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2.1 U.1 Molecular biology explains living processes in terms of the chemical substances involved
2.1 U.1 Molecular biology explains living processes in terms of the chemical substances involved
Be able to:
Define “molecular biology.”
Compare the benefits of a reductionist and systems approach to studying biology.
Recognize common functional groups.
Draw skeletal molecular structures from full structure diagrams
Molecular biology involves the explaining of biological processes from the structures of the molecules and how they interact with each other. There are many molecules important to living organisms including
water
carbohydrates
lipids
proteins
nucleic acids
Biological processes are regulated by enzymes, whose expression is controlled by gene activation. The relationship between genes and proteins are important in the regulation of system functions. Molecular biologists break down biochemical processes into their component parts known as reductionism. When they look at the sum of all these reactions as a whole, they can study the emergent properties of that system.
Systems biology focuses on complex interactions within biological systems, using a more holistic perspective approach to biological and biomedical research and how these interactions give rise to the function and behavior of that system. Reductionist thinking and methods form the basis for many of the well-developed areas of modern biology. This implies the study of areas that make up smaller spatial scales and is very specific and specialized.
2.1 U.2 Atoms can form four covalent bonds allowing a diversity of stable compounds to exist.
2.1 U.2 Atoms can form four covalent bonds allowing a diversity of stable compounds to exist.
Be able to:
Outline the number and type of bond carbon can form with other atoms.
An organic compound is a compound that contains carbon and is found in living things. Carbon is very unique in its bonding properties. The most important is its ability to form long chains of carbon. No other element can bond in this way.
Carbon has an extremely carbon-carbon bond. This allows carbon to make up many of the basic building blocks of life (fats, sugars, etc). Since carbon-carbon bonds are strong and stable, carbon can form an almost infinite number of compounds
2.1 U.3 Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids.
2.1 U.3 Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids.
Be able to:
List the four major classes of carbon compounds used by living organisms.
Carbohydrates
Carbohydrates are composed of carbon, hydrogen and oxygen
The general formula for carbohydrates is (CH2O)n.
Many carbohydrates are used for energy or structural purposes
Lipids
Lipids are compounds that are insoluble in water but soluble in nonpolar solvents.
Some lipids function in long-term energy storage. Animal fat is a lipid that has six times more energy per gram than carbohydrates.
Lipids are also an important component of cell membranes.
Some examples of lipids are triglycerides, steroids, waxes and phospholipids
Animal fats (saturated) are solid at room temperature and plant fats (unsaturated) are liquid at room temperature
Proteins
Proteins are composed of one or more chains of amino acids
All proteins are composed of carbon, hydrogen, oxygen and nitrogen
Proteins are distinguished by their “R” groups. Some of these also contain sulfur
Nucleic Acids
Nucleic acids are composed of smaller units called nucleotides, which are linked together to form a larger molecule (nucleic acid).
Each nucleotide contains a base, a sugar, and a phosphate group. The sugar is deoxyribose (DNA) or ribose (RNA). The bases of DNA are adenine, guanine, cytosine, and thymine. Uracil substitutes for Thymine in RNA
They are made from carbon, hydrogen, oxygen, nitrogen and phosphorus.
Roles of Elements
Sulphur (S): Found in certain amino acids (cysteine and methionine), allowing proteins to form disulphide bonds
Calcium (Ca): Found in bones and teeth, also involved in neurotransmitter release in synapses
Phosphorus (P): Component of nucleic acids and cell membranes
Iron (Fe): Found in haemoglobin (animals), allowing for oxygen transport
Sodium (Na): Involved in the generation of nerve impulses in neurons.
2.1 U.4 Metabolism is the web of all the enzyme-catalysed reactions in a cell or organism.
2.1 U.4 Metabolism is the web of all the enzyme-catalysed reactions in a cell or organism.
Be able to:
Define metabolism and catalysis.
State the role of enzymes in metabolism.
Metabolism is the sum of all chemical reactions that occur in living organisms. Metabolism describes the totality of chemical reactions that occur within a living organism in order to maintain life These reactions are catalyzed by enzymes and allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Many of these reactions occur in the cytoplasm, but some are extracellular including digestion and the transport of substances into and between different cells.
Enzymes are used to speed up the process of breaking down things (e.g.: pepsin and trypsin help break down proteins as you go through catabolic metabolism, starting from your long peptide chain all the way down to its building blocks, the amino acids.
2.1.U5 Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.
2.1.U5 Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.
Define anabolism, monomer and polymer.
Describe condensation (dehydration synthesis) reactions.
Using simple shapes to represent monomers, diagram a condensation reaction.
Anabolic reactions describe the set of metabolic reactions that build up complex molecules from simpler ones
The synthesis of organic molecules via anabolism typically occurs through condensation reactions
Anabolic reactions require energy as you are building large molecules from small ones (takes energy to build things). Some anabolic processes are protein synthesis,
Monosaccharides are joined via glycosidic linkages to form disaccharides and polysaccharides
Amino acids are joined via peptide bonds to make polypeptide chains
Glycerol and fatty acids are joined via an ester linkage to create triglycerides
Nucleotides are joined by phosphodiester bonds to form polynucleotide chains
If you can’t remember which one is which, think anabolic steroids are used to build muscles in athletes and bodybuilders and catapults are used to break down walls in wars.
Condensation is a chemical process by which 2 molecules are joined together to make a larger, more complex, molecule, with the loss of water. It is the basis for the synthesis of all the important biological macromolecules (carbohydrates, proteins, lipids, nucleic acids) from their simpler sub-units.
In all cases of condensation, molecules with projecting -H atoms are linked to other molecules with projecting -OH groups, producing H2O, ( H.OH ) also known as water, which then moves away from the original molecules.
