B1.1: Carbohydrates And Lipids Flashcards
Chemical properties of carbon - bio molecules
In all four major categories:
Carb, lipids, proteins, nucleic acids
4 electrons on outer shell
-> allow large stable molecules
Carbon -> arrange themselves to form a huge variety of chemical compounds:
Bond to other atoms
- long branched chains (glycogen)
- long straight chain molecule (cellulose)
- cyclic single rings (thymine, uracil…)
- multiple rings (adenine, guanine)
- tetrahedral structure (different 3D shape, different properties)
Double and triple bonds -> unsaturated compounds
What are some common functional groups?
OH (hydroxyl)
COOH (carboxyl)
NH2 (amino/amine)
H2PO4 (phosphate)
What is a monomer?
Smaller units from which larger molecules are made
what is a polymer?
molecules made from a large number of monomers joined together in a chain
-> polymerization
What is a macromolecule?
Very large molecules
1000+ atoms -> high molecular mass
polymers can be macromolecules, but not all macromolecules are polymers
polymers must have repeating subunits
Form by condensation reaction
Formation of polysaccharide
formed when two hydroxyl groups on different monosaccharides interact to form a strong covalent bond called a glycosidic bond
Formation of polypeptide
formed when two amino acid monomers interact to form a strong covalent bond called a peptide bond
How are polymers digested?
Hydrolysis reaction (breaking down with water)
Covalent bonds in macromolecules -> broken when water added
-> the -H and -OH from the water molecule are used to form the functional groups of the products
Examples of hydrolysis reaction
- hydrolysis of glycosidic bonds in poly- or disaccharides to produce monosaccharides
- hydrolysis of peptide bonds in polypeptides to produce amino acids
- hydrolysis of ester bonds in triglycerides to produce three fatty acids and glycerol
Saccharide:
Bond type
General formula
Properties
Glycosidic bond (condensation reaction)
CnH2nOn
Colorless crystalline molecules
Soluble in water
Différent types of monosaccharides
Formed from varying numbers of C atoms
Triose -> 3 C
Pentose -> 5 C
Hexose -> 6 C
What is glucose?
Basic hexose monosaccharide sugar molecule that is used in respiration to produce ATP
Chemical store of energy
Formed in photosynthesis
C6H12O6
What is the difference between alpha and beta glucose?
Alpha -> OH on C1 below
Beta -> OH on C1 above
Properties of glucose
- stable structure due to covalent bonds
- soluble in water due to polar nature
- easily transportable due to water solubility
- source of chemical energy when bonds are broken
What is ribose?
Basic monosaccharide pentose sugar
Found in RNA
a similar version in DNA
-> deoxyribose: has H in place of one of the OH
What is maltose?
- maltose (malt sugar) is formed from two alpha glucose molecules joined by a 1-4 glycosidic bond
- plants
What is sucrose?
- sucrose (table sugar) is formed from alpha glucose and fructose joined by an alpha 1-4 glycosidic bond
- plants
What is lactose?
- lactose (milk sugar) is formed from galactose and alpha glucose joined by a beta 1-4 glycosidic bond
- animals
What are polysaccharides used as?
Structure or energy source
-> able to do both bc of differences between a and b bonds
Starch (plants -> energy)
Glucose (plants -> energy)
Glycogen (humans -> storage)
Why are carbs good for both energy storage and structure? (Using examples)
Ex: starch and glycogen -> energy storage
Compact
Insoluble
-> soluble molecules will dissolve in cell lowering the water potential and causing water to move into cell -> too much water -> animal cell burst
Ex: cellulose -> structure
Strong and durable
Insoluble and slightly elastic
Chemically inert
Properties and uses of starch
Major carb storage molecule in plants
Usually stored as intracellular starch grains in organelles -> plastids
-> chlorophyll/amyloplast
Starch produced from glucose -> photosynthesis
Broken down during respiration -> energy -> source of carbon from producing other molecules
Structure of starch
2 different structural units:
Amylose (10-30%)
Glucose molecules joined by a 1-4 glycosidic bonds
Unbranched structure -> compact helical structure -> resist digestion
Amylopecitin (70-90%)
Glucose molecules joined by a 1-4 glycosidic bonds
Also contains more a 1-6 glycosidic bonds
-> results in highly branched structure
-> many terminal glucose -> easily hydrolyzed (easy take or add)
Properties and uses of cellulose
Plant cell walls - most abundant organic polymer
Very strong, prevents cell from bursting when excess water
Long chains of b glucose molecules joined by beta 1-4 glycosidic bonds
Glucose chains -> rope-like microfibrils -> layered to form network
Structure of cellulose
polysaccharide made up of many beta glucose molecules
glucose molecules are linked by beta 1-4 glycosidic bonds
-> to from glycosidic with b glucose -> every alternate must be inverted
Long straight unbranched chains
Alternate pattern -> good tensile strength (structure)
Properties and uses of glycogen
Animals store carb as glycogen
Stored in small granules in muscle and liver
Less dense and more soluble than starch -> broken down quicker -> higher metabolic requirements
Structure of glycogen
A glucose joined by 1-4 and 1-6 bonds
Similar structure to amylopectin -> more a 1-6 glycosidic bonds -> MORE branches
What is glycoprotein?
