Biological components 1.2 Flashcards
Name the 4 main inorganic compounds humans need
- Magnesium (Mg2+)
- iron (Fe2+)
- phosphate (Po43-)
- calcium (Ca2+)
What is the importance of magnesium in living organisms?
- plants= important constitute of chlorophyll therefore essential for photosynthesis.
- mammals= magnesium needed for bones
What happens to a plant if there is a lack of magnesium?
Chlorosis= plants without magnesium in the soil cannot make cholophyll so leaves turn yellow.
This means photosynthesis cannot take place leading to stunted growth due to the lack of glucose.
What is the use of iron in humans?
Iron is a constituent of haemoglobin which transports oxygen in red blood cells.
What can a lack of iron lead to in humans?
Anaemia
What is the use of phosphate ions I’m living organisms?
Making nucleotides including ATP and are a constituent of phospholipids found in biological membranes.
What is the use of calcium in living organisms?
Important structural component of bones and teeth in mammals.
Component of plant cell walls providing strength.
What is the use of water in the body?
- it’s a medium for metabolic reactions.
- important constituent of cells.
Why is water decribed to be a dipole/ polar molecule?
The hydrogen end is positively charge me and the oxygen is the negatively charged end but there is no overall charge.
(THESE CHARGES ARE NOT FULL CHARGES)
Where do hydrogen bonds from in water?
Between the positive on a hydrogen and negative on an oxygen of a different atom.
Describe a hydrogen bonds effect of water.
- weak
- when large numbers are present in water it makes the molecules hard to separate giving water a wide variety of physical properties.
List the properties of water
- solvent
- metabolite
- high specific heat capacity
- high latent heat of vaporisation
- cohesive
- high surface tension
- high density
- transparent
Describe the advantages of water being a solvent.
- universal solvent due to the polarity meaning most things will dissolve in it because they attract other polar molecules like ions
- transport medium like in the xylem of a plant transporting minerals.
- non polar molecules like lipids don’t dissolve in water.
Describe water being a metabolite.
Water can be used in biochemical reactions like photosynthesis.
HYDROLYSIS: Water splits a molecule.
CONDENSATION: Water is a product of a reaction.
Describe why water having a high specific heat capacity is useful.
- means a large amount of heat energy is needed to raise its temperature.
- creates a habitat for animals in the ocean as the temperature doesn’t fluctuate too much so the animals don’t have to adapt.
- endure the enzymes in cells to work efficiently
Explain why water having a high latent heat of vaporisation is useful.
- means a lot of energy is needed to change it from liquid to gas.
- useful in temperature control by sweating to keep the body cool.
Why is water being cohesive useful?
- water molecules attract forming hydrogen bonds. These are individually weak but in large amounts are strong.
- this allows columns of water to be drawn up the xylem vessel in plants.
Why is high surface tension useful in water?
-it allows a habitat to form for small insects like pond skaters because the molecules at the surface produce surface tension so the body of the insect is supported.
Why is high water density useful?
When frozen, ice is less dense than water so floats on the surface, insulating the water beneath so a stable habitat can form beneath.
What is water being transparent useful?
Light can pass through to allow aquatic plants to photosynthesise effectively.
What elements make up carbohydrates?
Carbon
Hydrogen
Oxygen
What is one single of sugar in carbohydrate (monomer).
Monosaccharide
What is the general formula for monosaccharides?
(CH2O)n
What determines the name of the monosaccharide?
The number of carbon atoms
Triose pentose hexose
What is the formula for a hexose?
C6 H12 O6
What shape do the carbon atoms of a monosaccharide form when dissolved in water?
Circle
What are the two isomers of glucose?
Alpha glucose
Beta glucose
How is beta glucose different to alpha glucose?
Beta glucose is the transverse of alpha glucose so the OH and H are swapped over.
What are the labels for the carbon atoms on a saccharide?
1-6
What are the functions of a monosaccharide?
- source of energy in respiration. C-H and C-C bonds are broken to release energy, transferred to make ATP.
- building block for larger molecules.
- intermediates in reactions
- constituent of nucleotides.
What is a disaccharide?
And dimer. Two monosaccharides bonded together with the elimination of water and has a glycosidic bond.
What is the biological role and component monosaccharide of maltose?
Glucose + glucose
In germinating seeds
What is the biological role and component monosaccharide of sucrose?
Glucose + fructose
Transport in phloem of flowering plants.
What is the biological role and component monosaccharide of lactose?
Glucose+ galactose
In mammalian milk
How do you test for the presence of reducing sugars?
-Benedicts test for reducing sugars.
