da Sathvik Srikalyani mancano 6 anni
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Plasmodesmata
Primary cell wall > secondary cell wall > plasma membrane
Chloroplast
Chloroplasts are the site of photosynthesis which converts solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic molecules such as sugars from CO2 and water.
gap junctions
tight junctions
desmosomes
Cytoskeletal elements
Intermediate filaments
made of one of several different proteins of the keratin family. Maintenance of cell shape, anchorage of nucleus and certain other organelles and formation of nuclear lamina.
Microfilaments
: made of actin. Maintain cell shape, changes cell shape, muscle contraction, cytoplasmic streaming, cell motility, cell division.
Microtubules
made of tubulin, maintains the shape of the cell, cell motility, chromosome movement in cell division, and organelle movements
Components of ECM include Proteoglycan molecule, Proteoglycan complex, and collagen fiber.
Mitochondria
Mitochondria is the site of cellular respiration, which uses O2 to create ATP by extracting energy from sugars and fats
Vacuoles
a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.
Central vacuole
develops by a coalescence of smaller vacuoles. The solution inside the central vacuole, called cell sap, is the plant cell’s main repository of inorganic ions, including potassium and chloride. Also absorb water.
Contractile vacuole
vacuole pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell.
Food vacuoles
contains digestive enzymes that digest nutrients
Endoplasmic Reticulum
network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis.
Smooth ER
The Smooth helps in protein and lipid storage.
Rough ER
The Rough makes and packages proteins.
Peroxisomes
produces hydrogen peroxide as a by-product and then converts it to water.
Lysosomes
digestive organelle where macromolecules are hydrolyzed.
Golgi
: is active in synthesis, modification, sorting, and secretion of cell products.
Ribosomes
complexes that produce proteins. Can be bound to ER or free floating.
Plasma membrane
is the membrane that encloses the cell and allows certain molecules to enter or exit the cell.
Nucleus
contains the DNA of the cell.
methanogens survive in anaerobic conditions, usually converting CO2 to CH4
Halophiles live very well in salty conditions
Facultative anaerobes can either survive in oxygen or in a lack of oxygen.
Obligate anaerobes can only survive when there is no oxygen present.
Obligate aerobes can only survive when oxygen is present
its ability to bond to 4 other chemical bonds gives carbon the ability to form versatile bonds
Its small atom size and 4 valence electrons which can be shared by other atoms that can share electrons creating covalent bonds
The electron configuration of carbon gives it covalent compatibility with many different elements
Heat
When bonds form, heat is released
When water absorbs heat, hydrogen bonds break
Heat of Vaporization
Water also has a high heat of vaporization-the quantity of heat a liquid must absorb for 1g of it to be converted to the gas phase. The high heat of vaporization is due to water’s hydrogen bonding abilities with other water molecules. A lot of energy is needed before the H-Bonds are broken before the molecules can exit the liquid state. This property leads to the phenomenon of evaporative cooling, fastest/”hottest” molecules escape reducing average kinetic energy.
Specific Heat
It takes a large amount of energy to cause a change in temperature and this due to its hydrogen bonds. A water molecule can potentially bond to 4 other water molecules. A calorie of heat causes a relatively small change in temperature because much of the ehat is used just to break the bonds before the water molecules can begin to move faster, increasing kinetic energy and thus temperature.
Surface Tension
Related to cohesion is water surface tension because at the surface water i molecules are arranged that they are bonded to molecules next to each other and to the water below. This asymmetry gives water an unusually high surface tension.
Cohesion
Water being a polar molecule, can H-Bond to other polar molecules as well and these feature is known as cohesion.
Adhesion
A water molecule can bond to 4 other water molecules through H-bonds because of the partial charges. This keeps water close together and gives way to the property of adhesion.
Messelson-Stahl Experiment
Other Important Experiments
Hershey and Chase:
Proved that DNA was the source of genetic material. During their experiment they tagged a virus (bacteriophage). They tagged the protein coat of the virus with 35S and tagged the DNA with 32P. Then they observed the bacteriophage attach on to a bacteria observed the 32P tagged DNA had entered the bacteria. The heavy pellet of in a test tube was radioactive
Experiments dealing with proteins
Proteins
Other Macro-molecules
Lipids
Steroids
A carbon skeleton consisting of 4 fused rings. May occur as components of membranes in the form of cholesterol.
Phospholipids
The hydrophobic fatty acids don’t interact with water but instead interact with other fatty acid tails. The negatively charged phosphate group interact with water The phosphate groups face outside the cell and inside the cell too.
