topic 2 biological molecules Flashcards
1
Q
What are the four primary types of biological molecules?
A
Carbohydrates, lipids, proteins, nitrogen
2
Q
What element do all biological molecules contain?
A
Carbon
3
Q
What elements do carbohydrates contain?
A
Carbon (C), hydrogen (H), and oxygen (O)
4
Q
What elements do lipids contain?
A
Carbon (C), hydrogen (H), and oxygen (O)
5
Q
What elements do proteins contain?
A
Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N)
6
Q
What elements do nucleic acids contain?
A
Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P)
7
Q
What are monomers?
A
Smaller units that combine to make a large molecule (polymer)
8
Q
What are polymers?
A
Large molecules made up of many monomers joined together
9
Q
What is the process by which monomers join to form a polymer called?
A
Polymerisation
10
Q
what are the monomer and polymers of carbohydrates
A
monomer - monosaccharides
polymer- Polysaccharides
11
Q
what are the monomer and polymers of proteins
A
monomer - amino acids
polymer - Polypeptides
12
Q
what are the monomer and polymers of nucleic acid
A
monomer - nucleotides
polymer - Polynucleotides
13
Q
How are most polymers synthesized and broken down?
A
Most polymers are synthesized via a condensation reaction and broken down via a hydrolysis reaction.
14
Q
What is a condensation reaction?
A
Condensation is the removal of water to form a chemical bond between two molecules.
15
Q
What is hydrolysis?
A
Hydrolysis is the addition of water to break a chemical bond between two molecules.
16
Q
What is an ion?
A
An ion is an atom with an electric charge.
17
Q
What is an inorganic ion?
A
An inorganic ion is an ion that does not contain carbon (with some exceptions).
18
Q
What is a cation?
A
A cation is an ion with a positive charge.
19
Q
What are some roles of the cation calcium (Ca²⁺) in living organisms?
A
Calcium plays roles in nerve impulse transmission, muscle contraction, and as a cofactor for enzymes.
20
Q
What are some roles of the cation sodium (Na⁺) in living organisms?
A
Sodium is involved in generating nerve impulses, muscle contraction, and the co-transport of glucose and amino acids.
21
Q
What are some roles of the cation potassium (K⁺) in living organisms?
A
Potassium is involved in generating nerve impulses, muscle contraction, and regulating fluid balance.
22
Q
What are some roles of the cation hydrogen (H⁺) in living organisms?
A
Hydrogen determines the pH of solutions and is used in photosynthesis reactions.
23
Q
What are some roles of the cation ammonium (NH+4) in living organisms?
A
-source of nitrogen for plants
24
Q
What are some roles of the cation Iron (Fe2+) in living organisms?
A
binds to oxygen within harmogoblin
25
what are anions
an ions with a negative charge
26
What are some roles of the anion chloride (Cl-) in living organisms?
- maintains blood pH in gas exchange
- cofactor for amylase enzyme
27
What are some roles of the anion phosphate (PO4 3-) in living organisms?
- component of nucleotides and phosphilipids
- bonds energy store in ATP
28
What are some roles of the anion hydroxide (OH-)in living organisms?
determines pH of solutions
29
What are some roles of the anion nitrate (NO3-) in living organisms?
source of nitrogen
30
What are some roles of the anion hydrogencarbonate (HCO3-) in living organisms?
maintains blood pH
31
what is a molecule of water made up of
one oxygen atom chemically bonded to two hydrogen atoms held together by two covalent bonds
oxygen shares one electron with each hydrogen atoms while hydrogen shares its one electron w oxygen
32
why is water a polar molecule
oxygen atom has a small negative charge and hydrogen atoms have a small positive charge. The electrons are puller slightly towards the oxygen atom giving it a slightly negative charge (S-) leaving the hydrogen atoms w a slightly positive charge (S+)
33
What does polar refer to?
Any molecule with an uneven charge distribution
34
What is the more specific term for polar molecules that exhibit two distinct poles?
Dipolar
## Footnote
Dipolar molecules clearly show a positive and a negative pole.
35
How do water molecules form hydrogen bonds?
The partially positive hydrogen end of one water molecule attracts the partially negative oxygen end of another molecule
This attraction is due to opposite charges between the molecules.
36
What are the forces of attraction between water molecules called?
