Biological molecules Flashcards
what is metabolism?
the total sum/rate of all chemical reactions within an organism
what are the two types of metabolism?
catabolic: larger complex molecules broken to smaller
C - the break down of substances releasing energy
anabolic: smaller molecules built to larger molecules
A - the synthesis of substances requiring energy
what are organic molecules?
contain carbon and hydrogen
what are monomers?
are small repeating units which join together to form larger molecules
what are polymers?
large molecules made up small repeating units called monomers
carbohydrate monomers + polymers?
monomers: monosaccharies
polymers: polysaccharides
proteins monomer + polymers?
monomer: amino acids
polymer: polypeptides/proteins
nucleic acid monomer + polymers?
monomers: nucleotides
polymers: dna/rna
what is a condensation reaction
joins to molecules together with the formation of a chemical bond and involves the elimination of water
what is a hydrolysis reaction?
breaks a chemical bond between 2 molecules involving the use of a water molecule
what is a carbohydrate?
a molecule that contains carbon,hydrogen and oxygen with the ratio 1:2:1
function of carbohydrates?
provide energy/important source of energy for plants and animals
what are the 3 main groups of carbohydrates
monsaccarides, disaccarides, polysaccarides
properties of monosaccharides?
water soluble, sweet tasting and form crystals
3 monosaccharides i need to know..?
glucose, fructose, galactose
which two monosaccharides make maltose?
where are the disaccharides found?
glucose + glucose 2.in malt sugar
which two monosaccharides make up sucrose?
where are the disaccharides found?
glucos + fructose 2.cane sugar
which two monosaccharides make up lactose
where are the disacchardies found?
glucose + galactose 2. milk sugar
draw and explain the difference between alpha and beta glucose
in alpha glucose the fist carbon has h on top oh on bottom whereas in beta glucose its switched
what type of molecules are Alpha and beta glucose?
Structural isomers
do monosaccharides need changing to be used in respiration?
they require little to no change
what is the general formula for monosaccharides?
CnH2n0
what is the general formula for disaccharides?
CnH2n-10n-1
if the number of carbon atoms is 3, 5, 6 the monosaccharide is called?
3= triose- glyceraldehyde
5=pentose - ribose
6=hexose - glucose, galactose
uses of monosaccharides?
building blocks and energy
biological role of monosaccharides as an energy source?
as an energy source a large amount of energy is stored between c-h bonds. this is released to form ATP. ATP is the energy currency of the cell.
biological role of monosaccharides as a building block?
repeated glucose molecules build up to form molecules such as starch and glycogen
what needs to happen to disaccharides before being used as energy?
need to be digested before they can be sued to release energy. Sugars are often in this form.
which one of the three main groups of carbohydrates are not sugars?
polysaccharides
give 3 examples of disaccharides
sucrose, lactose and maltose
what monomer is starch made up of?
alpha glucose
type of glycosidic bond?
amylose = 1-4 , amylopectin = 1-4 and 1-6 glycosidic bond
describe the main structure of the starch chain?
helical chain
what are the two forms of starch
amylose and amylopectin
describe the structure of amylose a form of starch?
straight chain, no branches forms coil/spiral structure
describe the structure of amylopectin another form of starch?
straight chain, branches at regular intervals formed by condensation
- what is the average size of a starch polysaccharide?
- reducing or non-reducing?
- solubility in water?
- found in..?
5 .molecule type?
- 1um-100um
- non-reducing
- insoluble
- plant cells
straight chain polysaccharide
explain the use of starch being insoluble?
doesn’t affect the water potential so water is not drawn out of cells by osmosis
explain the use of starch being large and insoluble?
does not diffuse out of cells
explain the use of starch beng coiled and compact?
can be stored in a small space
when starch is hydrolysed it forms..?
explain why this is useful?
alpha glucose. alpha glucose is easily tranpsorted and readily used in respiration
explain the use of starch having many branched ends
each branch can be acted on by enzymes, simultaeneously meaning that glucose monomers are released rapidly
what monomers is glycogen made up of?
alpha glucose
type of glycosidic bond?
1,6 - 1,4- glycosidic bond
main structure of glycogen?
very branched structure, provide more sites for glucose to be released fast
- relative size of glygogen molecule?
- type of molecule?
- reducing or non-reducing?
