Biochemistry Flashcards
What is the pH of human blood?
What happens if it is below or above that pH?
- Optimal pH is 7.2 for human blood
- Acidic and basic blood would damage blood cells
What do buffers do?
Application in the body?
- Buffers minimize changes in pH by taking up or releasing H+ or OH- ions in solution
- Cells use buffers to regulate pH levels
Difference between dehydration synthesis and hydrolysis?
- Dehydration synthesis is anabolic (brings things together) with two subunits as reactants and one subunit as a product (+creation of H2O)
- Hydrolysis is catabolic (breaks apart) and the reverse reaction of dehydration synthesis, one reactant + water —> two subunits
What do carbohydrates contain?
What are they used for?
- Contain a 1:2:1 ratio of C:H:O as well as many hydroxyl and carbonyl groups
- Used for energy, building materials in cells, and cell-cell ID during metabolic processes
What do monosaccharides contain (number of carbons)?
Give examples of them.
- Contain between 3, 5 or 6 carbons (triose, pentose or hexose)
- E.g. glucose, fructose, and galactose
Define glucose:
Glucose: Blood sugar, used by cells in the body first for energy
Define fructose:
Fructose: fruit sugar, principle sugar in fruits
Define galactose:
Galactose: sugar found in milk
What is similar in all monosaccharides? What is different?
- All have same molecular formula
- Differ in 3D shape and arrangement of H and OH
- They are isomers
What are disaccharides?
Disaccharides: two monosaccharides that form a covalent bond (glycosidic bond) in a dehydration synthesis reaction
Formation of the three disaccharides:
Glucose + fructose —> sucrose
Glucose + glucose —> maltose
Glucose + galactose —> lactose
Define polysaccharides:
Complex carbohydrate composed of hundreds to several thousand monosaccharide subunits joined by glycosidic bonds
Examples of polysaccharides?
- Starch
- Glycogen
- Cellulose
- Chitin
Characteristics of starch?
- form of glucose storage in plants
- monomer is alpha glucose
- insoluble due to large size
- linear or branched
Characteristics of glycogen?
- stored in muscle/liver cells of humans and animals
- monomer is alpha glucose
- insoluble
- highly branched
Characteristics of cellulose
- primary structural unit in plants
- monomer is beta glucose
- H-bonding produced tight bundles called microfibrils
- linear
- humans cannot digest beta glucose
Characteristics of chitin?
- makes up exoskeletons of insects and crustaceans
- monomer is N-acetyl-glucosamine
- linear
Characteristics of lipids?
- non polar molecule made mostly of carbon and hydrogen
- made with CHO
- insoluble in water (soluble in non polar substances)
- stores energy, builds membranes/cell parts, chemical signalling, insulation and protecting organs
Four main categories of lipids?
1) fatty acids (saturated and unsaturated)
2) fats (saturated and unsaturated)
3) phospholipids
4) steroids
Characteristics of fatty acids:
- consists of singular hydrocarbon chain with a hydroxyl group at one end
- numbered evenly from 14-22
- no double bonds=saturated
- double bonds= unsaturated
Saturated vs unsaturated
Saturated: solid at room temperature, no double bonds, found in animals
Unsaturated: liquid at room temperature, double bonds, found in plants
Characteristics of fats
- fatty acid + glycerol
- 1-3 fatty acids per fat
- made through dehydration synthesis
- can be saturated or unsaturated
Characteristics of phospholipids
- make up cell membranes
- glycerol + 2 fatty acids + polar phosphate group
- ampipathic: polar head is hydrophilic and non polar tail is hydrophobic
Characteristics of steroids
- lipids that contain 4 fused hydrocarbon rings + several different functional groups
- cholesterol is building block for other steroids and is important in cell membrane
- sex hormones are also steroids (testosterone and progesterone)