Hydrogen bonds
37
properties of water
- high specific heat capacity
- large latent heat if evapouratiob
- strong cohesion between water molecules
- an important solvent
- anomalous expansion of water
38
role of water
- solvent
- temperature control
- cooling mechanism
- habitat
- metabolite
- transport
39
water as a solvent
-many substances within cells are ionic compounds meaning consist of positive and negative ions and they split apart when added to water
-as its polar the negative oxygens are attracted to the positive ions while the positive hydrogens are attracted to negative ions. each ion is surrounded by water molecules and the compound dissolves
-biological reactions take place in solution
- universal solvent
40
water as a temperature buffer
- high specific heat capacity
- many hydrogen bonds between water molecules can absorb a lot of energy before being broken
- resistant to rapid changes in temperature
41
water as a cooling mechanism
-the hydrogen bonding neans a lot of energy is needed to evapourate 1kg of water
- hugh latent of heat vaporization
- water can be used as a method of cooling without losing too much water. when water evaporates it takes heat energy from the surface
-animals use it by sweating plants do it by evaporating water from their leaves
42
water as a habitat
- high specific heat capacity and high latent heat of evapouratiob so it does not change temperature of evapourate easily
- provides stable envirnoment to live in
- at a low temperature freezes to form ice , water molecules are held further apart making it less dense and floats forming an insulating layer at the surface so the later below does not freeze
43
water as a metabolite
involved in many chemical reactions including
- hydrolysis
- condensation
- photosynthesis
- aerobic respiration
44
water as a transport medium
- tendency of water molecules to stick together- cohesion
- tendency to stick to other materials - adhesion
- allows water to flow and carry substances w it
- when water meets air creates high surface tension which means small organisms can be supported
45
general formula for carbohydtrates
Cx(H2O)y
46
functiosns of carbohydrates
- energy supply for cells
- energy storage
- structural components
- cellular recogniton
- building blocks for biological molecules
47
3 types of carbohydrates
monosaccharides
disaccharides
polysaccharides
48
monosaccharides examples
- glucose
- fructose
- galactose
49
disaccharides examples
maltose
sucrose
lactose
50
polyscaccharides examples
starch
glycogen
cellulose
51
What are monosaccharides?
The simplest form of carbohydrates, also known as simple sugars.
52
What is the general formula for monosaccharides?
(CH₂O)n, where n can be any number from 3 to 7.
53
List the characteristics of monosaccharides.
* Soluble
* Sweet-tasting
* Found in many foods such as fruits, vegetables, and grains.
54
How are monosaccharides classified?
According to the number of carbon atoms in each molecule.
55
What are hexose sugars?
Monosaccharides that contain 6 carbon atoms.
56
Name three hexose sugars.
* Glucose
* Fructose
* Galactose
57
What are pentose sugars?
Monosaccharides that contain 5 carbon atoms.
58
Name two pentose sugars.
* Ribose
* Deoxyribose
59
What is the formula for glucose?
C₆H₁₂O₆
60
What is the primary energy source in animals and plants?
Glucose
61
True or False: Monosaccharides can be found in grains.
