B.1.1 Molecules - CARBOHYDRATES & LIPIDS Flashcards
Outline the number and type of bonds carbon can form with other atoms
Carbon can form FOUR covalent bonds due to having 4 valence electrons
Outline the cause and consequence of covalent bonds between atoms
CAUSE:
1. Atoms want to gain stability by forming a full outer shell of valence electrons
2. Atoms share electrons between them
CONSEQUENCE:
1. Formation of diverse compounds upon which life is based
2. Covalent bonds are the strongest bonds found in biological molecules
What are the common functional groups?
- Hydroxyl group (-OH)
- Carobonyl group (C=O)
- Carboxyl group (-COOH + H2O -> - COO⁻)
- Esters (acid + alcohol -> ester + water)
List four major classes of carbon compounds used by living organisms. Name their sub-units.
- Carbohydrates - monosaccharides
- Lipids - fats (triglycerides), glycerol, fatty acids
- Proteins - amino acids
- Nucleic acids - nucleotides (sugar + phosphate group + nitrogenous base)
List example molecules with the four different types of shapes of carbon compounds
- SHORT & STRAIGHT: amino acid alanine
- LONG & STRAIGHT: fatty acids
- BRANCHED: amino acid valine
- RING: alpha glucose
Define monomer and polymer
Monomers: small molecules which may be joined together in a repeating fashion to form more complex molecules, called polymers
Polymers: Any class of substances that are composed of macromolecules, which are multiples of monomers.
Describe condensation reactions. Describe anabolism.
Condensation reactions are chemical reactions in which two molecules combine to form a larger one, with a simultaneous elimination of a smaller molecule (water).
ANABOLISM is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.
CHARACTERISTICS:
1. Macromolecules are made from monomers
2. Water is released
3. A new covalent bond is formed
4. requires energy, endothermic (in the form of ATP)
5. requires specific enzymes
Outline the condensation reactions that form 3 different types of macromolecules
- POLYSACCHARIDES
- monosaccharide monomers join together
- glycosidic bond is formed
- water is released - POLYPEPTIDES
- NUCLEIC ACIDS
Describe hydrolysis reacitons
CATABOLISM is the breakdown of complex molecules into simpler molecules including the HYDROLYSIS Of macromolecules into monomers
Hydrolysis is the DIGESTION of polymer into monomers with the requirement of specific ENZYMES
- Requires enzymes that are specific to the molecules they are breaking down
- Macromolecules are broken into monomers
- Hydrolysis occurs, water is used to lyse/break the macromolecule
- Releases energy, exothermic
Identify pentose and hexose carbohydrates
Hexose – party hat man!
Outline the properties of glucose referring to solubility, transportability, stability, and energy yield from oxidation
SOLUBILITY:
- highly soluble
- hydrophilic
- forms hydrogen bonds
TRANSPORTABILITY:
- transports through the body via the bloodstream
- transport proteins like glucose transporters (GLUTs)
- hormone insulin regulates glucose uptake
STABILITY:
- relatively stable
- glucose can tus be later used without degradation
ENERGY YIELD FROM OXIDATION:
- glycolysis: glucose partially broken down -> ATP + pyruvate
- pyruvate is oxidised through citric acid cycle & oxidative phosphorylation
Compare the structure and function of amylose, amylopectin, and glycogen
GLYCOGEN:
1. 1’-4’ AND 1’-6’ glycosidic linkages
2. Made by animals and some fungi, found in liver & muscles
3. Polyssacharide formed by monosaccharide alpha-glucose via condensation reactions
4. Compact structure allows for large volume of glucose that acts as energy storage compound in cells
5. Insoluble and doesn’t effect osmotic potential or intake of water
STARCH - AYMLOPECTIN:
1. 1’-4’ AND 1’-6’ glycosidic linkages
2. ONLY branching/helical molecules
3. Polyssacharide formed by monosaccharide alpha-glucose via condensation reactions
4. Stored in root cells/leaves (temporary)/ amyloplast (plastid) as energy storage
5. Hydrophilic but insoluble due to size, doesn’t affect osmotic balance
