WHAT DO YOU ALREADY KNOW ABOUT CELLS? Class Warm-Up WHAT DO YOU ALREADY KNOW ABOUT CELLS?

Cell Structure and Function Chapter 7.1 Life is Cellular

The Discovery of the Cell Robert Hooke 1665 Englishman Looked 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 Cell Anton von Leeuwenhoek 1674 Holland, The Netherlands Considered to be the “Father of Microbiology” First to observe living microorganisms using a microscope Bacteria Protists

Microscopes Over the Ages

Co-Founders of The Cell Theory Matthias Schleiden, Botanist, 1837 All plants are made of cells. Theodor Schwann, Physiologist, 1838 All animals are made of cells Rudolf Virchow, 1858 All cells are made from the division of existing cells

The Discovery of the Cell The Cell Theory All living things are made up of cells. Cells are the basic units of structure and function in living things. 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?

Eukaryotic Prokaryotic (Bacteria) (Plant & Animal) Cheek Cells 400x Onion Cells 400x 400x Elodea Cells CLASS WARM Up Which Cells are prokaryotic and which are Eukaryotic? How do you Know? ‘

Compound Light Microscope Use lenses to magnify the image of an object by focusing light Cell structures as small as 1 millionth of a meter Magnification up to 2,000x Classroom microscopes go up to 400x How Big? Animation

Exploring the Cell Why are chemical stains/dyes used in microscopy? Most living cells are nearly transparent Stains allow the cells to be seen under the microscope Some reveal only certain compounds and structures within the cell Fluorescent dyes Different colors attached to different molecules Allows scientists to observe how materials move throughout the cell

Dissecting Microscope Also 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 images used 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 Microscopes 2 types: Transmission (TEM) and Scanning (SEM) Used for viewing NON-LIVING cells and organisms only Sends 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 meter DNA Protein molecules Viruses

SEM vs. TEM SEM (Scanning Electron Microscope) 3D images up to 200,000x magnified focuses 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 screen Cannot view the surface of specimens Up to 50 million times magnified Cool Electron Microscope Images

Types of Cells Prokaryotic Cells – cells that do not contain a nucleus Eukaryotic Cells – cells that contain a nucleus A B Nucleus – a large membrane-bound structure that contains genetic material (DNA) and controls many of the cell’s activities

Smaller and simpler cells 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 Assessment Learning Goals Explain 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? All living things are made up of cells Cells are the basic unit of structure and function New cells are produced from existing cells All of the above

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

Which of the following cells do not contain a nucleus? Animal cell Plant cell Bacterial cell

Both prokaryotes and eukaryotes have a nucleus have DNA have membrane bound organelles are the same size

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