What do all living things have in common?

Cells and the Cell Theory

Q 1

• Robert Hooke 1665• Built a microscope• Looked at thin slices of cork• Saw tiny “boxes”• Hooke named them “cells” which in

Latin means “little rooms”

• Hooke named them “cells” which in Latin means “little rooms”

• Leeuwenhoek 1673• Dutch merchant• Built his own microscopes• Looked at pond scum• Saw little animals moving in the water• Named them “animalcules”Q 2

• Matthias Schleiden 1830s• Studied plants• Decided that all plants were

made of cells

• Matthias Schleiden 1830s• Studied plants• Decided that all plants were

made of cells• Schwann 1839• Studied animals• Decided that animal tissues were made of

cells• Wrote the first two parts of the cell

theory.

• Wrote the first two parts of the cell theory.

All organisms are made of one or more cells

The cell is the basic unit of all living things

• Virchow 1858• Was a doctor• Stated that all cells come from other cells• Became the third part of the cell theory

All cells come from other cells

All organisms are made of one or more cells

The cell is the basic unit of all living things

All cells come from other cells

All organisms are made of one or more cells

The cell is the basic unit of all living things

All cells come from other cellsQ 3• Cell size

• Most cells are very small• There are very few that are large

• Cell size• Most cells are very small• There are very few that are large

• Surface area-to-volume ratio

• Cells need a 3:1 ratioof surface area to volume

Surface area –to-volume ratio = surface area volume

2”

2” 2”

Surface areah x w

2 x 2 = 4

Number of sides = 6

4 x 6 = 24

Volumeh x w x d

2 x 2 x 2 = 8

Surface area –to-volume ratio = surface area volume

Surface area = 24 Volume = 8

24 : 8 =The Cell Lives!3 : 1

x number of sides

3”

3” 3”

Surface areah x w

3 x 3 = 9

Number of sides = 6

9 x 6

Volumeh x w x d3 x 3 x 3

Surface area –to-volume ratio = surface area volume

Surface area = 54 Volume = 27

54 : 27 The Cell Dies!= 2 : 1

x number of sides

= 54

= 27

• Parts of the cell Cell membrane• Protective layer that covers the cell’s surface• Controls material going in and coming out of the cell• Hold in the fluid inside the cell called cytoplasm

• Parts of the cell Cell membrane Organelles• Structures in the cell that perform specific functions• Most organelles are surrounded by membranes• Some organelles float in the cytoplasm

Genetic material

• Genetic material• Deoxyribonucleic acid• DNA• The material that carries information to make

new cells• DNA is passed from parent to offspring• DNA controls the activities of a cell

• In some cells the DNA is found in an organelle called the nucleus

Q 4

• Bacterium do not have nuclei but have DNA

Two kinds of Cells Prokaryotes

Single celled organisms that do not have a nucleus• Bacteria is a prokaryotic cell• Bacteria are the smallest cells• Bacteria can be found almost anywhere• Soil and water• Your skin and teeth• Bacterial in your digestive system help you

digest food

• Bacteria can be found almost anywhere• Soil and water• Your skin and teeth• Bacterial in your digestive system help you

digest food

• Bacteria can be found almost anywhere• Soil and water• Your skin and teeth• Bacterial in your digestive system help you

digest food Eukaryotes

Contain a nucleus• These are the largest cells• 10 times larger than bacteria Most eukaryotes are multicellular• Multicellular organisms are made up of

billions of cells• Plants and animals are all multicellular and

eukaryotes

Eukaryotic Cells

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Cell Walls Rigid structure that gives support to the

plant cell• Made of cellulose• Complex sugar• Animals can not digest

Cell membrane (fence) Protective barrier that encloses a cell• Contains proteins, lipids, and phospholipids• Lipids are fats and cholesterol that do

not dissolve in water Proteins are building blocks of the cell

• Cytoskeleton• A web of proteins in the cytoplasm• Acts as both a muscle and a skeleton• Helps keep the cell membrane from

collapsing• Helps some cells move

Nucleus (office) Contains the DNA of the cell DNA is the instructions on how to build

proteins• Proteins control the chemical reactions

in the cell• In the center of the nucleus is the nucleolus• The nucleolus is where ribosomes are

made

Ribosomes (workers) Ribosomes are the smallest organelles Ribosomes make proteins

•Proteins are made of amino acids•There are 20 different amino acids•All cells need proteins to live

Endoplasmic Reticulum (factory) The organelle where proteins, lipids, and

other material are made Part of the internal delivery system• Smooth and rough ER• Rough ER has ribosomes attached• Makes proteins

• Smooth does not have ribosomes• Makes lipids• Breaks down toxic materials

Mitochondria (power plant) Main power source for the cell• Sugar is broken down to produce energy• Energy that is released is stored as ATP• Adenosine triphosphate

Mitochondria have their own DNA

Golgi Complex (custom shop) Organelle that packages and distributes

proteins Lipids and proteins are modified in the

Golgi Complex

Vesicle (transport) A bubble of membrane that surrounds

material that has to be moved out of the cell

• Some vesicles carry proteins from the ER to the Golgi complex

• Exocytosis• The transporting of larger particles that are moved out of

the cell

• Endocytosis• The transporting of larger particles that are moved into the

cell

• Lysosomes (demo crew)• Contain digestive enzymes • Vesicles that are responsible for

digestion in the cell• Destroy invaders• Usually only found in animal cells

Vacuoles (storage) Store digestive enzymes Aid digestion in the cell Store water In plant cells they help support the plant

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Cell Membrane

Nucleus

Golgi ComplexEndoplasmic Reticulum

Mitochondria

Mitochondria

Mitochondria

Vacuoles

Vacuoles

Vacuoles

Ribosomes

Vesicles

Lysosomes

• Organization of Living Things• Multicellular• Larger size• Longer life• Specialization

• Working together• Tissue• Several cells working together

• Organ• Several tissues working together

• Organ systems• Several organs working together

• Several organs working together

• Structure• The arrangement of the parts

• Function• The job they do