Biological Molecules Flashcards
What are the 4 key elements which make up biological molecules and are essential for all living organisms?
Hydrogen
Oxygen
Carbon
Nitrogen
What are Inorganic Ions?
Play and important part in living organisms
Occur in solution in the cytoplasm and body fluid of organisms in very low amounts.
What are Macronutrients?
Inorganic ions needed in small amounts.
What are examples of Macronutrients?
Inorganic ions such as- Magnesium, Iron, Phosphate and Calcium
What is the symbol for phospahte?
PO4 3-
What is magnesium’s importance?
Constituent for chlorophyll and so is essential for photosynthesis. Plants without it in the soil can’t make chlorophyll and so leaves are yellow (chlorosis)
What is magnesium required for?
Plant growth and development
What is iron’s importance?
A constituent of haemoglobin (which transports oxygen inside rbc’s)
A lack of this can lead to anaemia.
What is phosphate’s importance?
Used for making nucleic acids and is also a constituent of phospholipids, found in plasma membranes.
What are nucleic acids?
DNA, RNA, ATP
What is Calcium’s importance?
Structural component of bones and teeth in mammals and also a component of plant cell walls, providing strength
What does inorganic mean?
Compounds that don’t contain carbon bonded to hydrogen e.g. water, carbon dioxide and nitrogen gas
What are Micronutrients?
Inorganic nutrients needed in minute (trace) amounts e.g copper and zinc
What is a molecule?
Two or more atoms joined together(these atoms can be the same or different)
What is an organic compound?
Compounds that are based on carbon and contain carbon bonded to hydrogen e.g. carbohydrates, lipids and proteins
What can Carbohydrates and proteins form?
Very large polymers
What is polymerisation?
The linking of identical monomers to form larger molecules called polymers
What happens when 2 monomers link together and what is this reaction called?
Water is eliminated- condensation reaction
How can a condensation reaction be reversed?
By the chemical insertion of water to the polymer- hydrolysis reaction
What are carboHydrates?
Long chain units of sugar called saccharides.
What are the main functions of carbohydrates?
Storage and release of energy
Cellular Structures e.g. the cellulose walls of plant cells
What are monosaccharides?
small organic molecules (monomers) used as building blocks of complex carbohydrates
What are disaccharides?
two monosaccharides joined together by glycosidic bonds during a condensation reaction.
What’s are polysaccharides?
Large complex carbohydrates formed from very large numbers of monosaccharides joined together by glycosidic bonds.
What is the general formula for Monosaccharides?
Cn(H2O)n
What is a glyceraldehyde?
A triose used in metabolic reactions.
What is the most abundant monosaccharide?
Glucose
What is another feature of monosaccharides?
They have varying number of carbon atoms, for instance: ribose
What is ribose?
A pentose sugar ( a component of nucleic acid).
What is Glucose?
A monosaccharide containing 6 carbon atoms in each molecule, it has 2 isomers- alpha and beta glucose
Why is glucose of great importance?
It is the main substrate for respiration.
ABBA?
Alpha below, beta above
What are isomers?
Molecules with the same chemical formula (C6 H12 O6) but different arrangements of their atoms
What is the difference between Alpha and beta?
In alpha glucose the OH group in C1 points down and the H atom points up. In beta glucose the OH group on C1 points up and the H atom on C1 points down.
What are other examples of hexose monosaccharides?
Fructose and galactose.
Why are Fructose and Galactose isomers?
They have the chemical formula C6 H12 06 but have different arrangements of their atoms.
What are the features of glucose?
Small and therefore soluble in water
and easily transported in the bloodstream of animals phloem plants.
What are the functions of monosaccharides?
Source of energy in respiration
Building blocks for larger molecules
Intermediates in reactions
Constituent of nucleotides
What are the three classes of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
What are examples of monosaccharides?
glucose
Fructose
Galactose
Glyceraldehyde triose sugar
What are some other types of monosaccharides of biological importance?
Pentose sugars(e.g. deoxyribose sugar found in DNA nucleotides) and triose sugars that are intermediates in respiration and photosynthesis
what are the properties of monosaccharides?
small so all soluble in water and therefore can easily dissolve inside the cell and they are easily transported in the blood stream of animals
What are the names of the disaccharides?
Either alpha or beta
What is the general formula for disaccharides?
C12 H22 O11
how are disaccharides formed?
When 2 hexose sugars is combine into condensation reaction (where a new glycosidic bond is formed with the elimination of water)
What are examples of disaccharides?
maltose- a + b glucose
Sucrose (alpha)- glucose +fructose
Lactose (beta)- glucose + galactose
What is maltose?