-equal volume of benedicts reagent and testing solution heated to 80’C
- If present the solution turns from blue to BRICK RED
(Because the sugars donate an electron to reduce copper ll ions in copper sulphate to red l oxide)
-THIS WONT WORK FOR NON-REDUCING SUGARS
How do you test for non-reducing sugars?
- heat the sample with hydrochloride acid at 80’C
- add alkali like sodium hydroxide
- add benedicts reagent and heated as before.
- if turns red, a non reducing sugar is present.
What is a polysaccharide?
A complex polymer made up of monomers linked by glycosidic bonds.
What is the main source of energy in cells?
Glucose
Why can’t glucose be stored in cells?
Because it is soluble in water so it would increase the cells concentration consequently drawing in water by osmosis.
This is avoided by converting glucose into starch.
Where are starch grains found in high concentrations in plants?
- Seeds
- storage organs
- starch grains
What is starch comprised of?
Amylose and amylopectin
What is the monomer for starch?
Alpha- glucose
What is the structure of amylose?
- linear
- unbranched
- 1-4 glycosidic bond
- helix shape
- chains of alpha glucose
What is the structure of amylopectin?
- chains of alpha glucose
- 1-4 glycosidic bonds
- 1-6 glycosidic bonds =branches
What is the test for starch?
- iodine solution reacts with starch when mixed.
- colour change from orange/brown to blue/black.
What is the main storage product in animals?
Glycogen
What is the structure of glycogen?
1-4 and 1-6 alpha bonds, but has more 1-4 bonds than amylopectin so is a more branched than amylopectin.
Where can cellulose be found?
A plant cell wall as it is a structural polysaccharide.
What is the structure of cellulose?
- long parallel chains of beta-glucose.
- b-glucose monomers joined by 1-4 glycosidic bonds.
- every other b-glucose is upside down to form a bond with the one next to it. This allows hydrogen bonds to form between OH group in an adjacent chain=structural stability.
Describe a microfibril.
Cellulose molecules/chains become tightly cross linked. These microfibrils are held together in bundles called fibres.
What makes the plant cell wall so strong?
- laminated structure
- cell fibres run adjacent to each other.
What makes cellulose fibres freely permeable?
Spaces between fibres so water and it’s diluted can penetrate through the cell wall to the cell membrane.
Where can chitin be found?
The exoskeleton of insects and fungal cell walls.
What is the structure of chitin?
- long chains of a 1-4 glycosidic bonds.
- additional amino acid
- strong, waterproof and lightweight.
- hydrogen bonds form between chains to make microfibrils.
What elements are in lipids?
-Hydrogen
-carbon
-oxygen
=like carbohydrates but much less oxygen
What makes lipids insoluble?
They are non-polar compounds.
But they do dissolve in organic solvents like alcohols.
What is a triglyceride comprised of?
1 glycerol : 3 fatty acids.
The glycerol is always the same but the fatty acid combination can change.
What reaction joins fatty acids to glycerol?
Condensation, where 3 water molecules are removed and and Ester bond is formed between glycerol and fatty acid.
What bond form in a triglyceride?
Ester bond.
What reaction separates a triglyceride into a glycerol and 3 fatty acids?
Hydrolysis.
Describe the structure of a phospholipid.
- hydrophilic polar head= phosphate
- glycerol back bone
- hydrophobic non-polar tail= 2 fatty acids.
Describe a wax.
Waxes are lipids that melt above 45’C. They have a waterproofing role in animals (insect exoskeleton) and plants (leaf cuticle)
What is the difference between fats and oils?
- Fats are solid at Troon temperature / oils are liquid
- fats are saturated/ oils unsaturated
What makes a fatty acid saturated and why?
There are only single bonds between carbon atoms, so they are bonded to their full capacity. This makes the chain straight.
What type of fat is typically animal fats?
Saturated.
As they are semi solid at Troon temperature they are useful for storage.
What is the structure of an Unsaturated fat?
There is one or more double bond between the carbon atoms cause if the chain to bend.
Why are unsaturated fats typically liquid at room temperature?
Due to the double bond, the molecules can not align uniformly so it cannot solidify, meaning they are liquid at room temperature.
What type of fat is typically liquid at room temperature?
Plant lipids.
Like sunflower oil and olive oil.
What is the difference between mono-unsaturated fat and poly unsaturated fat?
- Mono unsaturated= one C-C double bond.
- polyunsaturated = many C-C double bonds.
What are the roles of phospholipids?
- comprises biological membranes
- electrical insulation
What is the role of triglycerides?
- energy reserves in big plants and animals as it contains mor me C-H bonds than carbohydrates.
