Basic Biochemistry Flashcards
1
Q
What are carbohydrates?
A
Carbohydrates are:
- Carbon molecules (carbon)
combined with
- Water (hydrate)
2
Q
What is a monomer?
A
A monomer is one of many small molecules that combine to form a larger molecule known as a polymer
3
Q
What is a polymer?
A
A polymer is a large molecule made up of repeating smaller molecules, monomers
4
Q
Examples of monomers?
A
Examples of monomers include:
- Monosaccharides
- Amino acids
- Nucleotides
5
Q
Examples of polymers?
A
Examples of polymers are:
- Carbohydrates
- Proteins
6
Q
What elements are most polymers comprised of?
A
Most of these polymers of biological molecules like carbohydrates and proteins are made up of just 4 elements:
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
7
Q
The basic monomer unit in a carbohydrate is called a?
A
Sugar or saccharide
8
Q
A single monomomer of a sugar is known as?
A
a “mono” saccharide
9
Q
A pair of saccharides are called?
A
“di”saccharide
10
Q
many saccharides joined together would be called?
A
polysaccharide
11
Q
Describe monosaccharides
A
Monosaccharides are:
- Sweet-tasting
- Soluble
substances that have the general formula (CH2O)n, where n can be any number from 3 to 7
12
Q
Examples of monosaccharides
A
Examples of monosaccharides include:
- Glucose
- Galactose
- Fructose
13
Q
Describe glucose
A
Glucose is a hexose - (6 carbon) sugar.
14
Q
What is the formula for glucose, given it is a 6 carbon sugar, and the general formula for working out the formula is (C H2 O)n.
A
n = 6
C6, H12, O6
15
Q
What is an isomer?
A
Each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
16
Q
Examples of disaccharride?
A
Sucrose, Lactose and Maltose
17
Q
What is reduction (in terms of a chemical reaction)
A
Reduction is the gain of electrons (or hydrogen).
OIL RIG
Oxidation is Loss
Reduction is Gain
18
Q
A reducing sugar is one which can….
A
Donate an electron to another chemical
19
Q
What is the name of the test for a reducing sugar?
A
Benedicts test
20
Q
If a reducing sugar is formed during Benedicts test what colour will the solution turn?
A
Orange
21
Q
What is the difference between a-Glucose and b-glucose?
A
The position of the -OH group in relation to the carbon atom (above-a and below-b)
22
Q
Glucose joins Glucose to make…
A
Maltose
23
Q
Glucose joins Fructose to make…
A
Sucrose
24
Q
When monosaccharides join a molucule of water is released. What is the name of this type of reaction
A
Condensation
25
When water is added to a di-saccharide what happens?
It breaks the glycosidic bond releasing the monomers
26
When water is added to a di-saccharide and it breaks the glycosidic bond this type of reaction is called a...
hydrolysis reaction
27
Hydrolysis means...
Hydrolysis is the breaking down of large molecules into smaller ones by the addition of water molecules
28
Sucrose, reducing or non-reducing sugar?
non-reducing
29
Maltose, reducing or non-reducing sugar?
Reducing
30
Starch is formed by...
The joining of many a-glucose molecules by glycosidic bonds in a series of condensation reactions.
31
Starch can be detected by what reaction?
Turning potassium iodide solution from yellow to blue-black.
32
What is the function of glucose in the human body?
The main sugar used by the body in respiration
33
When is maltose produced in the body?
When amalyse breaks down starch
34
What does the body use poly-saccharides for?
To store energy and as structural material
35
What are the main polysaccharides used in plants and animals.
The major polysaccharides are:
1. Starch and cellulose in plants
2. Glycogen in animals
36
What is the main role of starch?
energy storage
37
Does starch draw water into cells?
No, insoluble and no water potential
38
Does starch diffuse out of cells?
No, Large and insoluble.
39
When hydrolysed, starch forms a-glucose, which is....
1. Easily transported
| 2. Readily used in respiration
40
Branched forms of starch have many ends. What is the benefit of this to energy storage?
Because the branched form of starch has many ends, each of which can be acted on by enzymes simultaneously, meaning that glucose monomers are released very rapidly.
41
Starch is never found ....
...in animal cells. Glycogen is used for energy storage in animal cells instead.
42
What do animals use for energy storage instead of starch?
Glycogen
43
Glycogen is found where?
Animals and bacteria
44
Glycogen is never found where?
Plant cells
45
What are the differences in structure between glycogen and starch?
Glycogen is very similar in structure to starch, but:
1. Has shorter chains
2. Is more highly branched
46
Where is glycogen stored in the human body?
