Unit 1.1 Biological compounds Flashcards
What do all organisms need for survival
(b) What is it often called
All organisms need inorganic ions to survive
(b) These inorganic ions are often called
minerals.
Where do inorganic ions occur?
They occur in a solution in the cytoplasm and body fluid of organisms, some in high concentrations and others in very low concentrations
What are micronutrients and give 2 examples
Micronutrients are minerals needed in minute (trace) concentrations e.g. copper and zinc.
What are Macronutrients and give 2 examples
Macronutrients are needed in small concentrations e.g. magnesium and iron.
Name the four key inorganic ions in living organisms
Magnesium ions (Mg2+) Iron ions ( Fe2+) Calcium ions (Ca2+) Phosphate ions (PO4 3-)
What is the biological role for Magnesium in plants
Constituent of chlorophyll and therefore essential for photosynthesis
What is the biological role for Iron in animals
Constituent of haemoglobin, which transports oxygen in red blood cells
What is the biological role for Nitrate
Nitrogen derived from nitrate is needed for making nucleotides, including ATP, DNA and RNA. Nitrogen is also needed for amino acid formation.
What is the biological role for Phosphate in living organisms
Used for making nucleotides, including ATP, DNA and RNA. A constituent of phospholipids found in biological membranes. Hardens bones.
What is the biological role for Calcium in living organisms
Hardens bones and teeth (not strengthen). Also a component of plant cell walls.
What does the term ‘organic’ mean
Molecules that have a high proportion of carbon and hydrogen atoms
What does the term ‘inorganic’ mean
A molecule or ion that has no more than one carbon atom.
Why is water a polar molecule?
Due to the uneven distribution of charge within the molecule - The oxygen end of the molecule is more electronegative than the Hydrogen and the Hydrogen atoms have a positive charge.
What is a dipole
A polar molecule which has a positive and negative charge, separated by a very small distance - uneven distribution of charge
When two water molecules are in close contact, what do the opposing charges do and what do they form?
When two water molecules are in close contact the opposing charges attract each other forming a hydrogen bond.
What does the term ‘Hydrogen bond’ mean
The weak attractive force between a hydrogen atom (with a partial positive charge) and an atom with a partial negative charge, usually oxygen or nitrogen.
Are individual hydrogen bonds weak and what happens when there are many hydrogen bonds (between many water molecules)
Individual hydrogen bonds are weak, but many hydrogen bonds (between many water molecules) form a lattice-like framework which is much stronger.
What is cohesion?
A property of water molecules that creates an attraction between them and causes them to stick together
Name 8 properties of water
1 - Water is a solvent
2 - Water as a transport medium
3 - Chemical reactions take place in water
4 - Water has a high specific heat capacity
5 - Water has a high latent heat of vaporisation
6 - Cohesion
7 - Surface tension
8 - Density
Can ions and other polar molecules dissolve in water?
Yes
Can non-polar molecules such as lipids dissolve in water?
No
Why is water’s high specific heat capacity important for organisms?
Water acts as a temperature buffer, enabling endotherms to resist fluctuations in core temperature and to maintain optimum enzyme activity.
Why is water’s high high latent heat of vaporisation important for organisms?
When water evaporates, it has a cooling effect. This is important in homeostasis; organisms can lose heat though sweating or panting
What does evaporation of water from a surface cause?
Cooling
Why is water an important solvent for organisms?
Water is a polar universal solvent. It enables chemical reactions to take place within cells. the transport of materials in the plasma and the removal of metabolic waste
Why does water have a high surface tension?
Due to the ordered arrangement and cohesion of molecules at the surface of water
Why is high surface tension of water important for organisms? x2
- Enables the transport of water and nutrients through plants stems and small blood vessels in the body
- Allows small insects to ‘walk’ on water
Due to cohesion between water molecules what is need to change water from a liquid to a vapour state?
A large amount of heat energy is needed
What temperature does water have its maximum density?
4 degrees Celcius
How does ice float on water and what does it do to the water beneath it?
b) What does this reduce the tendency of?
