Organelles Flashcards
Organelles are mini organs within the cell like a little town
Nucleus (brain or gov)
Mitochondria (power plant or energy)
Ribosomes (produces proteins)
Endoplasmic reticulum (factory, foldings)
Golgi apparatus (post office)
Lysosomes (recycle and break down)
Cytoskeleton (scaffolding)
Nucleus - contains the body’s genetic information in the form of DNA
All body cells have a nucleus, except RBC. RBC loose their nucleus during development to maximise the space available to carry oxygen in the blood.
The nucleus controls all cell functions hence is the brain if the cell. It contains nucleolus which produces RNA
Nucleus is surrounded by a phospholipid structure (double layered nucleus membrane which separates the nucleus from the cytoplasm)
The nuclear membrane contains nuclear pores for substance movement in and out of nucleus
Cytoskeleton - acts like scaffolding, provides framework for the cell
Cytoskeleton is a network of protein filaments (microphones and micro filaments) that extends through the cytosol
These protein filaments assist in the following :
- Generate cell movement - eg enable WBC to migrate to sites of injury. In muscle cells they are organelles that enable muscle contraction
- Physical support and shape - they determine cell shape
- Cell division - they move chromosomes apart (mitosis)
Mitochondria (energy plants) produces energy. Bean shape structures found outside of the cell where energy is manufactured from nutrients entering the cell
They generate ATP. Currency of body cells. Our cells use ATP to perform various processes.
They contain a double layered membrane with fluid in between. The inner membrane has a series of folks called cristae which produce a vast surface area for reactions to take place such as ATP.
Greater surface area for chemical reactions. The body likes surface area the more area more processes the better
Mitochondria pt 2
Can be damaged easily by oxidative stress
Takes the o2 in your blood and reacts the o2 with various molecules. It reacts the o2 with glucose which extracts ATP.
Cells contain various amounts of mitochondria. Some thousands.
Muscle cells incl those in the heart are thought to contain the most
Heart is 95% muscle meaning it needs lots of energy for contracting.
When cells produce energy the also produce co2 as an output
Ribosomes - protein synthesis factory
High content of RNA
Ribosomes are either free (mobile) in cytoplasm or bound to rough endoplasmic reticulum (stationery)
Free ribosomes make protein for inside the cell whilst those on the rough ER make protein for outside the cell
They synthesis proteins for specific organelles which they export from the cell eg hormones
RNA that leaves the nucleus reaches the ribosomes. The way ribosomes produces proteins is from receiving the RNA molecule. The RNA molecule tells the ribosome what it wants it to produce.
Endoplasmic Reticulum (ER) factory
The ER is a network of membranes in the form of flagged sacs.
It extends from the nuclear envelope throughout the cytoplasm to the cell membrane
Rough ER has ribosomes. Continuous with nuclear membrane. Its outer surface is studded with ribosomes. If synthesises and transports proteins
Smooth ER. Helps detox liver. Helps produce fats (lipids) and hormones. Does not have ribosomes
It contains unique enzymes and performs the following
- Synthesises lipids and steroid hormones. Eg estrogen, testosterone, stress hormone cortisol.
- In the liver enzymes or smooth ER detoxify alcohol drugs etc
- In muscle it releases calcium for muscle contraction.
Golgi apparatus - cell post office
Modifies, sorts packages and transports proteins received from the rough ER
It consists of flattered membranous sacs most cells have Golgi
A transport vesicle that buds off from the rough ER lobes towards the Golgi and releases proteins into it. Enzymes modify the proteins and they bud off in transport vesicles
Golgi apparatus - cell post office
Modifies, sorts packages and transports proteins received from the rough ER
It consists of flattered membranous sacs most cells have Golgi
A transport vesicle that buds off from the rough ER lobes towards the Golgi and releases proteins into it. Enzymes modify the proteins and they bud off in transport vesicles
Lysosomes - Mobile recycling centre. Recycles and breaks down. They are vesicles that perform a key role in digestion
Contains as many as 60 powerful enzymes which can break down a variety of molecules once fused with them. It binds to the old molecule to breakdown and recycle
Lysosomes recycle worn out organelles they engulf and digest. Components are returned to cytosol for re use.
They digest foreign cells.
Certain WBC contain lysosomes that specialise in eating foreign cells. Pulls the foreign cell in and exposes them to the 60 enzymes. Known as phagocyte = WBC specialises in eating.
