Bio Molecules Flashcards
1
Q
What 3 shape can monosaccharide’s come in?
A
Straight Chain
Ring
Cyclic
2
Q
Name three disaccharides
A
Maltose
Sucrose
Lactose
3
Q
How do you form maltose?
A
a-glucose + a-glucose
4
Q
What 2 monosaccharides form the disaccharide, sucrose?
A
a-glucose + fructose
5
Q
What is the name of the disaccharide formed by galactose + a-glucose?
A
Lactose
6
Q
What type of reaction forms disaccharides?
A
Condensation
7
Q
What is required to break down disaccharide’s?
A
Water
8
Q
State the type of reaction where a substance is broken down with water
A
Hydrolysis
9
Q
Which type of glucose monomer is symmetrical?
A
Alpha Glucose
10
Q
What is the anomeric carbon?
A
The most reactive carbon in a molecule.
Usually bonded to 2 oxygens.
11
Q
What is the difference between a-glucose and b-glucose?
A
Beta glucose is not symmetrical whilst alpha glucose is
12
Q
State the definition of a structural isomer
A
A compound with the same molecular formula but a different arrangement of atoms
13
Q
Name the two forms of starch
A
Amylose and Amylopectin
14
Q
Give some similarities between Amylose and Amylopectin
A
- Polymers of a-glucose
- Helical structure
- Condensation reactions
- Contain 1,4 glycosidic bonds
15
Q
Name some points of contrast between Amylose and Amylopectin
A
- Amylopectin = Branched molecule
Amylose = Straight Chain molecule - Amylopectin contains 1,6 glycosidic bonds
for branches
16
Q
Give the specific name for the bonds between cellulose
A
1,4 glycosidic bonds
17
Q
What do chains of b-glucose form?
A
B-sheet —-> Cellulose microfibril —-> Cellulose Macrofibril
18
Q
Explain why cellulose has a high tensile strength
A
Because each cellulose chain is held together by hydrogen bonds
19
Q
What monosaccharide is cellulose made of?
A
B-glucose
20
Q
Which molecule is similar to glycogen?
A
Amylopectin
21
Q
Describe the specific bonds in glycogen
A
1,4 glycosidic bonds for chain
1,6 glycosidic bonds for branches
22
Q
Why is glycogen a better energy source than amylopectin?
A
It contains more branches than Amylopectin so is more compact and energy-dense
23
Q
What monomer forms glycogen?
A
Alpha-glucose units
24
Q
Where is glycogen stored mainly?
A
Muscles and Liver
25
State three functions of
Ca 2+ ions
- Increases bone rigidity
- Blood clotting
- Stimulates muscle contraction
- Regulates membrane permeability
26
Name three roles of Na+ ions
- Regulates of osmotic pressure
- Affects carbohydrates absorption
- Contributes to nerve transmission
- Maintains vacuole turgidity
27
What inorganic ion controls water levels in body fluids?
Potassium, K+ ions
28
State two roles of K+ ions
- Controlling water levels
- Needed for active transport
- Synthesis of protein + glycogen
- Healthy leaves
29
What are the main functions of H+ ions?
- Photosynthesis + Respiration
- Transporting O2 + CO2
- Regulates blood pH
30
State 2 roles of K+ ions
- Controls water levels
- Active Transport
- Protein Synthesis
- Healthy leaves
31
Give some roles of NH4+ ions
- Component of amino acids, chlorophyll
- Component of hormones and nucleic acid
- Nitrogen Cycle
32
State 3 roles of nitrate ions
- Component of proteins and vitamins
- Hormones
- Nitrogen Cycle
33
State 2 roles of HCO3- ions
- Regulates blood pH
- CO2 transport in blood
34
Give 2 roles of Cl- ions
- Urine production
- CO2 transport
- Affinity of haemoglobin
- Blood pH
35
Name some functions of phosphate ions
- Rigidity of bone and teeth
- Phospholipids
- Blood pH
- Root growth
36
What is the role of OH- ions?
- Regulation of blood pH
37
Why are lipids insoluble?
They aren't polar
38
What 2 components make up triglycerides?
Glycerol and Fatty Acids
39
Why is glycerol an alcohol?