Fat vs Fatty acid
A fat consists of a glycerol molecule attached to fatty acids. Fatty acids are long carbon skeletons that have a carboxyl group at one end that can attach to the OH groups of glycerols
components of triglyceride, including saturated and unsaturated fatty acids
Structure
A triglyceride is composed of a glycerol attached to 3 fatty acid tails. A phospholipid consists of a glycerol, 2 fatty acids, and a phosphate group.-which has a negative electrical charge.
why some triglycerides are liquid at room temperature and some solid
Saturated fats are solid at room temperature because they have no kinks in their fatty acid tails due to the lack of carbon double bonds. This leads to the fatty acid tails being flexible and be able to pack together in solidify. Unsaturated fats are liquid at room temperature because their fatty acid tails have kinks due to the carbon double bonds with leads to reduced flexibility and thus cannot pack together and solidify.
A triglyceride consists of glycerol bonded to three fatty acid chains. Saturated fats are those triglycerides that have fatty acid chains with no carbon double bonds. It’s SATURATED with hydrogens. Unsaturated fats are triglycerides with one or more fatty acid tail that has carbon double bonds. The double bonds in unsaturated fats are mostly cis but when saturated fats become hydrogenated, some trans carbon double bonds can form.
Monomers
Do not have any and that's why lipids are not considered polymers
Biological molecules that don’t mix well with water and are hydrophobic because they mostly consist of hydrocarbon chains.
Nucleic Acids
DNA and RNA
DNA VS RNA
DNA is composed of a deoxyribose sugar, is helical in shape, and runs antiparallel. It has the base pair Thymine. RNA is single stranded, has the ribose sugar, and instead of Thymine, as Uracil. The difference between the two sugars is that in the 2 prime location of the sugar, DNA lacks an oxygen so it’s just H at the 2nd carbon. Ribose has an oxygen so at the 2nd carbon there's an OH.
Nucleotide
Components of nucleotide
Different from nucleoside
A nucleoside has all the components of a nucleotide except a phosphate group
Nucleotide consists of a nitrogenous base, a 5 carbon sugar, and a phosphate group.
effects of physical and chemical agents on protein folding
Polarity effect on protein folding
If proteins are removed from an aqueous solution to a nonpolar environment, a protein refolds so that the hydrophobic regions now face outward toward the solvent.
Proteins and can only fold and function under certain conditions. If the temperature, pH, or salt concentration, etc become too extreme...the bonds holding the proteins together are destroyed causing the protein to unravel. This is called denaturation.
Bonding in Proteins
Covalent peptide bonds between main groups of amino acids in the primary structure. Hydrogen bonding between hydrogen and oxygens of main group in secondary structure. Hydrogen, ionic, and Van der Waal interactions between R groups in tertiary structure. R groups interact in quaternary structure.
Monomer
Amino acids
Formation of polymer from amino acids
Amino acids are bonded together through dehydration synthesis when an OH from a carboxyl group is bonded to an H from an amino group of another amino acid.
Side chain
R- group
Bonds between R groups
Hydrogen bonds between polar R groups, hydrophobic interactions and Van der Waals between non-groups, and ionic bonds between acidic and basic R groups
Main chain
The main chain of an amino acid consists of the amino group and then carboxyl group
The building blocks on proteins are called amino acids. They consist of an amino group, a carboxyl group, and an R group. Amino acids bond with other amino acids via the amino and carboxyl groups (main chain and polypeptide backbone) through dehydration reactions. The amino group is positively charged and the carboxyl group is negatively charged. It’s a zwitterion.
Griffith, Avery, McCleod and McCarty
Took two strain two strains of streptococcus pneumoniae. R strand and S strand. The strand had a capsule (Smooth) and the R did not. The S strain proved to be pathogenic when injected in mice. Living S cells in mice illes the mice, living R cells in mice had no effect on mouse health, heat killed S cells left the mice healthy too, BUT heat killed S cells injected with a mixture of R cells left the mice dead. This proved that the R bacteria had been transformed by some element from the S cells (unknown at the time but later proved to be DNA), was inherited by the R cells and enabled R cells to form capsules too
Proof of semi conservative. The two cultured bacteria in a heavy 15N and then transferred the bacteria to regular 14N. After each replication, the test tube was centrifuged to observe the location of the bands. After the first replication the band was in the middle because it was a complete mix of 14N and 15nN. After the second replication, there was a middle band and a higher band because now there was DNA with combo fo 15n and 14N in the middle and just 14N DNA at the top of the test tube.
