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Lecture 11

BLG 181 Lecture 11: Lecture 11

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BLG 181
Maria Arts

Lecture 11: Introduction to Macromolecules & Nutrients Evolutionary connection - all living organisms have same biochemistry, with same 4 types of macromolecules used as building blocks: nucleic acids, carbs, proteins, fats Macromolecules: Nucleic Acids - polymers of nucleotides - DNA & RNA are made up of nucleotides o Each nucleotides has central sugar, a phosphate group and a nitrogenous base o Recall mutations: genetic differences upon which natural selections can act - Remaining 3 macromolecules: carbs, proteins and lipids, fall into the category of nutrients - Nutrient: o nutrient is a component of food that is needed for a specific psychological function - maintain life o Essential nutrients : must be supplied in diet o Deficiency disorders: occur when the body lacks a nutrient required for normal function. without a particular nutrient = deficiency disorder o Macronutrient: required in fairly large amounts o Micronutrient: vitamins and minerals, needed in smaller amounts. Nutrient class Energy Major functions Major sources Food and energy - Energy dense: amount of energy (calories) in food/ unit weight - Nutrient rich: naturally abundant in vitamins, minerals and other nutrients. - Sources: on average, young adults in NA get energy dense food. veggie/ vegans eat more nutrient rich CARBOHYDRATES - molecules of carbohydrates, oxygen, and hydrogen - include: - also referred to as starch, sugar, fiber - simple carbohydrates o monosaccharides  consist of one subunit  glucose: the currency the body uses to provide energy  cells and brain need glucose for energy  every food gets broken down into glucose molecules to be used o Disaccharides  consists of two subunits  Sucrose: table sugar. glucose + fructose - lactose tolerance-intolerance o lactose: milk sugar, carb found in milk o enzyme lactase  Produced during infancy. produced by all animals  Splits disaccharides lactose into glucose and galactose o Without lactase:  Lactose cannot be broken down = abdominal pain, bloating, and diarrhea o Is tolerance and intolerance an adaptation?  for cultures or animals don’t utilize dairy products past infancy, they will be intolerant because their body don’t need to produce the enzyme  lactose tolerance: is an adaptation to environments where milk is available and utilized by adults  Adaptation: gives you benefit in an environment. If dairy is a regular source in a society, most likely lactose tolerant. - Galactosemia o Galactosemia: a genetically inherited mutation (autosomal recessive disorder) in one of the 3 enzymes in the galactose metabolism pathway that converts galactose to glucose o 3 enzymes include : galactose kinase, galactose 1-phosphate uridyl transferase, and galactose-6-phosphate epimerase  These enzymes are needed to convert galactose (monosaccharide) to glucose o Galactose: found in lactose (glucose + galactose) and all dairy products, sugar beets, seaweed o Without the enzymes, galactose concentrations build up to high levels and result in galactosemia o Screening: infact screening with blood works looks for the enzymes that are needed to break down galactose o No known cure just treatment  Avoids foods high in galactose ir. Dairy products o Is it an adaptation: NO  Not an adaption because:  Its build up leads to: o Brain damage, vision problems such as cataracts, enlarged liver, renal failure - Complex sugars – polysaccharides o Larger molecular chains made up of many sugar units - Complex carbohydrates o Polysaccharides:  Starch: energy storage form in plants. Extra stored molecules that are broken down to glucose when needed. potatoes, beets (all root plants) are rich in it  Glycogen: stored form of glucose in animal liver and muscles.  Cellulose found in cell walls of plants. most abundant compound on earth  Derived from plant material. not considered a nutrient  How do herbivores (ir., cows) get glucose from cellulose? o stomachs that are compartalized with prokaryotes tat break down the molecules and get the glucose o termites have celluloses that break down cellulose energy - - - - - - fiber o Not considered a nutrient. nondigestable carbohydrates o Soluble fibre – absorbs water, slows absorption of glucose, decreases hunger (peas, oats, plums, bananas)  delay the time of transit through the intestine o Insoluble fiber: adds bulk, (bran, flax, nuts, green beans)  speeds up intestinal transit, easier waste elimination o Benefits  protection against cardiovascular disease, obesity, type 2 diabetes, lowers blood pressure  may help with irritable bowel syndrome  may reduce risk of colon cancer o pears contain a type of fibre that you cannot breakdown but help with
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