STARCH - AMYLOSE:
1. ONLY 1’-4’ glycosidic linkages
2. Linear AND helical molecule
3. Polyssacharide formed by monosaccharide alpha-glucose via condensation reactions
4. Stored in root cells/leaves (temporary)/ amyloplast (plastid) as energy storage
5. Hydrophilic but insoluble due to size, doesn’t effect osmotic balance
Discuss the benefit of polysaccharide coiling and branching during polymerisation
- Compact/dense storage
- Efficient use of space
- Rapid energy release
Explain how condensation or hydrolysis of alpha-glucose monomers build or mobilise energy stores
CONDENSATION:
1. glycogen formation in animals for energy stores
2. starch formation in plants for energy stores
HYDROLYSIS
1. glycogen breakdown via hydrolysis
- Enzyme glycogen phosphorylases cleave alpha-1,4-glycosidic bonds that release glucose-1-phosphate
- molecules convert into glucose-6-phosphate
- enters glycolysis for energy production as part of cellular respiration
2. Starch undergoes hydrolysis
- Enzyme amylase cleaves alpha-1,5- glycosidic bonds in both amylose and amylopctin
- glucose moleules can be used for energy or other metabolic processes
Compare the structure of alpha-glucose and beta-glucose
Glucose’s two incomers have a difference in the orientation in the (-OH) hydroxyl group that is connected to the first carbon atom (on the right).
Alpha: on the bottom as HO
Beta: on the top as OH
Describe the structure and function of cellulose !!!!
STRUCTURE:
1. polyssacharide made of beta glucose monomers via condensation reactions
2. 1’-4’ glycosidic linkaes
3. Straight/unbranched cellulose fibrils linked via hydrogen bonds to form cellulose fibres
FUNCTION
1. Long chains of cellulose fibrils result in insoluble cellulose fibres
2. Tensile strength as a result of hydrogen bonds
3. Rigid structure -> resists osmotic potential
Discuss the consequences of the strength of cellulose in the plant cell wall
- structural integrity/rigid
- cell expansion & growth
- vascular tissue support
State the function of glycoproteins in the cell membrane
Glycoproteins are a sugar + protein
FUNCTION:
1. receptors for hormones, chemical signalling molcules
2. assists in binding cells together
3. cell to cell recognition
CELL TO CELL RECOGNITION
1. located on the outside of the cell
2. hydrophilic carbohydrate group associated with water
3. determines self from non-self
Antigens: molecules that produce an immune response
Antibodies: proteins that bind antigens because of the immune response
Explain why lipids are hydrphobic
- Hydrocarbon chains (fatty acids) or rings (steroid)
- doesn’t associate with water or hydrophilic or polar molecules
- Orients away from water
Outline the structure and function of fats, oils, waxes, and steroids
They are all triglercides – glyerol + 3 fatty acids -> ester bond + H20
OILS: liquid triglycerides @ room temperature
WAXES: esters of long chains fatty acids and long chain alcohols
- solid @ room temperature
- higher melting points
STEROIDS: different class of lipids and include molecules like cholesterol, hormones, and vitimin D
Explain the condensation reaction connecting fatty acids and glycerol to form a triglyceride
Fatty acids are long hydrocarbon chains with a carboxyl group (-COOH) at one end. Glyercol is a three-carbon alcohol with three hydroxyl (-OH) groups.
- Removes a hydroxyl group from glyerol + hydrogen atom from the carboyxl group of a fatty acid -> releases water molecule (H20)
- Remaining oxygen from glycerol hydroxyl of and carboxyl group combine to form an ester linkage
- An ester linkage is formed, and is covalent bond between oxygen of glycerol and carbon of fatty acid)
Explain the condensation reaction connecting fatty acids, glycerol, and a phosphate group to form a phospholipid. Describe the nature of phospholipids.
Amphipathic !!!!!! – contains both hydrophilic and hydrophobic properties
Phospholipids are a class of lipids that have a hydrophilic head and hydrophobic tails. This forms a lipid bilayer that constitutes cell membranes.
