LIFESCI 3M03 Module 3 Test Questions And Correct Detailed Answers Guaranteed Pass.
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Module
AC HPAT
Institution
AC HPAT
MODULE 3 LECTURE 1:
Define diffusion
Which 4 factors does it depend on?
What are the 2 components of random motion? - correct answer diffusion: random/non-directed motion of molecules and small particles in a liquid
factors:
1) driving for...
What are the 2 components of random motion? - correct answer diffusion:
random/non-directed motion of molecules and small particles in a liquid
factors:
1) driving force (i.e. gradient, temp.)
2) mechanical resistance of the surrounding medium
3) structural properties of the molecule
4) active forces causing non-thermal fluctuations (i.e. contraction/relaxation of cytoskeleton moves
cytoplasm causing active diffusion)
components of random motion:
1) passive/thermal component
2) active/motor-driven component
How does the function of diffusion differ between prokaryotic and eukaryotic cells?
What is the function of diffusion in embryos?
When is diffusion favourable? - correct answer prokaryotes: suitable for
transportation
,eukaryotes:
- suitable for transportation in micro-environments
- provides primary basis for signal transduction network in cytoplasm
embryos: important in development (i.e. morphogenesis to establish embryonic domains)
favourable when: molecules must travel relatively short distances
Time scales in diffusion:
- diffusion is dependant on _________
- why is diffusion sufficient at the synaptic cleft?
- as the distance traveled increases, the time it takes _________ - correct answer
- diffusion is dependent on DISTANCE THAT MUST BE TRAVELLED
- synaptic cleft: small distance must be traveled for molecule to have an effect (i.e. diffusion can occur
quickly)
- as distance increases, time also increases
Active Transport:
- Why is active transport needed between different cellular components and living cells?
- What are 2 characteristics of active transport?
- What are the 2 active transport mechanisms seen? - correct answer - cellular
components/living cells: associations between them cannot be accomplished by diffusion alone
,1) directed motion via molecular motors along biopolymers (i.e. MTs or MFs)
2) useful when movement is required along long distances
------------
1) assembly/disassembly of cytoskeletal filaments
2) molecular motor-directed active motion
Molecular Motors:
- Important for transport of which 3 components within a cell?
- What is required for their function?
- How is movement achieved? - correct answer - molecules, particles,
organelles
- ATP or GTP hydrolysis
- chemo-mechanical coupling: chemical energy from ATP/GTP is converted into force via conformational
changes in motor proteins
Classes of Molecular Motors:
- What are the 4 classes of molecular motors, and how do they function? - correct answer
1) polymerization motors: use actin/MT assembly to help cells generate direct force during movement
2) translational motors: move in a directional step-like fashion along polymerized protein track
3) translocation motors: help thread/pass through a hole (i.e. push/pull actions)
, 4) rotary motors: embedded in cell membrane and use rotation of mechanical elements to generate
torque
Cytoplasmic Streaming:
- what is it?
- where is this phenomenon observed? (5)
- what is its proposed purpose? - correct answer - cytoplasmic streaming:
circulation of cellular fluid (i.e. cyclosis) driven by motor proteins walking along filaments containing
organelles
- large cells in: algae, plants, amoebae, nematodes, flies
- purpose: by-product of transportation (i.e. may help overcome slowness of diffusion in large cells)
Cytoplasmic Streaming in Algal cells:
- which 2 components was myosin V found to interact with?
- what do actin filaments serve as?
- what is seen as vesicles move along actin filaments? - correct answer - ER and
stationary actin bundles
- actin filaments: serve as TRACKS for motor proteins
- as vesicles move, cytoplasm moves with it (i.e. directional/stream-like movement)
MODULE 3 LECTURE 2:
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