Cellular Biology Final

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Provide two pieces of evidence for the endosymbiotic theory.
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List 4 functions of the cytoskeleton1. spatial organization 2. intracellular trafficking 3. internal scaffold 4. cell mobilityContrast the processes of apoptosis and necrosis- apoptosis- programmed cell death mediated by capsizes that's intrinsic or extrinsic - necrosis- accidental cell death from trauma; cells swell and burst, elicit inflammatory responseName and define the 4 nonequivalent bonds we discussed.1. electrostatic- bonding between 2 oppositely charged molecules. 2. hydrogen bonding- bonding between H and N,O, or F 3. van der waals- weakest bonding; bonding between non polar molecules 4. hydrophobic force- repulsion from water cases hydrophobic groups to be held togetherCellular membranes serve many valuable functions. Provide, in detail, 4 of these.1. compartmentalization of the entire cell and of specific organelles. this allows specialized, independent activities 2. selectively permeable barrier that controls exchange of molecules and provides a mean of communication 3. respond to external stimuli through signal transduction of receptors and ligands 4. intracellular interaction with other cells and surfaces. allows adherence or exchange of materials.There are four forms of intercellular signaling. Describe in detail each form conveying how they are different from each other.1. contact dependent- cells are direct membrane-membrane contact. 2. paracrine- signals that are released into the extracellular space and act locally on neighboring cells. 3. synaptic- neurons that transmit signals electrically along their axons and release neurotransmitters at synapses. 4. endocrine- depend on endocrine cells, which secrete hormones into the bloodstream for distribution throughout the body.Provide a complete description of the 3 cytoskeletal filaments (include structural and functional differences, as well as defining characteristics).1. actin filaments- cell surface shape and locomotion; 2-stranded helical polymers; 5-9nm; mainly between plasma membrane; strength and support. 2. microtubules- positioning of organelles/vesicles; long, hollow cylinders made of tubuli; 25nm; centric, star-like cytoplasmic array. 3. intermediate filaments- mechanical strength; rope-like fibers; 10nm; protection and fortification.The mitotic spindle consists of 3 specialized microtubules. Provide a comprehensive overview of what the contributions are for each of these.1. astral microtubules- interact with cell cortex; grows and shrinks at plus-end 2. kinetochore microtubules- attach each chromosome to spindle pole; continuous flux toward the spindle ends. 3. interpolar microtubules- hold the 2 halves of the spindle together; continuous flux toward the spindle ends.List the 4 functional classes of cell junctions in animal tissues and give 2 attributes of each.1. anchoring junctions- transmit stress and they're tethered to cytoskeletal filaments. 2. occluding junctions- seas gap between cells and makes selective barrier. 3. channel-forming junctions- create passageways between cells and link cytoplasms of adjacent cells. 4. signaling junctions- complex and send signal transduction.Name three consequences of gene mutations on their protein product.1. loss of function 2. gain of function 3. conditional loss of function (temperature related)Enzymes are in constant motion within the cell. What kind of movements do they employ in order to encounter their substrates? Which type of motion would you expect to result in enzyme-substate complexes?- Enzymes bind to 2 substrates and orient them precisely. - Enzymes bind to substrates and rearrange electrons in the substrate, creating a partial negative and partial positive charges. - Enzymes strain the bound substrate , forcing it toward a transition state.Describe the process of retrieving endoplasm's reticulum resident proteins from the Golgi.KDEL retrieval process- KDEL receptor present in vesicular tubular clusters and the golgi apparatus captures the soluble ER resident proteins and carries them in COPI-coated transport vesicles back to the ER. In the environment, the ER resident proteins dissociate from the KDEL receptor, which is then returned to the golgi apparatus for reuse.Name and describe the 2 pathways involved in transport from the trans golgi network to the cell exterior.1. constitutive secretory pathway- continual vesicular transport from the TGN to the plasma membrane; operates in all eukaryotic cells. 2. regulated secretory pathway- molecules stored in secretory or synaptic vesicles; only fuse if they receive an appropriate signal; only in specialized secretory cells; regulated membrane fusion.Compare and contrast the differences between prokaryotes (bacteria) and eukaryotes with regard to the central dogma (DNA--RNA--Protein).-In eukaryotes, DNA undergoes replication and transcription in the nucleus and proteins are made in the cytoplasm. RNA travels across the nuclear membrane before it undergoes translation. - In prokaryotes, DNA transcription and RNA translation are not physically separated. The RNA transcript can be directly translated into protein.List everything you know about protein structure and function.Proteins are composed of amino acids linked by peptide bonds; proteins can be primary (linear a.a. sequence), secondary (alpha-helix or beta-barrel), tertiary (3D organization), or quaternary structure (multiple proteins together); protein folding is bound by noncovalent bonds; proteins can consist of domains; proteins function in enzymatic activity, as structural proteins for support, and as transport proteins.Describe the process of endocytosis.1. molecule recognized/bound to receptor 2. fusion with early endosome pH6 3. multi vesicular body formation and transport along microtubules. 4. fusion with late endosomes or each other to form late endosome pH 5.5 5. conversion to endolysosomes, then to lysosome pH 5