Biological Molecules Flashcards
what is a condensation reaction?
Condensation is the formation of larger, biological molecules (polymers) from smaller molecules (monomers).
what is the by- product of a condensation reaction?
water
condensation of sugars can form?
carbohydrates
condensation of amino acids produce?
proteins
condensation of two monosaccharides produce?
disaccharides
many disaccharides form?
polysaccharides
condensation of fatty acids and monoglycerides produce?
lipids
what is a hydrolysis reaction?
Hydrolysis is the break down of large, biological molecules into smaller molecules. The smaller molecules can then be taken up by the cells and used for a number of functions.
hydrolysis of protein produces?
amino acid
Hydrolysis of carbohydrates produces?
disaccharides and monosaccharides
Hydrolysis of lipids produce?
fatty acids and monoglycerides
We cannot survive without larger biological molecules including carbohydrates, proteins and lipids.
Describe
how larger biological molecules are made using biological terminology.
Larger biological molecules are called polymers and they are produced when smaller molecule monomers join together by a condensation reaction that releases water as a byproduct
Lipids are very important for our cell membranes, to keep us well insulated and lining our organs in our body.
Describe
how lipids are turned into smaller biological molecules.
Lipids are polymers (1) and they break down through hydrolysis reactions. (1)
Water is added to the reaction to split up the polymer into monoglycerides (1) and fatty acids. (1)
Describe
what happens when a protein (polypeptide) is broken down into its constituent monomers.
A hydrolysis reaction (1) takes place using water. (1)Amino acids are released. (1)
When we eat food, we need to chew and break food down. This is important to allow the small intestines to absorb key nutrients from food into our bloodstream, to where they need to go.
Describe
the outcome if hydrolysis reactions did not happen.
If hydrolysis reactions did not happen, larger biological molecule polymers (1) would not be able to break down into smaller molecule monomers. (1) Nutrients would not be produced and absorbed into the blood. (1)
Using your knowledge about polysaccharides,
describe
how a polysaccharide chain is made from monosaccharides.
Polysaccharides are made when 2 monosaccharides join together (1) by condensation reaction. (1) This produces a disaccharide. (1) Then 2 or more disaccharides (1) join together by glycosidic bonds to produce a polysaccharide. (1)
Name and
describe
the type of reaction through which polymers are formed.
Name - Polymerisation
Type - Condensation (using water)
What are carbohydrates made out of?
made of carbon, hydrogen and oxygen atoms
examples of monosaccharides (simple sugars)?
-glucose
-Galactose(found in milk)
-fructose(found in fruit)
what does ATP stand for?
adenosine triphosphate
what are isomers?
isomers have the same molecular formula but a different arrangement of atoms in space
when two monosaccharides join via a condensation reaction they form a?
disaccharide
example of disaccharides?
-maltose
-sucrose
-lactose
how do you make a maltose?
glucose + glucose=maltose
how do you make a lactose?
glucose + galactose=lactose
how do you make a sucrose?
glucose + fructose=sucrose
sucrose is normally a?
common table sugar
lactose is a sugar found in?
milk
polysaccharides are made up of?
three or more monosaccharides joined together by glyosidic bonds.
the chain may be branched or unbranched
types of polysaccharides?
starch
-glycogen
-cellulose
-chitin
what is the test for non-reducing sugars such as sucrose?
step 1:boil in dilute HCL (to hydrolyse the non-reducing sugar)
step 2:Neutralise the solution by adding sodium hydrogen carbonate
step 3: repeat the benedict’s test
.the test will now be positive if a non-reducing sugar is present
.if the solution remains blue, then no sugar is present
what is the structure of cellulose?
cellulose is a long chain of beta-glucose.
beta glucose molecules are linked by glyosidic bonds to form linear cellulose chain hat are unbranched.
what is the function of cellulose?
cellulose is the most abundant natural polymer.
-the cell walls of plants
How are the structures of cellulose and glycogen different?
