Topic 3 Flashcards
What do all biological molecules contain
Carbon
What elements doo carbohydrates contain
Carbon, hydrogen and oxygen
What elements do lipids contain
Carbon, hydrogen and oxygen
What elements do proteins contain
Carbon, hydrogen, oxygen, nitrogen and sulfur
What elements do nuclei acids contain
Carbon, hydrogen, oxygen, nitrogen and phosphorus
Cations: calcium ions
Involved in muscle contraction and nerve impulse transmission
Cations: sodium ions
Involved in co-transport, réabsorption of water in the kidney and nerve impulse transmission
Cations: potassium ions
Involved in stomatal opening and nerve impulse transmission
Cations: hydrogen ions
Involved in chemiosmosis, ph determination and catalysis of reactions
Cations: ammonium ions
Involved in nitrogen cycle, where bacteria convert ammonium ions into nitrate ions
Anions: nitrate
Mineral absorbed by plants to provide a source of nitrogen to make amino acids
Anions: hydrogencarbonate
Maintains the ph of the blood
Anions: chloride
Provides a negative charge to balance the positive sodium ion and potassium ions in cells
Anions: phosphate
Involved in the formation of phospholipids for cell membranes, nucleus acids and atp formation and in making bones
What type of molecule is water and why
It is a polar molecule, due to the unevenly distributed charge
What bonds form between the oxygen and a hydrogen atom and why
Hydrogen bonds from due to the positive and negative regions that interact with each other
Water is a … in a metabolic reaction such as … and … which is used in forming and breaking chemical bonds
Water is a metabolite in a metabolic reaction such as condensation and hydrolysis which is used in forming and breaking chemical bonds
Water is a … in which many metabolic reactions occur
Water is a solvent in which many metabolic reactions occur
Water has a … meaning a lot of energy is required to warm water up therefore … in living things therefore it acts as a …
Water has a high heat specific capacity meaning that a lot of energy is required to warm water up therefore minimising fluctuations in living therefore it acts as a buffer
Water has a… meaning evaporation of water provides a cooling a]effect with little water loss
Water has a relatively large latent heat of vaporisation, meaning evaporation of water provides a cooling effect with little water loss
Water has … … between molecules which enables effective transport of water in tube-like transport cells as the … … supports the column of water.As a result of strong cohesion the … … at the water-air boundary is …
Water has strong cohesion between molecules which enables effective transport of water in tube-like transport cells as the strong cohesion supports columns of water. As a result of strong cohesion the surface tension at the water-air boundary is high
What is the maximum density of water and what does this mean?
4 degrees, meaning ice is less dense than water and floats on top of it, creating an insulating layer, increasing chance of survival of organisms.
Why is water a good support
It is incompressible
What are monomers
Small units which are the components of larger molecules
Name some monomers
Monosaccharides such as glucose, amino acids and nucleotides.
What is hydrolysis
When water is added to break a chemical bond between 2 molecules
What are carbohydrates
Molecules which consist only of carbon, hydrogen and oxygen and are long chains of sugar units called saccharides
Name the 3 types of saccharides
Monosaccharides, disaccharides and polysaccharides
How are disaccharides and polysaccharides formed
In condensation reactions , joining monosaccharides using glycosidic bonds
Glucose is a …, containing 6 carbon atoms in each molecule, it is the main … … … it has 2 isomers … and … glucose
Glucose is a monosaccaride, containing 6 carbon atoms in each molecule. It is the main substrate for respiration. It has 2 isomers- alpha and beta glucose
Name 3 Disaccharides
Maltose, formed by condensation of 2 glucose molecules
Sucrose, formed by condensation of glucose and fructose
Lactose, formed by condensation of glucose and galactose
Polysaccharides are formed from many glucose units joined together and include
Glycogen and starch which are both formed by condensation of alpha glucose
Cellulose formed by the condensation of beta glucose
A covalent bond consists of…
A shared pair of electrons
Covalent molecules that contain only a few atoms are called…
Simple covalent molecules
Condensation reaction
Joining two molecules together by removing water
Hydrolysis reaction
Splitting apart molecules through the addition of water
Properties of simple covalent molecules
Low melting and boiling points
Liquid or gas at room temperature
Give examples of simple covalent molecules
Water, oxygen, carbon dioxide, chlorine and hydrogen
Anions: hydroxide
Catalysts, ph determination
Biological molecules are often… polymers are long-chain molecules made op by the linking of multiple individual molecules… in a repeating pattern.
