Chapter 7A View of the Cell: ARE THOSE OUR

CELLS?

Smallest unit that can carry out all the activities necessary for life.

Can survive on its own or has potential to do so

Is highly organized for metabolism

Senses and responds to environment

Has potential to reproduce

Section 7.1 Cell:

Anton Von Leeuwenhoek, the first person to observe "animalcules" through a microscope, didn’t at all like what he saw.

Fig. 4.1, p. 50-51

ROBERT HOOKE— “Cells”crude compound micriscope

The Cell Theory

Electron Microscopes

1930’s

Uses a beam of electrons

to magnify to to 500,000 X

Cell surfaces; internal

structures

CELL DIFFERENCES

Size; Shape; Types and number of Internal StructuresExample: muscle cells have a lot of __________________ for ATP production (high energy needs)

SIMILARITIES

Functionally

Two Basic Cell Types

1. Prokaryotes No Nucleus No internal membrane-bound organelles Bacteria (2 Kingdoms)

2. Eukaryotes Have internal membrane –bound organelles. Other 4 kingdoms. (Animalia, Plantae, Protista,

Fungi)

7.2 The Plasma MembraneSelectively permeable Water and small molecules like O2, CO2 , and nonpolar

molecules --freely pass through.

Charged particles (like ions) and large molecules need special assistance (proteins assist movement)

-------------------------------------------- Try an analogy---- -----------------------------------------------

.

animation

Click to view animation.

Plasma Membranes

Phospholipids-Polar “head” and 2 non-polar tails

Main component of membranes

Gives the membrane its fluid properties

Two layers of phospholipids-end to end.

The cell membrane's function, in general, revolves around is membrane proteins. General functions include: Receptor proteins which allow cells to communicate, transport proteins regulate what enters or leaves the cell, and marker proteins which identify the cell

The Phospholipid Bilayer

Polar and Nonpolar regions

A mosiac

The Fluid Mosaic Model

A mosaic of materials Phospholipid bilayer Proteins Cholesterol

Fluid—because the phospholipids are unsaturated. Some of the proteins are free to move within the

membrane too

Functions of Membrane Components

Cholesterol—give it some stability.

Transport ProteinsHelp regulate entry and

exit of molecules and ions.

Cell Surface Markers (have sugars attached). Attached to cell surface.Like a cell’s ID tag.

Class Work. May work with a partner, but each is to

complete this.P. 174

Draw prokaryotic cell, label cell components, color!!!

Same for the Eukaryotic cell.

How do they compare in size?

7.3 Eukaryotic Cell Structure

Cell Wall

Inflexible barrier.Support and protection

Porous—not selective

The Nucleus

1.Contains DNA—directions for making proteins Chromatin-thin; non-dividing cell

Chromosomes-compact, visible when cell is dividing

2. Nucleolus—this makes ribosomes.RNA forms, exits nucleus through Nuclear Pores to the CytoplasmNuclear Envelope

Cell functions

Like a candy factoryLots of ProductionNeed to move materials insideNeed to send Finished materials (candy) out to sell and waste productsMovement is regulated at the perimeter gate by security, allows controlled entry and egress.

HOMEWORK

READ 7.3

TERMS TO KNOW

Terminology in bold font-

describe

function

what organisms are they found in

Describe the advantage of highly folded membranes in cells.

Homework

1. Compare and contrast prokaryote and eukaryote cells.

2. Why are plasma membranes describes as a “fluid mosaic”?

What is the role of cholesterol in plasma membranes?

CELLS ARE LIKE LITTLE CANDY FACTORIES

Structure of Cells

Cell membrane FunctionCell Size is LimitedImportance of Water in formation of MembranePolar vs. Non-PolarHydrogen -Bonds

Cell Size is Limited

In most cases, a living thing grows because it produces MORE cellsAn adult simply has more cells than an infant, not simply larger cells.WHY more cells, not larger cells?Remember—Membrane Function…How fast exchange occurs depends upon the SURFACE AREA of the cellBUT, how quickly food & Waste are made depends on Cell Volume

animation

Click to view animation.

Plasma Membranes

1.Phospholipids-Polar “head” and 2 non-polar tails

Main component of cell membranes

Gives the membrane its fluid properties

Two layers of phospholipids

The cell membrane's function, in general, revolves around is membrane proteins. General functions include: Receptor proteins which allow cells to communicate, transport proteins regulate what enters or leaves the cell, and marker proteins which identify the cell

Phospholipid Bilayer up close and personal

Cell Membrane Proteins

How their structure related to their function in the membrane

2 types of CELLSEUKARYOTE VS.

PROKARYOTE Differences

AND

Similarities