Glycogen has a branched structure and forms coils, whereas cellulose is a straight chain.
Glycogen has both 1,4- and 1,6-glycosidic bonds.
Cellulose just has 1,4-glycosidic bonds.
Cellulose is made from beta-glucose monomers, whereas glycogen is made up of alpha-glucose monomers.
How does glycogen act as an energy source?
Glycogen can be hydrolysed to glucose.
The glucose could then be used to release energy through the process of respiration.
Name the monomer maltose is made from
Glucose
Explain how starch is adapted to its function in the cells of plants.
Starch is insoluble in water, so can be stored without affecting the cell’s water potential.
Starch is helical in shape, making it compact for storage.
Starch is a large molecule, so is unable to leave the cell.
What is structurally different between starch and cellulose that gives them different physical properties?
cellulose is formed by 1-4 glycosidic linkages and crosslinks, making it rigid. starch has 1-4 and 1-6 glycosidic linkages without the tight crosslinks of cellulose
what are Triglycerides?
Triglycerides are a type of lipid that are mainly used as energy storage molecules.
Formation of triglycerides
are formed by the condensation of one molecule of glycerol and three molecules of fatty acids.
ester bonds form between the glycerol and the fatty acid chains.
one water molecule is released per ester bond
What bond does the condensation reaction between glycerol and a fatty acid form?
ester bond
functions of triglycerides
-in energy release
-lipids contain lots of energy(9 cal per gram)
-triglycerides repel water
-lipid droplets
why is there lots of energy released when triglycerides are broken down?
because chemical energy is stored in the fatty acid hydrocarbons tails
why do triglycerides repel water?
there are insoluble in water because the fatty acid tails are hydrophobic.
-this means that the cells water potential is not affected by it
why is it important that triglycerides repel water?
because if triglycerides didn’t repel water the water would enter the cell through the process of osmosis this would make the cell swell up
what makes a fatty acid saturated?
if there are only single bonds between carbon atoms in the hydrocarbon chain.
Structure of saturated fatty acids
-carbon atoms are not joined by double bonds in saturated fatty acids
-in saturated fatty acids the number of hydrogen atoms attached to the carbon skeleton is maximised this means that the fatty acid is saturated
Structure of unsaturated fats
the main difference between saturated fates and unsaturated is their hydrocarbon tails
unsaturated fatty acids have one or more double bonds between carbon atoms in the hydrocarbon chain.
cooking oils are examples of unsaturated fatty acids.
unsaturated fats are liquid at room temperature because?
double bonds kink the carbon chain so unsaturated fats cannot pack together tightly
glucose is a monomer and its polymer’s are?
-starch
-cellulose
-glycogen
the three examples of polysaccharides we need to know are?
-starch
-cellulose
-glycogen
three examples of disaccharides are?
-sucrose
-maltose
-lactose
three examples of monosaccharides?
-glucose
-fructose
-galactose
what are isomers?
same molecular formula but different structure
disaccharides are made of two ?
and joined together by a?
formed by what type of reaction?
-monosaccharides
-glycosidic bond
-condensation reaction
glucose+glucose=?
maltose+water
glucose + galactose=?
lactose+water
glucose+fructose=?
sucrose+water
what are the monomers of starch?
alpha glucose
what are the monomers of cellulose?
beta glucose
what are the monomers of glycogen?
alpha glucose
what is the bond between monomers of starch?
1-4 glycosidic bonds in amylose
1-4 and 1-6 in amylopectin
what are the bonds between monomers in cellulose?
1-4 glycosidic bonds
what are the bonds between monomers in glycogen?
1-4 and 1-6 glycosidic bonds
what is the function of starch?
store of glucose
what is the function of cellulose?
structure strength for cell wall
what is the function for glycogen?
store of glucose
where is starch’s location?
plant cells (e.g chloroplast)
where is cellulose located?
plants-cell wall
where is glycogen located?
animals-mainly in muscle and liver cells
what is the structure of starch?
made of 2 polymers:
Amylose-an unbranched helix
Amylopectin- a branched molecule
what is the structure of cellulose?
polymer forms long straight chains. chains are held in parallel by many hydrogen bonds to form fibrils.
what is the structure of glycogen?
a highly branched molecule
how does the structure of starch help in its function?
