Cell Structure

L3 BiologyChapter 1 Section 2

What is a cell?

• Smallest unit of life that can carry out all the functions of a living thing.

• Various sizes and shapes• Organism- living thing

– Unicellular – multicellular

Microscope Development

• 1665 – Robert Hooke named cell• 1674 – Anton von Leeuwenhoek -

looked at cells in pond water and blood and published his observations

Cell Theory Developed

• 1838 – Schleiden – all plants are made of cells• 1839 – Schwann – all animals are made of cells

• 1855 – Virchow – all cells come from pre-existing cells

Modern Cell Theory

• Cells are the basic units of all life.• All organisms are made of one or

more cells• All cells come from pre-existing

cells

Microscopes

• Hand lens• Compound light microscope

Cells from Labs:

Electron Microscope

• Uses electrons for energy source• Specimen must be killed• Transmission electron microscope

(TEM) – take pictures of slices of specimen

TEM Examples

•Scanning electron microscope (SEM) – take pictures of surface of specimen

SEM Examples

Types of Cells

• Prokaryotic– Simple cell– No membrane-

bound organelles– Chromosome not

contained in nucleus

– Small cells– Ex - bacteria

• Eukaryotic– Complex cell– Membrane-bound

organelles– Chromosomes

contained in nucleus

– Larger cells– Ex – all other

organisms

BASIC CELL STRUCTURES• Cell Membrane – Double layer of lipids

(fats) that lets stuff in and out of cell

Cytoskeleton

• Cell support• Anchors

organelles• Transports

materials• Helps cell

move

Nucleus

• Control center of cell• Contains Chromosomes

• Humans have 46 in each cell• Made of DNA

- control heredity- control protein synthesis

• Surrounded by double membrane – nuclear membrane

• Cell Membrane

Nucleolus

• Within nucleus• May be more than one• Makes ribosomes• Rich in RNA

Cellular Organelles – small, specialized structures in the cell

Ribosomes• Make proteins• Some are free,some are attached to endoplasmic reticulum.• Smallest

organelles

Endoplasmic Reticulum (ER)

• Transports materials through the cytoplasm

• Rough ER – have ribosomes attached– Transport proteins– Helps make membranes

• Smooth ER – no ribosomes attached– Makes lipids– Detoxifies wastes

Golgi Body

• Packages cell secretions• Makes lysosomes

– Contain digestive enzymes for breaking down food in food vacuoles and old, worn out structures – ex – sperm tail after fertilization.

Mitochondrion• Site of cellular respiration – food is

broken down to release energy.

Structures used for Movement

• Cilia • Flagella

Eukaryotic Cells include Plant and Animal Cells

ANIMAL CELL STRUTURE

Plant cells have some parts that animal cells don’t

• Cell Wall • Central Vacuole• Plastids

– Chloroplasts – Leukoplasts – chromoplasts

What animal cells have that plant cells don’t

• Centrioles – function during cell division

• Lysosomes – contain digestive enzymes

Now you are ready to have a test on parts of a cell and what they do:

• Make a chart like below: Cell part appearance

functionCell membraneCytoplasmEtc.

In addition, you should be able to name some differences between prokaryotic

and eukaryotic cells

Make a chart like this: Feature Prokaryotic

Eukaryotic

THE END