Core Concepts: Biomolecules Flashcards
What is an inorganic molecule or ion
A molecule or ion that contains no more than 1 carbon atom
What is magnesium used for in plants and animals
Plants:
* Important constituent of chlorophyll
* Lack of magnesium - chlorosis - stunted growth
Animals:
* Mammals need magnesium for bones
What is iron (Fe²⁺) used for
Constituent of haemoglobin. Lack of iron causes anaemia
What are phosphates used for
- Used for making nucleotides including ATP
- Constituent of phospholipids - found in biological membranes
What is calcium used for in plants and animals
Plants:
* Component of plant cell walls - strength
Animals:
* Important structural component of bones and teeth
What is a dipole
A polar molecule with a positive and a negative charge
What is hydrolysis
The breakingdown of large molecules into smaller ones by addition of a water molecule
What is a condensation reaction
The chemical process where two molecules combine to form a more complex one. Releases water. New bond formed
What is a hydrogen bond
The weak attractive force between the partially positive charge of a hydrogen atom of one molecule and the partially negative charge of the other atom - O or N
What is Specific Heat Capaciy
The energy required to raise the temperature of 1g of a substance by 1°C
What is Latent Heat of Vapourisation
The energy required to convert 1 g of a liquid into vapour at the same time
What are the properties of water
- A solvent
- High Specific Heat Capacity
- High latent heat of vapourisation
- Cohesion
- High surface tension
- Ice is less dense than water
- Transparrent
How is water a solvent and why is it useful
Water molecules are dipoles. They attract charged particles and dissolve these in water. Water acts as a transport medium. Non Polar molecules don’t dissolve.
Why is water described as a universal water solvent
Because water is such a good solvent
How is water a metabolite
Water is used in many biochemical eactions as a reactant. Many reactions involve Hydrolysis or Condensation
Why does water have a high specific heat capacity and why is it important
The hydrogen bonds between water molecules restrict their movement, restricting an increase in kinetic energy nd therefore temperature. This prevents large fluctuations in water temperature, which keeps aquatic environments stable. Allows enzymes inside the cell to work efficiently
Why is it important for water to have a high latent heat of vapourisation
This is important for temperature control, where heat is used to vapourise water from sweat on the skin or from a leaf’s surface
How is water cohesive and why is it important
Water molecules attract eachother forming hydrogen bonds. Water molecules stick to eachother in a lattice. Allows columns of water to be drawn up xylem vessels in plants
Why is the fact that ice is less dense than water important
This forms an insulating layer over the surface of aquatic habitats; ponds and other aquatic habitats do not freeze solid so animals can still move/swim.
Why is water’s transparency important
Light can pass through and let aquatic plants photosynthesis effectively
What does an organic molecule mean
A molecule that has a high proportion of carbon atoms
What is a carbohydrate
An organic compound containing Carbon, Hydrogen, and Oxygen
What is the basic unit of a carbohydrate
a monosaccharide
What is a monosaccharide
- Small organic molecules
- Building blocks for larger carbohydrates
What is a monosaccharide with 3 carbon atoms called
Triose
What is a monosaccharide with 5 carbon atoms called
Pentose
What is a monosaccharide with 6 carbon atoms called
Hexose
What is an isomer
A molecule that has the same chemical formula but a different arrangement of atoms
Give 2 examples of Pentose sugars
- Ribose
- Deoxyribose
Give 3 examples of Hexose sugars
- Glucose
- Fructose
- Galactose
What is the formula for a Monosaccharide
(CH2O)n
What is the formula for a Triose Sugar
C3H6O3
What is the formula for a Pentose Sugar
C5H10O5
What is the formula of a Hexose Sugar
C6H12O6
What is the formula of Glucose
C6H12O6
What are the two isomers of Glucose
- Alpha (α)
- Beta (β)
What makes Glucose an α Glucose
Th OH is BELOW the C1
What makes Glucose β Glucose
The OH is ABOVE the C1
What monosaccharide is Galactose similar to
Glucose
How are Glucose and Galactose similar
Glucose and galactose all have a central ring of five carbon atoms and one oxygen atom, with a CH<syub>2</sub>XOH group at carbon atom 6. They can also exist in alpha and beta forms.</syub>
What makes Galactose α Galactose
The OH is Below C1
The OH is Above C2
The OH is Below C3
The OH is Below C4
What makes Galactose β Galactose
The OH is Above C1
The OH is Above C2
The OH is Below C3
The OH is Below C4
What are the functions of monosaccharides
- Source of energy in respiration
- Building Blocks for larger molecules
- Intermediates in reactions
- Constituents of nucleotides
What is a disaccharide
2 monosaccharide units bonded together with the formation of a glycosidic bond and elimination of water
How is a disaccharide formed
Condensation reaction
How is a disaccharide split into 2 monosaccharides
Hydrolysis reaction
α Glucose + α Glucose ⟶
Maltose
α Glucose + Fructose ⟶
Sucrose
α Glucose + Galactose ⟶
Lactose
Maltose is made of
α Glucose + α Glucose
Sucrose is made of
α Glucose + Fructose
Lactose is made of
α Glucose + Galactose
What are the component monosaccharides of maltose and what is a biological role
- α Glucose + α Glucose
- In Germinating Seedlings
What are the component monosaccharides of sucrose and what is a biological role
- α Glucose + Fructose
- Transport in phloem of flowering plants
What are the component monosaccharides of lactose and what is a biological role
- α Glucose + Galactose
- In mammal milk
How do you test for reducing sugars
Boil with benedicts solution ⟶ brick red precipitate / orange / yellow
How do you test for non reducing sugars
Get a negative result for a reducing sugar test. Heat with Hydrochloric acid, then add an alkali. Boil with Benedicts solution ⟶ brick red precipitate / orange / yellow
What is a qualitative test
Tells you if a molecule is present
What is a semi-qualitative test
Tells you the relative concentrations of solutions but no actual values
What is a quantitative test
Gives a numerical value for a concentration
What is a biosensor
A device that combines a biomolecule sucha s an enzyme with a tranducer to produce an electrical signal which measures the concentration of a chemical.
