Transcript Cell Structure

By
Sangarun sangarchat
[email protected]
This mean of cells:
The cell is one of the
most basic units of life
There are millions of
different types of
cells. There are cells
that are organisms onto
themselves, such as
microscopic amoeba and
bacteria cells.
Anatomy of cells
There are two types of
cells: eukaryotic and
prokaryotic. Prokaryotic
cells are usually
independent, while
eukaryotic cells are often
found in multicellular
organisms.
And there are cells that only function when
part of a larger organism, such as the cells
that make up your body. The cell is the
smallest unit of life in our bodies. In the body,
there are brain cells, skin cells, liver cells,
stomach cells, and the list goes on. All of
these cells have unique functions and
features.
Eukaryotic cells
Prokaryotic cells
Procaryotic
Procaryotic: These cells are simple in
structure, with no recognizable
organelles. They have an outer cell
wall that gives them shape. Just
under the rigid cell wall is the more
fluid cell membrane. The cytoplasm
enclosed within the cell membrane
does not exhibit much structure
when viewed by electron microscopy
Eukaryotic
Eucaryotic: The cells of protozoa, higher
plants and animals are highly structured.
These cells tend to be larger than the cells
of bacteria, and have developed specialized
packaging and transport mechanisms that
may be necessary to support their larger
size.
Eukaryotic Cell
Table 1: Comparison of features of prokaryotic
and eukaryotic cells
Prokaryotes
Eukaryotes
Typical organism
bacteria, archaea protists , fungi,
plants, animals
Typical size
~ 1–10 µm
~ 10–100 µm
(sperm cells,
apart from the tail,
are smaller)
Type of nucleus Type of nucleus nucleoid region;
no real
nucleusreal
nucleus with
double membrane
DNA
circular (usually) linear molecules
(chromosomes)
with histone
proteins
linear molecules coupled in
(chromosomes) cytoplasm
with histone
proteins
Ribosomes
0S+30S60
RNA-synthesis
inside the
nucleus
protein
synthesis in
cytoplasm
5S+40S
unicellular
amoeba
euglena
parameciun
amoeba
Amoeba Free-living
protozoan groups that
inhabit soils and natural
waters are extremely
diverse, not only in their
structure but also in the
manner in which they
feed, reproduce, and
move.
Euglena
Euglena is a genus of unicellular
protists. Currently, over 1,000
species of Euglena have been
described. There are many to be
discovered. Marin et al. (2003)
revised the genus to include
several species without
chloroplasts. It can
photosynthesis.
Cyanobacteria
blue-green algae
Cyanobacteria as bluegreen algaeis phylum
of bacter are aquatic
and photosynthetic, that
is, they live in the water,
and can manufacture
their own food. Because
they are bacteria, they
are quite small and
usually unicellular,
though they often grow in colonies large enough to
see. They have the distinction of being the oldest
known fossils, more than 3.5 billion years old, in fact!
It may surprise you then to know that the
cyanobacteria are still around; they are one of the
largest and most important groups of bacteria on
earth.
Paramecium
Paramecium is a
group of unicellular
ciliate protozoa, which
are commonly studied
as a representative of
the ciliate group, and
range from about 50 to
350 μm in length. Simple
cilia cover the body,
which allow the cell to
move with a
synchronous motion.
Animal Cell Structure
Cell Structure
Unit Membrane Typical Structure
- composed of protein and lipid (fat)
molecules
Cell Membrane
Structure - same as unit
membrane.
