Class Warm-Up

WHAT DO YOU ALREADY KNOW ABOUT CELLS?

Chapter 7.1 Life is Cellular

Cell Structure and Function

The Discovery of the CellRobert Hooke

1665EnglishmanLooked at a slice of cork (plant material) under an early microscope

Found the cork was made up of thousands of small chambers

He called these chambers “cells”

The Discovery of the CellAnton von Leeuwenhoek

1674 Holland, The NetherlandsConsidered to be the “Father of

Microbiology”First to observe living microorganisms using a microscope

BacteriaProtists

Microscopes Over the Ages

Co-Founders of The Cell Theory

Matthias Schleiden, Botanist, 1837All plants are made of cells.

Theodor Schwann, Physiologist, 1838All animals are made of cells

Rudolf Virchow, 1858All cells are made from the division of existing cells

The Discovery of the Cell

The Cell Theory1. All living things are made up of cells.2. Cells are the basic units of structure

and function in living things.3. New cells are produced from existing

cells.

Cells – the basic unit of life

Class Warm-Up 

"an unbelievably great company of living animalcules, a-swimming more nimbly than any I had ever seen up to this time. The biggest sort. . . bent their body into curves in going forwards. . . Moreover, the other animalcules were in such enormous numbers, that all the water. . . seemed to be alive."

Which scientist that we discussed yesterday would have said this? How do you know?

CLASS WARM UpWhich Cells are prokaryotic and

which are Eukaryotic? How do you Know?

‘

Cheek Cells

(Bacteria)

Elodea Cells

Onion Cells

400x

400x

400x

Eukaryotic Prokaryotic(Plant & Animal)

Compound Light MicroscopeUse lenses to magnify the

image of an object by focusing light

Cell structures as small as 1 millionth of a meter

Magnification up to 2,000xClassroom microscopes go up

to 400x

How Big? Animation

Exploring the CellWhy are chemical stains/dyes used in

microscopy?Most living cells are nearly transparent Stains allow the cells to be seen under the

microscopeSome reveal only certain compounds and

structures within the cellFluorescent dyes

Different colors attached to different moleculesAllows scientists to observe how materials move throughout the cell

Dissecting MicroscopeAlso referred to as the stereo

microscope designed for low magnification

observation of a sample, typically using light reflected from the surface of an object rather than transmitted through it.

3D imagesused to study the surfaces of solid

specimens or to carry out close work such as dissection, microsurgery, watch-making, and circuit board manufacture or inspection

Electron Microscopes2 types: Transmission (TEM) and

Scanning (SEM)Used for viewing NON-LIVING cells and

organisms onlySends an electron beam through a

vacuum to illuminate a specimen and produce a magnified image

Smaller cell structures as small as 1 billionth of a meterDNAProtein moleculesViruses

SEM vs. TEMSEM (Scanning Electron Microscope)3D imagesup to 200,000x magnifiedfocuses the electron beam to a very small point on the sample and scans over the sample to produce an image

TEM (Transmission Electron Microscope)sends an electron beam through a thin sample, projecting an image on a fluorescent screenCannot view the surface of specimensUp to 50 million times magnified

Cool Electron Microscope Images

Types of CellsProkaryotic Cells

– cells that do not contain a nucleus

Eukaryotic Cells – cells that contain a nucleus

Nucleus – a large membrane-bound structure that contains genetic material (DNA) and controls many of the cell’s activities

A B

Prokaryotes Eukaryotes Both

•No nucleus

•Smaller and simpler cells

•No membrane bound organelles

•Most primitive form of life on Earth

Example: Bacteria

•Nucleus

•Larger and more complex cells

•Have membrane bound organelles

Examples:•Plants•Animals•Fungi•Protists – single celled (unicellular) organisms

•Cell membrane

•DNA

•Ribosomes

•Cytoplasm

•Cytoskeleton

WOW!!! One cell has 2 meters of DNA.If all the DNA in your body was put end

to end, it would reach to the sun and back over 600 times!

Your body has about 75-100 trillion cells!90% of those cells are bacteria cells!!They can live as short as a day to as long as a

year!

Formative AssessmentLearning GoalsExplain the 3 parts of the cell theory.

Describe the differences, similarities and evolutionary links between prokaryotic and eukaryotic cells.

Which of the following statements are true?

1 2 3 4

4%

96%

0%0%

1. All living things are made up of cells

2. Cells are the basic unit of structure and function

3. New cells are produced from existing cells

4. All of the above

What is a membrane bound structure that contains genetic material and controls many of the cell’s activities?

1 2 3 4

0%

16%

76%

8%

1. Prokaryote2. Eukaryote3. Nucleus4. Cell membrane

Which of the following cells do not contain a nucleus?

1 2 3

0%

84%

16%

1. Animal cell2. Plant cell3. Bacterial cell

Both prokaryotes and eukaryotes

1 2 3 4

4%0%

16%

80%1. have a nucleus2. have DNA3. have membrane

bound organelles

4. are the same size

True or false? Eukaryotes are cells that do not have a nucleus.

1 2

100%

0%

1. True2. False