2.1.U6 Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers.
2.1.U6 Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers.
Be able to:
Define catabolism.
Contrast anabolism and catabolism.
Describe hydrolysis reactions.
Using simple shapes to represent monomers, diagram a hydrolysis reaction.
Catabolism is a metabolic reaction that break down larger molecules into smaller ones or their component parts
Catabolic reactions release energy which can sometimes be captured in the form of ATP. The breakdown of organic molecules through catabolism typically occurs through the hydrolysis reactions
Hydrolysis reactions require the consumption of water molecules to break the bonds within the polymer
Examples of catabolic reactions are digestion of food, cellular respiration, and break down of carbon compounds by decomposers
2.1.A1 Urea as an example of a compound that is produced by living organisms but can also be artificially synthesized.
2.1.A1 Urea as an example of a compound that is produced by living organisms but can also be artificially synthesized.
Be able to:
Draw the molecular structure of urea.
Describe how urea can be synthesized by living and artificial mechanisms.
In 1828, Friedrich Wöhler, a German physician and chemist by training, published a paper that describes the formation of urea, known since 1773 to be a major component of mammalian urine, by combining cyanic acid and ammonium in vitro. In these experiments the synthesis of an organic compound from two inorganic molecules was achieved for the first time. These results weakened significantly the vitalistic hypothesis on the functioning of living cells, Vitalism was a doctrine that dictated that organic molecules could only be synthesised by living systems. It was believed that living things possessed a certain “vital force” needed to make organic molecules. Organic compounds were thought to possess a non-physical element lacking from inorganic molecules.
Urea is a component of urine which is produced when there is an excess of amino acids in the body; way to secrete nitrogen. A series of enzyme catalyzed reactions produce urea in the liver, where it is transported by the blood to the kidney, where it is filtered out and excreted in the urine.
Urea can be produced artificially through different chemical reactions; however, the product is the same.
Urea is mainly used as a nitrogen source in fertilizer
2.1.S1 Drawing molecular diagrams of glucose, ribose, a saturated fatty acid and a generalized amino acid.
2.1.S1 Drawing molecular diagrams of glucose, ribose, a saturated fatty acid and a generalized amino acid.
Be able to:
Draw the molecular diagram of ribose.
Draw the molecular diagram of alpha-glucose.
Draw the molecular diagram of a saturated fatty acid.
Identify the carboxyl and methyl groups on a fatty acid.
Glucose
Is a reducing sugar that contains C6H12O6
Most commonly found in a ringed structure and is the main product formed by photosynthesis
Energy molecule used in aerobic respiration
Monomer of starch, glycogen, and cellulose
Fatty Acids
Main component of triglycerides and phospholipids
Fatty acids are non-polar and therefore hydrophobic
Chains consist of covalently bonded carbon with hydrogen
Saturated fatty acid’s are all single bonds and are therefore saturated with hydrogen.
Unsaturated fatty acid’s contain a double bond or double bonds.
Amino Acid
Composed of an amine (NH2) group, a carboxyl (COOH) group, and an R group.
20 amino acids exist that compose all proteins
Each amino acid differs because the R groups are different
2.1.S2 Identification of biochemical such as sugars, lipids, or amino acids from molecular drawings.
2.1.S2 Identification of biochemical such as sugars, lipids, or amino acids from molecular drawings.
Be able to:
Identify the four major classes of carbon compounds used by living organisms from given diagrams (examples will include D-ribose, alpha glucose, beta glucose, triglycerides, phospholipids and steroids).
State the generalized chemical formula of the carbohydrates. Identify the following carbohydrates from molecular
drawings.
D-ribose
alpha glucose
beta glucose
cellulose
glycogen
amylose starch
amylopectin starch
Compare the relative amount of oxygen atoms in lipids to the amount in carbohydrates.
Identify the following lipids from molecular drawings.
Triglycerides
phospholipids
steroids
Carbohydrates
The structure of complex carbohydrates may vary depending on the composition of monomeric subunits.
Glucose
Fructose
Galactose
Polysaccharides may differ according to the type of monosaccharide they possess and the way the subunits bond together. The generalized formula for carbohydrates is CH2O. All carbohydrate contain C, H and O
Glucose monomers can be combined to form a variety of different polymers – including glycogen, cellulose and starch
Lipids
Lipids contain C, H and O as well, but in different ratios and much less O then carbohydrates.
Lipids can be roughly organised into one of three main classes:
a. Compound lipids – Esters of fatty acids, alcohol and additional groups (e.g. phospholipids and glycolipids)
b. Simple (neutral) lipids – Esters of fatty acids and alcohol (e.g. triglycerides and waxes)
c. Derived lipids – Substances derived from simple or compound lipids (e.g. steroids and carotenoids)
Proteins
Amino acids join together by peptide bonds which form between the amine and carboxyl groups of adjacent amino acids. Proteins also contain C,H, O but they all have N. Some proteins also contain S in their R-groups
The fusion of two amino acids creates a dipeptide, with further additions resulting in the formation of a polypeptide chain. The subsequent folding of the chain depends on the order of amino acids in a sequence (based on chemical properties)
Nucleic Acids
There are two varieties: ribonucleic acid, or RNA, and deoxyribonucleic acid, or DNA. These polymers are long chains of components called bases, of which there are only five types. RNA is a single-strand molecule; DNA is a spiral of two cross-connected strands.
Nucleotides form bonds between the pentose sugar and phosphate group to form long polynucleotide chains.
In DNA, two complementary chains will pair up via hydrogen bonding between nitrogenous bases to form double strands. This double stranded molecule may then twist to form a double helical arrangement
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