- thermal insulation, when stored under the skin.
- protection against physical damage around the vital organs.
- metabolic water, released during chemical reactions in the body
What is the role of waxes?
- waterproofing to reduce water loss, found in the exoskeleton of insects and cuticle of plants.
What is the test for fats and oils?
Emulsion test:
- sample is mixed with absolute ethanol (which dissolves any lipid present)
- shake this with an equal volume of water
- dissolves lipids should come out of the solution as they are insolvable in water.
- an emulsion is formed if lipids present presenting a cloudy white colour.
What does LDL stand for?
Low density lipoprotein
What does HDL stand for?
High density lipoprotein
What are the two main causes of heart diseases?
- atherosclerosis (fatty deposits in the coronary arteries)
- hypertension (high blood pressure)
What are the factors contributing to heart diseases?
- age
- high saturated fat diet
- smoking
- lack of exercise
How are lipoproteins made in the body?
Food absorbed in the small intestine, lipids and proteins combine to make lipoproteins which travel around the body in the blood stream.
What happens if the diet is high in saturated fats?
- LDL cholesterol builds up.
- atheroma (fatty material) gets deposited on the coronary arteries.
- blood flow is therefore restricted.
- therefore less oxygen to the heart
- it is possible the whole artery can become blocked leading to a heart attack.
What happens if your dies is high in unsaturated fats?
- the body makes more HDL cholesterol which lowers the LDL.
- the HDL carries harmful fats alway for disposal in the liver.
- the higher the ration of HDL:LDL in a persons blood the Lower the risk of a cardiovascular and coronary heart disease.
What elements make up proteins?
Carbon, hydrogen, oxygen, nitrogen.
Some may also contain sulphur and phosphorous.
What is the monomer for proteins?
Amino acids
How many different amino acids are there?
20
What is a chain of amino acids called?
Polypeptide
What determines a protein and their shape?
The sequence of amino acids.
What is the structure of an amino acid?
- amino group = NH2
- carboxyl group = COOH
- carbon atom bonded to a hydrogen and a R group (R group is different for each amino acid)
What is a protein?
A linear sequence of amino acids.
Describe what happens during the condensation reaction to make a dipeptide
- Amino group of one amino acid reacts with the carboxyl group of another amino acid.
- water is eliminated.
- peptide bind is formed.
- this resulted in a dipeptide.
Between which molecules does a dipeptide bond form in a protein?
Carbon and nitrogen.
What are the four protein structure stages?
- Primary
- secondary
- tertiary
- quaternary
Describe the primary protein structure.
The type, number and sequence of amino acids linked by peptide bonds.
Describe the secondary protein structure.
- this is the shape the polypeptide forms as a result of hydrogen bonding.
- alpha-helix forms a spiral
- beta-pleated sheets
- hydrogen bonds between N-H and O=C
Describe the tertiary structure of a protein.
- further folding of secondary structure due to more hydrogen bonds and other bonds
- other bonds like- ionic, disulphide, hydrophobic.
- bonds help to maintain a 3D shape.
- if heated the protein will denature.
What is an example of a protein with an alpha helix shape?
Keratin
What is an example of a protein with a beta pleated sheet?
Silk
Describe the quaternary protein structure.
- more than one polypeptide chain courses together.
- 3D
- same bonds as tertiary
- eg= haemoglobin.
Describe a fibrous protein.
- long thing molecules
- shape makes them insoluble in water
- structural functions as bone
- polypeptides are in chains with many cross linkages, to form long fibres
- alpha he lives linked into chains
What are examples of fibrous protein?
Collagen and keratin.
Describe a globular protein.
- rounded and compact
- water soluble meaning they have many functions.
Give examples of globular proteins.
Enzymes, hormones, haemoglobin, antibodies.
What is the test for proteins and how would you test for it?
The biuret test:
- test a sample of solution for protein, a few drops of biuret reagent.
- the sodium hydroxide and copper sulphate react to make blue copper hydroxide, which react with the peptide bonds which is purple.
What is the bond linking two amino acids?
Peptide bonds
What is a long chain of monosaccharide molecule joined by a glycosidic bond?
Polysaccharide
What chemical element is present in proteins and NOT carbohydrates?
Nitrogen/ sulphur.
Which protein carries oxygen in red blood cells?
Haemoglobin.
Which part of the amino acid is different in each of the 20 amino acids?
R-group
What types of bonds are present in tertiary protein?
- ionic
- hydrogen
- disulphide
- hydrophobic
What is the first product of starch digestion which is later broken down into glucose by maltase?
Maltose