It has free -OH groups
40
Describe the structure of fatty acids
- Carboxyl Group
- Hydrocarbon Tail
41
Explain how fatty acids are acids
Carboxyl group ionises into H+ and COO- groups, producing free H+ ions
42
If a fatty acid is saturated, what does this means for the hydrocarbon tail?
There are no C=C bonds
43
What is the term for when a molecule has a single C=C bond?
Monounsaturated
44
Describe the changes to a fatty acid's structure when there are one or more C=C bonds
- Hydrocarbon tails becomes kinked
- Kink pushes molecules apart slightly
- Fatty acid becomes more fluid
45
What does the term 'polyunsaturated' mean?
There are more than one set of C=C bond
46
How does an ester bond form in a triglyceride?
- Condensation reaction between -COOH and -OH groups
- This forms water molecule and ester bond
47
Name 4 functions of triglycerides
- Energy Source/Store
- Buoyancy
- Protection
48
Describe how triglycerides are broken down
- Ester bond is hydrolysed
- Glycerol and fatty acids can be broken down completely into CO2 and H2O
49
Why are lipids a better store of energy than glucose?
They have a higher proportion of hydrogen atoms than carbohydrates
50
Why are triglycerides a good energy store?
They are insoluble in water so don't affect water potential of cell
51
Why does fat help mammals float?
Fat is less dense than water
52
How is fat used as protection in the human body?
Fat acts as a shock absorber around delicate organs
53
State the main difference between triglycerides and phospholipids
One fatty acid group is replaced by a phosphate group
54
Which part of a phospholipid has a negative charge?
The phosphate group
55
Explain how a phospholipid is amphipathic
- Fatty acid tails are hydrophobic
- Phosphate head is hydrophilic
56
What two structures can phospholipids form in water?
- Micelles (balls)
- Phospholipid bilayer
57
Explain how a phospholipid bilayer is quite stable
- Individual phospholipids are free to move around in the layer
- Phospholipids won't expose hydrophobic tail
58
What type of molecules can move between a phospholipid bilayer?
Small, non-polar molecules
59
What type of molecule is cholesterol?
Steroid alcohol
59
How would you describe a phospholipid bilayer's permeability?
Selectively permeable
60
What does a steroid alcohol consists of?
4 carbon-based rings
61
Is cholesterol attracted to water?
No, it is hydrophobic
62
Can cholesterol sit it the middle of a phosphate bilayer?
Yes, because it is hydrophobic and very small
63
What role does cholesterol do in-between a phospholipid bilayer?
It regulates membrane fluidity
64
Give 3 examples of steroid hormones
Testosterone, Oestrogen and Vitamin D
65
Why can steroid hormones, made of cholesterol, pass between a phospholipid bilayer?
Because they are small, hydrophobic molecules
66
What occurs in a condensation reaction?
2 molecules are joined together, releasing water
67
What is a dimer?
Two monomer, chemically bonded together
68
State the 5 elements in proteins
Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur
69
State all the elements in nucleic acids
Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus
70
Explain how a water molecule is polar
- Oxygen has more protons than the 2 hydrogens so a stronger force of attraction is exerted on the shared electrons
- Oxygen becomes slightly negative whilst Hydrogen becomes slightly positive
71
What is a hydrogen bond?
A weak interaction between slightly negative oxygen atoms and slightly positive hydrogen atoms
72
Explain how water, as a solid, is less dense than liquid water
- Below 4*C, due to water's polarity, molecules align themselves in a structure less dense than water
73
How is water being liquid at room temperature significant?
- Provides habitats for living things
- Forms major component in tissues
- Provides reaction medium for chemical reactions
74
How is ice's lower density than water important?
- Provides stable environment for organisms to live during winter
- Provides insulation of water beneath ice
75
Explain how water is a good solvent
- As it is a polar molecule, areas of positivity and negativity in the water molecule are attracted to areas of opposite charge in the solute
76
What property allows molecules/ions to react and be transported around an organism whilst dissolved?
Solvent
77
Explain how cohesion occurs
Hydrogen bonding pulls water molecules together, preventing them from being seperated
78
How does surface tension occur?
