Transcript Eukaryotic cells

Cells: Building Blocks of Life
Objective 2.0
• Identify functions of
organelles found in
eukaryotic cells,
including the nucleus,
cell membrane, cell
wall, mitochondria,
chloroplasts and
vacuoles.
The Inside Story
• Cells are so small that
the details of their
structure could not be
seen until better
methods of magnifying
and staining were
developed.
• We now know
everything inside a cell.
From the structures
covering the cells to the
organelles inside them,
they have structure that
helps to keep the cells
alive.
•Eukaryotic cell-
A cell that
contains a
central nucleus
and a
complicated
internal structure.
Two types of
eukaryotic
cells.
Animal cell
Plant cell
•Prokaryotic-A cell
that does not have
a nucleus or any
other membranecovered
organelles; also
called a bacterium.
Staphylococcus aureus
Gut bacteria
•Organelles- tiny
cellular
structures that
enable the cell to
live, grow, and
reproduce.
•Cell membrane- the
phospholipids layer
that surrounds the
cytoplasm, through
which substances
pass in and out of
the cell.
Cell membrane
•Cell Wall- The
outermost layer
of plants cells
that is made of
cellulose.
Plant cell wall
• Nucleus -The largest
and most visible
organelle found in a
eukaryotic cells;
contains the DNA and
serves as a control
center for the cell.
Red and White Blood Cells
• The job of a nucleus is to be
the control center of the cell.
The nucleus in a human cell
has forty-six chromosomes.
This stores the instruction of
the cell's activity. The
nucleus has a membrane
called a nuclear envelope.
The nucleus is like a vault. It
contains the cell's DNA.
• As you prepare to leave the
nucleus, you spot a small
object floating past. It is the
nucleolus or little nucleus.
For many years to function of
the nucleolus remained a
mystery to scientists. Today it
is believed the it is the site of
ribosome production.
•Nucleolus-a small
round body inside a
cell nucleus,
composed of protein
and RNA and it
makes ribosomes
for the cell.
Nucleolus
• DNA (deoxyribonucleic acid) -
Heredity material
that controls all the
activities of a cell,
contains the
information to make
new cells and
provide instructions
for making proteins.
•Chromosomes-rod
shaped cell
structure that
directs the activities
of a cell and passes
on the traits of a cell
to new cells.
•Cytoplasmcellular fluid
surrounding a
cell’s
organelles.
• Cytoplasm is composed of
65% water, with as much as
a billion molecules contained
within the cytoplasm of one
single cell. The cytoplasm
contains enzymes, and
dissolved nutrients like amino
acids and sugars. The water
allows for reactions to occur
within the cell
• DNA is contained in
the cytoplasm of
prokaryotes. Also in
prokaryotic
cytoplasm there are
ribosomes, which
produce proteins,
such as enzymes
and transport
proteins.
•Lysosome- A
special vesicle
(sack) in a cell that
digests food
particles, wastes
and foreign
invaders.
• Each lysosome contains
enzymes that break down
large food molecules into
smaller ones. These
smaller food molecule are
then passed on to the
mitochondria, where they
are “burned” to provide
energy for the cell.
• They are also
responsible for
digesting old cell parts.
Think of them as the
garbage men of the
cell. They go around
picking up waste and
disposing of the waste.
•The membrane
that surrounds the
lysosome keeps
the enzymes from
escaping and
digesting the entire
cell!
•VacuolesStores water
and other
materials.
•Mitochondriabreaks down
food molecules
to make ATP
(source of
energy).
• The power of the cell. Structurally, the
mitochondrion has a double-layered,
smooth outer membrane with inner folds
called cristae, the inner membrane in
which energy collecting chemical
reactions takes place.
•ChloroplastsMakes food using
the energy of
sunlight. This
process is called
photosynthesis.
• Endoplasmic ReticulumMakes lipids, breaks
down drugs and other
substances, packages up
proteins for release from
the cell. Two types smooth and rough.
• The rough endoplasmic
reticulum (rough ER) is a
series of folded sheets and
interlocking channels that
form something that
resembles a maze. Rough ER
is called 'rough' because of its
exterior coating of ribosomes.
These ribosomes, scattered
over the outside of rough ER.
•Ribosomes- the
site where amino
acids are hooked
together to make
proteins.
•Golgi Body
ComplexProcesses and
transports
materials out of
the cell.
Moving Small Particles
• Materials enter and leave a
cell by one of these methods:
Diffusion, osmosis, active
transport, passive transport,
endocytosis and exocytosis.
• Diffusion- is the
process by which
molecules of a
substance move from
areas of higher
concentration to areas
of lower concentration
of that substance.
Here’s an example.
Let’s test this out
• Let’s perform a few experiments to
find out how it works.
• I have a air freshener that I will
spray at the front of the room. The
person at the back of the room will
tell me when he/she smells the
scent.
Experiment #2
• I will drop some food
coloring into a glass of
water and watch what
happens. Can you
explain your
observation?
• Osmosis-is the
passage of water
from a region of high
water concentration
through a semipermeable membrane
to a region of low
water concentration.
•Using the definition
of osmosis, tell me
why you shouldn’t
drink salt water no
matter how thirsty
you are?
Answer
• The concentration of water
outside is lower the inside of the
cell. This is because there are
salt molecules taking up space
in the water. This means that
there are fewer water molecules.
The water leaves the cell, and
the cell starts to shrink. If too
much water leaves the cell, the
cell dries up and dies.
• Passive transport- is
a form of diffusion or
osmosis in which
materials move
across a membrane
without using the
cell’s energy.
• Sometimes, large
molecules cannot
cross the plasma
membrane, and are
"helped" across by
carrier proteins this process is called
facilitated diffusion.
• Facilitated Diffusion is a FORM of
ACTIVE TRANSPORT AND
THEREFORE REQUIRES NO
ENERGY INPUT.
• Active Transport this type of transport
requires that the cell
use energy, because
substances are
moving against the
concentration
gradient.
•Endocytosis cell takes in
large particles
by engulfing
them.
•Exocytosis cell gets rid of
particles,
opposite of
endocytosis.
The End.