Proteins Carbohydrates Lipids Water Edited by Janet A Renshaw School of Biological Sciences.
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Transcript of Proteins Carbohydrates Lipids Water Edited by Janet A Renshaw School of Biological Sciences.
ProteinsProteinsCarbohydratesCarbohydrates
LipidsLipidsWaterWater
Edited by Janet A Renshaw
School ofBiological Sciences
Introduction Carbohydrates Proteins Lipids Water Questions and Answers
EXIT
They are all based on the chemical elements carbon, hydrogen and oxygen.
Proteins can also contain the elements nitrogen, sulphur and phosphorous
The three main organic molecules are carbohydrates, proteins and lipids.
These molecules are very important in living organisms, they can be used as building blocks for cells and also for energy
The structures of these molecules are The structures of these molecules are
of key importance to their functionsof key importance to their functions
Carbohydrates
ProteinsLipids
Water is a very important molecule, it makes up between 45- 75% of the body mass of most organisms and without it life on earth would not have evolved.
Carbohydrates have roles in all forms of life and make up most of the organic matter on earth.
Monosaccharides are the basic monomer units of which carbohydrates are composed.
The most common monosaccharide is glucose
sta
rche
s
cellulose
glycogen
suga
rs
carbonhydrogenoxygen
Carbohydrate molecules consist of 3 elements
H
in the form the OH is hereOH
HOOH
OH
H
H
O
H2COH
H
This has a great effect on the property of molecules made when glucose molecules link together.
in the form the OH is here
H
OH
H
in the form the OH is hereOH
H
in the form the OH is hereOH in the form the OH is hereOHOH
HOOH
OH
H
H
O
H2COH
H
HOOH
OH
H
H
O
H2COH
H
HOOH
OH
H
H
O
H2COH
H
HOOH
OH
H
H
O
H2COH
Hin the form the OH is here
H
OH in the form the OH is here
H
OHOH
Glucose Glucose Glucose can exist in two forms, the form and the form.The two forms of glucose have the same properties.
The only difference between them is the position of one of the OH groups.
DisaccharidesDisaccharidesWhen 2 monosaccharides join together they form a larger disaccharide
molecule.
The linkage is via a glycosidic bond where they share an oxygen molecule and a water molecule is eliminated.
Monosaccharide
Monosaccharide
Removal of H20
Disaccharide
share
oxygen
Two monosaccharides can become linked by a condensation reaction.
H2O
Glycosidic Bond
Condensation Reaction between 2 glucose monomers
Examples of DisaccharidesExamples of DisaccharidesMaltose
Formed from 2 glucose molecules, formed in germinating seeds from the breakdown of starch, providing energy
Sucrose
Formed from 1 glucose and 1 fructose molecule and is the form in which carbohydrates are transported in the phloem in plants
Lactose
Formed from 1 glucose and 1 galactose molecule, it is an energy source found in the milk of nearly all mammals
PolysaccharidesPolysaccharidesCarbohydrates which are made from many linked monosaccharide
monomers form long chain-like molecules
called polymers.
- made from glucose
monomers
polysaccharides cellulose
glycogen
starch
StarchStarch
The other form is amylopectin which consists of branched chains of glucose, this forms a branched compact brush.
One form is amylose which consists of un-branched chains of glucose,this coils into a helical compact structure
Found in two forms, which are both made up of glucose
Starch is the main storage carbohydrate in plants.
Hydrolysis reaction:- A chemical process whereby a compound is cleaved into two or more simpler compounds along with the uptake of water
Amylase(enzyme)
Breaks down
maltose
glucose
sources of
energy
Starch
H2O
It is the main storage carbohydrate in
mammals found in liver and muscle cells.
It is more branched in structure than amylopectin.
The more branched the molecule, the quicker it can be made and broken.
GlycogenGlycogen
A polymer of glucose monomers.
Is a polymer of glucose
monomers.
It is an important component
of plant cell walls.
It does not spiral as with
glucose
glucose consists of chains that are straight and long, they lie parallel to each other bound together by hydrogen bonds.
