Module 2:Biological molecules Flashcards
Why is water a polar molecule?
due to an uneven distribution of charge within the molecule
the H atoms are more + charged than the O atoms so one end of the molecule is more positive
Which metabolic reactions is water a metabolite for?
condensation and hydrolysis
Is water a solvent?
yes
Does water have a high SHC?
If so , what benefits does this have?
yes
-it helps to minimise temp fluctuations in living things as lot of energy is required to warm it up
Does water have a high latent heat of vapourisation?
If so what benefits does this have?
yes
it means that evaporation has a cooling effect on the body with minimal water loss
Is water compressible ?
What does this provide?
no
this means it provides good support
What does strong cohesion between water molecules enable?
the effective transport of water in tube like transport cells as the strong cohesion supports the columns of water
Is ice less or more dense than water?
If less , what does this enable?
Its less dense than water meaning it floats above water which creates an insulating layer which prevents organisms in large bodies of water from freezing
What is a monomer?
Give 3 examples
What is a polymer?
the small units that are the components of larger molecules
( glucose , amino acids and nucleotides)
large molecules made from repeating monomer units joined together
What molecule is eliminated during a condensation reaction and what is a condensation reaction?
What is a hydrolysis reaction ?
a water molecule
a reaction that joins monomers by chemical bonds
a reaction that adds a water molecule to break a chemical bond between 2 molecules
What elements do carbohydrates contain?
carbon
hydrogen
oxygen
What is the structure of a carbohydrate?
a long chain of sugar units called saccharides
What are the three different types of saccharide?
monosaccharides-small simple sugars
disaccharides-made of two monosaccharides
polysaccharide-long chain of monosaccharides
Name three important functions of carbohydrates
-as a usable energy source for cells
-an energy storage molecule
-formation of cell wall in plants/fungi/bacteria
What do monosaccharides provide and how?
Give an example of a monosaccharide and describe its structure and function
a rapid source of energy
as they are small and simple they are readily absorbed and require little/no change before use in cell activity
Glucose-a hexose monosaccharide
its the main substrate for respiration
its breakdown releases ATP which is required by cells for every chemical reaction they undergo
Monosaccharides/disaccharides can’t be used to store energy , but why not?
they are chemically active and soluble in water so would affect the water potential of the cell
What are the two isomers of glucose and how do their molecular structures differ?
alpha and beta glucose
alpha-on the 1st carbon the H atom is at the top
beta-on the 1st carbon the OH group is at the top
What is the name of the covalent bond that links monosaccharides together?
glycosidic bonds
What are the 3 main disaccharides and what monosaccharides do they consist of?
maltose-2 glucose molecules
sucrose-glucose and fructose
lactose-glucose and galactose
Name the three main polysaccharides and which glucose isomer they consist of
starch(alpha) , cellulose
(beta) and glycogen(alpha)
What is the role of glycogen?
Describe its structure… (4)
it is the main energy storage in animals
-made of many alpha glucose monomers joined by glycosidic bonds in condensation reactions
-contains 1-4 and 1-6 glycosidic bonds
-has a highly branched structure which allows glucose and therfore energy to be released easily
-its a large molecule but is compact which maximises the amount of energy it can store
What is the role of starch?
How is it produced?
Which 2 polysaccharides does it consist of?
Is it soluble/insoluble and is it compact?
it is a major carb storage molecule in plants
from glucose made in photosynthesis
amylose and amylopectin
its insoluble and compact but it is easily broken down
Describe the structure of amylose…
unbranched structure consisting of alpha glucose monomers joined by 1-4 glycosidic bonds
-therefore it has a coiled(helix) structure making it very compact
Describe the structure of amylopectin…
a branched chain(every 20 monomers) made up of alpha glucose monomers joined by 1-4 and 1-6 glycosidic bonds
-its branched structure results in it being rapidly digested by enzymes which releases energy quickly
What is the role of cellulose?
Describe its structure…
What are microfibrils and what is their function?
it is the main component of plant cell walls
it has an unbranched structure consisting of beta glucose monomers joined by 1-4 glycosidic bonds
H bonds are present between monomers on the same/adjacent chains to prevent the structure spiralling and losing strength
-strong threads made of long cellulose chains joined by H bonds
-they provide structural support to plant cells
What is a lipid?
What elements do they contain
Are they polar/non polar
State the 2 types of lipids and what they mean , what is their state at room temp?
a biological molecule that is only soluble in organic solvents such as alcohols
-contain C , H and O , they are non polar
saturated-(solid)don’t contain any carbon-carbon double bonds
unsaturated-(liquid)contain 1 or more carbon-carbon double bonds
What does the presence of double bonds cause to happen in molecules?
causes them to kink so they are unable to pack closely together
the greater the number of double bonds , the weaker the intermolecular bonds resulting in lower melting point
What do triglycerides consist of?
1 glycerol molecule and 3 fatty acid chains joined by ester bonds in condensation reactions
What molecules are triglycerides and phospholipids examples of?
macromolecules
What is the role of triglycerides in plants and animal cells?
What molecule group does glycerol belong to?
What molecule group do the fatty acid chains belong to?
What group do both molecules contain?
to act as energy reserves
glycerol-alcohols group
fatty acids-carboxylic acids
an OH group
What elements do phospholipids contain?
How is a phospholipid different to a triglyceride.
Which part of phospholipids are hydrophilic / hydrophobic
C , H , O and phosphorus
one fatty acid chain is replaced by a phosphate group
the CHARGED phosphate heads are hydrophilic so they interact with and are attracted to water
the NON POLAR tails are repelled by water so they are hydrophobic
Name all the reducing and non reducing sugars
REDUCING-all monosaccharides and some disaccharides(lactose and maltose)
NON-REDUCING-disaccharides(sucrose) excluding lactose and maltose and simple polysaccharides
