2.2 Biological Molecules Flashcards
1
Q
What is a hydrogen bond.
When does this happen
A
Bond between atoms due to the interactions between positive + negative regions. This happens when an atom in a molecule has greater number of protons which exert strong attraction on electrons pulling them towards itself giving it a slightly negative charge while the other atoms has a slightly positive charge
2
Q
what is polar
A
when there is uneven distribution of electrons causing atoms to having regions of charges
3
Q
what is the strength of Hydrogen bonds
A
They are weak but many of them provide collective strength
4
Q
what are monomers
A
Individual molecules that bind to their identical molecules to form a polymer
5
Q
What are polymers
A
large molecules and chains that are made from smaller molecules called monomers
6
Q
Condensation reaction
A
Reaction that occurs when 2 molecules are joined together with the removal of water
7
Q
Hydrolysis Reaction
A
Reaction that occurs when a molecule is split into 2 smaller molecules with the addition of water
8
Q
Why is water liquid at room temperature
A
Due to many hydrogen bonds between water molecules which make it difficult for it become a gas
9
Q
What is the viscosity of water like
A
Has a low viscosity which allows it to flow around
10
Q
How does this help wildlife
A
- provides habitats for living things in rivers and lakes
- Forms a major component of tissue in living organism
- Provide reaction meduim for chemical reaction
11
Q
What is the density of any liquid like then compared to water
A
As liquid get colder the density increases. Water does the same until the temperature reaches 4 degrees at which the density stays the same
12
Q
Why is this
A
Due to the polar nature of water to allow water molecules to allign themselves in a less dense structure with more gaps
13
Q
How is this helpful
A
- Aquatic organisms have a stable environment in which to live in water
- Ponds and other bodies of water are insulated against extreme cold. The layers of ice reduces the rate of heat loss
14
Q
Why is water a good solvent
A
Due to the polarity of water the positive and negative parts of the water are attracted to positive and negative parts of the solute. The water molecules cluster around them and seperate them and keep them apart to allow it to dissolve
15
Q
How is this helpful
A
- Molecules and ions can be transported around living things whilst dissolved in water
- Molecules and ions can move around and react together. many such reactions happen in cytoplasm which is 70% water
16
Q
What is LHOV
A
Helps the molecules break away from each other to become gas
17
Q
Why does water have high LHOV
A
many hydrogen bonds
18
Q
How is this helpful
A
-keeps the temperature stable
-Sweat evaporating cools living things
19
Q
What is SHC
A
The energy needed to raise the temperature of 1kg of substance by 1 degree
20
Q
What is waters SHC
A
4.2Ki
21
Q
How is this helpful
A
- Living Organisms require a controlled temperature and stable environment for enzymes controlled reactions
- Aquatic organisms need a stable environment in which to live in
22
Q
how is water a good reactant
A
it is involved in many important reactions
23
Q
For example
A
Digestion + Synthesising large biological molecules
24
Q
what is cohesion
A
The hydrogen bonds between molecules are strong which pulls them together when you pour water on the surface it doesn’t spread instead it gathers together
25
where is cohesion used
collumns of water in plant vascular tissue are pulled up by the xylem tissue from the roots
26
what is surface tension
The water molecules at surface of water are bonded to those beneath making them more attracted to the water molecules beneath than the molecules in the air. This means that surface of water contracts ( due to molecules being pulled inwards ) which gives the surface of the water the ability to resist force applied due to surface tension
27
where is surface tension used
Insects like pond-skaters can walk on water
28
what elements are found in carbohydrates
C , H , O
29
3 uses of carbohydrates
1.Acts as a source of energy (glucose)
2. Acts as a store of energy (Starch & Glycogen)
3. Acts as a structural unit (Cellulose)
30
What are monosaccharides
Simplest carbohydrates and act as monomer for larger structures
31
3 monosaccharides
Fructose
Glucose
Galactose
32
what is the difference between alpha and beta glucose
in alpha glucose on the 1st carbon hydrogen in at the top while OH is at the bottom
33
What is a dissacharide
Formed when 2 monosaccharides join together by condensation
34
What does a condensation reaction form
1-4 Glycosidic Bond
35
A glucose + A glucose
maltose
36
A glucose + Fructose
sucrose
37
B Galactose + A glucose
Lactose
38
B Glucose + B glucose
cellobiose
39
What is a polysaccharide
polymers of monosaccharides bonded together using a condensation reaction
40
Homopolysaccharide
Polysaccharide that's made from 1 type of monosaccharide
41
Hetropolysaccharide
polysaccharide that's made from from different types of monosaccharide
42
what polymers are starch made from
2 alpha glucose
( Amylopectin , Amylose )
43
what bonds are there in starch
1,4 in amylose
1,4 + 1,6 in amylopectin
44
what is the function of starch