Helix can compact to fit a lot of glucose in a small space. Branched structure increases surface area for rapid hydrolysis back to glucose. INSOLUBLE so won’t affect water potential
how does the structure of cellulose lead to its function?
many hydrogen bonds provide collective strength
insoluble-won’t affect water potential
how does the structure of glycogen lead to its function ?
Branched structure increases surface area for rapid hydrolysis back to glucose
INSOLUBLE so won’t affect water potential
describe the structure of a triglycerides?
a glycerol joined together with 3 fatty acids via a condensation reaction
describe the structure of a phospholipids?
glycerol attached to to fatty acids and 1 phosphate group
in a triglyceride the bond between the glycerol and fatty acid is called?
ester bond
do saturated fatty acids have a carbon-carbon double bond?
no only single bond between carbon
what are the properties of triglyceride’s and why?
-ENERGY STORAGE, due to the large ratio of energy-storing carbon-hydrogen bonds , compared to the number of carbon atoms.
-can act as a METABOLIC WATER SOURCE, due to the high ratio of hydrogen to oxygen atoms. Release water if they are oxidised
-do not affect WATER POTENTIAL because their are hydrophobic
-relatively low mass therefore a lot can be stored without increasing the mass and preventing movement.
how are dipeptides formed?
when two amino acids join by a condensation reaction
how are polypeptides formed?
are formed by the condensation of many amino acids
what are the 4 levels of structure in a protein?
(small to big)
primary,secondary,tertiary and quaternary
what is the primary structure of protein?
the order of the amino acids in the polypeptide chain- this is a polymer
how are secondary structures created (protein)?
the sequence of amino acids causes parts of a protein molecule to bend into alpha helix shape or fold in beta pleated sheets
what holds the secondary structure together?
hydrogen bonds
how are tertiary structure made?
the further folding of the secondary structure forms a unique 3D shape
what bonds hold the tertiary structure?
ionic,hydrogen and disulphide bonds
what is the difference between tertiary structure and quaternary structure (proteins)?
their similar but the difference is that quaternary structure is a protein made up of more than one polypeptide chain.
what is the test for starch?
-add iodine if starch is present the colour change will turn orange to blue/black
what is the test for reducing sugars?
-add benedict’s reagent and heat
-positive test turns solution from blue to green or orange or red
test for non-reducing sugars?
following a negative benedict’s test, where the reagent remains blue
-add acid and boil -(this is acid hydrolysis)
-cool the solution then add an alkali to neutralise
-add benedict’s reagent and heat
-a positive test observation means the solution turns from blue to orange or brick red
what is the test for proteins?
-add biuret
-a positive test shows the solution turn from blue to purple
what is the test for lipids?
-dissolve the sample in ethanol and shake it.
-then,add distilled water
-a positive test observation=a white emulsion forms
what is a polynucleotide?
the polymer of nucleotides is called a polynucleotide
Some RNA (rRNA) is also combined with proteins to create?
ribosomes
the process of DNA replication is called?
semi-conservative replication
what are the 5 key properties of water?
-it is a METABOLITE (e.g in condensation and hydrolysis reactions)
-and important SOLVENT in reactions
-has a HIGH HEAT CAPACITY
-has a LARGE LATENT HEAT OF VAPORISATION
-has strong COHESION between water molecules. providing surface tension.
what is the role of hydrogen ions?
lower the PH of solutions and impact enzyme function and haemoglobin function
what is the role of iron ions?
a component of haemoglobin in the transport of oxygen
what is the role of sodium ions?
involved in the co-transport of glucose and amino acids in absorption.
what is the roles of potassium ions?
a component of DNA
