The Cell

1
The Cell

• Leslie Gushwa and Josh Klock

2
Cell Parts

• Cell Membrane, Cell Wall, Cytoplasm
• Protein Production- Nucleus, Nucleolus,
  Endoplasmic Reticulum, Ribosomes, Golgi Bodies,
  Lysosomes
• Energy- Mitochondrion, Chloroplasts (Energy-
  Mitochondrion, Chloroplasts)
• Miscellaneous- Microtubules, Microfilaments,
  Plastids

3
Cell Membrane

• It also connects the the endoplasmic reticulum,
  and the nuclear membrane. In the image below we
  have colored the membrane to highlight its
  composition. The yellow represents the
  phospholipids. The purple represents the membrane
  proteins

4
Cell Membrane

• The Cell membrane performs a number of critical
  functions for the cell. It regulates all that
  enters and leaves the cell in multicellular
  organisms it allows self recognition. In order to
  understand the function of the cell membrane you
  must understand its structure.

phospholipids
5
Cell MembraneClose-up

• Here we see a cross section of the cell membrane
  you should notice two different structures The
  phospholipids are the round yellow structures
  with the blue tails, the proteins are the lumpy
  structures that are scattered around among the
  phospholipids.

6

• This is a simple representation of a
  phospholipid. the yellow structure represents the
  HYDROPHILLIC or water loving section of the
  phospholipid. The blue tails that come off of the
  sphere represent the HYDROPHOBIC or water fearing
  end of the Phospholipid. Below is a structural
  model of a phospholipid that explains what these
  terms mean.

7
Cell Wall

• Cell walls are the rigid structure found
  surrounding plant cells. They provide support for
  the plant

8
Cytoplasm

• The term cytoplasm refers to everything between
  the cell membrane and the nuclear envelope. It
  consists of primarily of water. It also contains
  various organelles as well as salts, dissolved
  gasses and nutrients.

9
Cytoplasm

• Protein Producing Organelles Endoplasmic
  Reticulum, Ribosomes, Golgi Apparatus, Lysosomes
• Energy Producing Organelles -Mitochondrion,
  Chloroplasts
• Specialty Structures -centrioles, vacuoles, cell
  walls, cilia, flagella, plastids

10
NUCLEUS- nuclear envelope

• The nuclear envelope is a double membrane. Is has
  4 phospholipid layers. It is also has large pores
  through which materials pass back and forth.

11
Nucleus

• The headquarters of the cell. It is a large dark
  spot in EUKARYOTIC cells. It controls all cell
  activity. Close up you will see that the nuclear
  membrane has many pores. The nuclear membrane is
  continuous with the E.R.

12
With the outer membrane removed it is much easier
to see the contents of the nucleus.

• The thick ropy strands are the CHROMATIN. The
  large solid spot is the NUCLEOLUS. The nucleolus
  is a knot of chromatin. It manufactures
  ribosomes.

13
Chromatin

• Within the nucleus are found chromatin and a
  structure called the nucleolus. Chromatin is DNA
  in its active form. It consists of DNA looped
  around histone proteins. The nucleolus is a knot
  of chromatin. It is the nucleolus that
  manufactures ribosomes .

14
Endoplasmic Reticulum

• Smooth, no ribosomes
• rough, has ribosomes

15
Smooth E.R.

• The endoplasmic reticulum is a series of double
  membranes that loop back and forth between the
  cell membrane and the nucleus.
• These membranes fill the cytoplasm but you cannot
  see them because they are very transparent. There
  are two distinct types of E.R. The rough E.R.
  has ribosomes and is the site of protein
  synthesis the smooth E.R. has no ribosomes

16
R.E.R.

• The endoplasmic reticulum is a series of double
  membranes that loop back and forth between the
  cell membrane and the nucleus. These membranes
  fill the cytoplasm but you cannot see them
  because they are very transparent.

R.E.R.
17
Ribosome

• The ribosomes are the organ-elles which
  manufacture proteins. They are made of two
  separate parts. These structures are both made of
  ribosomal RNA.

18
GOLGI BODY
19
Golgi Apparatus

• The golgi body is responsible for packaging
  proteins for the cell. Once the proteins are
  produced by the rough E.R. they pass into the
  sack- like cisternae that are the main part of
  the golgi body.

These proteins are then squeezed off into the
little blebs which drift off into the cytoplasm.
20
Lysosome

• Lysosomes are called suicide sacks. They are
  produced by the golgi body. They consist of a
  single membrane surrounding powerful digestive
  enzymes. From this screen you can cut the
  lysosome and move it around.

21
Lysosomes

• With the outer membrane removed it is much easier
  to see the contents of the lysosome. Those lumpy
  brown structures are digestive enzymes.

22
"suicide sacks

• They dissolve bacteria and other foreign bodies.
  Under some conditions the lysosomes in a cell
  will break open and a cell will self destruct in
  a process called autolysis (giving rise to the
  name "suicide sacks").

23
The MITOCHONDRION is the powerhouse of the cell.
It is the site of respiration. It has a double
membrane. From this view you can see very little
gtgtgtgtgtgtgtgtgtgt
24

• The outer membrane is cut to get a better look.
  With the outer membrane removed it is much easier
  to see the contents of the mitochondrion. The
  white folded structure is the inner membrane.
  Most of AEROBIC RESPIRATION occurs along this
  membrane. Get a really good look by cutting the
  inner membrane. gtgtgtnext slidegtgtgtgtgt

25
The inner membranes is ruffled. It has a very
large surface area. These ruffles are called
cristae. Mitochondria have their own DNA and
manufacture some their own proteins. It is
thought that the mitochondrion evolved from
symbiotic bacteria that took up residence inside
the first eukaryotic cells.
26
INSIDE THE INNER MITOCHONDRION
27
Plastids

• Plastids are large organelles found on plants and
  some protists but not in animals or fungi. They
  can easily be seem through a light microscope.
  The other class of plastid are called leucoplasts
  (colorless plastids)

they usually store food molecules. Included in
this group are amyloplasts or starch plastids
shown here in potato root cell.
28
PLASTIDS- Chloroplast

• Chloroplasts represent one group of plastids
  called chromoplasts (colored plastids).

29
The chloroplast is the site of photosynthesis. It
consists of a double membrane. Cut the outer
membrane to get a better look inside.
With the outer membrane removed it is much easier
to see the contents of the chloroplast. The
stacks of disk-like structures are called the
GRANA. The membranes connecting them are the
THYLAKOID MEMBRANES.
30
Grana and Thylakoid Membranes

• The membranes that you see here are the site of
  photosynthesis. It is here that the energy
  harnessing process of photosynthesis occurs.

Dissolve the Remaining membrane and zoom in to
get a better look.
31
Microfilament

• These are hair like extensions off of the cell
  membrane. Cilia tend to be small and numerous and
  flagella tend to be large few. They beat back
  and forth rhythmically. In unicellular organisms
  their job is locomotion. In large multicell
  organisms their role is to move fluid past the
  cell. Notice the 92 arrangement of the
  microtubles.

32
Microtubule

• Centrioles are found only in animal cells. They
  function in cell division. Zoom in and notice the
  9 groups of 3 arrangement of the protein fibers.

33
CENTRIOLE ENLARGED
34
Vacuole

• Vacuoles are large empty appearing areas found
• in the cytoplasm. They are usually found in
  plant cells where they store waste. As a plant
  cell ages they get larger. In mature cells they
  occupy most of the cytoplasm.