Chapter 3 ~ Biological Molecules Flashcards
What are the elements in carbohydrates?
Carbon, hydrogen and oxygen
What are the elements in Lipids?
Carbon, hydrogen and Oxygen
What are the elements in proteins?
Carbon, hydrogen, oxygen, nitrogen and sulfur
What are the elements in nucleic acids
Carbon, hydrogen, oxygen, nitrogen and phosphorus
what are polymers and Monomers?
Polymers are long chain molecules which are made up by linking monomers in a repeating pattern.
Monomers are individual molecules which make up a polymer.
What is a condensation reaction?
It is the release of water
What is a hydrolysis reaction?
it is the addition of water
How does hydrogen bonds occur between water molecules
Within water, hydrogen bonds occur between the slightly negative oxygen atom of one water molecule and the slightly positive hydrogen atom on another molecule. Water is said to be polar as there is regions of negativity and positivity (between hydrogen and oxygen molecules). The electrons within water are shared unequally within the bonds holding the molecule together,
What are the characteristics of water
- it has a high boiling point due to the hydrogen bonding which requires lots of energy to overcome
- it acts as a coolant, buffers temperature changes during chemical reactions.
- it is an excellent solvent as it can form hydrogen bonds with other polar molecules/ charged ionic compounds. Many solutes are also able for it to be dissolved in.
- High latent heat of evaporation as lots of energy is required to convert it from liquid to gas.
- High specific heat capacity as hydrogen bonds absorb lots of energy and can buffer changes in temperature.
- It has strong cohesion, water molecules have the tendency to stick to other water molecules due to the slightly positive hydrogen which attracts slightly negative oxygen. the cohesive force allows water to flow allowing it to be a good transport medium. water molecules can also stick to other surfaced giving it adhesive forces.
- it can insulate large bodies of water as ice is less dense than liquid water because water molecules in ice are held, further apart allowing it to form an insulating layer letting aquatic organisims survive.
how does ice float
when water freezes it turns into ice which is less dense due to H bonds and therefore ice floats
monoscharides
single sugar unit
polyscharides
2 or more monoscharides linked together
what are carbohydrates?
long chains of sugar molecules formed from lots of individual sugar molecules joining together
2 or more monoscharides reacting together forms , what reaction occurs and what bond forms
disaccharide, condensation reaction occurs and glycosidic bond forms
polyscharides break down what reaction occurs
hydrolysis
examples of polysacharides
glycogen, cellulose and starch
examples of monoscharides
glucose fructose etc
examples of disaccharides
sucrose lactose and maltose
what is glucose
C6H1206 it is an hexose sugar which exists as 2 forms.
2 forms of glucose
alpha glucose
beta glucose
what is the differences between alpha and beta glucose
the position of the hydrogen and hydroxyl group on the right hand carbon
alpha has hydrogen
A bove the carbon
beta glucose has the hydrogen
B elow the carbon
PROPERTIES OF GLUCOSE
it is highly soluble in water making it easy to transport
it is the main energy source for animals and plants
reaction of 2 alpha glucose molecules reacting
the two hydroxyl groups interact and a condensation reaction occurs forming a 1,4 glycosidic bond (maltose)
how is sucrose maltose and lactose formed
maltose
2 alpha glucose
sucrose
1 alpha and fructose
lactose
1 beta glucpse and galactose
what is ribose
it is a monosacharide formed of RNA molecules. it is a pentose sugar with 5 carbon rings.
what are polysacharides
they are large insoluble monosacharides joined with glycosdic bonds . Starch and glycogen are examples which are stroage molecules
properties of starch
storage in plants. hydrolysed when glucose is needed
insoluble in water so the water potential of cells is not affected
what are the 2 forms of starch
amylose and amylopectin
amylose
unbranched spiralling chains of alpha glucose molecules joined together by 1,4 glycosidic bonds it is coiled meaning it is compact allowing many amylose to be packed into one cell.
amylopectin
branched chains of alpha glucose molecules (1,4 glycosidic bonds) it branches to increase SA so enzyme can break it quickly when needed for respiration.
what is the energy store in animals
glycogen
glycogen
branched chains of alpha glucose giving it large sa for enzyme action to release glucose when energy is needed.it is insoluble branched and compact making it ideal for storage.
where is cellulose found and what it is used for and structure
it is found in cell walls and it is to give strength.
long and unbranched chains of beta glucose molecules linked together by hydrogen bonds to form microfibrils which give plants structural support and shape in cell walls
what is the test for reducing and non reducing sugars
BENEDICTS TEST
REDUCING SUGAR PRESENT
BLUE TO BRICK RED
NON REDUCING SUGAR
- HCL TO BREAK GLYCOSIDIC BONDS
- BENEDICTS AGAIN
.