Glycerol is a three-carbon alcohol with 3 hydroxyl groups (-OH)
Fatty acids are long hydrocarbon chains with 1 carboxyl group (-COOH) at the end
A phosphate group is a functional group with a central phosphorus atom bonded to oxygen
- 2 fatty acids connect to glycerol through ester linkages -> releases 2 H2O
- Phosphate group added to the remaining hydroxyl group of glycerol – attached via phosphodiester bond (replaces fatty acids) – acts as hydrophilic phosphate head
Define organic as it is applied to compounds that make up life. Identify the exceptions.
Organic molecules based on carbons are:
- carbohydrates
- lipids
- proteins
- nucleic acids
Molecules that are NOT organic are carbon dioxide, carbon monoxide, or hydogen carbonates
State 4 examples of monosaccharides
- Glucose
- Fructose (hexose)
- Galactose (hexose)
- Ribose (pentose)
Define disaccharide. State 3 examples and their subunits
A disaccharide is a type of carbohydrate composed of 2 monosaccharides units linked through a glycosidic bond via condensation reaction.
- Sucrose: glucose + fructose
- Lactose: glucose + galactose
- Maltose: glucose + glucose
Describe the properties of carbohydrates. What are the different types of their subunits?
CARBOHYDRATES:
- organic compounds that are formed from various combinations of simple (monosaccharides) or complex (polysaccharides) sugars
- carbon-based
- repeating units of CH2O
- ring structures
MONOSACHARRIDES: alpha glucose, beta glucose & ribose
POLYSACCHARIDES: amylopectin, amylose, glycogen, cellulose
Describe the properties of lipids. What is an example of this, and what are their subunits?
LIPIDS:
1. nonpolar molecules
2. not soluble in water
examples: cholesterol, phospholipids, & triglycerides
TRIGLYCERIDES:
1. subunits: glycerol + 3 fatty acid molecules
2. length of fatty acid chain is variable
3. may be saturated or unsaturated
Describe the properties of proteins. What is the difference between peptides, polypeptides, and proteins? What are amino acids molecules made of?
PROTEINS:
1. made of amino acid molecules
2. contain carbon, hydrogen, oxygen, and nitrogen (sometimes sulfur)
3. complex biomolecules which are composed of one or more polypeptide chains folded
Dipeptide: 2 amino acids linked by a peptide bond
Peptide: 2+ amino acids linked by peptide bonds
Polypeptides: longer chains of amino acids w/ 3D structure
Proteins: 1+ polypeptides w/ 3D structure
Amino acids: amino group + carboxyl group + r group
Describe the properties of nucleic acids. What are the subunits? What is the subunit made of? What are some examples of nucleic acids?
NUCLEIC ACIDS:
1. contains carbon, hydrogen, oxygen nitrogen, and phosphorus
2. Made of subunits called NUCLEOTIDES
3. Nucleotides made of sugar + base + phosphate group
Examples: RNA, DNA
Describe saturated and unsatruated fatty acids.
SATURATED:
1. Single bonds between carbons
2. Straight, no bend
3. Allows for right packing between fatty acid molecules
UNSATURATED:
1. mono-unsaturated (one) or poly-unsaturated (many) double bonds between carbons
2. can either be trans - straight
3. or CIS - bent
Describe the difference between cis and trans double bonds/fatty acids
CIS:
1. hydrogens on the same side of the double bond
2. bent shape
3. loosely packed
4. common in nature
5. low melting temperatures/liquid @ room temp
6. lowers LDL, lowers risk of heart attack & atherosclerosis
TRANS:
1. hydrogens on opposite side
2. straight shape
3. tightly packed
4. less common
5. high melting temperature/solid @ room temp
6. increases LDL, increases risk of heart attack & atherosclerosis
Outline how triglycerides allow for energy storage and thermal insulation.
Lipids or triglycerides in adipose tissue are used fro long term energy storage and thermal insulation.
ENERGY STORAGE:
1. insoluble and do not effect osmotic balance of cells or tissues
2. fats/lipids are stored as triglyerides in adipose tissue/blubber
3. contains 2x amount of energy as carbohydrates per gram and 2x as energy storage efficent than starches
THERMAL INSULATION
1. lipids are buoyant
2. provides thermal insulation
3. prevents heat loss
