biological compounds Flashcards
State the isomer found in cellulose and starch (1)
- cellulose - beta
- starch - alpha
Explain how the tructure of starch and celluloe related to functions as storage and structural molecule (4)
starch
* amylose/ amylopectin
* glycosidic bond alpha 1-4
* molecules coil and branch in amylopectin
* eay to remove glucose
cellulose
* alternate unit rotate/180
* straightchain only
* hydrogen bonds / cross linking
* gives strength of stability / microfibrils
State the type of reaction ivolved in the breakdown of the monoglyceride (1)
hydrolysis
Apart from energy storage state two function of triglycerides in a mammal (2)
- protection of internal organs against impact
- thermal insultation
- buoynacy waterproofing skin
- source of metabolic water
Explain why triglycerides are not conidered polymers (1)
glycerol and fatty acid have different structures
Stearic acid has the chemical formula C17H35COOH and oleic acids has the chemical formula C17H33COOH what type of fatty acid is oleic acid (2)0
- oleic acid is unsaturated
- contains at least one C=C double bond
- not fully saturated with hydrogen atoms
Decribe a biochemical test for the prescence of glucose in a solution (2)
- add benedicts test and boil
- change from blue to brick red
Explain why a positive result is seen with glucose with benedicts test but not for sucrose (1)
- sucrose is a non reducing sugar
What is the role of magnesium , iron, phosphate, calcium (4)
- magnesium - component of chlorophyll
- iron - component of haemoglobin
- phosphate - coponent of nucleic acids/DNA/RNA/nucleotide
- calcium - hardens bone / teeth
Name the bond between parallel chains of cellulose (1)
- hydrogen bonds
Explain the importance of hydrogen bonding in the role of cellulose in plant cell wall (2)
- holds together cellulose chains / form microfibril
- stengthen cell walls / strong /rigin
- can resit turgor/ osmotic pressure/ prevent plant cells bursting
Name chemical reaction by which monomers join together to form cellulose (1)
condensation
In chitin what additional compound replaces one of OH group in each of its monosaccharides (1)
- amino acid / glucosamine / amine
State the structural role of chitin in insects and describe its properties that make it suitable for this role (1)
- exoskeleton - strong / waterproof/light/rigidty / tough
Name the storage polysaccharide found in animal cells and plants cell (2)
- animal - glycogen
- plant - starch
What are the products formed when a triglyceride is broken down (2)
- glycerol
- 3 fatty acids
What is the types of bond broken in a triglyceride and describe the process (3)
- ester
- hydrolysis
- chemical insertion of bond
Describe two functions of lipids in plants (2)
- energy storage
- respiratory substrate
- source of energy
- waxy cuticle
- leaf waterproofing
- membrane structure
State how the structure of a saturated fatty acid differs from the structure of an unsaturated fatty acid (2)
- saturated - no double bonds
- fewer hydrogen atoms
- comparative reasons
Describe a test to show that a solution contains amino acids (2)
- add biuret test
- blue to purple
Suggest a problem that could aride in using this test if very low concnetration of polymer present in solution (1)
- little colour change
- mauve may be masked
State the inorganic ion present in haem group (1)
iron
Why does haemoglobin have a quantenary structure (2)
- four polypeptide chain
- in tertiary form
Name how alpha helix structure is maintained (2)
hydrogen bonding
state the level of protein structure shown by haemoglobin (1)
quantenary
Name two types of bonds present to maintain 3D shape of the polypeptide chain (1)
- disulphide bond
- ionic bond
- hydrogen bond
- hydrophobic interactions
Describe two ways in which the structure of phospholipids differ from triglycerides (2)
phospholipid
* 2 fatty acids
* phosphate head
* hydrophillic head and hydrophobic fatty acid tails
triglyceride
* 3 fatty acids
* no phosphate
* non polar / hydrophobic
Name the type of bond formed between two amino acids (1)
peptide
Name the molecule produced when lactose is broken down (1)
glucose and galactose