storing glucose
45
location of starch
plant cells
46
how does structure of starch lead to its function
- helix is compact to fit a lot of space
- Branched structure increase surface area for rapid hydrolysis back to glucose
- Insoluble ( won't affect water potential )
47
what is the structure of amylose like
- unbranched chain coils to form helix
- The hydrogen bonds keep it in place
- The hydroxyl on carbon-2 is situated on the inside of coil making it less soluble and allowing it to maintain the coil structure due to h-bonds
48
what is the structure of amylopectin like
- Coils up to form spirals
- Held together by hydrogen bonds
- Branches emerge from the spiral
49
what monomers are glycogen made from
a glucose
50
what bonds are there
1,4
1,6
51
why does the structure coil less
the 1,4 bond chains are smaller
52
what is the function of glycogen
storing glucose
53
Where is it found
found in animal cells ( mainly muscle + liver cells )
54
How does the structure of glycogen lead to its function
- More branched than starch meaning it has higher S.A for rapid hydrolysis back to glucose
- Insoluble ( won't affect water potential )
55
what monomers are cellulose made from
B glucose
56
what bonds do they contain
1,4 glycosidic bonds and hydrogen bonds to form a fibril
57
what is the function of cellulose
strengthen the cell wall
58
where is it found
in plants
59
what is the structure like
long straight chains that are parallel to one another and have hydrogen bonds holding them together to form a fibril
60
how does structure lead to function
insoluble ( won't affect water potential )
61
what needs to happen for 2 cellulose molecules to combine through condensation reaction
the 2nd cellulose must rotate 180 degrees
62
Why does the 2nd cellulose rotate?
the OH groups are on different sides so they need to rotate 180 degrees to align them together
63
how is a microfibril formed
when 60-70 cellulose chains bond together
64
how is macrofibril formed
formed when 300 microfibrils join together
65
How does the macrofibril provide extra strength
run in all directions + criss-cross for extra strength
66
what are 2 adaptations
- There is space between macrofibril to allow water + mineral ions to pass through making the cell-permeable
- Due to high tensile strength cell doesn't burst
67
what are lipids
Group of substances that contain high number of carbon + hydrogen atoms but a low number of oxygen. They are insoluble in water as they are non-polar but are soluble in alcohol
68
why aren't they polymers
made from different compounds
69
What are triglycerides
Type of lipid that's made up of glycerol and 3 fatty acids that are bonded to the glycerol
70
what is glycerol
alcohol that contains 3 carbon atoms and has 3 -OH groups
71
what are fatty acids
chains of hydrocarbons with (COOH) attached to one end. Carbon atoms are even number
72
why is the structure of fatty acids acidic
The carboxyl group is ionised into the H+ and COO- group. The release of H+ makes it acidic
73
What happens if a fatty acid is monounsaturated or polyunsaturated
produces a kink wherever the double bond is
74
What does the kink do
The kink pushes the molecules apart which makes them more fluid
75
What is an ester bond
A covalent bond formed by a condensation reaction between the -OH of the carboxyl group and -OH group of the alcohol
76
5 functions of triglycerides
1. Energy Source: Can be broken down in respiration to release energy + generate ATP. The first step is to hydrolyse the ester bond and then fatty acid + glycerol can be broken into CO2 and H20
2. Energy Store: insoluble in water so they can store energy without affecting water potential
3. Insulation: Adipose tissue is a storage location for lipids in whales acting as a thermal insulator. Lipids in nerve cells can act as electrical insulators
4. Buyancy: As fat is less dense than water it's used by aqautic mammals to keep them afloat
5. Protection: Humans have fat around delicate + important organs to act as shock absorbers. The peptidoglycan cell wall of some bacteria is covered in lipid rich outer coat
77
What is a phospholipid
Type of lipid which contains a glycerol that's bonded to 2 fatty acids as well as a phosphate group
78
What is a phosphate ester bond
When a condensation reaction takes place between glycerol and phosphate group
79
What happens to phospholipid when reacting with water
When surrounded by water hydrogen atoms disassociate themselves from phosphate group
80
what is the head of phospholipid
phosphate group + glycerol
81
what is the tail of phospholipid
the fatty acids
82
what does hydrophilic mean and which part is it
A hydrophilic is a molecule that is attracted to water due to it having a charge . The head is hydrophilic
83
what does hydrophobic mean and which part is it
molecule that's repelled by water due to it not having a charge. The tail is hydrophobic
84
what does amphipathic mean
molecule that has both polar & non-polar regions. (head=polar while the tail=non-polar)
85
what is a phospholipd bilayer
a bilayer is formed when 2 layers of phospholipid tails (hydrophobic) point each other inwards while 2 rows of phopholipid heads (hydrophilic) are outwards and pointed away from each other.
