EL 7-11 Flashcards
(55 cards)
• What are the 7 structures that make up the end-membrane system?
Nuclear envelope, CM, ER, golgi apparatus, vesicles, vacuoles and lysosomes
• What is the function of the endomembrane system?
- synthesis
- transport
- modification
- metabolism
- detoxification
Describe ER
network of membranous sacs and tubes= cisternae
- rough= ribosomes, synthesis of secretory proteins, modification of proteins and transport via vesicles
- smooth= no ribosomes, synthesis of lipids, detoxification and storage of calcium ions
Describe ribosomes
- complex of mRNA and proteins
- 2 subunits
- protein synthesis
Describe golgi apparatus
- flattened membranous sacs stacked on top of one another
- modifies, packages and transports products from the ER
describe the distinct structural directionality of golgi apparatus
- Cis face= products enter from ER
- Trans face= gives off vesicles that travel to other sites
Describe vesicles and vacuoles
- Large vesicles= vacuoles
- derived from ER and golgi apparatus
- functions are transport, storage and water balance
Describe lysosomes
- sac containing hydrolytic enzymes
- function is intracellular digestion
Describe mitochondrion
-double membrane
-own DNA
-ATP production
-
Describe chloroplasts
- contains green pigment chlorophyll
- own DNA
- light into chemical energy via photosynthesis
Describe mitochondrion
- double membrane
- own DNA
- ATP production
• Describe the structure of a microtubule
- Hollow rods constructed from a globular protein called tubulin
- each tubulin protein is a dimer( a and b-tubulin)
- grow in length by adding tubulin dimers/ disassembling them
• What is the ability to grow and shrink called?
Dynamic instability
• What are the main functions of microtubules?
- maintaining cell shape
- Transport
- Cell motility
- chromosome movement
what are centrosomes and centrioles and centriole’s structure
centrosome is the microtubule organising center which contains 2 centrioles at right angles to each other
-each centriole has 9 sets of 3 microtubules
• What are the two motor proteins and towards what do each of them go?
- kinesis towards +
- dyneins towards -
• How do microtubules bend?
- Large motor proteins (dyneins) are attached along each outer microtubule
- Dynein walks along microtuble
what is the common structure of cillia and flagella?
Basal body
axoneme( 9+2. pattern)
• How do microtubules bend?
- Large motor proteins (dyneins) are attached along each outer microtubule
- Dynein walks along microtubule
what are the functions of microfilaments?
- maintenance of cell shape
- muscle contraction
- cytoplasmic streaming
- cell motility
- division of animal cells
• What are the 2 things that help with muscle contraction?
- Microfilaments
- Myosin
Describe the 5 step process of muscle contraction
1) the myosin head is bound to ATP and is in its low-energy configuration.
2) The myosin head hydrolyzes ATP to ADP and Pi (inorganic phosphate) and is in its high-energy configuration.
3) The myosin head binds to actin, forming a cross-bridge with the thin filament.
4) The myosin couples release of ADP and Pi to a power stroke that slides the thin filament along the myosin and returns the myosin head to a low-energy state.
5) Binding of a new molecule of ATP releases the myosin head from actin, and a new cycle begins.
what causes the shortening of the muscle cell?
the walking of myosin projections drives parallel myosin and actin filaments past each other so that the actin filaments approach each other in the middle. this shortens the cell.
How does actin microfilaments cause division of animal cells?
Cleavage furrow is caused by contractile ring of actin microfilaments, interaction between myosin and microfilaments cause ring to contract and helps pinch parent cell into 2 daughter cells