Biological molecules are often polymers. Polymers are long chain molecules made up by the linking of multiple individual molecules called monomers in a repeating
In carbohydrates the monomers are… (…)
Sugars (saccharides)
In proteins the monomers are…
Amino acid
Why is water so important
-water is a metabolite in many reactions, including: hydrolysis reactions and condensation reactions.
- a cell’s metabolic reactions occur in aqueous solution
-water molecules can stick together
What is the structure of water
- 2 hydrogen atoms covalently bonded to one oxygen atom
- each hydrogen shares a pair of electrons with the oxygen
- oxygen has a greater affinity for electrons so it pulls electrons closer
- making oxygen slightly negative and the hydrogens slightly positive
-making water a polar molecule
Why is water a very stable structure
The numerous hydrogen bonds
What produces surface tension in water
The cohesion between water molecules, making a solid-like surface
Why is water attracted to any substance that is polar
Because it has polar molecules
What is a hydrophilic
A substance that becomes part of water’s hydrogen-bonded structure by dissolving in water
What is a hydrophobic
A substance that cannot become apart of water’s hydrogen-bonded structure and won’t dissolve in water
Name the 2 things that can’t dissolve in water
- triglycerides
- large polymers
What is specific heat capacity of water and what is the value
The specific heat capacity of water is when water absorbs/loses a relatively large amount of heat before it changes temperature
It has a value of 4.184 kJ kg-1K-1
What is latent heat of vaporisation and what is it’s value
Latent heat of vaporisation is when water absorbs a large amount of heat before it turns into water vapour
It has a value of 2.26 MJ kg-1K-1
Properties of ionic compounds
High melting point
Most are soluble in polar solvents such as water
Most are insoluble in non polar solvents such as benzene and hexane
Molten compounds conduct electricity well
Properties of covalent compounds
Gases, liquids or low melting solids
Most are insoluble in polar solvents
Most are soluble in non polar solvents
Liquid molten compounds do not conduct electricity
why is water a dipolaire molecule
It has 2 charge regions
Why is water polar
Each hydrogen atom shares its electrons with the atom of oxygen
Because the oxygen atom has more protons than the hydrogen atoms, it pulls more strongly on these electrons
So the oxygen end of the molecule has a slight negative charge and the hydrogen has a slight positive charge
What 3 structures do carbohydrates exist in
Monosaccharides
Disaccharides
Polysaccharides
what is a monosaccharide
Small, simple sugars
What is a disaccharide
Large sugars
What is a polysaccaride
Long chain carbohydrates
Example molecules of monosaccarides
Glucose, fructose, galactose and ribose
Example molecules of disaccharides
Lactose, maltose, sucrose
Example molecules of polysaccharides
Glycogen, cellulose and starch
What are disaccarides formed from
2 monosaccharides
What are polysaccharides formed from
Many monosaccharides
Glucose is … and contains… carbon atoms which means it is a … sugar
Glucose is abundant and contains 6 carbon atoms which means it is a hexose
State 2 properties of glucose
It is the major energy source in most cells
It is highly soluble
Why is water a good solvent
Dissolves many substances which enables easy transport inside cells e.g blood and xylem
Why is it good that water is a liquid at room temperature
It provides a liquid environment inside cells
Why is it good that water has a high specific heat capacity
Water resists temperature change, which provides a stable environment, meaning organisms use less energy to control body temperature and they change temperature more slowly
Why is it good that water has a high latent heat of vaporisation
It provides a cooling effect through sweating
Why is it good that water has a maximum temperature of 4 degrees
The density of water decreases so ice can float on water, allowing equation organisms to inhabit on top of ice and prevents ice further down freezing. Insulated layer