Found in seeds and is an important source of glucose during germination
what is sucrose?
transported through the phloem of all plants
What is lactose?
It is found in mammalian milk and is an important source of energy for their young
What is hydrolysis reaction used to do?
break down disaccharides into their respective monomers
what is the general formula of maltose, sucrose, lactose?
CH2 OH
why is the bond between the two sugars called a 1-4 glycosidic bond?
The bond is between carbon 1 of one monosaccharide and carbon 4 of the second monosaccharide
how are polysaccharides formed?
The monomers, which are monosaccharides (such as glucose) are linked together, by glycosidic bonds formed by a series of condensation reactions
what is the smallest polysaccharide made up of?
three Monosaccharide monomers are linked together
Why are polysaccharides insoluble?
They are usually made up of thousands of monomers, which gives them a large size
What are the two types of functions that polysaccharides usually have?
structural, or storage
what is glucose’s function in the body?
glucose id the main source of energy in cells and must be stored in an appropriate form
why is glucose converted into a storage polysaccharide like starch and glycogen?
glucose is soluble in water, and this would affect osmosis within the cell
What are shared functions of starch and glycogen?
-Insoluble, so don’t affect
-Compact so can be stored in a small place in the cell
-Easily hydrolysed to release to glucose for respiration
What are examples of polysaccharides?
starch
Glycogen
Cellulose
chitin
what is starch?
 Glucose energy storage polysaccharide in plant cells made up of two different molecules- amylopectin and amylose.
What is the starch polymer made up of?
Thousands of Alpha glucose monomers
what is the structure of amylose?
straight chained, helical polymer, containing alpha 1-4 glycosidic bonds
why can amylose store a lot of energy?
it is coiled, so it is a very compact molecule
What is the structure of amylopectin?
Branched polymer containing alpha 1-4 and alpha 1-6 glycosidic bonds
how is energy released quickly by amylopectin?
It is rapidly digested by enzymes due to presence of many side branches
what is glycogen?
an animal, glucose energy storage polysaccharide found inside liver and muscle cells made up of many alpha glucose molecules
Why is glycogen being highly branched important?
this allows the quick release of glucose(energy) from the end of the branches to be used in respiration
what type of bonds does glycogen have?
1-4 and 1-6 glycosidic bonds
what does glycogen being large but compact mean?
maximises the amount of energy it can store
what is the most abundant organic molecule on Earth?
Cellulose
what is cellulose?
 A polysaccharide made up of beta glucose monomers
why is cellulose important in plants?
it is important as a structural carbohydrate, and it is the most important component in the plant cell wall
what is the structure of Cellulose?
consists of long, parallel chains of beta glucose molecules joined by 1-4 glycosidic bonds
what type of bonds between the straight chains in Cellulose?
Hydrogen bonds
What are the functions of cellulose?
give the plant rigidity because of the cellulose cell wall is inelastic and has a high tensile strength to prevent the plant cells bursting
what is cellulose is structure?
-Beta glucose monomers joined by glycosidic bonds with each adjacent beta glucose molecule rotated at 180° to each other
-Forming straight chains
-Many straight chains joined together by many hydrogen bonds forms a strong microfibril
-Many microfibrils form a strong Celulose bundle
what contributes to Celulose’s structural stability?
each beta glucose molecule is rotated 180° to each other
How does cellulose form a helix structure?
rotates
how are microfibrils formed?
Between 60 and 70 cellulose molecules, molecules become tightly, cross-linked, and hydrogen bonds form between them
what is chitin’s structure?
similar structure to Celulose but differs in that some of the OH groups of each of the beta glucose molecules are replaced by nitrogen containing acetylamine groups
What is chitin made up of?
B glucose monomers with amino acid side chains( contains amino acid groups)
what does the additions of chitins structure make?
they make chitin a muco-polysaccharide
what are the functions of chitin?
-forms that exoskeleton of arthropods, such as insects(bees), arachnids(spiders) and crustaceans (e.g crabs
-Also forms the cell wall of fungi
what are the properties of chitin?
light weight
Waterproof
Strong
Insoluble
b(1-4) bonds
What do 2 things are lipids?
Triglycerides and phospholipids
What are lipids made from?
The same element as carbohydrates but lipids contain proportionally less oxygen than carbon hydrates
what are triglycerides made up of?
Two main components glycerol and fatty acids
why are triglycerides not polymers?
-they are made up of two different types of subunit (glycerol and fatty acids) which have different structures
-Triglycerides are not made from identical monomers
What is glycerol?
And alcohol with the formula C3H8O3
what is the structure of glycerol?