CelluloseCellulose
Proteins have many roles in living organisms and are extremely important. There are many different types of proteins with different functions, for example,
Antibodies are protective proteins and as part of the immune system they help fight disease
Biological molecule with enzyme
Biological moleculeBiological molecule
with enzymeBiological molecule
with enzymeEnzyme
Enzymes are proteins which speed up the rate of biological reactions
Haemoglobin is a protein that transports oxygen in the blood.
ANTIBODIESDISEASE
The R group can contain hydrogen and/or carbon and sometimes oxygen, sulphur and nitrogen.
This is the basic structure of an amino acid.
Proteins are polymers made up of monomers called amino acids.
There are 20 different amino acids, amino acids can join in any order to
produce an infinite number of different proteins.
The only thing that changes between different amino acids is the R group
A condensation reaction joins two amino acids together forming a dipeptide. The bond formed between them is called a peptide bond
H2O
Peptide Bond
A chain of many amino acids linked by peptide bonds is called a polypeptide. A protein can consist of one or more polypeptides.
Proteins can get broken down by hydrolysis reactions into polypeptides, dipeptides and amino acids.
The primary structure :- this is the sequence of amino acids in the polypeptide formed from many condensation reactions
Protein StructureProtein Structure
There are four different levels of protein structure.
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
aminoacid
H2O H2O H2O H2O H2O H2O H2O H2O H2O
The secondary structure :- where the polypeptide chains can fold
into stable 3D regular shapes. One secondary structure is the -helix
where the chains fold into a helical shape. Another structure is the
strand
-helix structure
The tertiary structure :- this is when further folding occurs and this is the overall shape of the polypeptide chain.
This is the tertiary structure of the alpha chain of the protein, haemoglobin.
This 3D shape is maintained by a series of weak interactions which are mostly hydrogen bonds.
The quaternary structure :- polypeptides can associate with other polypeptides and they way in which they bind together to form the molecule is the quaternary structure.
Quaternary Structure taken by means of rasmol (www.dkfz-heidelberg.de)
Globular proteins, for example
enzymes, form roughly a spherical
shape and most of them are soluble
in water.
Proteins fit into two subgroups, globular proteins and fibrous proteins.
The function of a globular protein is determined by its shape, so its shape
is vital.
The usual function for this subgroup is a chemical function.
Molecular representation of an enzyme
Substrate
Protein SubgroupsProtein Subgroups
Fibrous proteins do not form a spherical structure they form long chains
and they are insoluble.
Fibrous proteins have structural roles, like giving strength or elasticity to
certain tissues.
Muscle Fibre (www.uoguelph.ca)
Proteins can become denatured causing their shape to change therefore affecting their function.
Example shows an enzyme becoming denatured and losing hold on a substrate
A protein can vibrate due to an increase in temperature, which can cause it to become denatured, causing the weak bonds holding the tertiary or quaternary structure together to break.
Lipids are insoluble.
They are important dietary constituents as they are full of energy, contain certain vitamins and have a major role in cell membranes.
Two major types of lipids are triglycerides and phospholipids.
fats
oils
stero
ids
wa
xes carbon
hydrogen
oxygen
Unlike carbohydrates and proteins, lipids do not form polymers.
Lipid molecules consist of 3 elements
The formula for fatty acids is R-COOH, where the R, which is the hydrocarbon chain can be saturated or unsaturated.
They are formed from a glycerol molecule linked by ester bonds to three fatty acids.
Ester bond:-This is formed from a condensation reaction where the carboxyl group of a fatty acid and an OH group from the glycerol join and water is lost so they share an oxygen atom.
TriglyceridesTriglycerides
This group of lipids are the
fats and oils.
Glycerol 3 saturated fatty acids
ester bond
3H2O
Triglyceride Molecule
The phosphate group is soluble in water, it is water loving, which is termed hydrophillic.
The fatty acids are insoluble in water, they repel water, which is known as hydrophobic.
