Cells: The Basic Unit of Life

•Essential Questions•What are cells made of?•Where do you find cells?•Why do cells look different?•How do cells work?

I. Cells – basic building block of life• Cytology: study of cells

• Cyto- having to do with cells• -ology means the study of

• Cytopathology: the study of cellular disease and the use of cellular changes for the diagnosis of disease.

• Cell biology: the study of (normal) cellular anatomy, function and chemistry.

II. Cell History Robert Hooke (1665)

• English Scientist• Looked at a thin slice of

cork (oak tree) through a compound microscope

• Observed tiny, hollow, room like structures

• Called these structures “cells” because they reminded him of the rooms that monks lived in

• He only saw the cell walls because the cork cells weren’t alive

Anton Van Leeuwenhoek (roughly same time as Hooke, 1680?)

• Dutch fabric merchant and amateur scientist

• Looked at blood, rainwater, and scrapings from teeth through a simple microscope (1 lens)

• Observed living cells; called some ‘animalcules’

• Some of those ‘animalcules’ are now called bacteria

• Father of Microbiology

Co-Founders of Cell Theory

Matthias Schleiden (1838)• German

Botanist• Viewed plant

parts under a microscope

• Discovered that plant parts are made of cells

Theodor Schwann (1839)• German

Zoologist• Viewed animal

parts under a microscope

• Discovered that animal parts are made of cells

Rudolf Virchow (1855)

• German physician and politician, known for his advancement of public health

• First to recognize leukemia cells

• Stated that all living cells come from other living cells

• Important contributor to cell theory

III. Cell Theory• The contributions of

Hooke, Van Leeuwenhoek, Schleiden, Schwann and Virchow helped to form the modern cell theory

• 1. All living things are made of cells

• 2. All cells come from other cells

• 3. The cell is the basic unit of organization in organisms

All Living Things…• Consist of organized parts (cells -> tissues

-> organs -> organ systems -> organisms)• Obtain energy from their surroundings

(food chain)• Perform chemical reactions (metabolize)• Change with time (evolve)• Respond to their environment (adapt)• Reproduce (heredity)

IV. Types of CellsProkaryote

• Simple cell• Lacks a nucleus and

membrane bound organelles• Has circular DNA and

ribosomes• Ex: Bacteria and Archaea are

two domains of prokaryotes

Eukaryote

• More complex cell• Has membrane bound

organelles and nucleus• Possess chromosomes• Ex: are plant and animal

cells

V. Parts of Eukaryotic Cells

Organelle: small, membrane bound structure inside the cell that determines the function of the cell; tiny organs

V. Parts of Eukaryotic Cells, cont.

A. Plasma Membrane – phospholipid bilayer, controls what enters and exits the cell, Gateway

V. Parts of Eukaryotic Cells, cont.B. Cytoplasm- gel-like substance that

surrounds and suspends the organelles, Jell-O of the CellConsists of cytosol- The cytosol is a complex mixture of substances dissolved in water

V. Parts of Eukaryotic Cells, cont.C. Cytoskeleton – network of

microfilaments and microtubules that form the inner structure of the cell, similar to your bones, Skeleton

V. Parts of Eukaryotic Cells, cont.D. Golgi bodies – set of smooth

membranes that form flattened sacs that modify, sort and package proteins for transport to other organelles or exiting the cell FedEx

-small round packages are called vesicles

V. Parts of Eukaryotic Cells, cont.E. Mitchondria – site where cellular

respiration occurs, chemical energy is released from glucose

- Inside folds increase chemical workspace and are called: mitochondrial matrix

- Powerhouse

V. Parts of Eukaryotic Cells, cont.

F. Lysosome – these membrane bound sacs contain enzymes that can digest cellular waste, damaged organelles, and bacteria brought into cell. Can also destroy entire cell

-Suicide sac

V. Parts of Eukaryotic Cells, cont.G. Ribosomes – tiny, round

organelles that are used to make (synthesize) proteins

- workbench

V. Parts of Eukaryotic Cells, cont.H. Endoplasmic Reticulum1. Smooth- works to detoxify cells and

transport materials, MoDOT Highway2. Rough – has ribosomes on it, makes

the phospholipids and proteins, Liver or Highway

V. Parts of Eukaryotic Cells, cont.I. Vacuole – membrane

bound structures that usually hold water and provide structure for the cell

Storage units

V. Parts of Eukaryotic Cells, cont.J. Nucleus – controls all cellular functions

Brain1. Nuclear Membrane – plasma membrane surrounding and containing the nucleus2. Nuclear Pores- tiny holes in nuclear membrane that allow RNA to pass in and out of nucleus3. Chromosomes/Chromatin – Chromatin is DNA free floating, when it prepares for division it coils into chromosomes4. Nucleolus – site of concentrated DNA in the nucleus

V. Parts of Eukaryotic Cells, cont.• Outside the cell

• Cilia – motile for movement or non-motile for sensory (below, pink)

• Flagella – Single ‘tail’ for movement• Microvilli – are cellular membrane

protrusions that increase the surface area (below, B&W)

V. Parts of Eukaryotic Cells, cont.Animals Only

1. Centrioles – two bundles of nine microtubules, found close to nucleus and lie at 90 degree angle

Plants Only

1. Cell Wall – made from cellulose, outside membrane

2. Chloroplasts – contain stacks of thylakoids called granum & space between stacks is called stroma

3. Plastids – organelles capable of storing food for the plant

4. Chlorophyll – pigment used to capture sun’s energy

5. Chromoplasts- give flowers and fruits their coloring

How are cells organized?

• Specialized cells -> tissue

• Groups of tissue -> organs

• Organs -> organ systems

• Muscle cells -> muscle tissue

• Muscles -> heart

• Heart -> circulatory system

What will it look like to me?

Take a look at these images and see if you remember looking at these

Onion Cells – may look like bubbles

More plant cells…

More than likely- a bunch of bubbles but they really are plant cells!

Now just a few more…• Here are some various types of cells• Notice the different shapes and what type of cell they

are. Do you think this has to do with their function? • Think about it and take the time to notice how perfectly

they are all designed for their jobs.

Blood cells – RBC, WBC, and platelets

Human Bone Marrow – Stem CellsSo much debate over these little things that

could save countless lives

Cardiac Muscle This is what the tissue looks like from your heart

Nerve CellsThis looks like a lightening storm- fitting because it is an electrical storm of synapses firing electrical signals back and forth for your cells to communicate

YeastMicroscopic organism one-celled organism

Cancer Cell - Cancer is an uncontrolled growth of cells, caused by mutation of

genes in cells