Intro to B.M, proteins, water Flashcards
What is metabolism?
the total sum of all the chemical reactions taking place in an organism
What does catabolic mean and what is it’s relationship to energy?
larger molecules broken down into smaller ones, releases energy
What does anabolic mean and what is it’s relationship to energy?
smaller molecules built up into larger ones, requires energy
What is the monomer of carbohydrates?
monosaccharides
What is the polymer of carbohydrates?
polysaccharides
What is the monomer of proteins?
amino acids
What is the polymer of proteins?
polypeptides
What is the monomer of nucleic acids?
nucleotides
What is the polymer of nucleic acids?
polynucleotide
What is a condensation reaction?
joins 2 molecules together forming a larger molecules by a covalent bond and elimimating a water molecule
What is a hydrolysis reaction?
a covalent bond is broken and smaller molecules are formed, and must be in the presence of water
What is an example of a series of hydrolysis reactions?
digestion
What is a glycosidic bond and how is it formed?
the bond joining two monosaccharides together, between two hydroxyl groups (take the OH from one and a H from the other, leaving an O)
What are three different examples of monosaccharides?
glucose (alpha and beta), fructose, galactose
Where is the hydroxyl group in a-glucose?
below the 1st carbon
Where is the hydroxyl group in b-glucose?
above the 1st carbon
What 3 elements make up carbohydrates?
C/H/O
What is the ratio of the 3 elements that make up carbohydrates?
1:2:1 (C/H/O)
What properties do monosaccharides and disaccharides have that polysaccharides do not?
sweet and soluble
What are the properties of monosaccharides?
rapid source of energy, readily absorbed
What are the properties of disaccharides?
need to be hydrolysed before they can be used to release energy, and sugars are often stored in this form
Glucose + glucose =
maltose
Glucose + fructose =
sucrose
Glucose + galactose =
lactose
What is the test and result for reducing sugars?
add benedicts solution and heat, will go from blue to green/orange/brick red
What is the test and result for non-reducing sugars?
boil with hydrochloric acid, then neutralise it, then do the benedicts test plus heat
What is the test and result for starch?
add iodine solution, will go from yellow/brown to blue/black
What is the test and result for protein?
add biuret solution, will go from blue to purple
Name 3 polysaccharides
glycogen/starch/cellulose
Name 2 types of starch
amylose/amylopectin
What is the structure of amylose?
straight chain with no branches, forms a coil/spiral/helix structure as it is made up of alpha 1,4 glycosidic bonds
What is the structure of amylopectin?
forms a chain with branches at regular intervals, as it is made up of alpha 1,4 glycosidic bonds and alpha 1,6 glycosidic bonds
What is the function of starch?
used for storage in plants
Name why starch is used for it’s job
insoluble - no osmotic effect
does not diffuse in/out of cells - energy supply for cells and is very compact
branched form of amylopectin - can be acted on at a greater rate than unbranched by enzymes so that the glucose monomers can be released quickly
What is the structure of glycogen?
similar to amylopectin, made up of alpha glucose with 1,4 and 1,6 glycosidic bonds leading to a branched structure, but with shorter chains
Where is glycogen found?
animals and bacteria but NOT plant cells
What is the function of glycogen?
used for storage in animals
Why is glycogen good for it’s job?
it is branched - more enzymes can act on it at once
insoluble - no osmotic effect
compact - store a lot in a small space
doesn’t diffuse in/out of cells - constant energy supply
What is the structure of cellulose?
made up of beta glucose and so forms long, straight, unbranched chains as it has beta 1,4 glycosidic bonds, and every other/alternate b-glucose molecule is inverted
What is the function of cellulose?
it is found in plant cells for structure
Why can cellulose do it’s job and what else is involved?
the long unbranched chains that are made up of the b-glucose monomers run parallel to each other and are cross linked by many hydrogen bonds that collectively provide strength, these molecules are grouped to form microfibrils, which are joined by pectin and hemicellulose, and the microfibrils are grouped to form fibres which provides strength
What are the functions of proteins?
enzymes/hormones/transport/movement/structural/protection
What does an amino acid contain?
