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