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Biochemistry
Biochemistry is the study of the structure, composition and chemical processes in all living organisms. It covers the structures and functions of various cellular components, including proteins, carbohydrates, nucleic acids, lipids, and other biomolecules.
8,065 Questions
What enzyme unravels the DNA helix?
DNA Helicase.
- an enzyme, is responsible for unwinding and unzipping the double helix.
Is citric acid inorganic or organic?
From a chemical perspective? It's an organic compound, it contains carbon.
Was it organically produced, that is, made without pesticides? Maybe. Probably not if the label doesn't say.
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I am not sure of understanding the question :
If organic refers to 'organically grown' or 'certified organic farming', etc :
May be citric acid can be extracted from some organically grown fruits in a way that would match an organic certification standard, and therefore qualify for an 'organic' labelling. Nevertheless, I would be quite puzzled at reading this on some food packaging.
An other way of understanding the question is that there can be 'organic' sources for citric acid (ex. some fruits) by contrast with 'non organic' sources of citric acid (chemical synthesis).
According to USDA National Organic Program regulation 205.605, nonagricultural citric acid may be used as an ingredient in processed products labeled as "organic" or "made with organic citric acid" only if it is produced by microbial fermentation of carbohydrate substances.
Where are Reactants written where on a chemical equation?
Reactants are typically written on the left side of a chemical equation, separated from the products by an arrow pointing towards the products. It represents the starting substances that undergo a chemical reaction to form the products on the right side of the equation.
All the enzymes are protein or protein conjugates(with lipids or carbohydrates)
Pectin (from Greek πηκτικός - pektikos, "congealed, curdled"[1]) is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot[2]. It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits, and is used in food as a gelling agent particularly in jams and jellies. It is also used in fillings, sweets, as a stabilizer in fruit juices and milk drinks and as a source of dietary fiber.Contents [hide]
In Biology
In plant cells, pectin consists of a complex set of polysaccharides (see below) that are present in most primary cell walls and particularly abundant in the non-woody parts of terrestrial plants. Pectin is present throughout primary cell walls but also in the middle lamella between plant cells where it helps to bind cells together.
The amount, structure and chemical composition of the pectin differs between plants, within a plant over time and in different parts of a plant. During ripening, pectin is broken down by the enzymes pectinase and pectinesterase; in this process the fruit becomes softer as the middle lamella breaks down and cells become separated from each other. A similar process of cell separation caused by pectin breakdown occurs in the abscission zone of the petioles of deciduous plants at leaf fall.
Pectin is a natural part of human diet, but does not contribute significantly to nutrition. The daily intake of pectin from fruit and vegetables can be estimated to be around 5 g (assuming consumption of approximately 500 g fruit and vegetable per day).
In human digestion, pectin goes through the small intestine more or less intact. Pectin is thus a soluble dietary fiber.
Consumption of pectin has been shown to reduce blood cholesterol levels.[citation needed] The mechanism appears to be an increase of viscosity in the intestinal tract, leading to a reduced absorption of cholesterol from bile or food.[3] In the large intestine and colon, microorganisms degrade pectin and liberate short-chain fatty acids that have positive influence on health (prebiotic effect).[citation needed]
In Chemistry
Pectins are a family of complex polysaccharides that contain 1,4-linked α-D-galactosyluronic acid residues. Three pectic polysaccharides have been isolated from plant primary cell walls and structurally characterized. These are:
Homogalacturonans
Substituted galacturonans
Rhamnogalacturonans
Homogalacturonans are linear chains of α-(1-4)-linked D-galacturonic acid[4].
Substituted galacturonans are characterized by the presence of saccharide appendant residues (such as D-xylose or D-apiose in the respective cases of xylogalacturonan and apiogalacturonan) branching from a backbone of D-galacturonic acid residues[5][6].
Rhamnogalacturonan I pectins (RG-I) contain a backbone of the repeating disaccharide: 4)-α-D-galacturonic acid-(1,2)-α-L-rhamnose-(1. From many of the rhamnose residues, sidechains of various neutral sugars branch off. The neutral sugars are mainly D-galactose, L-arabinose and D-xylose, the types and proportions of neutral sugars varying with the origin of pectin[7][8][9].