Function
- acts as a boundary layer to
contain the cytoplasm (fluid
in cell)
- interlocking
surfaces bind cells together
- selectively permeable to select
chemicals that pass in and out of cells
Cell Wall
Cell Wall Structure
- a non-living secretion of
the cell membrane,
composed of
cellulose
- cellulose fibrils
deposited in alternating
layers for strength
- contains pits (openings)
that make it totally
permeable
Function of cell wall
- provides protection from physical injury
Chloroplast
Chloroplast Structure
- composed of a
double layer of modified
membrane (protein,
chlorophyll, lipid)
- inner membrane
invaginates to form
layers called "grana"
(sing., granum) where
chlorophyll is
concentrated
Centriole
Centriole Structure
- nine triplets of
microtubules form one
centriole
- two centrioles form
one centrosome
Function
- forms spindle
fibres to separate
chromosomes during cell
division
Vacuole
Vacuole Structure
- a single layer of unit
membrane enclosing fluid in
a sack
Function
- produces turgor pressure
against cell wall for support
- stores water and various
chemicals
- may store insoluble
wastes
Endoplasmic Reticulum (ER)
Endoplasmic
Reticulum (ER)
Structure
- sheets of unit
membrane with
ribosomes on the
outside
- forms a tubular
network throughout
the cell
Endoplasmic Reticulum (ER)
Function
- transports chemicals between cells and
within cells
- provides a large surface area for the
organization of chemical reactions and synthesis
Some Endoplasmic Reticulum have not
Ribosome on the outside. It’s function are
synthesis steroid and detoxification of poisons
Ribosome
Ribosome Structure
- non-membraneous,
spherical bodies composed
of
RNA (ribonucleic acid) and
protein enzymes
Function
- site of protein synthesis
Golgi Apparatus
Golgi Apparatus Structure
- stacks of flattened sacs of
unit membrane (cisternae)
- vesicles pinch off the dges
Function
- modifies chemicals to make
them functional
- packaging chemicals in
Vesicles for send out off cell.
Mitochondrion
Mitochondrion Structure
- composed of modified
double unit membrane
(protein, lipid)
- inner membrane infolded
to form cristae
Function
- site of cellular respiration
ie. the release of chemical
energy from food
Glucose+Oxygen ---> Carbondioxide + Water + Energy
Lysosome
Lysosome Structure
- membrane bound bag
containing hydrolytic
enzymes
- hydrolytic enzyme =
(water split biological
catalyst)
i.e. using
water to split chemical
bonds
Lysosome
Function
- break large molecules into small
molecules by inserting a
molecule of water into the chemical
bond
Nucleus
nuclear envelope
nucleolus
chromatin
nucleoplasm
Nucleus
Nuclear Envelope
Structure
- two unit
membranes with a fluidfilled space
- nuclear pores
present
- outer membrane
may be continuous with
endoplasmic reticulum
Nuclear Envelope
Function
- selectively permeable to
control movement in or out
- contains nuclear
contents
Chromatin
Chromatin Structure
- composed of long
thin strands of DNA
Function
- contains instructions
that control cell
metabolism and heredity
Nucleolus
Nucleolus Structure
- non - membraneous
matrix of RNA
(ribonucleic acid) and
protein
Function
- works with
ribosomes in the
synthesis of protein
Chromosomes
- Usually in the form of
chromatin
- Contains genetic information
- Composed of DNA
- Thicken for cellular division
- Set number per species (i.e.
23 pairs for human)
Write answers to the following: in notebook
1. Are euglena unicellular or multicellular?
2. What Kingdom do euglena belong to? What
Phylum?
3. What organelle carries out photosynthesis?
4. On which end is the flagellum located?
5. Define autotrophic.
6. Define heterotrophic.
7. Describe the two ways in which the euglena
get their nutrients.
8. What is the eyespot used for?
9. What is the function of the nucleus?
10. What is the function of the contractile
vacuole? What would happen if the cell did not
have this organelle.
Cell Structure
1..................................................................
2..................................................................
3....................................................................
4....................................................................
5....................................................................
Cell Structure
6…………………………………….
7…………………………..…….….
8…………………………………..
9……………………………………
10……………………......................
Write answers to the following:
11. This structure is made of DNA
12. Produces ATP
13. Creates turgor pressure
14. New proteins are made on the
15. This organelle controls entry into the cell
*************************