- solubility in water
- 20-30um
- branched polysaccharide
- reducing
- partially soluble
why is glycogen insoluble
doesn’t tend to be drawn into cells by osmosis (doesn’t affect the water potential and does not diffuse out of cells)
why is glycogen compact
large amount of energy can be stored in a small space
why is glycogen highly branched
more ends can be acted on by enzymes simultaeneously more rapid break down to form glucose monomers for respiration
what monomers is cellulose made from?
beta glucose
type of glycosidic bond?
1,4 glycosidic bond
main structure?
linear structure
- size of molecule
- type of molecule?
- reducing or non-reducing?
- solubility in water?
- 2-10nm
- straight chain polysaccharide
- non-reducing
4.insoluble
explain how cellulose molecules are adapted to their function?
- inward prsssure prevents cells from bursting as water enters by osmosis -?
- long straight unbranched chains of many glucose molecules to strengthen cell wall
- forms many firm hydrogen bonds between individual chains in cellulose microfibrils = strengthing effect
- cellulose molecules are grouped to form microfibrills and microfibrils that are grouped form fibres providing more strength
describe the test for starch?
add a few drops of iodine solution. positive result = blue/black neg result= yellow/brown
describe the test for protein?
using biuret solution = sodium hydroxide and a few drops of copper sulphate. positive result = purple/lilac
neg result = blue
describe the test for lipids
add ethanol to test sample and shake, add equal amounts of water. positive result = white emulsion is formed neg= clear
all monosaccharides and some disaccharides are…?
reducing sugars
What is a reducing suar?
a reducing sugar is a sugar that can donate electrons (reduce) another chemical
describe the test for reducing sugar?
heat (water bath) test sample with benedicts solution. positive result = orange-red precipitate
neg result = blue/green
why is Benedicts test semi-quantitative?
when heated with benedicts some solutions give different colours e.g brown, yellow, green, red. the differences in colour mean that it can be used to estimate the approximate amount of reducing sugar in a sample.
green = very low amount
yellow = low
brown = medium
red - high
some disaccharides are..?
Non-reducing sugars
describe the test for non- reducing sugar
- reducing sugar test
- boil solution with HCL to hydrolyse the glycosidic bond
- neutralise with sodium hydrogen carnonate
- heat with benedicts
positive result - green–> orange-red precipitate
negative result- no colour change
what is the result for a reducing and non-reducing?
more intensely coloured precipitate deep orange-red
what is the function of proteins?
providing structure, regulating body processes, transporting materials, balancing fluids, helping with immunity, and providing energy.
draw and explain the structure of an amino acid?
amine group, carboxylic group and r-group
how many types of amino acids are there?
20 different types so twenty different r groups
what properties does the r group decide?
if the molecule is hydrophobic, hydrophillic, positively, negatively charged
- where do plants get their protein from?
- how do animals get their protein?
- why cant access amino acids be stored in animals?
- nitrates from the soil
- from plants-digest-proteins-amino acids
- leads to toxicity deamination. deamination is the removal of amino acids. amino groups converted into urea and removed in urine.
four levels of structure in a protein
1. primary structure - what is it determined by?
2. what does the sequence of amino acids determine?
- protein sequencing happens here . it is determined by a gene that codes for a polypeptide and a peptide bond forms.
- determines the properties and functions of that protein
- . secondary structure- explain?
- folds into right handed alpha felix?
- this means that..?
- folding of the polypeptide chain
- the polypeptide would for a coil/helix structure, hydrogen bonds run parallel along the long helical axis
- it has a strong stable structure due to many hydrogen bonds
- secondary structure
- also folds into a beta pleated sheet?
- which folds back on its self forming a zigzag sheet, held together by hydrogen bonds
- tiertiary structure - explain
- the bonds which hold the tiertiary structure are?
final 3D shape where helixes and pleates are twisted and folded again
- disulphide - fairly strong, not easily broken
-ionic - between oppositly charged r groups, strong but weaker than disulphide bonds, not easily broken by chnages in ph
-hydrogen- between slightly oppositely charged groups, easily broken
- what happens if the structure is heated?
- what happens if kinetic energy increases?
- why are most bonds weak?
- starts to unravel and starts to denature so can not function anymore
- molecules vibrate and breaks some bond holding structure
- because most bonds are not covalent
what else happens at tiertiary structure?
forms globular or fibrous proteins
what are globular proteins?
roll into a compact globe/ball shaped structure,
hydrophobic inward, hydrophillic outward,
are enzymes, plasm proteins and antibodies, have metabolic roles
what re fibrous proteins?
form fibres, regular/repetitive sequences of amino acids,
usually insoluble in water
have structural roles
what is quaternity structure of a protein?
made up of multiple polypeptide chains
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