Download Cell Organelles Powerpoint 1

Bell-Ringer
1) What are organelles?
a) parts of cells which help it divide
b) substances which perform specific
tasks for the cell
c) parts of all cells which help the cell
move through different environments
d) substances which provide the cell with
the energy needed to run life processes
2) The cell to the right
is a...
a) bacteria cell
b) prokaryote
c) monokaryote
d) eukaryote
3) We know the answer to #2 because...
a) The cell has a membrane-bound nucleus
b) The cell has clearly defined organelles
c) The cell has ribosomes in the cytoplasm
d) The cell has a plasma membrane
4) The best reason to explain why cells are
so small is...
a) being small allows them to maximize
their chemical reactions
b) being small makes it easier to move
materials in and out of the cell
c) being small makes it harder for a cell to
loose the organelles inside it
d) being small gives the cell the ability to
thrive in a variety of environments.
Organelles
-part 1-
Cell Membrane
• The cell membrane (and the membranes
covering some organelles) are made of
phospholipids.
Cell Membrane
• Phospholipids have two distinct parts:
– A hydrophilic (water-loving) head
– A hydrophobic (water-fearing) tail
Cell Membrane
• The lipids line up so that their polar heads
point outward toward water and their tails
point inward, away from water.
Cell Membrane
• Embedded within the plasma membrane
are various types of proteins.
Cell Membrane
• These proteins perform specific tasks, such as:
– Helping transport substances across the membrane
– Signaling other cells
Cell Membrane
• Scientists describe a cell’s plasma membrane
as being a “fluid mosaic.”
• This means that the cell membrane acts more
like a fluid than a solid.
Cell Membrane
• Members of the membrane can move around
each other – the pattern of lipids and proteins in
the membrane is constantly changing.
• Example: The cell membrane is a lot like a
layer of oil in a beaker of water.
Nucleus
• Most of the functions of eukaryotic cells
are controlled by the nucleus.
• The nucleus houses and protects the cell’s
genetic information – its DNA.
Nucleus
• The nucleus houses and protects the cell’s
genetic information – its DNA.
• The nucleus is often found near the center
of the cell.
Nucleus
• When a cell is not dividing, the DNA in the
nucleus is found in the form of chromatin
(stringy, thread-like DNA).
• When a cell is dividing, the chromatin
condenses to form chromosomes.
Nucleus
• The nucleus is covered by a double
membrane called the nuclear envelope.
• There are tiny holes in the envelope,
nuclear pores, which allow materials to
pass in and out of the nucleus.
Mitochondria
• The mitochondria is the power-house of
the cell.
Mitochondria
• It is responsible for transferring energy
from organic molecules to ATP.
• ATP is the energy source that power’s all
of the cell’s chemical reactions.

Mitochondria
• Because the mitochondria supply energy,
highly active cells (like muscle cells) have
a high number of mitochondria.
Ribosomes
Ribosomes
• Ribosomes are small, spherical objects
that are responsible for building proteins.
• Ribosomes build proteins by attaching
amino acids together.
Ribosomes
• Ribosomes are one of a few organelles
that are not surrounded by a membrane.
• Ribosomes are found in two places:
– Floating freely in the cytoplasm
– Attached to the Endoplasmic Reticulum
Endoplasmic Reticulum
There are two different types of
Endoplasmic Reticulum:
1) Rough ER
2) Smooth ER
Endoplasmic Reticulum
• The Endoplasmic Reticulum (ER)
functions as a cellular pathway.
• It helps transport molecules from one part
of the cell to another.
Endoplasmic Reticulum
• The Rough ER is covered in ribosomes.
• It is responsible for transporting materials,
as well as producing phospholipids and
proteins.
Endoplasmic Reticulum
• Some ribosomes on the rough ER make
digestive enzymes to help break down
food.
Endoplasmic Reticulum
• The Smooth ER does not contain ribosomes.
• Besides transporting materials, it is also
responsible for creating numerous products:
– Cholesterol
– Estrogen / Testosterone
Exit Slip
1) If you were to remove all the ribosomes
from a cell, the cell would also not have...
a) DNA
b) Nucleic Acids
c) Proteins
d) Lipids
2) What biological compound is closely
related to the mitochondria?
a) Proteins
b) ATP
c) DNA
d) Carbohydrates
3) Which answer below is the Endoplasmic
Reticulum most like...
a) a power plant – providing energy
b) a brain – the control center
c) a factory – making products
d) a highway – transporting materials
4) What words best describe the plasma
membrane?
a) stiff conglomerate
b) fluid mosaic
c) liquid smooth
d) strong mixture