biochemistry Flashcards
describe the structure of a water molecule
one atom of oxygen joined to two atoms of hydrogen by shared electrons. Because the shared negative hydrogen electrons are pulled towards the oxygen atom the other side of the hydrogen atom is left with a slight positive charge. Unshared negative electrons on the oxygen atom give it a light negative charge. This makes water a polar molecule
state properties of water that make it useful for living organisms
waters polarity makes it useful as a solvent in living organisms e.g. important substances in biological reactions are ionic. Waters polarity makes it very cohesive, waters less dense when its solid, hydrogen bonds give water a high specific heat capacity and hydrogen bonds give water a high latent heat of evaporation
why when water freezes is it less dense?
water becomes denser with lowering temperature. When near freezing point presence of hydrogen bonds means the molecule form a structure that is of a lower density hence why it floats on water.
what is the difference between an alpha glucose molecule and a beta glucose molecule?
the H and Oh are flipped to be the opposite way- alpha OH is at the bottom and in beat OH is at the top.
what is the bond between monosaccharaides?
glycosidic
what are the reactions that join monosaccharides and split disaccharides and polysaccharides?
condensation joins and hydrolysis splits
what else is produced when monosaccharieds join?
water
what is required when disaccharides and polysaccharides split?
water
what are carbohydrates made up of?
carbon, hydrogen and oxygen
what are the roles of carbohydrates?
provide energy, provide support and energy storage
give 3 examples of hexose monosaccharides
glucose, fructose and galactose
what is the difference between ribose and deoxyribose?
ribose has an OH group but deoxyribose does not- deoxyribose does not contain oxygen
what monomers is maltose made of and where is it found?
2 alpha glucose molecules, it is found in brewing sugars and breakdown of starch
what monomers is sucrose made of and where is it found?
alpha glucose and fructose, found in table sugar and plants
what monomers is lactose made of and where is it found?
alpha glucose and galactose, found in milk
what property do storage carbohydrates need?
compact
what property do structural polysaccharides need?
straight chains
what is the repeating unit of storage polysachharides?
alpha glucose
what is the significance of an OH group on the storage polysaccharide?
it starts to make the polymer coil which gives the coiled compact shape
what is the storage carbohydrate for animals?
glycogen
what is the storage carbohydrate of plants and what is it made from?
starch, made from amylose and amylopectin
give the roles of proteins
cellular structure, movement, defense transport and communication
what is the role of enzymes?
regulate chemical reactions
what elements are proteins made of?
carbon, hydrogen, oxygen, nitrogen and sulfur
what is the monomer of proteins?
amino acids
how many types of amino acids are there?
20
what can am amino acid be described as and why?
amphoteric as it has both basic and acidic group atatched to it
what is it called when two amino acids join and what is the bond that is formed called?
dipeptide- peptide bond
what is the primary structure of a protein?
number, order and type of amino acid
what is the secondary structure of an protein?
alpha helix and beata pleated sheet produced by hydrogen bonding
describe a disulphide bond
where 2 cysteine AA are found together strong double (S=S) formed between the sulphur atoms within the cysteine monomers
describe an ionic bond
if 2 oppositley charged “R” groups are found close to each other ionic bonds form
describe hydrogen bonds
typical everyday hydrogen bonds not as strong as sulphide and ionic but lots of them
describe hydrophibic and hydrophilic bonds
in water based environment a globular protein will orientate itself such that its hydrophobic parts are towards its center and hydrophilic parts towards the otuside
what is the quaternary structure of a protein?
the relationship amongst many polypeptides of a protein
give the properties of long fibrous protiens
mostly consist of repeating squences of AA, insoluble in water due to high proportion of AA with hydrophobil “R” groups in the primary structure
what is the usual role of fibrous proteins?
structural roles
describe the structure of collagen
made of 3 polypeptides wound together in a long strong structure
give 4 uses of collagen
1- structure of bones , 2-cartilage & connective tissue, 3-prevents high pressure blood for bursting arteries 4- main component of tendons which connect bones to skeletal muscles
where is keratin found and what amino acid is in abundance?
outer layer of skin, hair and nails- large proportion of cysteine - lots of S=S bonds
what does the large proportion cysteine mean? what determines the flexibility
lots of strong sulphide bonds forming strong & insoluble materials. the amount of S=S bonds determines flexibility
where is elastin found?
in connective tissue, arteioles , arteies and alvioli of the lungs
what is the purpose of elastin?
allows tissue to return to shape after stretching and contracting also allows skin to retain shape after being stretched
properties of globular proteins & example
compact spherical shape and soluble, enzymes and antibodies
describe the folding of a globular protein
tertiary structure , folding ensures that the hydrophobic “R” groups are kept away from the aqueous environment , hydrophilic “R” groups are on the outside
describe the conjugated protein insulin
2- polypeptide chains - start alpha helix end beta pleated , both chains fold into a tertiary structure linked by dispulhide bonds, hydrophilic r groups on outside = soluble
what are conjugated proteins made of?
polypeptide, globular protein and prosthetic group
what are lipoprotein and glycoproteins ?
lipids or carbohydrates join with proteins to form lipoproteins or glycoproteins
describe the conjugated protein heamoglobin
2 aplha and beta polypeptide chains and inorgainic prosthetic haem group with each chain, the Fe2+ heam guop is where oxygen molecules bind
describe the conjugated enzyme catalase
has a quaternary structure made of 4 haem prosthetic groups. Fe2+ ion allows enzyme to interact with hydorgen peroxide- this is a common breakdown of metabolosim
what is the difference between an alkane and an alkene?
alkene has a double bond alkanes do not
what elements do lipids contain?
carbon, hydrogen & oxygen
why are lipids not polymers? what are they?
they have no repeating units they are called macromolecules
describe the behavior of lipids with water
they repel water and are relatively insoluble in water
where are lipids stored?
in adipose tissue in the skin
what are the roles of lipids?
structural components, insulation, hormone production, buoyancy in aquatic animals, respiration to release energy, produce more water than the respiration of water
why are lipids used as as an energy source?
1g of fat releases twice as much energy as 1g of glucose as they have a higher proportion of hydrogen atoms than carbohydrates and hardly any oxygen atoms
what is an essential fatty acid?
an acid that must be ingested
why is a fatty acid an acid?
hydrocarbon chain form 2 to 20 carbons long, carboxyl groups ionise into H+ and -COO- therefore an acid
what is the ratio of glycerol to fatty acids in a triglyceride?
one glycerol molecule linked to 3 fatty acids
whats the name of the bond formed , how many water molecules are produced in the formation of a triglyceride and what is the formation of the bond called?
ester, 3 and esterification
what is the difference between a saturated and unsaturated fatty acid?
saturated have no double bonds in the hydrocarbon chain, in an unsaturated fatty acid a kink is formed from the double bond making it more fluid
what is the result of the difference? Give and example of a saturated fatty acid and unsaturated fatty acid
unsaturated are liquid at room temperature e.g. plant oil and saturated are solid at room temperature e.g. lard
where are phospholipids found?
major component of cell membranes
how do phospholipids differ from triglycerides?
each have a hydrophilic head and 2 hydrophobic tails
what are is the hydrophilic head made of and what are the hydrophobic tails made of?
tail- 2 fatty acids, heads- glycerol and a phosphate group
what is another name for cholesterol?
strerol or steroid alcohol
describe the structure of cholestrol
4 carbon base rings -(isoprene)
where is it found and what does it do?
eukaryotic plasma membrane and regulates the fluidity of the membrane
where in the body is cholesterol made?
the liver
what can be made from cholesterol?
steroid hormones and vitamin D