Ice is less dense than water and therefore floats on the surface and insulates the water beneath it
b) This reduces the tendency for large bodies of water to freeze completely allowing organisms to survive.
What are carbohydrates?
Carbohydrates are organic compounds which contain the atoms carbon, hydrogen and oxygen. They are long chains of sugar called saccharides
What are the 3 types of saccharides?
Monosaccharides, disaccharides and polysaccharides
What do two monosaccharides form?
Disaccharide
What do many monosaccharide molecules form?
Polysaccharide
What are monosaccharides?
Monosaccharides are small organic molecules used as building blocks of complex carbohydrates
Give 2 features of a monosaccharide
Sweet and soluble
What is the general formula for monosaccharides?
(CH2O)n
How can monosaccharides be grouped?
Be grouped according to the number of carbon atoms they have.
How many carbon atoms does a triose have?
A triose sugar has three carbon atoms,
How many carbon atoms does a pentose have?
A pentose sugar has five carbon atoms
How many carbon atoms does a hexose have?
A hexose sugar has six carbon atoms.
What is glyceraldehyde?
A triose used in metabolic reactions
What is a ribose?
A pentose sugar which is a component of nucleic acid
What is glucose?
b) What is it the main substrate for?
c) How many isomers does it have and what are they?
Glucose is a monosaccharide containing 6 carbon atoms in each molecule.
b) It is the main substrate for respiration therefore it has great importance
c) It has 2 isomers - alpha and beta glucose
What is the function of triose?
Important in metabolism. Triose sugars are intermediates in the reactions of respiration of respiration and photosynthesis
What is the function of pentose?
Pentose is constituents of nucleotides e.g. deoxyribose in DNA, ribose in RNA, ATP and ADP
What is the function of hexose?
a) Source of energy in what?
b) Which bonds are broken to release energy and later transferred to make what?
Glucose is a hexose sugar.
a) Glucose is a source of energy in respiration.
b) Carbon-hydrogen and carbon-carbon bonds are broken to release energy, which is transferred to make adenosine triphosphate (ATP).
What is the name of the bond formed when 2 monosaccharides react?
b) What type of reaction is it?
Glycosidic bond
b) A condensation reaction
What are disaccharides?
Disaccharides are composed of two monosaccharide sub-units bonded with the formation of a glycosidic bond and the elimination of water. This is an example of a condensation reaction.
What is Maltose and how is it formed?
b) What is its biological role?
Maltose is a disaccharide formed by the condensation of 2 glucose molecules
b) In germinating seeds
What is Sucrose and how it it formed?
b) What is its biological role?
Sucrose is a disaccharide formed by the condensation of glucose and fructose
b) A product of photosynthesis which is transported in the phloem
What is Lactose and how it it formed?
b) What is its biological role?
Lactose is a disaccharide formed by the condensation of glucose and galactose
b) Found in mammalian milk
How can a glycosidic bond be broken?
By hydrolysis
What is Benedict’s reagent used to test?
b) What is needed for this reaction?
Used to test for reducing sugars
b) Heat (80 degrees celcius or above)
What do reducing sugars reduce and form?
Reduce blue copper ll sulphate forming copper 1 sulphate
What must Sucrose be firstly done by boiling in what
b) What 2x things are formed?
c) What must be done to the acid and with what?
Sucrose must first be hydrolysed by boiling in dilute hydrochloric acid. Glucose and fructose are formed. The acid must be neutralised with dilute sodium hydroxide before testing with Benedict’s reagent.
For the testing of reducing sugars, when glucose and fructose are formed, what do they donate and what do they reduce?
b) What does this form?
Glucose and fructose are reducing sugars
which readily donate an electron to reduce copper II sulphate
b) This forms the brick-red precipitate copper I sulphate.
What is a polysaccharide?
What are the formed from?, What are they linked by and how was the link formed?
Polysaccharides are large complex polymers. They are formed from very large numbers of identical monosaccharide units, which are their monomers, linked by glycosidic bonds formed by condensation reaction.