Ch.3 Proteins & Processes Flashcards
Proteins
polymer of amino acids (amino acids are the monomers)
Polypeptides
chains of amino acids; min ‘ bimum of 51 amino acids required to a be a polypeptide,
4 levels of protein structure
Primary Structure 1 degree: amino acid chains
Secondary structure 2 degree: amino acid chains either form pleated sheets or helices (helix); HELD TOGETHER BY HYDROGEN / BONDS
Tertiary Structure 3 degree: sheets and helices fold to form a protein;
Quaternary Structure degree 4: 2 or more polypeptide chains, associating into ONE larger molecule
Why does protein shape matter so much?
shape determines overall function: specifically for destroying bacteria, needs to be the same shape as it
Difference between RNA and DNA
RNA: has ribs
DNA: deoxy-ribos = missing an oxygen
Nucleic acids
chains of nucleotides; monomers are nucleotides
A C T G nucleic acids and what they bond with
A & T: Adenine and Thymine
C & G: Cytosin and guanine
Uracil
in RNA, equivalent to thymine in DNA
How are chains of nucleic acids held together in DNA?
through hydrogen bonds
mRNA function and definition
messenger RNA: message that leaves nucleus
Messenger RNA molecules carry the genetic information needed to make proteins. They carry the information from the DNA in the nucleus of the cell to the cytoplasm where the proteins are made.
Codon function and definition
tell cell which amino acid goes in chain to get the polypeptide chain outcome
What is translation, where does it occur, and what does it do? What is another name for translation?
WHERE?-Occurs in cytoplasm of the cell
-WHAT? translates RNA to protein (translating from one ‘cellular’ language to another)
-HOW? translation is protein synthesis
What is transcription, where does it occur, and what does it do?
-WHERE? occurs in nucleus
-WHAT? takes it from nucleic acid to nucleic acid (DNA TO RNA) which is the same cellular language
What happens if the polypeptide chain doesn’t fold properly into the protein?
this is a mutation: won’t be folded which means it can’t fully function or it might die
Three major groups of Lipids and properties
fats, phospholipids, steroids
NOT MACROMOLECULES
-All non polar: won’t dissolve in water
Hydrophobic
What is the phospholipid bilayer of the cell membrane? (Nuclear membrane)
Seperates extracellular fluid from intracellular fluid: acts as a barrier
Because the extracellular fluid is essentially water, only the hydrophilic heads can be in it and the hydrophilic tails are tucked in
Structure of the phospholipid molecule
two tails: hydrophobic, no polar regions
Hydrophilic head: has polar regions
Rough Endoplasmic Reticulum
folded layers of membrane where proteins are FOLDED/ASSEMBLED
studded with ribosomes
Cytosol
fluid in which the cell’s internal structures are suspended: intracellular fluid
Microtubules in Neurons
tiny tube that transports molecules and helps give the cell its shape (part of the cytoskeleton)
Golgi body of the neuron
same as Golgi apparatus
tells cells where proteins should go
Membranous structure that PACKAGES protein molecules for transport
Lysosomes of the neuron
sacs containing digestive enzymes that break down wastes; if it bursts through the phospholipid membrane the cell will digest itself
Microfilaments of the neuron
threadlike fibers making up much of the cell’s skeleton
Cytoplasm
everything between the plasma membrane and nucleus
Chromatim
untangles chromosomes?f
Nucleolus
produces ribosomal subscripts
Break down of the ER, Golgi apparatus, vesicles, and lysosomes metaphorical functions
ER: assembly/protein folding into vesicles
Golgi: shipping and receiving, sorts/modifies proteins, directs it where it should go
Vesicles: transport (sacs made of membranes)
Lysosymes: recycling center of dead tissue/organelles, digestive enzymes
What synthesizes polypeptides?
ribosomes
Transcription steps 1-4
1: DNA UNCOILS to expose a gene, a sequence of nucleotide baes that encode a protein
2: one strand of the gene serves as a template for transcribing a molecule of mRNA
3: the mRNA leaves the nucleus and comes in contact with ribosomes in the endoplasmic reticulum
4: as a ribosome moves along the mRNA, it translates the bases into a specific amino acid chain, which forms the protein
Exocytosis
Difference between myelinated and unmyelinated in axon potential propagation
Action potential propagation along unmyelinated axons requires activation of voltage-gated sodium channels along the entire length of the axon. In sharp contrast, action potential propagation along myelinated axons requires activation of voltage-gated sodium channels only in the nodal spaces.
types of passive transport
diffusion, facilitated diffusion: all don’t require energy
facilitated diffusion require transport proteins, move from high concentration to low concentration facilitated by carrier proteins or pores in the membran
diffusion, direction of concentration gradient: This spread of particles through random motion from an area of high concentration to an area of lower concentration
function of trans membrane proteins
some proteins are embedded in and span the cell; some proteins change shape when other chemicals bind to them, others change shape in response to changes in electrical charge or temperature
channel, gated channel, pump
channel: opening in a protein embedded in the cell membrane that allows thew passage of ions: they have specificity for ions; certain ions have to go through certain channels to pass A leaky channel always remains open for substances and ions, whereas the gated-ion channels open in response to the specific changes in the membrane potential of the channel.
Gated channel: protein embedded in a cell membrane that allows substances to pass through on some occasions but not others
Pump: protein in the cell membrane that ACTIVELY transports a substance across the membrane, against its concentration gradient
sodium potassium pump function
The sodium-potassium pump is a trans-membrane protein that helps establish the resting membrane potential of cells, particularly neurons. In a process that requires ATP, the pump moves three sodium ions out of the cell for every two potassium ions it brings in.
active transport
requires energy, Both active transport and facilitated diffusion do use proteins to assist in transport. However, active transport works against the concentration gradient, moving substances from areas of low concentration to areas of high concentration.
Define equilibrium
equilibrium, of molecules on both sides of the membrane. At equilibrium, movement of molecules does not stop. At equilibrium, there is equal movement of materials in both directions, maintaining equal concentration.
Ligand
binds to receptor site to alter protein shape