True
62
features of glucose
- it is soluble ( the hydroxyl group can form hydrogen bonds with water)
- its bonds store lots of energy which is released when the bonds are broken
63
2 isomers of glucose
- alpha glucose
- beta glucose
64
what is the difference between the two forms of glucose
the orientation of the hydroxyl group on carbon 1 ( on beta glucose the hydroxyl group is above the ring)
65
when are disaccharides formed
when two monosaccharides join together by a condensation reaction
66
what is maltose made up of
alpha glucose joined to aloha glucose
67
what is sucrose made up of
glucose joined to fructose
68
what is lactose made up of
glucose and galactose
69
condensation reaction of 2 monosaccharides into a disscaride
- the hydroxyl group on carbon 1 and 4 are reacting togetehr so a 1-4 glycosidic bond forms ( but can also form between other carbons)
- when the hydroxyl group react it forms a glycosidic bond a water molecule is released
70
hydrolysis reaction of 2 monosaccharides into a disscaride
when a water molecule is added the glycosidic bond is broken to release 2 monossacarides
71
what are polysaccharides
complex carbohydrates made up of many monosaccharides joined together via glycosidic bonds
72
what is starch used for
used by plants to store excess glucose. Starch can be hydrolyzed back into glucose when plants require energy. Due to the solubility if glucose if a cell contains a large amount if glucose this cab cause water to move into the cell by osmosis so plant cells store glucose as starch
73
what is starch made up of
many aloha glucose monomers joined vis glycosidic bonds to form chains
74
two forms starch chains come in
- amylose
- amylopectin
75
amylose
- long unbranched chain of alpha glucose joined by 1-4 glycosidic bonds
- formed by condensation reaction
- angles of hydrogen bonds cause the chain to coil into a helix shape to make a compact structure
76
amylopectin
- long branched chain of aloha gluvoee joined by bith 1-4 glycosidic bonds and 1-6 glycosidic bonds
- polymer of alpha glucose
- its side branches allow enzymes to hydrolyse alpha glucose monomers easliy
77
features of starch that help it to function as a store of energy
- insoluble
- large
- many side branches
- compact
- hydrolyses to release alpha glucose monomers
78
what is glycogen used for
used by animals to store excess glucose
79
what is glycogen made up of
many alpha glucose molecules joined via 1-4 and 1-6 glycosidic bonds to form highly branched chains
80
features that allow glycogen to function as a store of enegery
- insoluble
- compact
- more highly branched than starch
- large
- hydrolysis to release alpha glucose monomers
81
cellulose primary use
provide structural support for plant cell walls
82
what is cellulose made up of
beta glucose monomers joined together via glycosidic bonds
83
how beta glucose bond to form cellulose
- the hydroxyl groups on carbon 1 and carbon 4 of beta glucose molecules are too far to react bcs the hydroxyl group on carbon 1 points above the plane of the ring
- every second beta glucose molecule is flipped by 180• so they can react
- when many beta glucose monomers join together they form long straight unbranched chains. The alternating inversion of the beta glucose molecules allows for hydrogen bonds to form between neighboring chains. the number of the bonds make cellulose strong
- multiple cellulose chains become tightly crosslinked via hydrogen bonds to form bundles called microfibrils
- microfibrils join together to make macrofibrils which combine to make string cellulose fibers in the plant cell wall
84
adaptions of cellulose for its role
- long, straight and unbranched chains provide rigidity to cell wall
- hydrogen bonds crosslink the chains to add collective tensile strngeth
- microfibrils add additional strength
85
sugars can be grouped into 2 categories
reducing sugars - monosaccharides and some disaccharides ( like maltose and lactose)
non reducing sugars - some disaccharides and all polysaccharides
86
test for reducing sugars
- grind w mortal and pestle and distilled water add more water when paste then filter
- place 4cm3 of food sample in boiling tube and ads 3cm3 of benedict's reagent
- heat mixture in water bath for 2 mins, observe then another 2 mins
87
reducing sugar test positive result
blue to brick red
88
non reducing sugars must be _____ into _______ components before tested like reducing sugars
hydrolyzed
monosaccharide
89
test for non reducing sugars
- carry out test for reducing sugars if result is negative continue
- add 4cm3 of food sample to 2cm3 of dilute hydrochloric acid
- heat mixture gently in water bath for 2 mins
- allow boiling tubes to cool
- neutralise the mixture by gradually adding sodium hydrogen carbonate till no more effervescence is observed
- check pH w indicator paper. If pH is lower than pH 7 repeat step before
- add 2cm3 of benedicts reagent (retest for reducing sugar)
- place in test tube water bath for 2 mins
90
test results for different concentrations of reducing sugars
- blue - no reducing sugar presnt