an amine group (NH2)
a carboxyl group (COOH)
C-H in the middle
a variable group (R)
What happens in a condensation reaction between two amino acids?
the hydroxyl group from one and the hydrogen from the other form water and a peptide bond between the C and the N is formed
What are the four types of protein structure?
primary/secondary/tertiary/quaternary
Describe the primary structure of a protein
it is a chain of amino acids in a specific sequence
Describe the secondary structure of a protein
the primary structure folds into an alpha helix or a beta pleated sheet due to the hydrogen bonds forming between the COOH group and the NH2 group of adjacent amino acids
Describe the tertiary structure
the protein folds further due to more bonds being formed between R groups like disulphide bridges and ionic bonds, giving it a 3D shape, which can be lost if the enzyme is denatured due to pH or temperature
Describe the quaternary structure
more than one polypeptide chain together in a specific structure
What are the two types of protein with examples?
globular - enzymes / fibrous - collagen
Describe the structure of fibrous proteins
formed from parallel polypeptide chains held together by cross links, which form long rope-like fibres with high tensile strength that are generally insoluble in water
Describe the structure of globular proteins
usually have a spherical shape due to tightly folded polypeptide chains, where hydrophobic groups are on the inside but hydrophilic groups are on the outside, making them soluble in water
What causes enzymes to denature?
pH/temp changes/salt concentration/specific conditions vary protein to protein
What is chromatography?
a technique used to separate and identify chemicals within a mixture, and it relies on the movement of a gas or liquid through a medium
What is the equation to figure out the R.F value?
distance travelled by pigment/ distance travelled by solvent
What is different about the chromatography process for amino acids?
the spots can be invisible so need to be sprayed with ninhydrin to make them visible, and then heat it up which develops purple spots
What type of molecule is water and why?
water is a dipolar molecule due to it’s unevenly distributed charge (the negative oxygen and the positive hydrogen)
What is the bond angle in water?
104.5
What are the 5 key properties of water?
metabolite
important solvent
high specific heat capacity
large latent heat of vaporisation
strong cohesion
Explain why being a metabolite is good for water
involved in many chemical reactions like hydrolysis and condensation reactions, cytoplasm is made up of water and 90% of plasma in blood is water
Explain why it is important that water is a good solvent
polar molecules will readily dissolve in it (are hydrophilic) so essential substances can be transported easily as they can dissolve in water
Why is it important that water has a high specific heat capacity?
lots of energy required to raise the temperature of water which is because some of the heat energy is used to break the hydrogen bonds between water molecules - meaning water remains relatively stable temperature wise despite external fluctuations, meaning the internal temperatures of organisms should be stable too which prevents the denaturing of enzymes
Why is it important that water has a large latent heat of vaporisation?
lots of energy required to make water a gas from a liquid due to the hydrogen bonds joining the molecules together - this is good for organisms as it means water provides a cooling effect due to sweating, as when you sweat a large amount of heat energy from the skin is transferred to the water to evaporate it which removes a lot of the heat and cools the organism
Explain why having strong cohesion is a positive characteristic of water
water molecules have strong cohesive forces due to their ability to form hydrogen bonds with each other - an example would be in the xylem in the transpiration stream where the stream of water is continuous due to the cohesive nature of water, pulling more water through as each molecule leaves - cohesion also provides surface tension to water which enables some small invertebrates to move and live on the surface which therefore provides them a habitat
What is the difference between cohesion and adhesion?
cohesion - water and water
adhesion - water and other molecules
Why is it important that water is colourless and therefore transparent?
so that sunlight can pass through it and reach cells for photosynthesis in plants
Why does the density of water decrease when it is frozen?
because it expands when frozen so its mass per unit volume decreases
Why is it important that frozen water (ice) is less dense than water?
as ice forms an insulating layer over water
What are the bonds in proteins called?
peptide bonds
How many amino acids are there?
around 20
In the tertiary structure, which bonds are affected by what?
hydrogen bonds- temperature and pH
ionic bonds- pH
disulphide bridges- reducing agents