What is a Polysaccharide
Large complex polymers. Their Monomers are Monosaccharide units and they are linked by Glycosydic Bonds
Why must Glucose be stored as glycogen or starch inside cells
Glucose is soluble in water, and so it would increase the solute concentration and therefore draw in water by osmosis.
Epxlain the features of a good Storage molecule
- Long branches - glucose molecules can be easily added or removed
- Insoluble - no osmotic effect
- Can’t diffuse out of the cell
- Compact - can be stored in small spaces
- High energy content in C–H & C–C
What are the storage polysaccharides
- Starch
- Amylose
- Amylopectin - Glycogen
What is the monomer of Amylose
α Glucose
What is the position of the bond(s) in Amylose
1 - 4
What is the orientationof the monomers of Amylose
Same way up
What shape does Amylose form
The chain spirals in a coil
What is the monomer for Amylopectin
α Glucose
What is the position of the bond(s) on Amylopectin
1 - 4 & 1 - 6
What is the orientation for the monomers on Amylopectin
Same way up
What is the shape of Amylopectin
The chain coils and forms some branches
What is the monomer for Glycogen
α Glucose
What is the position of the bond(s) for Glycogen
1 - 4 & 1 - 6
What is the orientation of the monomers for Glycogen
Same way up
What is the shape of Glycogen
Forms coils and many branches
How do you test for starch
Add a few drops of iodine
Positive result - Blue/Black
Where is starch found
In plants - in the leaf
Where is Glycogen found
In animals - primarily in the liver or muscle
What are the features of a structural molecule
- Long straight chains, crosslinked with Hydrogen bonds for strength
- Insoluble
- Chitin is lightweight and waterproof
- Cellulose is freely permeable to water which goes through the crosshatch
What is the monomer of Cellulose
ß Glucose
What is the position of the bonds of Cellulose
1 - 4
What is the orientation of the monomers in Cellulose
Every adjacent monomer inverts and rotates 180°
What is the shape of Cellulose
Long straight chains crosslink with hydrogen bonds
Form microfibrils.
What is the monomer for Chitin
ß Glucose
What is the position of the bonds for Chitin
1 - 4
What is the orientation of the monomers for Chitin
Every adjacent monomer inverts and rotates 180°
What shape does Chitin form
Long straight chains crosslink with hydrogen bonds
Form Mucopolysaccharides
Where is cellulose found
In the plant cell wall
Where is Chitin found
In insect exosleletons and Fungi cell walls
Why is Chitin not a true polysaccharide
There is a nitrate atom in the acetylamine group
What are lipids
Lipids contain carbon, hydrogen and oxygen, but much less oxygen in proportion to the carbon and hydrogen.
Are lipids polar or non-polar
Non-polar
Are lipids soluble in water
No
Why aren’t lipids soluble in water
They are non-polar and can’t form hydrogen bonds with water
What are Triglycerides
One glycerol and 3 fatty acids bonded together
What does glycerol contain
- 3 OH Groups
- 3 Carbons Bonded
- Saturated with Hydrogen
What does a fatty acid consist of
- A Carboxyll group
- Saturated Hydrocarbon Chain
How is a Triglyceride formed
- 3 Fatty acids join to a glycerol by condensation
- 3 H2O molecules are released
- Ester Bonds are formed between the glycerol and Fatty Acids
What bond is formed when a Triglyceride is formed
Ester
What is an Ester Bond
Where an oxygen atom joins 2 atoms together. One of the two is a carbon atom double bonded to another oxygen
What is a saturated fatty acid
A fatty acid with only single bonds between the carbon atoms
What do lipids containing only saturated fatty acids generally form at room temperature and why.
Fform fats at room temperature. Fatty acid tails are straight and can pack closely together. Stronger forces of attraction form which means more energy is needed to break the bonds and melt the fat therefore the melting point is higher.
What is an unsaturated fatty acid
A fatty acid with one or more double bonds between carbon atoms
What is a Monounsaturated Fat
1 double Carbon bond in the Fatty Acid
What is a Polyunsaturated Fat
2 or more double Carbon bonds in the Fatty Acids
What do lipids containing unsaturated fatty acids generally form at room temperature and why.