86
how is the membrane selectively permeable
only allows small + non-polar molecules to move through the tail bilayer
87
what is cholesterol and structure
-comes from sterol family ( type of lipid which isn't made from glycerol or fatty acids)
- consists of 4 carbon based rings
- contains hydroxyl group making it hydrophobic which allows it to sit between hydrophobic section
88
role of cholesterol
- regulates fluidity of membrane to prevent it becoming too stiff or too fluid
- Cholesterol creates testosteron, oestrogen and vitamin D
89
why can they pass through the bilayer and other membranes
- Since they are small + hydrophobic they can pass through bilayer and other membranes of the cell
90
what is a protein
large polymer comprised with f ping chain of amino acids
91
what are 3 roles of proteins
1 they form structural components of animals e.g muscle, tendons, bones
2 they adapt specific shapes as enzymes
3 membranes have proteins constituents that’s act as corner + pores for active transport across membranes + facilitated diffusion
92
what elements does it contain
Each amino acid contains C,H,N,O and S sometimes
93
what is the structure of an amino acid
All protein chains of amino acid contain amine group (NH3) at one and + carboxyl group (-COOH) at the other
-The R group can vary by size polarity and charge
94
what is a peptide bond
A covalent bond formed when two amino acids are joined together in a condensation reaction
95
what does protease enzyme do
Protease enzymes break down protein peptides bond in digestion
96
what is a dipeptide
When two amino acids join they are a dipeptide
97
what is a polypeptide
Polypeptide is when many amino acids join together
98
what is the primary structure
It is the sequence of amino acid in the polypeptide chain.
99
why it it important
The function of protein depends on the structure, which depends on the amino acid order.
100
what is the secondary structure
The coiling or folding of the amino acid chains to form either an a-helix or B pleated sheet. This is due to H bonds. (Between C equals O And H in the amine a group) to hold the structure.
101
what is the tertiary structure
Further folding of a secondary structure which forms 3D unique shape and is held by; Iconic, Hydrogen, disulphide Bonds.
The iconic + sulphide Form between R groups of different amino acids.
disulphide bonds only sometimes occur as there must be sulphur in R- group.
102
what is the quaternary structure
Where proteins consist of more than one polypeptide chain bonded together.
103
what is hydrogen bond in the tertiary structure
Form between C = O in carboxyl groups and H in an amine group.
104
what is the ionic bond between tertiary structure
Form between carboxyl + amine groups that are part of R groups
105
what are the hydrophobic and hydrophilic interactions in the tertiary structure
R groups are hydrophobic + tend to stay in the middle of polypeptide to stay away from H2O.
The hydrophilic parts are found at edge to be close to water.
Hydrophobic + Hydrophilic interactions cause twisting of amino acids which charge shape of the protein.
These interactions can be especially Important influence given that most protein are tube found surrounded by H2O inside a living Organism.
106
what are disulphide bonds
Bond formed Between 2 sulphurs in R group and forms a bridge.
These are strong covalent bonds.
Made from Cysteine amino acid (They contain s)
107
What are fibrous proteins
They are long thin protein that is insoluble in water.