-Contains three carbon teach linked to a hydroxyl group (COH)
what are the properties of glycerol ?
- dissolves in water
-Hydrophilic molecule
what is glycerol constant in?
all triglycerides and phospholipids molecules we study
what is the general formula for fatty acids?
CH3 (CH2)n COOH
why can the specific fatty acid only undergo one condensation reaction?
Only one OH group
How many types of fatty acids are there?
There are several types of fatty acids
what determines the name of the fatty acid and proteins given?
(CH2)n
what is n (in glycerol) often a number between?
14 and 22
what are fatty acids made up of?
- three parts
a methyl group (CH3), a long hydrocarbon chain (CH2) and a carboxyl group (COOH) (constant)
how does one fatty acid differ from another?
By the length of the hydrocarbon chain( the ‘n’ is the number of CH2 units in the hydrocarbon chain; the higher the number the longer the fatty acid chain)
what is the variation in lipid structure due to?
How many different types of fatty acid?
What is the name given to a lipid affected by?
The name of the fatty acid
what are the properties of lipids?
insoluble and immiscible in water, but dissolve in other compounds e.g. ethanol (soluble in these organic solvents)
What is the test for lipids?
Ethanol( lipids dissolved in at an added to water, and shaken- white cloudy emulsion forms)
how are lipids formed?
By condensation reactions between one glycerol and 3 fatty acids
how do lipids differ from carbohydrates?
A portion of oxygen is much less in lipids
Why are lipids not polymers?
No formed from identical repeating monomers
why why can lipids only undergo three condensation reactions?
Because there are only three hydroxide molecules
what is the variation in lipid structure due to?
The many different types of fatty acid
What can saturated triglycerides do to the body?
increase cholesterol levels in the blood, which increases the risk of heart disease
What type of fatty acid do saturated triglycerides contain?
Saturated fatty acids
What are features of saturated fatty acids?
-hydrocarbon chain in saturated fatty acids contain no carbon to carbon double bonds
-has a straight hydrocarbon chain
why are saturated fatty acids called saturated?
has the maximum number of hydrogen atoms bound to the carbon atoms in the hydrocarbon chain
Why are unsaturated fatty acids, healthy?
they provide essentials
what are the features of unsaturated fatty acids?
-One or more carbon to carbon double bond in the hydrocarbon chain meaning that the hydrocarbon change does not contain the maximum number of hydrogen atoms(unsaturated)
why are saturated fats, which don’t contain any double bonds solid at room temperature?
The greater the number of unsaturated bonds, the weaker, the intermolecular bonds resulting in the lower melting point
How are triglycerides formed?
1 glycerol molecule combines with three fatty acid molecules and each fatty acid is linked to the glycerol by an ester bond
How many ester bonds will one triglyceride have in total?
Three
What do many types of fatty acids vary in?
chain length, presence and number of double bonds
what do low-density lipoproteins contain and transport and do? (bad cholesterol)
-saturated fats and cause harm
-fatty materials can block major arteries (plaque) and cause a heart attack.
what do you high-density lipoproteins do (good cholesterol)
-contain and transport unsaturated fats and carry harmful fats away to the liver for disposal
-A higher proportion of HDL in the blood lower, the risk of heart disease
what are house implications that a high intake of fat can cause?
Atherosclerosis
Aneurysm
Myocardial infraction
how are lipids used as an energy storage in seeds and animals?
Because they release a lot more energy than carbohydrates, when used as alternative respiratory substrate
how do lipids protect vital organs?
they are used as shock absorption and so prevent physical damage to internal organs (fats are laid down round delicate organs, and the fat that acts as cushion)
how can the lipids be used as thermal insulation?
Fat is stored in special connective tissue under the skin of animals e.g. The blubber in whales seals and polar bears is the leopard that reduces heat loss
how can lipids be used for buoyancy?
As lipids are less dense than water, they float and so have a role in maintaining buoyancy, an organisms such as fish
How can lipids produce metabolic water?
when they are oxidised by respiration
This is important in desert animal, such as the camel his hump is made of fat
How are lipids used waterproofing?
-what is a hydrophobic in cover the eco-skeleton of insects in the cuticle of plant leaves
-Both provide the waterproofing property and reduce water loss
How are phospholipids and triglycerides different?
-phospholipids have a glycerol, two fatty acids and a phosphate group
-triglycerides also have more carbons
where are phospholipids usually found?
On the cell membrane of an organism
What hydro are the fatty acid tails?
Hydrophobic
what hydro is the polar head group?
Hydrophilic
What does the phospholipid control?
The intake and outtake of water
Why are phospholipids an important component of?