Usually oils at room temperature. The double bonds make the fatty acid tails kink so they can’t pack as closely together. The forces of attraction between the fatty acids are weaker, so less energy is needed to break the bonds and melt the fat so they have a lower melting point.
What is a phospholipid
A lipid containing:
* A Glycerol
* A Phosphate ion - Hydrophyllic Head
* 2 Fatty Acid chains - Hydrophobic Tail
What are Waxes
Lipids that melt above 45°C
What are the functions of Triglycerides
- Thermal Insulation- Prevent heat loss or gain (when hot)
- Protection - Fat is often stored around delicate organs
- Produces Metabolic Water - Released from chemical reactions
- Energy Reserve - 1g of Lipids release 2x the amount of energy as 1g of Carbohydrates because there are more C – H Bonds
What is the function of waxes
Waterproofing - e.g waxy cuticle on leaves
What is the function of Phospholipids
- Structure - Forms a phospholipid bilayer in biological membranes
- Electrical Insulation - e.g the myelin sheath that surrounds the axons of nerve cells
How do you test for Lipids
Mix a sample with ethanol and then shake with water. Form a white cloudy solution
What are the main causes of heart disease
- Hypertension
- Atheroma - Atherosclerosis
What factors contribute to heart diseases
- Diet high in unsaturated fats
- Smoking or Vaping
- Lack of Exercise
- Age
What happens if a diet is high in Saturated Fat
- Low Density Lipoprotein builds up and cause an atheroma to form
- Bloodflow is restricted to the heart
- Less oxygen and Glucose is delivered to cardiac muscle
- Results in angina or if completely blocked a Myocardial Infarction
What happens if a diet is high in Unsaturated Fat
- More High Density Lipoprotein is produced
- These carry harmful fat to the liver for breakdown
- The higher the ratio of HDL:LDL the lower the risk of cardiovascular and coronary heart disease
Is HDL good for the body
Yes
Is LDL good for the body
No
What are proteins
Polymers made up of about 20 amino acids
What atoms do proteins contain
- N
- C
- H
- O
What is the structure of an amino acid
A central Carbon atom bonded to:
* An amino group - NH2
* A Carboxyl Group called the C terminal
* A Hydrogen Atom
* The R Group
How to Amino Acids Polymerise
Through a Condensation reaction
What is the bond between two amino acids called
Peptide Bond
What is a peptide bond
The Chemical bond formed by a condensation reaction between the amino acid and the carboxyl group of another
Do two amino acids bonded together have the same chemical proprties if they are arranged differently
No
What is the Primary Structure
The sequence of amino acids in a polypeptide chain
Based on:
* which amino acids are present
* the number of each type of amino acid present
* the sequence of amino acids in the polypeptide chain
What is the Secondary Structure
The shape the polypeptide forms as a result of hydrogen bonding between the –CO groups and –NH groups in the peptide bonds. This causes the polypeptide chain to be twisted into a 3d shape.
The two most common types are:
* alpha helix
* beta pleated sheet
What is the tertiary structure
The protein folds even more to give a more complex 35 globular shape.
This tertiary structure is maintained by:
* Ionic bonds - formed from charged variable groups
* Covalent bonds - formed between 2 variable groups containing sulfur atoms to form a disulfide bridge. Strong and more difficult to break
* Additional hydrogen bonds - form between polar variable groups
* Hydrophobic interactions - take place when the variable groups are non-polar, and found on the inside of the protein
Many globular proteins have a metabolic function in organisms:
* Enzymes – active sites to bind to a substrate
* Antibodies – sites for binding to antigens
* Hormones – sites for binding to specific receptors
What bonds maintain a 3d globular shape
- Hydrogen Bonds
- Ionic Bonds
- Disulphide bonds
- Hydrophobic Interactions
What functions to 3d globular proteins have
Metabolic functions such as:
* Enzymes – active sites to bind to a substrate
* Antibodies – sites for binding to antigens
* Hormones – sites for binding to specific receptors
What is Quaternary Structure
The arrangement of several polypeptide chains to form a fully functioning protein. They may also be associated with non-protein groups and form large, complex molecules, such as haemoglobin.
What are Fibrous Proteins
Long thin molecules with structural functions. Polypeptides in parallel chains or in sheets with many cross-linkages forming long fibres. Fibrous Proteins are strong and tough.
Give an example of a fibrous protein
Collagen
What is Collagen
A fibrous protein, providing the strength and toughness needeed in tendons.
What is the structure of collagen
Fibrous protein. A single fibre consists of three identical polypeptide chains twisted around eachother like a rope. The three chains are linked by hydrogen bonds, making them very stable.
What is a Globular protein
Compact proteins folded into spherical molecules. Soluble in water.
What are functions of globular proteins
Many different functions including:
* Enzymes
* Antibodies
* Plasma Proteins
* Hormones
What is Haemoglobin
Globular Protein onsisting of four folded polypeptide chains, and at the centre of which is the iron-containing group - Haem.
How do you test for protein
Add a few drops of biuret reagent. If a protein is present, the colour changes from Blue → Purple