Transcript Cells - Fort Bend ISD

Cells
The basic units of life!!!
The cell
How were cells discovered?
 Robert Hooke
– Discovered the first cell using a early compound
microscope.
 Cork
Cell Theory
 1. All living things are composed of cells
 2. Cells are the basic units of structure and
function in living things
 3. New cells are produced from existing
cells.
2 Categories of Cells
 They are categorized by if they contain a
nucleus or not.
 The categories are:
– 1. Eukaryotes
– 2. Prokaryotes
Eukaryotes
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Contain a nucleus
Large
Very complex
Highly specialized
Contain internal membranes
 Examples: Animals, plants, fungi, and
protists
Prokaryotes
 Small
 Not specialized
 No true nucleus (they do still have genetic
information)
 Example:
– Bacteria
What is the main job of the cell?
 To make proteins.
 The cell has many complex processes that it
goes through in order to make new proteins
for our body to use.
 The next series of slides will walk you
through each organelle and its job.
Eukaryotic Cell Structure
 The cell is divided into 2 main parts.
– 1. The nucleus
– 2. The cytoplasm
 Both of these structures work together to get
all jobs done inside the cell.
The Nucleus
“inventor”
 The control center of the cell
 Contains all of the cells DNA
– Includes coded instructions for making proteins.
– The nucleus has the following structures inside
of it:
 Nuclear envelope
 Chromatin (tiny pieces that later become
chromosomes)
 nucleolus
The Cytoplasm
“the shop”
• Located just outside the nucleus
• Hold all of the cells organelles.
– Organelles are “tiny” cellular organs
 The cellular organelles we will be covering
today are the following:
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Ribosome's
Endoplasmic reticulum
Golgi apparatus
Cytoskeleton
--Vacuoles
--Mitochondria
--Lysosomes
Ribosomes
“finished instructions”
 This is where proteins are assembled.
 They are found in the cytoplasm and
attached to the endoplasmic reticulum.
 Their main job is to assemble proteins
following detailed instructions handed down
to them from the nucleus.
Endoplasmic Reticulum
“assembly line”
 This is where lipids are assembled to be
sent out into the cell membrane.
 There are 2 types
 1. Smooth ER
– No ribosomes, assembles lipids, makes
enzymes
 2. Rough ER
– Has ribosomes on it, also stores proteins until
they are sent to the Golgi Apparatus.
Golgi Apparatus
“customization”
 Modifies, sorts, and packages the proteins
from the ER.
 Prepares and stores proteins in the cell or
excretes them from the cell into other parts
of the body.
 The finishing touches are put on the proteins
here before they leave the cell.
Lysosomes
“cleanup crew”
 There job is to break down waste and
recycle it to be used by the cell.
 They are filled with enzymes that help them
break down and digest lipids,
carbohydrates, and proteins.
Mitochondria
“Power Source”
 Convert food into chemical energy the cell
can use.
Cytoskeleton
“Shop Walls”
 Helps the cell maintain it’s shape
 Also involved in movement
Vacuole
 They are saclike in structure
 Function: they store materials like water,
salts, proteins, and carbohydrates.
Flagellum
It is a long tail or whip like structure.
Its function is to provide a cell with movement.
Example: Sperm cell
Cilia
 These are very tiny hairs located on the
outside of some very small eukaryotes.
 Function: To provide movement.
 Also found inside the nose and inside the
lining of the respiratory and digestive tract.
Chloroplast
 Only found in plant cells
 Function: They capture energy from the sun
and convert it into chemical energy that the
plant can use.
– This process is called photosynthesis
 Structure: They look like green skittles.
Centrioles
 They are made up of tiny fibers called
tubulin.
 Located near the nucleus
 Help the cell divide.
Cell Wall
 They are found in plants, algae, and fungi.
 Structure: They are thick and rough. They
have many pores in them that allow water,
oxygen and carbon dioxide through.
 Function: Provide support and protection for
the cell.
Cell Membrane
 Also known as the phospholipid bi-layer.
– Structure: Made of 2 layers of lipids. There are
also proteins stuck inside of the lipid layers that
act as doorways to allow large molecules to
pass.
 Function: Controls what enters and leaves
the cell. Also provides protection.