Water, Carbs and Lipids Flashcards
What is the bonding in water? (2)
- Hydrogen bonding between molecules
- due to the slight -ve charge on the O and slight +ve on the H
What properties does water have that are necessary in the blood? (3)
- A liquid
- Good transport medium due to cohesion and and adhesion (capillary action)
- Solvent so it can carry dissolved nutrients etc
What properties does water have that make it good for aquatic environments? (4)
- High specific heat capacity so stable temperatures
- Ice floats and is less dense so forms an insulating layer. Aquatic life can live underneath it
- Good solvent for necessary gasses (oxygen, carbon dioxide)
- Surface tension allows for small animals to inhabit the surface of the water
What properties does water have that are necessary for mitochondria? (3)
- Good transport medium
- Solvent so chemical reactions can take place in it
- High specific heat capacity so temperatures are stable and are always at best temperature for body enzymes (37ºC)
Why does glucose need to be stored as starch? (2)
- Polar molecule
- Soluble
What properties does water have that make it good for humans? (3)
- Coolant (for sweating) and keeping body temperatures stable
- Necessary for hydrolysis reactions
- Solvent for minerals and sugars
What are carbohydrates?
Examples of monosaccharides and polysaccharides (3 for each)
- Molecules that contain only carbon, hydrogen and oxygen
Monosaccharides - glucose, fructose, ribose
Polysaccharides - Glycogen, cellulose and starch
Difference between alpha and beta glucose?
OH group on carbon-1 is below on alpha and above on beta
Condensation reaction between two alpha glucose particles? (3)
- Forms 1-4 glycosidic bond
- Forms Maltose
- Forms one water molecule
How is sucrose and lactose formed?
- Sucrose: Glucose + Fructose - 1-4 glycosidic bonds
- Lactose: Galactose + Glucose - beta 1-4 glycosidic bonds
How and where is starch stored? (2)
- Inter-cellular starch grains in organelles called plastids. - Includes chloroplasts and colourless amyloplast in potatoes
Structure of amylose? (3)
- Alpha 1-4 glycosidic bonds between glucose
- Chain curves to form helix (hydrogen bonding)
- Unbranched
Structure of amylopectin? (3)
- Alpha 1-6 glycosidic bonds between glucose
- Highly branched structure
- 1-4 glycosidic bonds
Why is starch important for plants? (4)
- Has fewer branches so good for long term storage.
- Insoluble - Doesn’t affect water potential
- Compact so good storage molecule
- Easily hydrolysed to glucose when energy is needed
Order glucose, fructose and galactose from most to least sweet.
Fructose, glucose, galactose.
Where are sugars found in genetics?
Ribose - a pentose sugar. The sugar present in RNA and DNA nucleotides.
What is the structure of cellulose for its function? (4)
- Used for cell wall
- Beta glucose
- 1-4 glycosidic bond
- Rope-like microfibrils
How does cellulose rotation work?
Each glucose is flipped 180º and allows hydrogen bonds to form between hydroxyl groups on adjacent parallel chains. More structural ability
What are lipids properties and functions? (6)
- Membrane/hormone formation
- Electrical/thermal insulation
- Cushioning
- Waterproof
- Buoyancy
- Non-polar
What is the structure of triglycerides? (2)
- Glycerol bonded with 3 fatty acids (releases 3 H2O).
- Glycerol is hydrophilic while acids are hydrophobic.
Which fats do plants contain?
Unsaturated triglycerides (oils) - healthier
What are phospholipids used for as they replace the fatty acids with a polar phosphate ion (hydrophilic head)? (2)
- Allows it to be surfactant.
- Used in membranes as the heads react with the cytoplasm and H2O
Saturated vs. unsaturated fats and their effects? (4)
- Saturated - only single bonds
- solid at room temperature
- Unsaturated - has at least one double bond
- liquid at room tempurature
What is cholesterol? (3)
- A sterol.
- Stabalsies fluidity of membranes.
- Carried in lipoproteins
What is meant by a reducing sugar?
A sugar that can donate electrons or reduce another molecule or chemical.
How do you carry out a test for reducing sugars? (4)
1) Place the sample to be tested in a water boiling tube. If it isn’t a liquid grind it up or blend it in water
2) Add equal volume Benedict’s reagent
3) Heat the mixture gently in a boiling water bath for five minutes.
- If reducing sugars are present, it will go from blue to red
What is the iodine test for starch? (2)
- A few drops of iodine dissolved in potassium iodide solution is mixed with a sample
- If starch is present, colour changes from yellow/brown to purple/black.
How do you test for lipids?
Emulsion test:
Add ethanol and shake.
If white emulsion forms on top, there is lipid present.
differenves betwwen cellulose and amylose
….
