Any biological molecule that has low solubility in water and high solubility in non polar organic solvents. Six major groups: fatty acids, triacylglycerols, phospholipids, glycolipids, steroids, and terpenes.
Building blocks for most lipids. They usually have an even number of carbons, and humans have a maximum of 24. They can be saturated or unsaturated.
Fats and Oils are constructed from a 3 carbon backbone called glycerol, which is attached to 3 fatty acids. Their fcn is to store energy, thermal insulation, and padding to an organism.
TRICLYGLYCEROLS OR TRIGLYCERIDES
Built from glycerol backbones but a polar phosphate group replaces one of the fatty acids. One end is polar and the fatty acid side is non polar, this is called amphipathic. Which is well suited for membranes.
Similar to Trigylcerides except that they have one or more carbohydrates attached to the 3-carbon glycerol backbone instead of a phosphate group. Also amphipathic and found in membranes of myelinated cells of human nerves.
Are a 4-ringed structure. They include some hormones of Vitamin D and Cholesterol, an important membrane component.
6th class of lipis include Vitamin A for vision.
Include: Prostaglandins, thromboxanes, and leukotrienes. They are released from cell membranes as local hormones that regulate blood pressure, body temp, and smooth muscle contractions.
Transport lipids because insoluble in aqueous solutions. It contains a lipid core and surrounded by a hydrophilic shell of phospholipids and apoproteins. Note the greater the ratio btwn lipid:protein the lower the density. In humans called chylomicrons (VLDL, LDL, and HDL)
Built from a chain of amino acids linked together by peptide bonds. 10 of these amino acids are essential, therefore can not be manufactured and need to be ingested directly.
Primary Structure: number and sequence in a polypeptide Secondary Sructure: Alpha Helix(lie alongside ea other) or Beta Sheets(strands lie in the same direction or opposite direction parallel. Tertiary Structure: 3-D w/curls and folds assisted by proline Quaternary Structure: turns
AMINO ACID STRUCTURES
1. Covalent Disulfide Bonds-btwn 2 cysteine amino acids on different parts of the chain 2. Electrostatic interactions mostly btwn acidic and basic side chains 3. Hydrogen Bonds 4. van der Waals forces 5. Hydrophobic side chains pushed away from water
Forces creating the Tertiary Structure
Conformation is disrupted, usually secondary, tertiary, and quaternary. Amino acid sequence places a crucial role in structure
Fcn as enzymes, hormones, membrane pumps and channels, membrane receptors, intercellular and intracellular transport and storage, osmotic regulators, in human responses, etc.
Made from long polymers. They maintain and strengthen cellular and matrix structure. For example, Collagen is the most abundant structural protein in the human body.
Proteins with carbohydrate groups attached. A component of cellular plasma membranes. Proteoglycans are also a mixture but more than 50% carbohydrates, usually major component in extracellular matrix.
Proteins which require a posthetic heme group in order to fcn (hemoglobin and cytochromes of the electron transport chain in the inner-membrane of mitochondria.
Also known as sugars made with carbons and water. Glucose is the most common six carbon sugar and accounts for 80% of the carbs absorbed by humans.
The cell can oxidize glucose transferring its chemical energy to a more readily usable form, ATP. If cell has sufficient ATP, glycogen is the polymerized polysaccharide or converted to fat. Found in muscle and liver cells.
Liver regulates blood glucose level and one of the few cells capable of reforming glucose from glycogen and releasing it back into the blood stream. Certain epithelial cells in the digestive tract and the proximal tube of kidney can absorb glucose against a conc. gradient. (done via 2ndary active transport while all others are facilitated diffusion
GLUCOSE AND GLYCOGEN
Increases the rate of facilitated diffusion for glucose and other mono saccharides. Without insulin only neural and hepatic cells have the ability to absorb sufficient amounts of glucose via facilitated diffusion.
Form starch and cellulose from glucose. Starch has 2 forms: amylose and amylopectin. Amylose is an isomer of cellulose that may be branched or unbranched and has the same alpha linkages as glycogen. Amylopectic resemble glycogen but diff branching .
PLANTS AND STARCH
Has beta linkages. Animals have the enzymes to digest the alpha linkages of starch and glycogen but not the beta linkages of cellulose. Some animals like cows and termites have bacteria in their digestive system that release an enzyme to digest these beta linkages.
PLANTS AND CELLULOSE
Have 3 components: 5-C Sugar, nitrogenous base, and a phosphate group. The most common nucleotides are adenine, guanine, cytosine,thymine, and uracil. Nucleotides form polymers to create nucleic acids, DNA and RNA. Written in the 5'-->3' direction.
Nucleotides are joined by phosphodiester bonds between the phosphate group and of one nucleotide and the 3rd Carbon of the pentose of the other nucleotide forming long strands.
Two strands are joined by hydrogen bonds to make a double helix. Adenine and thymine form hydrogen bonds, while cysteine and guanine form 3. DNA is written such that the top runs 5'-->3' while the bottom runs 3'-->5'.
