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Title: Cell Biology Pt. 2
Description: Notes on cell biology from an Anatomy and Physiology module.
Description: Notes on cell biology from an Anatomy and Physiology module.
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Cell Biology Continued
Nucleus to screen for disorders
...
It is the site where most cellular activities are accomplished
...
g
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Cytoplasmic Organelles
Endoplasmic Reticulum
The endoplasmic reticulum is a system of interconnected flattened membranes
...
It is a continuation of the nuclear envelope
...
o Where proteins are produced
...
Smooth Endoplasmic Reticulum
-
No ribosomes
Major site of lipid (fat) synthesis
Most smooth endoplasmic reticulum is found closer to the plasma membrane
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- Myosin – muscle
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- Collagen – produced by fibroblasts
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Energy store
o 1g fat = 9cal
o Very energy dense
Insulation
o Hypodermus (sub-cutaneous layer)
Protects organs
Toxin store
o If liver can’t metabolise toxins it is directed into the fat supplies
§ Phthalates (found in plastic bottles)
• Can’t be broken down in the liver
• Turned into breast tissue
• Mimics oestrogen
Nucleolus
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Located in the center of the nucleus
Generates strands of ribosomal RNA (rRNA)
o The strands leave the nucleus > reach rough endoplasmic reticulum >
fold up into ribosomes
...
o Refines the proteins by adding sugar residues
...
**
o Prepares proteins in secretary vesicles to be released
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o Digestive enzyme
Mitochondria
-
-
Release energy inside cells
...
§ Respiratory enzymes are located on the inner membrane surface
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They can reproduce inside the cell
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Play a major role in creating new memories
...
Cytoskeleton
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Anchors components of the cytoplasm in place
Can contract and relax
Move things around the cell
...
- Controls movement of material into and out of the cell – membrane transport
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- Behaves like a fluid – fluid structure – able to flow
...
-
Channel proteins – form channels through membrane
...
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Receptor proteins
o Very few cells don’t have insulin receptors
...
-
Phagocytes
o Cell eating
o Only possible because membrane is fluid and able to entrap bacteria
...
o Used to produce variety of chemical signals
o Arachidonic acid is a 20 carbon polyunsaturated fatty acid (PUSA), found
esterified in the fatty acid side chains of membrane phospholipids
...
o Amino acids can then enter the cyclo-oxygenase (COX)
o COX converts Arachidonic acid into prostaglandins
§ Cause pain and swelling
...
-
Membrane proteins
Channel proteins – form channels through membrane
...
- Known as the cells fingerprint/barcode
- Involved in cell recognition
The Recognition of Self
The major histocompatibility complex (MHC)
Each individual has a set of ‘self’ glycoproteins on the surface of their cells that are
referred to as the major histocompatibility complex (MHC)
...
MHC proteins are found on most cell types, with the exception of erythrocytes
...
This occurs in the developing foetus
...
This prevents the white blood cells attacking
the body’s own cells
...
Organ transplantation
For an organ to be suitable for transplant, it must be compatible with the recipient
...
This process is termed ‘tissue typing’
...
g
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o Heart bypass surgery – vein taken from leg and then put into heart
...
Isograft
- Involves transplanting organs between genetically identical individuals
o Would be no rejection as genetically identical individuals share the
same set of MHC proteins
...
-
Involves transplanting of organs or tissues from a genetically non-identical
individual
o Look for MHC similarities
o Could begin rejection after 5-6 years
§ Have to regularly take immunosuppressive drugs to slow down
rejection
...
Pregnancy
- Foetus is an allograft – a piece of foreign material in the body
...
§ More likely to catch an infection
...
- These foetal cells are still found living within the mother’s body decades after
delivery
...
- Those in the thymic gland are utilized in thymic education where the cells of
the mother’s immune system learn to recognise and ignore the MHC proteins
on the foetal cells
...
Babies are often miscarried when they have some physical abnormality
...
‘Little soldier hypothesis’ ???
Membrane extensions
Non-motile extensions
- Microvilli
o Finger like projections
o They increase the surface area of the cell
o Found in the gut and kidneys – anywhere where absorption takes
place
...
• Green – dust, bacteria and viruses
...
Bordetella pertussis
- Causes whooping cough
- Attacks and destroys the ciliated epithelium
o Does grow back eventually
§ Ciliated epithelium destroyed by smoking only grows back in
patches
...
- Men can carry it with no major problems
...
- In the human body, simple diffusion generally involves material that is
soluble in lipid
...
- Facilitated diffusion is important to allow water-soluble material, particularly
sugars, into cells
...
Title: Cell Biology Pt. 2
Description: Notes on cell biology from an Anatomy and Physiology module.
Description: Notes on cell biology from an Anatomy and Physiology module.