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Index
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MLB111 (BSc Biological Science UP)
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Chapter 1
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Level 1
level: Level 1
Questions and Answers List
level questions: Level 1
Question
Answer
The dynamic consistency of the internal environment
Homeostasis
It is the ratio of size increase, usually with the aid of a microscope lens
Magnification
The minimum distance two points can be apart and still be distinguished as two points
Resolution
Used to determine the function of organelles. The process purifies different part of the cell so that they can be studied with physical and biochemical methods
Cell fractionation
Interrelated membrane bound organelles that extend from the nuclear envelope to the plasma membrane
Endomembrane system
Town Hall. Contains genetic info. Nucleolus: rRNA synthesis takes place. Nuclear envelope: 2 phospholipid bi-layers and nuclear pores
Nucleus
Rehab Detoxification and lipid synthesis. Find more in liver and kidney. Produces steroid hormones.
Smooth ER
Factory Protein synthesis Lumen is modified by adding carbohydrates to it to make a glycoprotein membrane
Rough ER
- SER pumps ions from cytosol into lumen - When the muscle cell is stimulated by nerve impulses Ca2+ iond rush back to the cytosol - Triggers muscle contraction
Muscle Contraction
recycling truck/hit-man Contain hydrolytic (breaks down into lipids and fats) enzymes Digest food particles Recycle defective organelles Apoptosis (programmed cell death) Primary: Bud off Golgi complex Secondary: Fusion of primary lysosomes with vesicle containing ingested materials
Lysosomes
Police station Protection against oxidative stress Catalase catalyses (breaks down) hydrogen peroxide into water and oxygen which is released back into the cytoplasm. Hydrogen peroxide is a by-product of fatty acids.
Peroxisomes
Reservoir Storage of water, salt, pigments or waste In plant cells the cell sap provides rigidity and turgidity Vacuoles consist of single membrane (tonoplast) built from Golgi body.
Central Vacuole
Powerhouse Releases energy needed for chemical activities in the form of ATP (Adenosine Triphosphate)
Mitochondria
Contain chlorophyll. ATP energy, carbohydrates and photosynthesis Contains thylakoids
Chloroplasts / Plastids
Butcher (we get our protein here) Synthesis of proteins Made of a large and small subunit. Free ribosomes in cytoplasm synthesise nuclear, mitochondrial and other proteins Membrane associated ribosomes synthesise proteins in the membrane system and those destined for export.
Ribosomes
Post office Storage, modification and packaging Processes, sorts and modifis proteins and other materials received from ER. Cis face- near nucleus and receives from ER Trans face- close to plasma membrane and packages nucleus into vesicles ER (glycoprotein made in Lumen)--> cis (vesicle to transport) --> trans (modification) --> plasma membrane (transport vesicles)
Golgi Complex
Mitochondria and chloroplasts have their own ribosomes which means they can make their own protein. Belief that they were endocytosed longer in cells and thus lost their ability to be autonomous. Evidence: can grow and reproduce on their own own ribosomes
Endosymbiont Theory
20-25nm diameter alpha and beta heterodimers which join to form alternating subunits Adding to the + side allows it to elongate more rapidly
What is the structure of microtubules?
Scaffold for cell shape Bracts for organelle Locomotion (cilia/flagella) Spindles in mitosis
Function of microtubules
found on - end of MTOC centrosome --> cell division centriole
Where are microtubules found?
small, hollow, cylindrical 9 interconnected triplet microtubles (27)
Structure of centriole
Miotic spindle between centrioles in animal cell division
Function of centriole
structural: assembly motor: ATP to produce movement (kinesin and dyneim)
MAP (microtubule associated proteins)
Motor protein which pulls organelles and vesicles on microtubules
Kinesin
Initiates movement of cilium or falgellum The side arms of the microtubule doublet use ATP to allow the dyneim to reach for its neighbour and pull the microtubule along. Resulting in sliding but cross lining proteins which ultimately cause bending.
Dyneim
-disassemble and reassemble for movement -functions as a mechanical support structure eg. myosin and actin in muscle cells
Actin/ microfilament
Heterogenous, fibrous proteins Function: cell shape - dynamic and stability and they anchor nucleus and other organelles eg. keriton
Intermediate filaments