Wetness of water
There is a lot of cohesion because the water molecules can form hydrogen bonds
-adhesion because water can stick to polar substances
Capillarity of water
Water can move upwards against gravity, so water molecules stick to tube by adhesion which helps move water form shoots to roots in plants
Surface tension in water
The uneven distribution of water molecules causes water to form a skin which aquatic animals can be supported by
Other properties of water
Colour less + transparent: enables plants to photosynthesise underwater
Low viscosity: helps capillaries flow in plants
Difficult to compress: acts as a structural support
… is a disaccharide formed by the condensation of 2 glucose molecules
Maltose
… is a disaccaride formed by condensation of glucose and fructose
Sucrose
… is a disaccharide formed by the condensation of glucose and galactose
Lactose
… and … are formed by the condensation of alpha glucose
Glycogen and starch
… is formed by the condensation of beta glucose
Cellulose
Amylose is an … chain of glucose molecules joined by …-… glycosidic bonds, as a result of that amylose is … and thus it is a very… molecule meaning it can store a lot of energy.
Amylose is an un branched chain of glucose molecules join by 1-4 glycosidic bonds,a s a result of that amylose is coiled and thus it is a very compact molecule meaning it can store a lot of energy
Amylopectin is a … chain and is made up of glucose molecules joined by 1,4 and …,… glycosidic bonds, due to the presence of many side branches it is rapidly … by others enzymes, therefore releases a lot of energy
Amylopectin is a branched chain and is made up of glucose molecules joined by 1,4 and 1,6 glycosidic bonds, due to the presence of many side branches it is rapidly digested by others enzymes, therefore releases a lot of energy
Cellulose is composed of long, un branched, chains of … glucose which are joined by glycosidic bond. … are strong threads which are made of long cellulose chain joined together by … bonds and they provide … … in plant cells
Cellulose is composed of long, un branched, chains of beta glucose which are joined by glycosidic bond. Microfibrils are strong threads which are made of long cellulose chain joined together by hydrogen bonds and they provide structural support in plant cells
What is the Benedict’s test used for
Sugars
Benedict’s test-reducing sugars
Add 2cm^3 of the sample to be tested in a test tube, add 2cm^3 of Benedict’s reagent
Heat/boil mixture for 5 mins
Negative result = blue
Positive result = green, yellow, brown, orange, red
Benedict’s test- non-reducing sugars
Add 2cm^3 of sample to be tested to test tube, add hydrochloric acid and heat for 3 mins to hydrolyse the glycosidic bond
Add sodium hydrogen carbonate powder to neutralise the solution
Add 2cm^3 of Benedict’s reagent and heat/boil mixture for 5 mins
Negative - blue
Positive - green, yellow, brown, orange, red
Name 2 reducing sugars
All monosaccharides, maltose and lactose
Name a non-reducing sugar
Sucrose
Name 7 important structures of lipids
-cell membrane structure
-hormones
-energy storage molecules
-thermal insulation
-mechanical protection
-electrical insulation of nerves
-waterproofing and buoyancy
Are lipids soluble or insoluble
Insoluble in water but soluble in organic compounds (ethanol)
What is the most common types of lipids
Triglycerides, steroids, cholesterol
What bonds are formed during the condensation to form triglycerides
Ester bonds (3)
Food test for proteins
Biuret reagent -purple
Food test- starch
Iodine solution- black
Food test- glucose
Benedict’s reagent- b,g,y,o,r
Food test- lipids
Ethanol - cloudy
Surfactants
Amphipathic molecules form a layer on the surface of water
What is a sterol and name and example of one
They are lipids found in cells, complex alcohol molecules, cholesterol is an example made in the liver and intestine
Where are lipids stored and what is its role
Adipose tissue, heat insulation, protection of organs, energy source
