2.3: Carbohydrates and Lipids Flashcards
monosaccharides?
simples sugars (1 molecule)
glucose
- C6H12O6
- hexose
- sugar that fuels respiration
- base unit for many polymers
- 5 C form corners on ring with 6th corner taken by O
galactose
- C6H12O2 (same formula but less sweet, isomers)
-hexose - commonly found in milk but also cereals
fructose
- hexose
- commonly found in fruits and honey
- sweetest naturally occuring carbohydrate
ribose
- pentose sugar
- backbone of RNA
difference between ribose and deroxyribose: - deoxyribose used in DNA
- deoxyribose has H instead of OH on 2nd corner
monosaccharides are the _________ of polysaccharides
monomers
glucose + glucose ––––>
maltose + water (condensation reaction with glycosidic bond)
glycosidic linkage
bond that links sugars together when a hydroxyl group and H atom link
fructose + alpha glucose –––>
sucrose + water (condensation reaction with glycosidic bond)
maltose
- C12H22O11
- dimer of glucose
- produced from plants and monosaccharides
- commonly found in starchy plants
lactose
- C12H22O11
- produced by animals, alpha-glucose and galactose
- commonly found in milk
sucrose
- C12H22O11
- produced by plants, glucose and fructose
- commonly found in sugar beet and sugar cane`
polysaccharides
complex carbohydrates (polymers made of 2 or more monomers)
- composed of several hundred to several thousand monomers of glucose
- very long and often branched
on which carbons do glycosidic bonds form
1-4 or 1-6
functions of polysaccharides?
energy storage or structural support
3 types of polysaccharides?
- cellulose
- starch (amylose and amylopectin)
- glycogen
abt cellulose?
- size: 1500 units ish
- orientation/bonding: 1-4 bonds, alternatively oriented
- from beta-glucose and made in plant cells
- straight chained
- unbranched chain
- properties of molecule: bonded by hydrogen bonds; linked molecules for cellulose microfibrils; have very high tensile strength
- functions/use: prevents bursting of cell walls in plants; tensile strength from cellulose helps with this
abt starch?
- size: 300 to 3000 units form helix shape (amylose); 2000-200000 units for gobular shape (amylopectin)
- orientation/bonding: molecules oriented same direction; c1 & c4 link (amylose); both c1 & c4 link and c1 &c6 link (amylopectin)
- from alpha glucose and made in plant cells
- curved chain
- unbranched (amylose) and branched (amylopectin)
- properties of molecule: insoluble, does not affect osmotic balance of cells; varying size in molecules
- functions/use: stores energy by adding extra glucose molecules to starch; stores enegry in seeds and storage organs
abt glycogen
- size: 30,000 units ish
- (C6H10O5)n
- from alpha-glucose
- bonding of molecule: 1-4 and 1-6 bonds
- curved chain
- branched chain
- from animals and some fungi; stored in liver and some muscles in humans
- properties of molecule: compact molecule
- when large amounts of glucose cause osmotic problems, glycogen does not, so can easily add glucose to glycogen
- funtion: energy storage, similaer to starch
cellulose 3d structure
straight, linaear shape, unbranched
amylose 3d structure
curved, forms helix shape, unbranched
amylopectin 3d structure
curved, forms overal gobular structure, branched
glycogen 3d structure
curved, helix structure and branches are also helix structured, compact, branched
purpose of carbohydrates in body?
energy storage in humans
how to recognize ingredients on food labels that are sugars?
usually end in “ose”
relationship between simple carbohydrates and polysaccharides?
polysaccharides are complex carbohydrates, long chains
4 monosaccharides and indicate where you would find these sugars
- glucose: used in respiration
- galactose: found in milk
- fructose: found in fruits and honey
- ribose: used in RNA
amylose vs amylopectin?
–––– compare
- both are starches
- made from alpha glucose
- molecules oriented the same way
- same properties and use
–––– contrast
amylose:
- c1 and c4 bonds
- unbranched
amylopectin:
- c1 and c4 bonds; c1 and c6 bonds
- branched
glycogen vs cellulose
––– compare:
- both are from same monomer, glucose
- both have glycosidic bonds
–––– contrast:
- glyocogen made in animals; cellulose made in plants
- glycogen from alpha glucose; cellulose from beta-glucose
- glycogen oriented same way; cellulose oriented alternatively
- glycogen c1-c4 and c1-c6 bonds; cellulose c1-c4 bonds only
t or f: all lipids are unsoluble in water
true
t or f: triglycerides are one of the principal groups of lipids, and are stored in the adipose tissue in humans
true
t or f: fats are liquid at body temperature (37oC) and solid at room temperature (20oC), whereas oils are liquids at both temperatures
true
t or f: triglycerides are formed by linking fatty acid chains to a glycerol molecule through a hydrolysis reaction.