Due to these properties
phospholipids form cell
membranes when in water
PhospholipidsPhospholipidsFatty acid
Fatty acidglycerol
phosphate
water
glycerol glycerolglycerol
fatty acids
phosphates
Simplified structure of a phospholipid molecule used in
diagrams of membranes
Phospholipid Bilayer formed in
water
H2O
H2O
H2OH2O
H2O
H2O H2O
Water is an inorganic substance.
It has many essential properties, it has these properties because of the way in which the molecules in water bond together.
The biological importance of water is dependent on its
physical properties.
Some Important Properties of WaterSome Important Properties of Water
Solvent Properties
Water is a polar molecule and it’s polarity makes it an excellent solvent
for other polar molecules.
There is a whole range of other polar molecules, which
include small organic units such as glucose and amino
acids, also ions like calcium,potassium and sodium.
Non-polar substances do not dissolve in water.
Specific Heat Capacity
Water has a high specific heat capacity,
which means it has temperature stability.
It takes a large amount of heat (energy)
to raise the temperature of water
measurably. Due to this water containing
organisms are stable thermally.
Latent Heat of Evaporation
Due to the high specific heat capacity, water resists
evaporation into gas better than other liquids do.
This is significant to humans and other animals as we
rely on the evaporation of water from our body surface as
a cooling device.
Now go to the next page to start testing your knowledge.
This section is to test your knowledge on what has been covered in this package.
To get the answer click on the answer button
You will need paper and a pen to help you answer some of the questions
Question 1 What is the name of this
carbohydrate monomer ?
Question 2 Draw a diagram to show how two of these monomers form a
disaccharide and label the bond
CARBOHYDRATESCARBOHYDRATES
Click here for answer
Click here to see diagram
Question 4 What are the two forms of the polysaccharide starch ?
Question 5 What are the differences between the two forms ?
Question 3 What is the name of the disaccharide formed ?
Click here for answer
Click here for answer
Click here for answer
PROTEINSPROTEINS
Question 6 What three elements can be found in proteins but not in
carbohydrates and lipids ?
Question 7 There are two subgroups of proteins, globular proteins and
fibrous proteins.
Which subgroup -
a) is soluble in water ?
b) has structural roles ?
c) form long chains ?
d) is spherical in shape ?
Click here for answer
Click here for answers
Question 8 What type of reaction occurs to join amino acids together?
Question 9 What is the name of the bond formed between amino acids
in a protein ?
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Click here for answer
LIPIDSLIPIDS
Question 10 What are the two major types of lipids?
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Question 11 How is an ester bond formed in a triglyceride?
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Question 12 The phosphate group of a phospholipid is soluble in water,
what is the term used for this type of molecule
Question 13 Fatty acids are insoluble in water, what is the term used for
this type of molecule?
Click here for answer
Click here for answer
Question 14 Name two important properties of water.
WATERWATER
Question 15 Water is a polar molecule do Non-polar substances
dissolve in water?
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Q1
Answer Answer This carbohydrate monomer
is glucose
Q2
Glycosidic Bond
AnswerAnswer
H20
Q3
Answer Answer The disaccharide formed
is maltose
Q4
AnswerAnswer The two forms of starch are amylose and amylopectin
Q5
Answer Answer Amylose consists of unbranched chains of glucose and has a helical compact structure
Amylopectin consists of branched chains of glucose and has a branched compact structure
Q6
Answer Answer Nitrogen, sulphur and phosphorous
Q7
Globular proteinsa) soluble in water ?
Fibrous proteinsb) structural roles ?
Fibrous proteinsc) form long chains ?
Globular proteinsd) spherical in shape ?
AnswerAnswer
Q8
AnswerAnswer A condensation reaction
Q9
AnswerAnswer A peptide bond
Q10
Answer Answer Triglycerides and phospholipids
Q11
Answer Answer
An Ester bond is formed from a condensation reaction where the carboxyl group of a fatty acid and an OH group from the glycerol join and water is lost so they share an oxygen atom.
Q12
Answer Answer The phosphate is termed
as a hydrophillic molecule
Q13
Answer Answer Fatty acids are
hydrophobic molecules
Q14
Answer Answer
Two from any of these
- solvent properties
- high specific heat capacity
- high latent heat of evaporation
Q15
Answer Answer No