Key Points:
1.
Structure (and importance) of cell
membrane
2.
Structure (and function) of organelles
3.
Interconnections between cells to
maintain structural stability in body
tissues.
A typical cell
1.
Cell membrane
2.
Cytoplasm
non-membranous
organelles
cytosol
membranous
organelles
Cell membrane (plasma membrane)
The ________ ________ model describes the structure of the plasma
membrane. In this model the membrane is seen as a bilayer of
______________ in which protein molecules are embedded.
(fill the blanks)
Name the functions of
cell membrane proteins
1. _____________
2. _____________
3. _____________
4. _____________
5. _____________
Cell membrane (plasma membrane)
The fluid mosaic model describes the structure of the plasma
membrane. In this model the membrane is seen as a bilayer of
phospholipids in which protein molecules are embedded.
Functions of proteins
1. Cell adhesion
molecule
2. Carriers
3. Pumps
4. Ion channels
5. Receptors
6. Enzymes
Non-membranous Organelles
Name the non-membranous
organelles.
1.
2.
3.
4.
Non-membranous Organelles
1.
Cytoskeleton
2.
Microvilli
3.
Cilia,
Centrioles,
Flagella
4.
Ribosomes
Cytoskeleton
Q. Name the 4 major components:
1. ________________
2. ________________
3. ________________
4. ________________
Q. What is its function:
____________
Cytoskeleton
Answer:
The 4 major components are,
1. Microfilaments (mostly actin)
2. Intermediate filaments
3. Thick filaments (composed of
myosin subunits)
4. Microtubules (composed of
tubulin subunits)
Function: support & movement of
cellular structures & materials
2 centrioles
direct formation
of mitotic spindle
In 9+0 array
The centrosome, also called the "microtubule organizing center", is an
area in the cell where microtubles are produced.
Within an animal cell centrosome there is a pair of small organelles, the
centrioles, each made up of a ring of nine groups of microtubules. There
are three fused microtubules in each group.
The two centrioles are arranged such that one is perpendicular to the
other.
During animal cell division, the centrosome divides and the centrioles
replicate (make new copies). The result is two centrosomes, each with its
own pair of centrioles. The two centrosomes move to opposite ends of
the nucleus, and from each centrosome, microtubules grow into a
"spindle" which is responsible for separating replicated chromosomes
into the two daughter cells.
Cilia
These are thread-like projections of certain cells that beat in a
regular fashion to create currents that sweep materials along;
In 9+2 array
Q. Name sites where cilia can
be found.
1. _____________
2. _____________
Answer:
1. Respiratory epithelium
2. Fallopian tube
Flagella
These may extend to the rear of a cell and push it forward by snakelike
wriggling, or stick out in front and draw it along.
Q. Where can flagella be found in humans? __________________
Answer: Sperm
Each sperm cell is propelled by
a trailing flagellum that
accelerates the little torpedo
forward in its quest to fertilize
an egg.
Ribosomes
Q.
Ribosomes are made up of 60%
_______ & 40% _______.
They are active in _______
synthesis.
There are 2 types of ribosomes
1. __________
Answers:
60% RNA + 40% Protein
Active in protein synthesis
2. __________
There are Fixed (on RER)and
free ribosomes
Membranous
Organelles
Nucleus
The nucleus is the control center of the cell. It is the largest organelle in the cell
and it contains the DNA of the cell.
The DNA of all cells is made up of ______________.
DNA + _________proteins = Nucleosome
____________ + Linker DNA = Chromatin
Answer:
The DNA of all cells is made up of
chromosomes.
DNA + Histone proteins =
Nucleosome
Nucleosome + Linker DNA =
Chromatin
Inside the nucleus is another organelle called the nucleolus. The
nucleolus is responsible for making ribosomes.
The fenestrations on the surface of the nucleus are the nuclear pores.
These are where ribosomes, and other materials move in and out of the
cell.
Mitochondria
Mitochondria are sometimes described as "cellular power plants"
because they generate most of the cell's supply of adenosine
triphosphate (ATP), used as a source of chemical energy
Every type of cell has a different amount of mitochondria.. There are
more mitochondria in cells that have to perform lots of work, for
example- your leg muscle cells, heart muscle cells etc.
Q. The mitochondrion has its own
independent genome inherited from
which gametocyte?
Answer:
Ovum
Smooth(SER) & Rough (RER)
endoplasmic reticulum
Chambers = cysternae
Function: Synthesis  Storage  Transport
Fill in the blanks
ER is a network of membranes throughout the cytoplasm of the cell. There are
two types of ER.
When ______________are attached it is called rough ER (RER)and smooth
ER (SER) when there are no ______________ attached.
The rough endoplasmic reticulum is where most ________________ occurs in
the cell. The function of the smooth endoplasmic reticulum is to synthesize
__________in the cell. The smooth ER is also helps in the ___________of
harmful substances in the cell.
Answer
ER is a network of membranes throughout the cytoplasm of the cell. There are
two types of ER.
When ribosomes are attached it is called rough ER (RER)and smooth ER
(SER) when there are no ribosomes attached.
The rough endoplasmic reticulum is where most protein synthesis occurs in
the cell. The function of the smooth endoplasmic reticulum is to synthesize
lipids in the cell. The smooth ER is also helps in the detoxification of harmful
substances in the cell.
Golgi Apparatus
•Packaging and shipping of proteins
•Cell membrane renewal
vesicles come from ?
Lysosomes
Function as the cell's recycling compartment.
Lysosomes receive cellular and endocytosed proteins and lipids that need
digesting. The metabolites that result are transported either by vesicles or
directly across the membrane.
Q. Name “A” , “B”, “C” & “D”
Answer:
Intercellular Attachments
1) Gap Junctions
channel proteins interlock
and form pores
Q. Where are they abundantly seen?
Answer:
abundant in cardiac and smooth
muscle
2) Tight Junctions
Interlocking membrane
proteins
Q. Where are they
abundantly seen?
Answer:
Found near surface of cells lining the
digestive tract.
3) Desmosomes
Proteoglycan layer reinforced by transmembrane proteins (cell adhesion
molecules or CAMs)
Belt, button and hemidesmosomes
Q. Where are they abundantly seen?
Answer: Found in superficial layers of skin