Another structural type of pectin is rhamnogalacturonan II (RG-II), which is a less frequent complex, highly branched polysaccharide[10]. Rhamnogalacturonan II is classified by some authors within the group of substituted galacturonans since the rhamnogalacturonan II backbone is made exclusively of D-galacturonic acid units[11].
Isolated pectin has a molecular weight of typically 60–130,000 g/mol, varying with origin and extraction conditions.
In nature, around 80% of carboxyl groups of galacturonic acid are esterified with methanol. This proportion is decreased more or less during pectin extraction. The ratio of esterified to non-esterified galacturonic acid determines the behavior of pectin in food applications. This is why pectins are classified as high- vs. low-ester pectins – or in short HM vs. LM-pectins, with more or less than half of all the galacturonic acid esterified.
The non-esterified galacturonic acid units can be either free acids (carboxyl groups) or salts with sodium, potassium or calcium. The salts of partially esterified pectins are called pectinates, if the degree of esterification is below 5% the salts are called pectates, the insoluble acid form, pectic acid.
Some plants like sugar beet, potatoes and pears contain pectins with acetylated galacturonic acid in addition to methyl esters. Acetylation prevents gel-formation but increases the stabilising and emulsifying effects of pectin.
Amidated pectin is a modified form of pectin. Here, some of the galacturonic acid is converted with ammonia to carboxylic acid amide. These pectins are more tolerant of varying calcium concentrations that occur in use.[12]
To prepare a pectin-gel, the ingredients are heated, dissolving the pectin. Upon cooling below gelling temperature, a gel starts to form. If gel formation is too strong, syneresis or a granular texture are the result, whilst weak gelling leads to excessively soft gels. In high-ester pectins at soluble solids content above 60% and a pH-value between 2.8 and 3.6, hydrogen bonds and hydrophobic interactions bind the individual pectin chains together. These bonds form as water is bound by sugar and forces pectin strands to stick together. These form a 3-dimensional molecular net that creates the macromolecular gel. The gelling-mechanism is called a low-water-activity gel or sugar-acid-pectin gel.
In low-ester pectins, ionic bridges are formed between calcium ions and the ionised carboxyl groups of the galacturonic acid. This is idealised in the so-called “egg box-model”. Low-ester pectins need calcium to form a gel, but can do so at lower soluble solids and higher pH-values than high-ester pectins.
Amidated pectins behave like low-ester pectins but need less calcium and are more tolerant of excess calcium. Also, gels from amidated pectin are thermo-reversible – they can be heated and after cooling solidify again, whereas conventional pectin-gels will afterwards remain liquid.
High-ester pectins set at higher temperatures than low-ester pectins. However, gelling reactions with calcium increase as the degree of esterification falls. Similarly, lower pH-values or higher soluble solids (normally sugars) increase gelling speed. Suitable pectins can therefore be selected for jams and for jellies, or for higher sugar confectionery jellies.
Why is rubisco the most important enzyme on earth?
Because, if no Rubisco is avalible to fix CO2, the Calvin Cycle would not be in action, photosynthesis would be incomplete, the ususal products: Proteins, Lipids, Carbohydrates (O2) and vitamins/minerals would not be made. After all the food stores ran out, all Hetrotrophs and Autotrophs would have no food to survive.
So Basically, Rubisco is the bain of life.
What happens to your body if you doesn't get vitamin A?
Food sources :
Beef liver
Chicken liver
Egg substitute
fortified milk
Cheddar cheese
egg
carrots
mango
spinach
cantaloupe
kale
red pepperSource(s):http://healthlink.mcw.edu/article/980793…
What molecules make up the rails or sides of the DNA structure?
Molecules are the units that your DNA is made up of. DNA is made up of two groups: purines and pyrimidines (which in turn are made up of thymine, uracil, cytosine, guanine).
DNA is a molecule, a very large and complex molecule .
Does proteins determine Genes?
No, proteins do not determine genes. Genes are segments of DNA that encode instructions for making proteins. Proteins are the products of gene expression, meaning that genes are responsible for determining the sequence and structure of proteins.
Examples:
- Catalase. It catalyzes the decomposition of hydrogen peroxide into water and oxygen.
2H2O2 -> 2H2O + O2
One molecule of catalase can break 40 million molecules of hydrogen peroxide each second.
