cell cycle Flashcards
made of lipids and proteins, phospholipid bilayer, fluid mosaic model (constant movement of different types of molecules in a pattern making it impossible to form a fully impenetrable barrier), semi-permeable
plasma membrane
contains primary genome of the cell. transcription of RNA, controlled import and export of both RNA and proteins
nucleus
3 types: actin (forms filaments that provide cells with mechanical support and driving forces for movement), microtubules (the components of cell skeleton that determine the shape of the cell), intermediate filaments (structural function bear tension to maintain the shape of the cell and anchor nucleus and other organelles)
cytoskeleton
nuclear envelope, rough ER, smooth ER, golgi apparatus,
endomembrane system
lipid membrane that separates nucleus from the cytoplasm
nuclear envelope
protein biosynthesis, vesicles where synthesized proteins are packaged; lipid biosynthesis; primary store of the important secondary messenger Ca2+ in animal cells
rough ER, smooth ER
double membrane, a major site of primary metabolism, oxidative phosphorylation (harnesses the reduction of oxygen to generate ATP), fatty acid catabolism (body accessing energy stored as triglycerides), has a circular genome, evolved from symbiotic relationship with prokaryote
mitochondria
breaks down larger molecules back to useful building blocks, degradation of materials taken into the cell via endocytosis, degredation of misfolded proteins, plants have lytic vacuole instead
lysosome
double membrane, photon antenna complex, site of carbon capture, site of fatty acid biosynthesis, has a circular genome, evolved from symbiotic relationship with prokaryote
chloroplast
beta-oxidation of VLCFAs (process of breaking down very long chain fatty acids), metabolism of ROS (reactive oxygen species=byproducts of aerobic metabolism, oxidative bursts (rapid production of ROS); ROS detoxification
peroxisome
often takes up the majority of plant cell, regulates turgor in cell/plant, primary store of the important secondary messenger Ca2+, stores water and nutrients, stores cytotoxic compounds
vacuole
the process in which cells make proteins through transcription and translation
protein synthesis
DNA is a double helix with the bases on the inside and the sugar-phosphate backbones on the outside of the molecule; bases on the opposite strands are paired by hydrogen bonds between adenine (A) and thymine (T), and between guanine (G) and cytosine (C), the two DNA strands run in opposite directions defined by the 5’ and 3’ groups of deoxyribose
nucleic acid base pairing
takes place on ribosome where mRNA is read and translated into the string of amino acid chains that make up synthesized proteins
translation
recognizes and binds to its corresponding codon in the ribosome, transfers the appropriate amino acid to the end of the growing amino acid chain, then continues (with ribosome) to decode the mRNA molecule until the entire sequence is translated into a protein; aminoacyl AMP creates a charged tRNA using aminoacyl tRNA synthetase
tRNA
initiation=ribosome binds mRNA at start codon, elongation=polypeptide chain elongates by successively adding amino acids, termination=when a stop codon is encountered polypeptide is released and ribosome dissociates
translation
made up of large ribosomal subunit (60S) and small ribosomal subunit (40S); A site=aminoacyl tRNA site, P site=peptidyl tRNA site, E site=exit site
ribosome
initiation tRNA binds eukaryotic initiation factor (elF2), small ribosomal subunit (40S) binds initiator tRNA and multiple other elFs, initiator tRNA and elF2 complex binds the 40S complex, mRNA and associated elFs bind the small ribosomal subunit and elF4E binds the 5’ mRNA cap and polyA binding protein (PABP) binds the polyA 3’ tail of the mRNA, initiator tRNA/small ribosomal subunit bind the mRNA complex and scans the mRNA for first start codon-ribosome scanning requires energy provided by ATP hydrolysis, once the start codon is located, GTP hydrolysis occurs, releasing the elFs and allowing the large ribosomal subunit (60S) to bind to complete the ribosome
initiation of translation
following initiation, the first methionine tRNA is within the P site of the ribosome, the next tRNA binds to the A site along with eEF (elongation factor) if the correct base pairing is achieved between the mRNA codon (proofreading) and the tRNA anti-codon then GTP is hydrolyzed and eEF is released, the tRNA catalyzes the formation of a peptide bond between the amino acids in the P and A sites and the methionine is released from the initiator tRNA, the ribosome translocates down the mRNA molecule three nucleotides so that the E and P sites are now occupied by tRNA’s, tRNA in the E site exits ribosome
elongation of translation
stop codon aligns in the amino-acyl (A) position of the ribosome, release factor (a protein) binds to stop codon in A site, release factor allows growing peptide to be released from the final tRNA and the ribosome, once peptide released the ribosome complex disassembles
termination of translation