THE CELLChapter 1

DO NOW

1.1. Do we have eukaryotic or prokaryotic cells?

Chapter Objectives

• Differentiate unicellular and multicellular organisms.

• List the characteristics of life/living things.

• Identify the scientists that observed and discovered cells.

• List the 3 parts of the cell theory.

• Compare light, SEM, and TEM microscopes.

• Compare prokaryotic vs. eukaryotic cells AND plant vs. animal cells.

• Explain the term specialization and compare to our bodies.

DO NOW …

• What are cells?

• Name different types of cells you know of...

• What is a difference between living and non-living things?

What is a cell?

• Basic structural and functional unit of all living organisms!

• They come in different shapes + sizes

How were cells discovered?

The light microscope

helped discover

cells!

Who discovered the cell?

ROBERT HOOKE

• Observed dead cork cells

• Said boxes looked like tiny rooms or jail “cells”.

• Used a microscope at 30x magnification

Who else discovered the cell?

ANTON VAN LEEUWENHOEK

• Observed pond water

• 1st to observe “living” cells

• Used a microscope at 300x magnification

← Cork cells!

*Cork is from tree bark (dead cells)

Animalcules ➔

Do you have these recipes at home?

People thought organisms grew from non-living materials!

Fransisco Redi Experiment

• Placed meat in both an open container and a closed container to see what happened.

Redi’s Conclusion

• Maggots come from flies, NOT the meat!

• Life must come from life, which proved that spontaneous generation is not real!

• People still did not believe him but he was right.

Louis Pasteur Experiment

• Showed that bacteria are present in air and do not appear spontaneously.

Louis Pasteur Conclusions

• Discovered that cells MUST come from other cells

• Disproved “Spontaneous Generation” and said life cannot just appear out of no where.

• Helped verify Redi’s research!

DO NOW

1. Give an example of a multicellular organism and unicellular organism.

2. What type of cells did Robert Hooke observe?

Pasteurization

• Pasteur came up with the idea of Pasteurization after discovering bacteria could contaminate milk from the air.

• This process kills the bacteria so that it does not harm us!

• Used in milk, cheese, yogurt, etc.

• Cell Theory = • Every living thing is made of one or

more cells• Cells carry out the functions needed

to support life• Cells come only from other living

cells

Unicellular vs. Multicellular

• Unicellular – a single cell

• Multicellular – made up of many cells

Characteristics of Life

1. Organization

2. The ability to develop and grow

3. The ability to respond to the environment

4. The ability to reproduce

Section 1.2 - Microscopes

How small are cells?

• Unit used = micrometer (um)

One millionth of a meter

• Most cells range from 1 um to 1000

um.

Types of Microscopes

1. Light Microscope

2. SEM Microscope

3. TEM Microscope

Light Microscope

• Uses thin light

• Looks at thin specimen

• Total Magnification = 40x-1000x

• Use to see cells, but not detailed organelles

SEM vs. TEM

SEM• “Scanning electron

microscope”

• Beams of electrons bounce of the surface of the coated cell.

• Images appear 3D

• Total Magnification = 100,000x

• Must be dead ☹. Specimen coated in metal

TEM• “Transmission electron

microscope”

• Electrons pass through the think section.

• Images appear 2D

• Total Magnification = 300,000x

• Allows us to see organelles inside the cell

SEM

TEM

Prokaryotic vs. Eukaryotic cells

What are the differences you can see?

Prokaryotic Cells

• Have circular DNA

• NO nucleus

• Does not have membrane bound organelles ex: snow globe

• Most unicellular organisms are prokaryotes

Example: Bacteria

Eukaryotic Cells

• Have linear DNA – double helix shape

• Has nucleus

• Have membrane bound organelles

• Most multicellular organisms are eukaryotic cells. Some are unicellular though.

Example: You!

Section 1.3 – cell functions

• 3 domains of life:• Eukarya – Have a nucleus. Plants, animals,

and fungi.• Bacteria – prokaryotics. • Archaea – “ancient”. Genetically different

from bacteria.

Specialization

•Specific cells perform specific functions.

Ex: Blood cells can only be blood cells. Muscle cells cannot be turned into blood cells.

Tissue and organs

• Tissue – group of similar cells that are organized to do a specific job.

• Organ – different tissues working together to perform a particular function.

Stem Cells to determine specialization

• https://www.youtube.com/watch?v=evH0I7Coc54

DNA

• Rosalind Franklin – used x-rays to produce images of DNA

• Watson and Crick – put together a 3D model of DNA and present it to the world in 1953