Cell membranes
What are amino acids?
The monomers from which proteins are made
What elements do amino acids contain in addition to carbon hydrogen and oxygen?
nitrogen and sulphur is found in some amino acids, such as cysteine
what are the three functional groups of amino acids?
Amine
R group
carboxylic
What are amino acids joined by?
Peptide bonds formed in condensation reactions
What does the R group do?
changes properties/functions and changes the name
How many different variable groups are there?
20 e.g. glycine and serine
what is the general formula for amino acids?
R, NH2 CH OOH
what are naturally occurring amino acids?
lacine
alanine
glutamic acid
glycine
histidine
what is the structure of proteins the determined by?
The order number of amino acids in a protein
How are dipeptides formed?
Two amino acids combined in a condensation reaction
where does an ionic bond occur?
between oppositely charged r groups
where do hydrogen bonds occur?
Between some hydrogen and oxygen atoms in a polypeptide chain
Where do you disulphide bonds form between?
r groups which contain sulphur bonds these bonds are very strong
what are the properties of proteins?
-Crystalline
-Colourless
-Amphoteric and so can act as buffers
what does amphoteric mean?
Can be defined as having characteristics of an acid and base and are capable of reacting chemically as either in acid or base
What are the monomers of polypeptides?
Amino acids
What do polypeptides form?
Proteins
What structure do protein sometimes have?
Tertiary structure
what structure do proteins occasionally have?
Quaternary structure
What does the primary structure (only involves peptide bonds) of a polypeptide refer to?
The number of the sequence of amino acids in a polypeptide chain.
Why do proteins differ from each other?
because of their constituent amino acids
How is the secondary structure formed?
The primary structure of the polypeptide can coil to form either an alpha helix or a beta pleated sheet
what is the most common type of secondary structure?
Alpha helix held in a spiral shape by hydrogen bonds
What is the shape of an alpha helix determined by?
The type of bonding present
What types of proteins are secondary structure?
Fibrous proteins
What do some fibrous proteins have?
alpha helices is linked into rope strands e.g. keratin and collagen
Where is keratin found?
hair and nails
where is collagen found?
connective tissue and the skin
what is the less commonly secondary structure (also stabilised by hydrogen bonds)?
The beta pleated sheet which is a flat, zigzag structure e.g the protein silk
can both a helices and beta pleated sheets be present in the same protein?
yes
how is the tertiary structure formed?
By bending and twisting of the polypeptide helix into a more compact 3-D structure
What are proteins are tertiary structure?
fibrous or globular(enzymes, hormones, plasma and cell membrane proteins)
what bonds are the tertiary structure, shape maintained by?
Disulphide bridges
Ionic bonds
Hydrogen bond
(these form globular proteins)
how does the secondary structure become the tertiary structure?
-secondary structure is folded and held in a specific 3-D shape by bonds or interactions that form r groups of some of the amino acids in the polypeptide chain
what can fibrous proteins such as keratin be used to form? (they are long)
fibres
why is collagen fibres protein of great strength?
-due to the presence of both hydrogen and covalent bonds
-Collagen, molecules are wraparound each other to form fibrils, which forms strong collagen fibres
what does collagen form the structure of?
-bones
-cartilage
-connective tissue -is a main connective component of tendons, which connects muscles to bones
where are hydrophobic r group interactions?
on the inside or the proteins
Where are hydrophilic r groups found?
On the outside of the protein
When does the quaternary structure occur
where more than one type of polypeptide chain, each with a tertiary structure, combine to form a protein complex
How is the quaternary structure formed?
The tertiary structures are joined together by bonds, similar to those within the tertiary structures themselves
What bands are found in the tertiary structures?
ionic
Hydrogen
Disulphide
Hydrophobic interactions
What are quaternary protein sometimes associated with?
non-protein groups called prosthetic groups
What is an example of a quaternary structure of protein?
haemoglobin (a protein that carries oxygen in blood)
what is haemoglobin made of?
four polypeptide chains each with a tertiary structure.
what non-protein components does haemoglobin have?
haem groups, contain iron (Fe2+)
how are proteins classified?
According to their structure
What type of functions do fibrous proteins carry out?
Structural functions
What are the properties of fibrous proteins?
tough
Non-specific
Insoluble
What are the tertiary globular proteins?
Enzymes
Antibodies
plasma
Hormones
What are globular proteins that are quaternary proteins ?
haemoglobin
Antibodies
What are the properties of globular proteins?
-compact and folded into spherical molecules
-have a specific shape
-Soluble in water
why do globular proteins have a spherical shape?
caused by tightly folded, polypeptide chains (tertiary structure)
