cell Flashcards
Nucleus overall function
Information storage, processing, and execution
Endomembrane overall function
Protein, carbohydrate, lipid biosynthesis
Lipid and polysaccharide granules overall function
Energy storage
Chloroplast and mitochondria overall function
Energy metabolism
Cytoskeleton, plasma membrane overall function
Structural and transport functions
Plasma membrane composition
Lipid bilayer with proteins floating and protruding from it; some proteins associate with membrane, some proteins traverse the membrane (one side on inner cytoplasmic side and other on outer face of cell)
Plasma membrane function
Selective permeable barrier, facilitates diffusion of substances in and out of cell; interface for cells where info is received from extracellular environment; constant internal environment and separate and distinct structural and chemical environments
Surface to volume ratio
Smaller cells can be more efficient and easier for functions to take place, applies to internal and external functions of cells
Nucleus overview/function
Often largest in organelle, consists of nuclear envelope, nucleolus, and chromatin, contains most of genetic info DNA (some in mitochondria and chloroplast), process instructions that allows cells to differentiate into a specific cell type
Nuclear envelope structure
Consists of a double folded plasma membrane, bounded on the inside by a nuclear lamina (network of protein keratin fibers that helps maintain its shape), nuclear pores in membrane to allow materials to pass between nucleus and cytoplasm (octagonal w/ 8 protein granules) *think mochi donut hole, some places is continuous with ER
Nucleolus structure
Consists of ribosomes and RNA, site where ribosomes are assembled/synthesized, have a lot of active proteins synthesis
Chromatin structure
Consists of DNA and associated proteins, histones are structural proteins associated with/ DNA, many regulatory proteins have functions in controlling gene expression
Endoplasmic reticulum structure
Smooth ER, rough ER (with ribosomes on outer membrane, ER lumen, cisternae, ribosomes, transitional ER, transport vesicle
Overall ER structure
Networks of interconnecting membrane enclosed sacs distributed in cytoplasm, folded into series of tubules (cisternae), internal compartment (lumen) is called the cisternae space and has distinct protein and ion composition (separate), ER where much of membrane of cell is found, 15% of entire fluid volume of cell is inside ER, ER folding generates surface area much greater than than plasma membrane, ER is continuous with the outer nuclear envelope membrane at some points
ER main function
PROTEIN SYNTHESIS
Rough ER (RER) function and info
Ribosomes attached which synthesize polypeptides, polypeptides either directed into ER’s cisternae space of incorporated into the ER membrane
Polypeptides in the ER’s cisternae space
Can be modified to change their folding and/or have carbohydrate groups added (glycoproteins) to manufacture the process of protein maturation
Polypeptides entering ER and secretion
Some entering ER have address info that instructs their final destination, some transported (secreted) out of the cell, other remain inside the cell in the ER of in lysosomes
Membrane and lumen proteins remaining inside ER
Maintain ER’s function, some transported to Golgi apparatus
Ribosomes function
Sites of protein synthesis, consist of a type of RNA and more than 50 proteins
Ribosomes location/where they are found
Free in cytoplasm and synthesize cytoplasmic soluble proteins, bound to ER that synthesize proteins more insoluble and destined for membranes and secretion, mitochondria and chloroplasts
Ribosomes structure
Large subunit, small subunit. Type of RNA and more than 50 proteins
Signaling mechanism for targeting proteins to the ER
SRP (signal recognition particle/protein attaches to signal peptide (needed) where SRP receptor protein attaches on membrane at translocation complex, SRP opens complex and is removed once polypeptide is attached to membrane, protein moves inside, ribosome and mRNA detach and protein is enclosed in ER membrane
Smooth Endoplasmic Reticulum (SER) liver cell function
(5) the site for the synthesis and hydrolysis of glycogen, drug detoxification (alc), cholesterol and steroid synthesis, and phospholipid synthesis’s also important reservoir for calcium ions
How cell knows to put things in certain places
Depending on address label, ER signal sequence, targeting sequence (Mitochondira, chloroplast, nucleus, membrane matrix), cytosolic protein
Ribosome, ER, protein now in lumen, moves to
Golgi apparatus
Golgi apparatus functions
Responsible for the production and maturation of proteins and some polysaccharides
Golgi apparatus structure
Similar in structure to smooth ER, usually series o stacked discs or arc (cisternae) in cell
Transport of materials to and out of Golgi apparatus
Material in transport vesicles from RER fuse with the Golgi apparatus at its CIS face, processed materials leave at the TRANS faces definite direction or polarity to structure
Cis face of Golgi apparatus
Receiving side, protein contains in vesicle exchanges by fusing to membrane of golgi
Trans face of the Golgi apparatus
Shipping side, bubbles either membrane proteins of lysosome proteins produced in vesicles
Cisternas of Golgi
Move around, on edges and around
Protein process in Golgi