Carb + protein (via covalent bond)
Uses of glycoproteins
Type of protein found in plasma membrane -> shorty chain of monosaccharides attached to it
-> oligosaccharide (oligo - few)
Displayed on the outside of cell and allows other cells to recognize them
Receptor molecules:
Cell recognition/identification
Cell signaling molecules
Endocytosis
Cell adhesion and stabilization
Example of glycoproteins
ABO BLOOD GROUPS
Gp-> act as antigens -> can identify cells as either self or non-self
- blood type A individuals have type A glycoprotein antigens
- blood type B individuals have type B glycoprotein antigens
- blood type AB individuals have both types of glycoprotein antigens
- blood type O individuals have neither
Blood transfusion -> wrong type -> antibodies don’t recognize and clump -> block blood vessels
Examples of lipids
Fats
Oils
Waxes
Steroids
Cholesterol
What is a lipid?
diverse group of compounds that are insoluble in water but soluble in organic solvents (ex: ethanol)
most common:
triglycerides (sometimes known as true fats or neutral fats)
3 fatty acid chains (has HC (saturated or unsaturated) chain and can be any length)
1 glycerol
Organisms -> energy source
2x of carbs
38KJ/g
What effects lipid solubility?
Structure
Lipids -> hydrocarbon molecules -> non-polar covalent bonds
Nonpolar -> lipids are insoluble in water/polar solvents
In living organisms -> improved bu combining lipid molecules with other molecules (glycolipids, lipoproteins)
What is the role of lipids in humans/mammals?
Adipose tissue
Insulation -> mammals have it under skin to reduce heat loss
- adipose cell shrink when fat is respired
- seals + walruses -> endotherms -> thick adipose issue (blubber) -> trap heat generated by respiration
Protection -> around delicate organs (kidneys) cushion impact
- subcutaneous fats -> below skin
- visceral fats -> major internal organs
The role of lipids in plants?
Seeds -> evolved to store fats -> energy from growing seedling plant
olives,sunflowers,nuts,coconutsandoilseed rapeare good examples of crops whose oils are harvested for edible oil production by humans
Why is lipid good as long term storage?
Add 1/6 as much mass as carbs
Fats -> stored as pure droplets
- whereas 1g of glycogen + 2g water
Lipids -> respired -> water produced (lot compared to carbs)
- metabolic water -> can be used like drinking water
Ex:
camel -> hump has lipid rich storage organ
Birds -> egg lipid rich yolk (energy and water)
Insoluble -> not transported around the body easily -> remains in storage cell
Formation of triglycerides
Esterification
-> an ester bond forms when the hydroxyl group of a glycerol molecule bonds with the carboxyl group of a fatty acid (-OH → -COOH)
Ester bond formed when condensation reaction
-> 1 triglyceride, 3 water
Formation of phospholipids
Formed from glycerol and fatty acids
2 fatty acid + Phosphate ion + glycerol
Phosphate -> polar = soluble in water/hydrophilic
Phospholipids -> amphipathic -> both hydrophobic and hydrophilic regions
- can form mono layers or bilayers when in water
What is a saturated fatty acid?
Only contains single bonds between carbon atoms
Molecule straight (stearic acid)
Each carbon in HC tail (- final one) -> bonded to 2 H atoms
can pack together tightly → + mp, solid at room temp, used as storage
What is a unsaturated fatty acid?
Contains double bonds between carbon atoms -> kink in the chain
Cannot pack tightly -> liquid -> lower mp (oils)
HC tail doesn’t contain max number of H atoms possible -> at least 1 double bond
Monounsaturated fats -> 1 double bond
Polyunsaturated fats -> more that one
What is the difference between cis and trans fatty acids?
Depends on arrangement of atoms/groups around a double bond in an unsaturated fatty acid
Cis -> greatest kink, chains that are unable to pack tightly together
Bonds H on the same side of the C double bond
Liquid lipid
trans -> one bond on top, on the bottom
Pack closer -> the kink of the bonds cancel out -> straighter
Mimic saturated fats -> same health risks
Usually created
Solid lipid
How are membranes formed?
Hydrophilic phosphate head bonds with 2 hydrophobic fatty acid tails
- thephosphate head ispolar, so is hydrophilic and thereforesolublein water
- thefatty acid tail isnonpolar, so is hydrophobic and thereforeinsolublein water
Placed in water -> phosphate head towards water, fatty acid tails away from water -> phospholipid monolayer
Phospholipid mixed with mater -> bilayer
- because amphipathic -> barrier to most water soluble substances -> nonpolar fatty acids prevent polar from passing through (no leaks)
Steroids and passing through the phospholipid bilayer
Small nonpolar -> soluble in lipid bilayer -> can cross membrane
Larger nonpolar -> can enter the cell due to hydrophobic properties (ex: steroid hormones)
- and their lipid structure
- can easily travel into and out of cell and nuclei
Steroids:
Contain cholesterol (lipid)
Have 4 fused rings of carbon atoms
Ex: oestradiol and testosterone (produced by gonadal tissue in reproductive organs)
