim a beam of electrons at

a cell to produce

an image

Magnifies

images up to

500,000 times

the actual size9560x

7.1 Cell Discovery and Theory

Chapter 7

Plasma Membrane

Thin, flexible boundary between the cell

and its environment

7.2 The Plasma Membrane

Cellular Structure and Function

Allows nutrients into the cell

Allows waste to leave the cell

Chapter 7

Cell Membrane (cont.)

Membranes can be permeable, selectively

permeable or impermeable

Permeable-anything can pass through

Selectively permeable (semi-permeable)-certain

things can pass (most cell membranes are selectively

permeable)

Impermeable-nothing can pass

The plasma membrane is composed of the

phospholipid bilayer.

Cellular Structure and Function

A phospholipid molecule is composed of a glycerol

backbone, two fatty acid chains, and a phosphate

group.

7.2 The Plasma Membrane

Chapter 7

Fluid Mosaic Model

Cellular Structure and Function

The phospholipid

bilayer allows other

molecules to “float”in the membrane.

Other Components

Proteins

Cholesterol

Carbohydrates

7.2 The Plasma Membrane

Chapter 7

Proteins

Cellular Structure and Function

Transmit signals inside the cell

Act as a support structure

Provide pathways for substances to enter and leave

7.2 The Plasma Membrane

Chapter 7

Cholesterol

Cellular Structure and Function

Prevents fatty acid tails from sticking together

7.2 The Plasma Membrane

Chapter 7

Carbohydrates

Cellular Structure and Function

Identify chemical signals

7.2 The Plasma Membrane

Chapter 7

Passive Transport

Movement of particles across the cell

membrane without using energy

7.4 Cellular Transport

Cellular Structure and Function

Modes of Three Passive Transport

Diffusion

Facilitated Diffusion

Osmosis

Chapter 7

Diffusion

Movement of particles from an area of high

concentration to an area of lower concentration

Cellular Structure and Function

Initial Conditions DiffusionLow High

High Low

7.4 Cellular Transport

Chapter 7

Diffusion is controlled by

Cellular Structure and Function

Temperature

Pressure

Concentration

Dynamic Equilibrium

Reached when diffusion of material into the

cell equals diffusion of material out of the cell

Molecules continue to move, but the overall

concentration remains the same.

Occurs when the concentrations are evenly

spread.

7.4 Cellular Transport

Chapter 7

Diffusion in a Cell

Cellular Structure and Function

7.4 Cellular Transport

Chapter 7

Facilitated Diffusion

Cellular Structure and Function

Movement of materials across the plasma

membrane using proteins

7.4 Cellular Transport

Chapter 7

Cellular Structure and Function

Carrier ProteinsChannel Proteins

7.4 Cellular Transport

Chapter 7

Osmosis

Cellular Structure and Function

Diffusion of water across a selectively

permeable membrane

Three Types of Solutions

Isotonic

Hypotonic

Hypertonic

7.4 Cellular Transport

Chapter 7

Blood CellPlant Cell

Isotonic Solution

Cellular Structure and Function

Water and dissolved substances diffuse into

and out of the cell at the same rate. The

concentration or amount inside the cell is

equal to the amount outside the cell.

11,397x

7.4 Cellular Transport

Chapter 7

Blood Cell

Hypotonic Solution

Cellular Structure and Function

Solute concentration is higher inside the cell

and lower in the solution. Causes water to enter into the cell in an

attempt to reach equilibrium (equal

concentrations).

Plant Cell

13,000x

7.4 Cellular Transport

Chapter 7

Plant Cell

Hypertonic Solution

Cellular Structure and Function

Solute concentration is lower inside the cell

and higher in the solution.

Causes water to exit the cell in an attempt to

reach equilibrium (equal concentrations)

Blood Cell

13,000x

7.4 Cellular Transport

Chapter 7

Active Transport

Cellular Structure and Function

Movement of particles across the cell

membrane using energy

Active Transport Using Carrier Proteins

7.4 Cellular Transport

Chapter 7

Types of Active Transport Pumps

Cellular Structure and Function

Na+/K+ ATPase pump or NA/K Pump

Moves three Na+ ions out of the cell and

two K+ ions into the cell

7.4 Cellular Transport

Chapter 7

Cellular Structure and Function

Endocytosis

Process by which the

cell surrounds and takes

particles into the cell

Exocytosis

Secretion of material out

of the plasma membrane

7.4 Cellular Transport

Chapter 7