- Water molecules on the surface are more attracted to other water molecules than air molecules above the water
- This means the water's surface contracts, resisting any force applied
79
How is water an important reactant?
Water is required for hydrolysis, photosynthesis and synthesis of biological molecules
80
Explain how water's high specific heat capacity is important
- Water molecules are held together by hydrogen bonds which require lots of energy to increase kinetic energy
- This prevents water from freezing or evaporating whilst in an organism so it can actually be used
81
What are the monomers that form proteins?
Amino Acids
82
How are proteins used in membranes?
- Membranes have protein components that act as carriers and pores for molecular movement
83
Describe the structure of an amino acid
- Amino Group
- Carboxyl Group
- Hydrogen atom
- R group
- All bonded to central carbon
84
Which group in amino acids varies between molecules?
R group
85
Explain why amino acids are amphoteric
- They have acidic and basic properties:
- Carboxyl group ionises, forming H+ ions
- Amino group accepts H+ ions
86
Name the bond that joins amino acids
Peptide bond
87
What type of reaction are proteins broken down in?
Hydrolysis
88
Where does the peptide bond form in a dipeptide?
- Bond forms through removal of:
- OH from carboxyl group
- H from amino group
89
What is the primary structure?
The sequence of amino acids in a molecule
90
Describe the term 'tertiary structure'
The 3D shape of a protein
91
What is the quaternary structure?
- The specific structure where a protein consists of more than one polypeptide chain
92
What is the secondary structure of a protein?
The coiling or folding of an amino acid chain, due to hydrogen bond formation between different parts of the chain
93
What does the primary structure of a protein determine?
The function of a protein
94
What are the 2 main secondary structures of proteins?
- a-helix
- B-pleated sheet
95
How is an a-helix protein structure held together?
Through hydrogen bonds between -NH groups and -CO groups
96
What does the quaternary structure of a protein describe?
The arrangement of polypeptide chains in a protein
97
Name 3 different bonds that hold proteins together
Hydrogen bonds
Ionic bonds
Disulfide Links
98
Where do ionic bonds form in proteins?
Between carboxyl and amino groups that are part of R groups
99
Where do disulfide links form?
Between R groups of 2 cysteines
100
Give 3 properties of fibrous proteins
- Insoluble in water
- Have regular, repetitive sequences of amino acids
- Form fibres with a structural function
101
State some properties of globular proteins
- Tendency to roll into spherical shape
- Water soluble
- Specific shapes allow them to perform specific functions
102
Name 2 examples of fibrous proteins
Collagen, Keratin, Elastin
103
Give some examples of globular proteins
Enzymes (Pepsin)
Hormones (Insulin)
Haemoglobin
104
Give 2 examples of how collagen is used in the body
- Strengthens artery walls to prevent bursting
- Reinforces bones along with Calcium Phosphate
- Tendons
- Cartilage
105
Explain why keratin contains lots of disulfide links between polypeptide chain
Keratin is rich in cysteine
106
Give an advantage of using keratin for nails
Provide a barrier to infection and water
107
What is the function of elastin in the lungs?
To allow for inflation and deflation of lungs without deforming the lung's shape
108
Other than the lungs, where can you find elastin?
Skin
109
How does haemoglobin bind to oxygen?
O2 molecule binds to Fe ion and 4 haem groups
110
Describe the structure of haemoglobin
Made of 4 polypeptides; 2 a-globin and 2 b-globin chains
111
Why is haemoglobin described as a conjugated protein?
Due to the Fe ion
112
How are amino acid chains connected in insulin?
Disulfide bridges
113
Explain how insulin is soluble
Amino acids with hydrophilic R groups are on the outside of the tertiary structure
114
Explain the process by which insulin lowers blood glucose levels
- Insulin binds to glycoprotein receptors
- Receptors instruct fat cells to increase their uptake of glucose from the blood
115
Why is pepsin stable in acidic conditions?
- It contains 43 amino acids with acidic R groups
116
What is special about Pepsin's tertiary structure?
Symmetrical
117
Describe pepsin's structure
Made of single polypeptide chain of 327 amino acids
118
Describe the bonding in pepsin
Structure held together by hydrogen bonds and 2 disulfide bridges
119
