Cell Structure
L3 Biology
Chapter 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
Cell membrane
Cytoplasm
Etc.
appearance
function
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