Carbohydrates, Lipids, Cellular Respiration, and Photosynthesis (Review #3) Flashcards
Monosaccharides Overview
-(“single sugars”) – General formula = CnH2nOn
-3 types (based on number of carbon atoms)
–Trioses (3 carbons) = C3H6O3
–Pentoses (5 carbons) = C5H10O5
–Hexoses (6 carbons) = C6H12O6
Disaccharides
Maltose, lactose, sucrose
Lactose: Milk sugars for feeding young
Sucrose: form of sugar transported from leaves to other locations
Polysaccharides
Starch, glycogen, cellulose (all made of glucose, but put together differently = different structure = different functions)
Glycogen: Stores glucose in liver/ muscle cells
Cellulose: makes up plant cell walls (𝛽-glucose subunits; are linear and have high tensile strength)
Starch: stores glucose; made of α-glucose subunits (2 forms: amylose and amylopectin)
Structure of Amylose and Amylopectin in Starch:
Amylose is linear/ helical and subunits are bound in a 1-4 arrangement
Amylopectin is branched and subunits are bound in 1-4 AND 1-6 arrangements
Monosaccharide Specific Details
Glucose, galactose, fructose
Glucose: Chemical fuel for cellular respiration (ATP)
Fructose: Fruit sugar (makes them sweet)
Condensation reactions create…. and hydrolysis reactions break…. (glycosidic linkages)
glycosidic linkages between sugars, and hydrolysis reactions break glycosidic linkages between sugars
Condensation reactions create….. Hydrolysis reactions break…. (Esther linkages)
ester linkages between glycerol and fatty acids. Hydrolysis reactions break ester linkages between glycerol and fatty acids.
Fatty Acids Overview
Fatty acids in lipids are hydrocarbon chains that vary in length (number of carbons, usually 11-23) and in the number and locations of double bonds
ALL fatty acids have a carboxyl group at one end (COOH) and a methyl group (CH3) at the other end (called the “omega” end)
Unsaturated Fatty Acids
have one or more C=C double bonds between carbon atoms (forming bends or “kinks” in the fatty acid chains)
Bent/ kinked
Monounsaturated fatty acids have one C=C
double bond
Polyunsaturated fatty acids have two
or more C=C double bonds
Omega-3 fatty acids (1st C=C double
bond is on 3rd carbon from omega/ methyl end)
Omega-6 fatty acids (1st C=C double bond is on
6th carbon from omega/ methyl end)
Note: C=C bonds with hydrogen atoms on SAME side = CIS
C=C bonds with hydrogen atoms on OPPOSITE sides = TRANS
Saturated Fatty Acids
have no C=C double bonds (they are “saturated,” or “maxed out” with the carbon atoms being bonded to as many hydrogen atoms as possible – they form linear fatty acid chains)
Linear/ straight (no C=C double bonds)
Animal fats are saturated fats
Diets rich in contribute to CHD, high LDL cholesterol, atherosclerosis, hypertension, obesity, clots/ thrombosis
Hydrogenated Fatty Acids
olyunsaturated fats are often hydrogenated (or partially hydrogenated) in food processing
Hydrogen atoms are added to the molecules, eliminating some (or all) of the C=C double bonds/ kinks and bends in the fatty acid chain (straightens, or partially straightens fatty acid molecule)
WHY? Higher melting temperatures (crispier french fries from hydrogenated oils due to higher oil temp, chocolate coatings/ baked goods etc. do not melt on shelves/ have longer shelf lives, “butters” are more spreadable etc.)
Cis Fatty Acids
Naturally occurring polyunsaturated fatty acids are curved (called cis fatty acids). Hydrogenated fatty acids are straightened/ linear double bonds (called trans fatty acids).
Trans Fats
Trans double bonds are not fully recognized by enzymes that break down fats in the body (not the right shape!), causing them to remain in the bloodstream for extended amounts of time.
Trans fats in the diet ARE eventually incorporated into living tissues (as best as they can be), but because they are unnatural fats, they do not properly bind to natural enzymes etc. in the body, contributing to:
High cholesterol, heart disease, liver dysfunction, cardiovascular disease
Fats and Dietary Suggestions
Living organisms NEED fats (cell membranes, energy storage, cushioning, heat retention, immune system etc.)
Low-fat diets aren’t necessarily the “key” to better health (although counting calories based on lipid content is important for the health of many people) – it’s the TYPE of fats in the diet that are important!
All fats contribute the SAME relative amount of calories (per gram of lipid) to a food (9 calories per gram)
Polyunsaturated (best), monounsaturated (good), saturated (ok, but should be limited), trans (HORRIBLE!)
BMI=
weight (kg)/ height (m)^2
or
(weight (lbs)/ height (in)^2) x 703
Carbohydrate Energy Storage
Stored as glycogen (animals) and starch (plants)
Glycogen and starch are hydrolyzed to glucose when energy needed
Short-term energy storage (disrupt osmotic balance of tissues in large quantities)
Lipid Energy Storage
Stored as triglycerides (in adipose cells in liver/ muscle tissue)
Triglycerides are hydrolyzed to glycerol and fatty acids when energy needed
Long-term energy storage (hydrophobic, so do not disrupt osmotic balance and can be stored for long periods of time)
Twice the energy content (per unit mass/ per gram) of carbohydrates
(-Lipids = 9 calories per gram
-Carbohydrates = 4 calories per gram)
Note: Proteins also contain 4 cal/ gram
ATP Structure and
Function
Adenosine
triphosphate (ATP =
3 phosphates)
*One phosphate group
broken off releases
energy for cells and
creates ADP
Adenosine diphosphate (ADP = 2 phosphates)
*Can be “recharged” (like a battery) by adding a phosphate
group back onto it, using energy from the breakdown of food
molecules (like glucose) – cellular respiration!