They are made from repeating sequences of amino acids and are metabolically inactive leading them to have structural roles in an organism
108
3 examples of fibrous proteins
Collagen
Elastin
Keratin
109
Collagen
Found in the artery wall and a layer of collagen prevents the artery from bursting when withstanding HP
Tendons are made from collagen and connect muscle to bones allowing them to pull bones
Cartilages + Connective tissue are made from collagen
Bones are made from collagen + then reinforced with calcium phosphate which makes them hard
110
Keratin
Is found in body parts that need to be hard to provide mechanical protection as well as acting as an impermeable barrier to infection being waterproof and preventing entry of waterborn pollutants
Keratin can be found in nails, claws, hooves, horns, and scales
They are rich in cystine which means they have many disulphide bridges in its polypeptide as well as having many H-bonds to provide additional strength
111
Elastin
Due to coiling and cross linking of the elastin molecules its long and extensible (stretchy)
Skin can stretch around bones and muscles due to elastin
Elastin in lungs allow them to deflate and inflate
They are also found in the bladder to help it expand to store urine
Elastin also helps our blood vessels widen and stretch + recoil as blood is pumped through them helping maintain the pressure wave of blood as it passes through
112
what are globular proteins
Type of 3d protein that is spherical and soluble in water and having metabolic roles
They have Hydrophobic R groups on the inside the hydrophilic R groups on the outside
113
3 examples of globular proteins
Haemoglobin
Insulin
Catalase
114
Haemoglobin
A globular protein that is found in red blood cells
Made from 4 polypeptide chains making it have a quaternary structure (2 Alpha Globin chains + 2 Beta Globin chains)
At each polypeptide group there is a prosthetic group attached (a non-protein component that forms a permanent part of a functioning protein molecule) making a conjugated protein (protein which has another chemical group)
The 4 prosthetic group in haemoglobin are called haem groups and contain iron ion (Fe2+)
One O2 molecule binds to each haem group allowing for each haemoglobin to transplant 4 O2 molecules
115
Insulin
Made from 2 polypeptide chains – the A chain has an alpha helix while the Beta chain has a Beta-pleated sheet
The 2 chains are linked by disulphide links
Amino acids with hydrophilic R groups are on the outside of molecule making it soluble in water
The shape of insulin allows for it to bind to glycoprotein receptor on the outside of muscle + fat cells to increase its uptake of glucose from blood and to increase the rate of glucose consumption making a lower blood glucose concentration
Since its soluble it dissolves in blood + easily transported around body
116
Catalase
- Quaternary protein consisting of 4 haem prosthetic groups
- Presence of Fe2+ ion in the prosthetic group & allow it to interact & break down Hydrogen peroxide
- Hydrogen Peroxide is a by product of metabolism and is harmful to cells if it accumulates
117
role of calcuim ions
Increases rigidity of bones, teeth and cartilage and I a component of the exoskeleton
Important for clotting blood and muscle contraction
Activator for several enzymes such as lipase
Stimulates muscle contraction
Regulates permeability of cell membrane
Important for cell wall development in plants and formation of middle lamella between cell walls
118
roles of soduim ions
Involved in regulation of osmotic pressure, control of water levels in body fluid and maintenance of pH
Affects absorption of carbohydrates in the intestine & water in the kidney
Contributes to nervous transmission and muscle contraction
Constituent of vacuole in plants which helps maintain turgidity
119
roles of pottassuim ions
Involved in control of water levels in bodily fluids and maintenance of pH
Assists active transport of material across the cell membrane
Involved in synthesis of glycogen and protein, and breakdown of glucose
Generates healthy leaves and flowers in flowering plants
Contributes to nervous transmission and muscle contraction
Component of vacuoles in plants helping to maintain turgidity
120
Role of hydrogen ions
Involved in photosynthesis and respiration
Involves in transport of oxygen and carbon dioxide in the blood
Involved in regulation of blood pH
121
Role of ammonia ions
A component of amino acid, proteins, vitamins, and chlorophyll
Some hormones are made of proteins e.g. insulin
An essential component of nucleic acid
Involved in maintenance of pH in the human body
A component of the nitrogen cycle
122
Role of nitrate ions
A component of amino acids, proteins, vitamins, and chlorophyll
An essential component of nucleic acids
Some hormones are made of proteins which contain nitrogen e.g. insulin
A component of nitrogen cycle
123
Role of hydrogen carbonate ion
Involved in regulation of blood pH
Involved in transport of carbon dioxide into and out of the blood
124
Role of chlorine ions
Helps in production of urine and maintaining water balance
Involved in transport of carbon dioxide into and out of blood
Regulates affinity of haemoglobin to oxygen through allosteric effects on the haemoglobin molecule
Involved in regulation of blood pH
Used to produce hydrochloric acid in the stomach
125
Role of phosphate ion
Increases rigidity of bone, teeth and cartilage and is a component of the exoskeleton of crustaceans
Component of phospholipids, ATP, nucleic acids, and several important enzymes
Involved in regulation of blood pH
Helps root growth in plants
126
Role of hydroxide ion
Involved in regulation of blood pH
