Chapter 3 Cell Structure Cells are the basic building blocks for all _________…it is important to understand their structures and functions life

Chapter 3 Section 1 Looking at Cells Objectives Describe how scientists measure the length of objects. Relate magnification and resolution in the use of microscopes. Analyze how light microscopes function. Compare light microscopes with electron microscopes. Describe the scanning tunneling microscope.

New Vocabulary Light microscope Electron microscope Magnification Resolution Scanning Tunneling Microscope

microscope Leeuwenhoek animalcules Most cells are too small to be seen with the naked eye Scientists were not aware of cells until they invented the __________________ Anton van _____________________ was the first person to view single-celled organisms He viewed pond water with a microscope and observed many living creatures that he called _________________ microscope Leeuwenhoek animalcules

1665 In ________, an English scientist named Robert _________ observed a thin piece of _________ using a microscope He saw that the cork contained tiny “rooms” that reminded him of the rooms that monks lived in called ___________ You can also think of a ________ cell Hooke cork cells jail

metric International System SI decimal ten Chapter 3 Section 1 Looking at Cells Cell measurements taken by scientists are expressed in ____________ units. The official name of the metric system is the _________________ _________________ of Measurement…abbreviated _____ SI is a ________________ system, so all relationships between SI units are based on powers of __________ metric International System SI decimal ten

meter Time kg kelvin A Amount of substance Luminous intensity There are seven SI base units… measurement unit symbol Length m second s Mass kilogram Temperature K mole mol Electric current ampere candela cd meter Time kg kelvin Amount of substance A Luminous intensity

prefix Nano- Chapter 3 Section 1 Looking at Cells Most SI base units have a ____________ that indicates the relationship of that unit to a base unit What prefix on the chart indicates the smallest size? Nano-

Chapter 3 Section 1 Looking at Cells Power 103 100 10-2 10-3 10-6 10-9 Let’s place the appropriate power next to each prefix Power 103 100 10-2 10-3 10-6 10-9

Chapter 3 What prefix is usually used for cell sizes? Micro = µ Section 1 Looking at Cells What prefix is usually used for cell sizes? Micro = µ

Chapter 3 Section 1 Looking at Cells When looking at a cell with a microscope, it is necessary to have good… ____________________ the quality of making an image appear _____________ than its actual size ___________________ is a measure of the ___________ of an image Magnification larger Resolution clarity

There are three main types of microscopes… Light Electron Tunneling

light Light microscopes use ___________ to magnify an image Simple light microscopes use ______ lens Compound light microscopes use ______ lenses 1 2

An image produced by a microscope is called a _______________ They are labeled with the… Specimen Type of microscope magnification micrograph

Chapter 3 Section 1 Looking at Cells large Light waves are too _______ to clearly magnify objects smaller than a few __________________ nanometers

smaller Electron beams are _____________ than light waves so electron microscopes can magnify smaller objects with better _____________________ resolution

vacuum gas live Chapter 3 Section 1 Looking at Cells The electron beam and specimen must be in a _______________ so that the electron beam will not bounce off of _________ molecules. This prevents ________ organisms from being viewed with an electron microscope vacuum gas live

Transmission metal Chapter 3 ____________________ Electron Microscope Section 1 Looking at Cells Transmission ____________________ Electron Microscope An electron beam is directed at a very thin slice of a specimen stained with ___________ ions. Some structures become more heavily stained than others. metal

absorb The heavily stained parts _____________ electrons, those that are lightly stained allow electrons to ___________ through. The electrons that pass through strike a fluorescent screen, forming an image that allows you to see _______________ structures pass Internal

Scanning coated Chapter 3 _______________________ Electron Microscope Section 1 Looking at Cells Scanning _______________________ Electron Microscope An electron beam is focused on a specimen ________ with a very thin layer of metal. coated

three-dimensional surface The electrons that bounce off the specimen form an image on a fluorescent screen. The image shows __________________ details of the ______________ of a specimen. three-dimensional surface

voltage “tunnel” computer three-dimensional live atoms Chapter 3 Section 1 Looking at Cells Scanning Tunneling Microscope A needle-like probe measures differences in ______________ caused by electrons that leak, or ____________, from the surface of the object being viewed. A ________________ tracks the movement of the probe and produces a __________________ image of the surface of the specimen. STMs allow _______________ specimens and objects as small as ______________ to be viewed! voltage “tunnel” computer three-dimensional live atoms

STM image of an iron atoms

Question #1 What metric prefix is used most often while measuring cells? Micro- (µ)

Magnification – enlarging an object Resolution - clarity Question #2 What is the difference between magnification and resolution? Magnification – enlarging an object Resolution - clarity

Simple – one lens Compound – two lenses Question #3 What is the difference between a simple and compound microscope? Simple – one lens Compound – two lenses

Transmission electron microscope Question #4 Which type of electron microscope allows you to see internal cell structures? Transmission electron microscope

Scanning tunneling microscope Question #5 Which type of microscope allows you to observe live specimens and objects as small as an atom? Scanning tunneling microscope