Download Eukaryotic cells

CELLS
Cell Discovery and Theory

Robert Hooke
discovered
cells using a
simple
microscope in
1665. He
called them
cells because
they reminded
him of small
rooms where
monks live.
Cell Theory



In 1838, Matthias Schleiden and Theodor
Schwann concluded all living things are made of
one or more cells.
In 1855, Rudolph Virchow proposed all cells
come from other living cells.
Many years later, scientists concluded that cells
give living organisms structure.
Common Features of Cells
All cells have a cell membrane, cytoplasm,
ribosomes, and DNA.
 Which of the four features above is
most important for cell survival?

Characteristics of Microscopes
Since cells are not able to be seen by our
eyes, we need microscopes to magnify
them.
 Microscopes enable biologists to examine
the details of cell structure and to
understand how organisms function.

Types of Microscopes



Compound Light Microscopes have a low
magnification and can be used to examine living
cells.
Electron Microscopes have a high magnification
but cannot be used to examine living cells.
Scanning Tunneling Microscopes use a
computer to generate a three-dimensional image
of the object.
Basic Cell Types
Prokaryotic cells are the smallest and
simplest cells on Earth. The best example
of a prokaryote is bacteria.
 Characteristics of Prokaryotes

 surrounded
by a cell wall
 DNA moving freely inside the cell
 some have flagella to help them move
 don’t have a nucleus
Eukaryotic cells are larger and more
complex. They have a nucleus and other
organelles.
 Cell Animation

Cell Organelles

cytoskeleton: eukaryotic cells have a
cytoskeleton of microscopic protein fibers
that provide structure and support for the cell
and its organelles

nucleus: tells the cell what to do and
stores DNA
 the
nucleus is surrounded by a double membrane
called the nuclear envelope that helps protect the
DNA inside
 when a cell prepares to divide, the DNA inside the
nucleus forms chromosomes. This helps genetic
information get transferred from the old cell to the
new cell.

Production of Proteins
 proteins
are made or created inside ribosomes
which are found on another cell organelle called the
endoplasmic reticulum (ER)
 proteins are important because they help with
chemical reactions

Distribution of Proteins
 proteins
must be programmed so they know what
job to perform inside the cell
 the Golgi apparatus is the organelle that programs
proteins

Lysosomes
 some
proteins are special because they help
breakdown and digest substances inside the cell

Mitochondria
 make
and store energy from carbon compounds
(carbohydrates, lipids, proteins)
 The energy stored is ATP
 Which
types of body cells would need the
most mitochondria to make energy for the
body?
Structures in Plant Cells

Cell Wall
used for support and protection
 maintains an upright shape for all plants


Chloroplasts
structures that give plants their green color
 help to capture energy from the Sun to make food


Central vacuole
used to store excess water for the plant when the
environment gets dry
 also helps give a plant it’s shape
