Topic 1.1 - 1.3 carbs, lipids, proteins, enzymes, inorganic ions, water Flashcards
Describe the structure of collagen
Made up of 3 α-chains forming a triple gamme helix.
Helices are held together by hydrogen bonds.
Explain why it is important that the lipid composition of the membrane of prokaryotic organisms changes if the temperature changes 3 marks 3 points
annoying q
- because membranes control permeability
- such as uptake of nutrient/oxygen
- because membranes need to be fluid for movement/cell division
What type of bond do carboydrates, proteins and lipids have in common
covalend (literally between atoms ie C-H)
What are the two main features of cellulose
NB cellulose is required for STRUCTURE not STORAGE (like starch)
- strong and rigid
- fully permeable
How come cellulose is strong and rigid
and why is this important
many hydrogen bonds between microfibrils (chains) collectively provides great strength and rigidity
important becuase it prevents plant cells from bursting when water enters so turgidity can be maintained
How come cellulose is fully permeable
2 points
- polar nature of glucose allows water/minerals to diffuse through
- large gaps between different microfibrils which allows substanes to get close to cell membrane
Describe the structure of cellulose
- composed of long, unbranched chains of beta glucose monomers
- every other β glucose monomer is inverted
- (exposes OH groups so H bonds can form)
- β glucose molecules joined by 1,4 glycosidic bonds
- Microfibres and microfibrils are long threads which are made up of long cellulose chains joined together by **H bonds **
What two polysacharrides are in starch?
- amylose
- amylopectin
Describe amylose
structure and what means
4 points
- unbranched chain of glucose molecules
- joined by 1,4 glycosidic bonds
- as a result it is coiled
- very compact so can store a lot of energy
Describe amylopectin and what its structure means for its properties
5 points
- made up of glucose molecules joined by 1,4 glycosidic bonds and 1,6 glycosidic bonds
- makes it a branched molecule
- due to presence of many side branches it is rapidly digested by enxymes
- therefore energy is released qucikly
- it is also compoct, not as compact as amylose
is amylose or amylopectin more compact
amylose
Are the melting points of unsaturated or saturated lipids lower?
why
unsaturated
because the IMFs are weaker due to double bonds forming kinks in the chain (less conact surface area for VDW forces)
properties of lipids
5 features
- waterproof (because fatty acid tail is hydrophobic)
- very compact
- better gram for gram energy release than carbohgydrates or proetins becauyse more C-O bonds are hydrolysed
- lipids are non polar and insoluble in water, so good for stroage as don’t affect WP of cell and dont interfere with water based reactions in cytoplasm
- conduct heat slowly, good insulators
Firbous proteins
5 points
- long parallel polypeptides
- very little tertiary/quaternary structure-mainly secondary
- occasional cross-linkages which form microfibres for tensile strength
- insoluble
- used for structural purposes
globular proteins
- complex tertiary/quarternary structure
- form colloids in water
- many uses eg hormones and antibodies
what is the purpose of collagen
forms the structure of bones, cartilage and connective tissue
structure of haemoglobin
also is it water soluble
- fur polypeptide chains; two alpha, two beta
- each subunit contains a haem group which contains the Fe2+ ion
-( it carries oxygen)
yes
what is sucrose made of
glucose and fructose
A glycoprotein has a carbohydrate attracted to a protein molecule. Describe the three-dimensional structure of a glycoprotein
- proteins consist of amino acids joined by peptide bonds
have bonds between R groups involved in maintaining 3D structure (also ionic h ) - carbohydrates consist of monosaccharides
joined by glycosidic bonds
plants
what do calcium ions do
needed to form calcium pectate for middle lamellae in plants
plants
what are magnesium ions for
needed to produce chlorophyll