TEST FOR STARCH
IODINE ORANGE BROWN TO BLUE BLACK
what are lipids commonly known as
fats and oils
the fats are solid at room temp and oils are liquid
what are large complex lipid molecules known as
macromolecules which are built from repeating units or monomers like polysaccharides.
what are the three types of lipids
triglycerides, phospholipids and cholestorol
what are triglycerides and phospholipids both made up of
glycerol connected to a fatty acid through ester bonds. however triglycerides have 3 fatty acids whereas phospholipids have 2 fatty acids and a phosphate group
what is esterfication
the hydroxyl group from glycerol and fatty acids interact which forms 3 water molecules containing an ester bond. it is a condensation reaction
what are the roles of lipids
- membrane formation (phospholipids)
- hormone production
- electrical insulation
- waterproofing
- thermal insulation
- buoyancy
- cushioning
triglyceride
energy store
insoluble in water
phosopholipids
main component of cell membranes, form a phospholipid bilayer with hydrophobic tails facing eachother and hydrophillic heads facing outwards, it forms a barrier to prevent polar molecules entering or leaving cell.
cholestrol
found in cell membrane and help strengthen the membrane, pushes hydrophobic tails of phospholipids together making it more rigid. it helps regulate fluidity by ensuring membrane fluid is at low temp.
sterols
steroids and alcohols
test for lipids
emulsion test, milky emulsion will form
what are peptides
polymers made up of amino acid molecules
what is a protein
polymer of amino acids joined togetehr by peptide bonds
amino acid structure
r group, amine group, carboxyl group and hydrogen attached to a central carbon
what makes each amino acid different
the R group
peptide bond formation and breaking
formation:
condensation reaction
amino acid and amino acid react to form a dipeptide containg a peptide bon (conh)
breaking:
hydrolysis
dipeptide and water
levels of protein structure
primary
secondary
quaternary
tertiary
primary is the
sequence in which an amino acid is joined
secondary structure of a protein is the
basic repeating structure of amino acids interact forming hydrogen bonds pulled into a coil shape called an ALPHA helix or Beta pleated sheet which is polypeptide chains lied parrallel to eachother by H bonds.
tertoary structure is
the folding of protein which gives it a 3d effect
what is the quaternary structure
the structure formed from interaction of polypeptide chains
alpha helix is
basic repeating structure of amino acids interact forming hydrogen bonds pulled into a coil shape called an ALPHA helix
beta pleated sheet is
Beta pleated sheet which is polypeptide chains lied parrallel to eachother by H bonds.
what are the two types of proteins
globular and fibrous
globular proteins are
compact
water soluble
spherical
the proteins are folded into their tertiary structure
hydrophobic inside and hydrophilic outside allowing it to be soluble
essential in regulating processes in life
what are conjugated proteins
they are globular proteins which contains a prosthetic group
what are examples of globular proteins
haemoglobin which is a quaternary protein with 4 polypeptides,2 alpha and 2 beta. each alpha and beta containing an prosthetic haem group which combine reversibly with an oxygen.
catalase enzyme which contains 4 haem prosthetic groups which allows it to speed up breakdown of hydrogen peroxide.
what are fibrous proteins
they are long and insolunle due to high proportions of hydrophobic r groups
they are strong long molecules with no 3d structure
examples of fibrous proteins
elastin
found in elastic fibres in the walls of blood vessels and alveoli which can expand
collagen
found in connective tissues within skin, tendons and ligaments and nervous systems, it contains 3 polypeptides wound together in a log and strong rope structure and is flexible.
keratin
present in hair, skin and nails contains many disulfide bonds forming strong inflexible insoluble materials
test for proteins
biuret test, blue to purple