Proteins are modified throughout and become final product that can either be used by the cell or secreted, modification using specialized enzymes within Golgi, main groups lysosomes and secretory vesicles
Where do newly synthesized proteins go from golgi
- Outside the cell
- Insertes in cell membrane
- Remain in cytoplasm as soluble proteins
- Used to maintain organelle function either as organelle structure or inside organelle
Lysosomes functions
Garbage disposal unit, acidic pH5 environment, important for the digestion of all macromolecules, can recycle cell organelles in autophagy, can be used to digest food particles brought into cell by phagocytosis
Phagocytosis
Food broken down by lysosomes
Autophagy
Lysosome breaking down organelles
Chloroplast and mitochondria energy metabolism similarities
Can move around the cell and divide, hav own ribosomes and DNA used to synthesize some of their proteins, once were independent prokaryotic organisms (symbiotic relationship)
Mitochondria structure
Almost all eukaryotic cels (small), double membrane structure and has an outer smooth membrane and and inner membrane folded into series called cristae, rest made up of matrix containing many enzymes important for cellular respiration (energy derived from carbs and lipid ATP, etc) and ATP synthesis, has own DNA, free ribosomes
Compartmentalization
Physical separation of cell functions, PH allows enzymes to function efficiently, ionic gradients for generation of ATP, spatial arrangement of enzymes that allows enzymes required for specific metabolic pathway to be close to one another, separation and efficiency
Cytoskeleton main functions
Structural and transport functions
specific functions of cytoskeleton
Maintains cel shape, provides support and anchor pints for organelles, provides mechanisms for cell )flagella and pseudopodia) and organism movement (muscle contraction), tracks for motor proteins that move materials and organelles within cells
3 main types of cytoskeleton components
Microfilaments, intermediate filaments, microtubules
Microfilaments info
Made up of actin monomers, line the plasma membrane, in chain like structures, smallest of 3
Intermediate filaments
Dispersed in cytoplasm, can be attached to organelles, made of fibrous subunits (keratins), have spider web like structure in cell
Microtubule info
Largest of 3, tubes, made up of tubulin dimer, beta and alpha tubulin monomer
Microtublules functions
Maintenance of cell shape, cell motility, chromosome movements in cell divisions, organelle movement
Microfilaments functions
Maintenance of cell shape, changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility, cell division
Intermediate filament functions
Maintenance of cell shape, anchorage of nucleus and certain other organelles, formation of nuclear lamina
Centorsomes
Important for cell division in animals cells, centrole and mircotublule
Microtubule
Structural components of cilia and flagella, covered by the cells plasma membrane, flagella loner than cilia, cell only have a couple flagella, cilia in great numbers
Motor proteins info
Walks along the mircotubule, powered by ATP, proteins walk along, like little feet
Flagella movement 3 types of junctions and connection Al structures between animal cells
Tight junctions, desmosomes, gap junctions
Tight junctions function
Form belts around cells, outer part of plasma membranes between cells touch each other and contain tight junction proteins (occluding and claudins) that act as seals to limit the loss of fluid and ions, are important for controlling the loss of fluid between one biological compartment and another
Desmosomes function
Functions as anchors between cells, intermediate filaments of the cytoskeleton are important of desmosomes
Gap junctions function
Provide linkage between cytoplasmic compartment of two cells, formed from proteins called connexons that form a tube between cell, important for cell communication
2 things a cell must do to function efficiently
Control its internal environment, control its interactions with the external environment, control what goes in and out
Plasma membrane lipid bilayer proteins
Some proteins associate with the membrane, some traverse the membrane with one part exposed on the inner cytoplasmic side and other on outside of cell
Phospholipid molecule
Amphipathic
Amphipathic molecule
Contain hydrophobic and hydrophilic regions
Membranes are fluid, not static, influenced by 3 things
Chemical structure of the phospholipid, how much cholesterol is in the environment. The temperature of local environment (move lateral, rarely flip flop)
Lipid composition in membrane
Membranes with more unsaturated fatty acids (kink in C double bond, can{t pack tightly) are more fluid than those with saturated fatty acids (think butter)
Cholesterol amphipathic molecule
Hydrophobic functional groups (CH3= and hydrophilic function groups (OH), reduces membrane fluidity at 37C, can prevent tight packing at lower temps, prevents too much moving at higher temps and packing at lower temps
Transmembrane proteins
Specialize proteins arranged throughout membrane as they straddle the membrane, also have hydrophobic and hydrophilic regions like phospholipids
Structure of transmembrane protein
N’terminus on extra cellular side, C’terminus on cytoplasmic side, alpha helix coils in part next to internal part of membrane