- green - low concentration
- orange - medium concentration
- brick red - high conventration
91
test for starch
- place 3cm3 of food sample in test tube
- add 1cm3 of iodine solution and shake
- if starch is present solution turns from orange to blue black
92
do lipids have a higher or lower proportion of oxygen than carbohydrates
lower
93
are lipids polymers
No
94
roles of lipids
- energy supply - oxidized to provide energy to cells
- structural components - phosphlolipids
- water proofing - insoluble lipids form water resistant barriers
- insulation - help retain heat or act as electrical insulator
- protection - delicate organs are surrounded by layer of fat
95
what are most lipids made up of
fatty acids and a glycerol
96
what do fatty acids consist of
a carboxyl group (-COOH) attached to a hydrocarbon chain (R group)
97
2 types of fatty acids
- saturated fatty acids
- unsaturated fatty acids
98
saturated fatty acids
- have hydrocarbon cabins that are saturated with hydrogen meaning all carbon atoms are bonded to the maximum number of hydrogen atoms
- the hydrocarbon chain has no carbon to carbon bonds
- lipids that contain saturated fatty acids have higher melting point so normally solid at room tempreture (fats)
99
unsaturated fatty scids
- have hydrocarbon chains that do not contain maxiumum number of hydrogen atoms bonded to the carbon atoms
- hydrocarbon chain has at least one carbon to carbon double bond which causes the chain to kink ( bend)
- lipids that contain unsaturated fatty acids have lower melting points so are usually liquid at room temp (oils)
100
unsaturated fats can be either _____ or _____
monosaturated - one double bond
polyunsaturated - two or more double bonds
101
test for lipids ( emulsion test)
- grind food w small amount of distilled water and mortar and pestle
- must not filter food sample bcs lipids can stick to the filter paper
- add 3cm3 of ethanol and 3cm3 of distilled water
- shake
- if lipids are present a white cloudy emulsion will form. if solution stays clear lipids are not present
experiment must not be carried out near flames - highly flammable
102
triglycerides
- type of lipid used as a store of energy in animals, plants and some bacteria
- consists of a glycerol backbone attached to 3 fatty acids
103
features that allow triglycerides to store energy efficiently
- long hydrocarbon tails- hydrogen bonds can b broken to release energy
- low mass to energy ratio
- insoluble
- high ratio of hydrogen to oxygen atoms
104
how are triglycerides synthesised
- condensation reactions
- hydroxyl groups on the glycerol and on the 3 fatty acids react to release 3 water molecules
- results in 3 ester bonds ( etserification)
105
how are triglycerides broken down
-hydrolysis recation
- addition of 3 water molecules breaks the ester bonds (covalent bonds)
- in the digestive system lipase enzymes break the ester bonds
106
phospholipids
a type of lipid used as a structural component of the cell membrane
- consists of phosphate group , a glycerol, 2 fatty acids
107
a phospholipid is made up of 2 parts
- a hydrophilic head - contains a glycerol and phosphate
- a hydrophobic tail - contains fatty acids
- phosphate group is polar and hydrophilic - attract water
- fatty acids are hydrophobic - repel water
108
phospholipid bilayer
the arrangement phospholipids arrange themselves in water. the hydrophilic heads are facing outwards and hydrophilic tails inwards creating a hydrophobic center so water soluble substances cannot pass through
109
cholesterol
-type of lipid known as sterol
-used by animals to increase the stabilty of the cell membrane
- also used to make vitamin D, steroid hormones and bile
110
explain the hydrophobic and philic interactions of cholesterol
cholesterol is polar like phospholipids
-the hydroxyl group is hydrophilic the rest is hydrophobic so cholesterol can insert into cell membranes. the hydroxyl group can interact w the head groups of the phospholipids while the rest of the molecule interacts w the fatty acid tails
111
cholesterol role in cell membrane
- binds to the phospholipids fatty acid tails causing them to pack more closely together reducing the fluidity
112
cholesterol uses
- starting point for a range of hormones bcs they are based off cholesterol (eg estrogen) they can interact w receptors inside the cell and pass through the membrane
- used in the body to make vitamin D
- used to make bile in the liver
113
functions of proteins in living organisms
-enzymes
-antibodies
-transport
-structural components
-hormones
-muscle contraction
114
amino acid structure
- comtain elements carbon, hydrogen, nitrogen, oxygen
-all have
• a central carbon atom
• an amino group (-NH2)
• an carboxyl group (-COOH)
• an hydrogen atom (-H)
• an R group or a variable side group
H H O
\ | //
N - C - C
/ | \
H R OH
115
how are dipeptides synthesised
- condensation revation
- the hydroxyl group of one amino acid reacts w the hydrogen of another and releases a water molecule and forms a peptide bond between the carbon of one amino acid and the nitrogen of another. 3 or more make a polypeptide