- Carbonic anhydrase. It is found in red blood cells where it catalyzes the reaction
CO2 + H2O ↔ H+ + HCO3−
It enables red blood cells to transport carbon dioxide from the tissues to the lungs. [Discussion]
One molecule of carbonic anhydrase can process one million molecules of CO2 each second.
Acetylcholinesterase. It catalyzes the breakdown of the neurotransmitter acetylcholine at several types of synapses as well as at the neuromuscular junction - the specialized synapse that triggers the contraction of skeletal muscle.
One molecule of acetylcholinesterase breaks down 25,000 molecules of acetylcholine each second. This speed makes possible the rapid "resetting" of the synapse for transmission of another nerve impulse.
Lipases are the enzymes that cleave fats. Fats are known scientifically as lipids, so the enzyme responsible for its break-down is called lipase.
What is a carcinogenic hydrocarbon?
A carcinogenic hydrocarbon is a compound that has the potential to cause cancer. These substances are often found in products of incomplete combustion, such as tobacco smoke or exhaust fumes from vehicles. Examples include polycyclic aromatic hydrocarbons (PAHs) and benzene.
What happens to starch at the molecular level when it is acted upon by amylase?
the amylase degrades the starch
What piece of DNA is made of sugar a phosphate and a base?
A base sugar and phosphate are combined to make up a nucleotide
What are the three monosaccharides in raffinose?
Raffinose is the trisaccharide of fructose, galactose and glucose. Its actual name is: beta-D-fructofuranosyl-O-alpha-D-galactopyranosyl-(1-6)-alpha-D-glucopyranoside.
Colorimetry is the measurement of the wavelength and the intensity of electromagnetic radiation in the visible region of the spectrum. Colorimetry can help find the concentration of substances, since the amount and colour of the light that is absorbed or transmitted depends on properties of the solution, including the concentration of particles in it. A colorimeter is an instrument that compares the amount of light getting through a solution with the amount that can get through a sample of pure solvent. A colorimeter contains a photocell is able to detect the amount of light which passes through the solution under investigation. The more light that hits the photocell, the higher the current it produces, hence showing the absorbance of light. A colorimeter takes 3 wideband readings along the visible spectrum to obtain a rough estimate of a color sample. Pigments absorb light at different wavelengths.
Who discovered the secret of DNA sequencing?
Fred Sanger discovered how to sequence DNA in 1951 after the Ferranti Mark 1 computer was delivered to his lab at the University of Manchester. This computer allowed molecular biology research to be analysed in new ways, which ultimately led to DNA sequencing.
What temperature and pH do enzymes like to work at?
They like to work at or near body temperature with a pH of 7. Since there is a high concentration of water in cells and water's pH is 7, it makes sense that they like 7.
What is the principle involved in the isolation of casein from milk?
It is about isoelectric precipitation. This involves the principle on isoelectric pH of a certain solution. Casein has its isoelectric pH at 4.6. Therefore, it is insoluble in solutions with pH lower than 4.6. The pH of milk is around 6.6 which gives casein the negative charge and makes it a soluble salt. Once you add an acid to the solution, the negative charge of casein becomes neutral, precipitating the neutral protein (casein).
Can all animal cells undergo cellular respiration?
yes, animals, by definition, consume food (carbs, lipids, proteins) so that they can break it down. carbs (specifically glucose) undergo oxidation to put its bond energy into ATP (adenosine tri phosphate).
What is a difference in the structure of proteins and polysaccharides?
Polysaccharides are essentially many carbon sugar "rings" linked together. They are carbohydrates, and our bodies break them down into monosaccharides (single "rings") to gain energy. To provide energy is their main function. In contrast, a peptide bond is formed between two amino acids via dehydration synthesis. Amino acids are the monomers for proteins within the body, who function in part to catalyze reactions and carry out other directions of DNA. Many peptide bonded amino acids = a polypeptide. The most basic difference would be that polypeptides are proteins, where as polysaccharides are carbohydrates.
The characteristic globular shape of a polypeptide is?
determined by its amino acid sequence and interactions between amino acid side chains. The folding of the polypeptide into a specific shape is influenced by factors such as hydrogen bonding, disulfide bridges, and hydrophobic interactions. This globular shape is essential for the proper functioning of proteins in cells.