FALSE They link through a condensation reaction. This is the rxn that links monomers together
t or f: fat molecules conduct heat well
FALSE Fat molecules are great insulators because they don’t conduct heat well
general structural formula for a fatty acid
chain or ring of carbon atoms and hydrogen atoms + carboxylic group
what reaction causes triglycerides to form
a condensation reaction between glycerol and fatty acifs
glycerol + three fatty acids ––––>
triglyceride + 3H20
lipids are glycerol combined with 1, 2 or 3 fatty acids, therefore _________________
triglycerides are lipids
revserse reaction of condensation?
hydrolysis; is catalysed by lipase
what type of bonds are formed between fatty acids and glycerol?
covalent bonds called ester bonds
Saturated, monounsaturated or polyunsaturated: oleic acid
monosaturated
Saturated, monounsaturated or polyunsaturated: caproic acid
saturated
Saturated, monounsaturated or polyunsaturated: alpha-linolenic acid
polysaturated
cis-isomers
- common in nature
- H atoms are on same side of the two C atoms
- double bonds cause bend in fatty acid chain
- loosely packed
- lower melting points (liquid at room temp)
trans-isomers
- rare in nature (usually artificially procued)
- H atoms on different sides of the two C atoms
- double bond does not cause bend in fatty acid chain
- closely packed
- higher melting points (solid at room temp)
contrast energy storage for lipids vs carbohydrates
- lipids used in long term energy storage; carbohydrates in short term energy storage
abt lipids
- stored in specialized groups of cells called adipose tissue
- located immediately below skin and around some organis such as kidneys)
funtions of lipids
structure: phospholipids are main component of cell membranes
hormonal signalling: steroids are involved in hormonal signalling
insulation: heat insulators (fats in animals); electrical insulators (neurons)
protection: triglycerides may form tissue layer to protect many key internal organs
storage of energy: triglycerides can be used as long term energy storage
reasons to use lipids rather than carbohydrates for long term energy storage
- amount of energy released in cell respiration per gram of lipids is double that for carbohydrates (and protein)
- can store same amount of energy as in sugars but half the mass if using fat as storage molecule
- lipids add 1/6 as much mass to body as carbohydrates
- fats are pure droplets; 1g of glycogen needs to be stored with 2g of water
- good for animals where energy stores need to be carried
- mass used for storage= (energy contained in 1g of lipids)/ (energy contained in 2g of carbohydrates + 4g of associated water)= 1/6
why is glycogen needed at all?
- can be rapidly broken down to glucose and transported to blood where needed
- fats in adipose tissue cannot be mobilized as quickly
- glucose can be used in anaerobic or aerobic cell respiration; fats and fatty acids in aeorobic respiration only
define glycogen
- is the medium term storage molecule in animals
- stored in liver and muscles
- readily availible energy
define glucose
- in the bloodstream for immediate use
- used in cellular respiration to produce ATP
- or could be converted to glycogen or fat
storage of carbohydrates vs lipids
carbs:
- starch in plants
- glycogen in animals
lipids
- fats and oils in plants
- fats in animals
long/short term storage carbohydrates vs lipids
carbs:
- starch for long term
- glycogen for short term
lipids
- long term
energy per gram carbohydrates vs lipids
carbs:
- 17kJ/g
lipids
- 38kJ/g
ease of digestion/ release of energy carbohydrates vs lipids
carbs:
- easy to release energy
lipids:
- harder to release
- needs more oxygen to release
solubility in water carbohydrates vs lipids
carbs: soluble
lipids: not soluble
use of oxygen in metabolism (and consequence) carbohydrates vs lipids
carbs:
- needs less oxygen
- useful for high demand activity
lipids:
- needs more oxygen
- less efficient to release energy
what is body mass index
BMI used to asses whetehr a person’s body mass is at healthy level, too high or too low
some conditions for underweight
malnutrition
not enough food supplies
anorexia nervosa
risks that incease with obesity
type 2 diabetes
coronary heart disease
BMI formula
mass in kg/ (heigh in metres)^2
- bmi in kbm^-2
Health Risks of Fats
trans fats can cause
- coronary heart disease
- coronary ateries are blocked by fatty deposits, leads to blood clot formation and heart attacks
- evidence: high conc. of trans-fats found in arteries of patients who died of CHD, therefore transfats prob cause CHD
saturated fatty acids also show postive correlation but is not proven taht they cause the disease