116
how is a dipeptide broken down
- hydrolysis reaction
- a water molecule is added
- carried out by protease in digestive system
- peptide ( covalent) bond is broken
117
test for poteins
- 3cm3 of food solution in test tube
- 3cm3 of dilute sodium hydroxide and mix
- 10 drops of dilute copper (II) sulfate
sodium hydroxide and copper (II) sulfate are components of biruet solution
- turns purple if present if not remains blue
- presence of peptide bonds changed the colour so just amino acids have a negative result
118
primary structure of proteins
the specific order of amino acids in a polypeptide held together by peptide bonds
determined by DNA sequence of the gene which encodes that polypeptide
119
secondary structure of protein
involves hydrogen bonds forming between the amino group of one amino acid and the carboxyl group of another amino acid further down the chain
- oxygen atoms in the C=O group have a small negative charge and hydrogen atoms in the N-H group have a small positive charge. the charges attract each other
- this causes the polypeptide chain to coil into either an aloha helix or beta pleated structure
120
tertiary structure of protein
-forms when the polypeptide chain folds and twists further to create a complex 3D structure
- the specific structure is held together by many bonds including
• hydrogen bonds
• ionic bonds
• disulfide bridges
• hydrophobic and philic interactions
critical for how a protein functions
121
quaternary structure of a protein
- involves 2 or more polypeptide chains held together by the same binds found in tertiary structure
- can also involve the addition of non protein groups known as prosthetic groups. proteins w a prosthetic group are called conjugated groups
122
proteins can be grouped into 2 categories
globular
fibrous
123
globular proteins
- compact, spherical, soluble proteins
- have hydrophilic amino acids on there surface
- hydrophilic R groups interact w water making them soluble in water
- hydrophobic amino acids on R groups are found in the centre
124
globular proteins metabolic roles
- enzymes
- hormones
- antibodies
125
different types of prosthetic groups in globular proteins
lipids- lipoproteins
carbohydrates- glycoproteins
metal ions
126
harmogoblin
-globular protein that binds reversibly to oxygen in the lungs and carry it around the body in red blood cells
- made of 4 subunits 2 alpha and 2 bets subunits
- conjugated protein- Fe2+ ion (iron)
- iron bunds reversibly w oxygen
has 4 so can carry 4 oxygen molecules
- when oxygen attached the quaternary structure changes slightly making it easier for more oxygen to attach
127
features that allow haemogoblin to transport oxygen around the body
- four polypeptide chains- 4 oxygen can be carried at once
- haem group- iron
- compact globular structure
128
insulin
-globular protein that is a hormone
- used to regulate blood glucose conc.
- travel in blood so soluble
- bind to specific receptor molecules so need specific shape to fit
- made of 2 polypeptide chains held together by disulfide bonds
129
lysoszyme
-enzyme found in salova and tears
-function is to catalyse the breakdown of a milecule in the bacterial cell wall. this helps to to defend the body against bacteria
- reacts w a specific substrate. specifity is due to the structure of the enzyme
- consists of a single polypeptide chain that folds to form a groove along the surface which is the active site
130
fibrous proteins
long rope like molecules
have a large proportion of amino acids with hydrophobic R groups meaning they are insoluble
131
collagen
fibrous protein used as a structural component in tendons which connect muscles to bones, ligaments which connect bones to each other skin, cartilage, bones, teeth and walls of blood vessles
- very strong made of 3 polypeptides tightly wound around each-other forming triple helix.
- every third amino acid is glycine and the R group is hydrogen so it has smallest R group so the polypeptides can wrap tightly. large number of hydrogen bonds also form helping stabilize the quaternary structure
- lots of these form microfibrils and fibers that are staggered so there are no weak spots
132
keratin
group of fibrous proteins found in the hair ,skins outer surface and nails
-extremely strong and insoluble in water. contain lots of amino acid cysteine which allows disulfide bonds to form making it strong and less soluble
- flexible or rigid depending on the number of disulfide bond
- long stranded molecuels
133
elastin
-fibrous protein found in elastic connective tissue such as the walls of blood vessles
- nakes skin wupple and elastic
- found in blood vessels so it can stretch when blood pulses through and recoil
- long strands containing hydrophobic regions that are cross linked to eachother.normally the hydrophobic regions on different strands associate causing the elastin molecule to group together but when stretched the strands move apart but remain attached at crosslinks. after stretching molecules reassociate springing back together