One strand and no helix formed and uracil replaces thymine. Other important nucleotides include ATP: source of readily available energy in a cell; cyclic AMP: important in 2nd msger systems; NADH and FADH2: coenzymes involved in Kreb's cycle.
RNA and Other Important Nucleotides
Dissolved inorganic ions inside and outside the cell. Assist in transport of substances entering and existing the cell. They give strength when solidify and act as cofactors assisting enzymes or protein fcn.
Canabolic is breaking down of molecules to smaller components (e.g. hydrolysis and condensation); whereas, anabolic is constructing molecules from smaller units (e.g. hydrolysis and elimination.
CATABOLIC AND ANABOLIC
Globular proteins. It's fcn is to act as a catalyst, lower the activation energy for a biological reaction and increase the rate of reaction.
Reactants which enzymes act on. They are generally smaller than the enzyme. The position on the enzyme where the substrate binds is usually with numerous noncovalent bonds called an active site.
Demonstrates enzyme specificity, meaning enzymes are designed to work on specific substrates or groups of closely related substrates.
THE LOCK AND KEY THEORY
The shape of both the enzyme and the substrate are altered upon binding. The alterations helps the reaction proceed.
INDUCED FIT THEORY
Enzymes exhibit this characteristic as the relative concentration of substrate increases, the rate of the reaction also increases, but to a lesser and lesser degree until a maximum rate (Vmax) has been achieved.
Nonprotein component that can either be a coenzyme or metal ions.
Coenzymes are divided into 2 categories: cosubstrates (bind to a specific enzyme and transfer some chemical group to another substrate. It reverts to its original shape through enzymatic reactions) and
prosthetic (remain bound to enzyme and is unchanged thru rxn) groups.
Agents which bind covalently (some non-covalently) to enzymes and disrupt their function. Tend to be highly toxic.
Compete with the substrate by binding reversibly with non-covalent bonds to the active site. The raise the apparent Km but doesn't change Vmax.
Bind non-convalently to an enzyme at a spot other than the active site and change the conformation of the of the enzyme. Don't resemble the substrate and don't prevent the substrate from binding. Often act on more than one enzyme. Lower Vmax, Km stays the same
Many enzymes released into their environment in their inactive form called ZYMOGEN or PROENZYME. Specific bonds need to be cleaved, environment change, or instigated by other enzymes in order for proenzyme to become activated
PROTEOLYTIC CLEAVAGE (enzyme regulation)
Some enzymes activated or deactivated by phosphorylation or addition of some other modifier such as AMP
REVERSIBLE COVALENT MODIFICATION
Protein units that associate with certain enzymes to activate or inhibit their activity
Modification of the enzyme configuration resulting from binding to the activator or inhibitor at a specific binding site on an enzyme
Shut down mechanism for a series of enzymatic reactions when that series has produced a sufficient amount of product.
The product returns to activate the enzyme.
First substrate changes the shape of the enzyme allowing other substrates to bind more easily.
Cooperativity is in the presence of the allosteric inhibitor
Catalyze addition of one substrate to a double bond of a second substrate is sometimes called a synthase.
Governs an addition reaction, but requires energy from ATP or some other nucleotide. Sometimes called Synthetases
Enzyme which phosphorylates something, while a Phosphatase is is an ezyme which de-phosphorylates something
KINASE v. PHOSPHATASE
Respiration that does not require oxygen. Glycolysis (occurs in cystol) is the first step of anaerobic respiration, which breaks a 6-C glucose into 2 3-C molecules of pyruvate, 2 ATPs, and 2 NADHs
DNA is transcribed to RNA, which is translated yo amino acids forming a protein. DNA-->RNA-->PROTEIN
THE CENTRAL DOGMA
When a new double strand is created, it contains one strand from the original DNA, and one newly synthesized strand
DNA REPLICATION IS SEMI-CONSERVATIVE and BI-DIRECTIONAL
The enzyme that builds the new DNA strand, can't initiate a strand from 2 nt but can only add nt to an existing strand. Reads the parental strand 3' to 5', creating the new strand in the 5' to 3' direction
~10 ribonucleotides long can initiate a strand.
1. Helicase unzips the double helix 2. RNA Polymerase builds a primer 3. DNA Polymerase assembles the leading and lagging strand 4. Primer is removed 5. Okazaki fragments are joined
Messenger RNA: delivers the DNA code for amino acids to the cytosol where proteins are manufactured Ribosomal RNA: combines with proteins to form ribosomes in nucleolus Transfer RNA: collects amino acids in the cytosol and transfers them to the ribosomes for incorporation into a protein
mRNA rRna tRNA
DNA is double stranded-RNA single DNA made from deoxyribose-RNA ribose DNA has thymine-RNA uracil DNA replication-RNA transcription In animals DNA only in nucleus and mitochondrial matrix-RNA also in cytosol DNA only one major type-RNA 3 major
DIFFERENCES between DNA and RNA
Requires a promoter (sequence of DNA nt that designates the beginning point). Promoter is a spot on the DNA that tells RNA Polymerase where to begin. A Primer is a short piece of RNA that jump starts replication
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