In the liver and in the muscles
47
What is the main energy storage molecule in human bodies?
Fat
48
Glycogen is insoluble. Its osmotic potential is therefore...
Low....meaning it doesn't draw water into cells
49
Can glycogen diffuse out of cells?
No, it's insoluble.
50
Glycogen is branched. So what?
Glycogen is therefore more rapidly broken down to form glucose monomers
51
Glycogen is more efficient at storing and breaking down glucose. Why is this important to animals and not to plants?
Metabolic and respiratory rate is higher and requires more energy
52
Cellulose is different from starch and glycogen, how?
Cellulose is made of monomers of B-glucose rather than 2. a-glucose
53
Rather than forming a coiled chain like starch, cellulose has what chains?
1. Straight
2. Unbranched
chains
54
The structure of cellulose is important why?
straight, unbranched chains run parallel to one another, allowing hydrogen bonds to form cross-linkages between adjacent chains.
55
Cellulose molecules are grouped together to form what?
Microfibrils
56
Microfibrils arranged in groups are called what?
Fibres
57
What is about 33% of plant matter?
Cellulose
58
The most common organic compound on earth is?
cellulose
59
Why can't humans digest cellulose?
We don't produce the enzyme cellulase.
60
What is amylopectin
branched starch
61
Lipids contain what?
Carbon
Hydrogen
Oxygen
62
Are lipids soluble in water?
No
63
Lipids are soluble in organic solvents like...
Alcohol
| Acetone
64
The main groups of lipids are?
The main groups of lipids are:
1. Triglycerides
2. Phospholipid
65
A triglyceride is what?
A triglyceride is an individual lipid molecule made up of:
1. A glycerol molecule
2. 3 fatty acids
66
Fats are made up of what, compared to oils which are made of?
1. Fats are generally made of saturated fatty acids
,while
2. Oils are made of unsaturated fatty acids
67
As well as a source of energy lipids have what structural role in cells?
Phospholipids contribute to the:
1. Flexibility of cell membranes
2. Transfer of lipid-soluble substances across them
68
When oxidised what do lipids release?
When oxidised, lipids:
1. Provide more than twice the energy as the same mass of carbohydrate
2. Release valuable water
69
Lipids are hydrophilic or hydrophobic?
Hydrophobic
70
Lipids can be used for energy and structure but also for...
insulation as they are slow conductors of heat
71
What properties of lipids make them important in nerve cells?
Lipids act as electrical insulation around nerve cells = myelin sheath.
72
Where is fat stored in the human body?
Around delicate internal organs such as the kidney for protection
73
Triglycerides are so called because they have what?
Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride)
74
Hydrolysis of a triglyceride produces what?
1. 3 fatty acids
2. Glycerol
The 3 fatty acids may:
1. All be the same, thereby forming a simple triglyceride
Or,
2. Be different, in which case a mixed triglyceride is produced
75
As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from what?
As the glycerol molecule in all triglycerides is the same, the differences in the properties of different:
1. Fats
2. Oils
come from variations in the fatty acids
76
There are how many different fatty acids?
There are over 70 different fatty acids
77
There are over 70 different fatty acids and all have what?
There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached
78
There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.
If this chain has no carbon-carbon double bonds, the fatty acid is then described as what?
If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated
79
There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.
If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because what?
If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms
80
If there is a single double bond, the fatty acid is what?
If there is a single double bond, the fatty acid is mono-unsaturated
81
In other words, all the carbon atoms are saturated with hydrogen atoms.
If there is a single double bond, the fatty acid is mono-unsaturated.
If more than one double bond is present, the fatty acid is what?
If more than one double bond is present, the fatty acid is polyunsaturated
82
Polyunsaturated, more than one double bond between carbon atoms.
The double bonds cause the molecule to do what?
Bend. Therefore they cannot pack tightly toghether and this is what makes them a liquid at room temperature
83
The structure of triglycerides related to their properties:
1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.
2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because what?
Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume
84
The structure of triglycerides related to their properties:
1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.
2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.
This is especially beneficial to animals, because it what?
This is especially beneficial to animals, because it reduces the mass they have to carry as they move around
85
Being large, non-polar molecules, triglycerides are what?
triglycerides are insoluble in water
86
Being large, non-polar molecules, triglycerides are insoluble in water.
As a result, their storage does not affect what?
As a result, their storage does not affect:
1. Osmosis in cells
Or,
2. The water potential of them
87
Water potential is
Water potential is the:
1. Pressure created by water molecules
2. Measure of the extent to which a solution gives out water
88
The greater the number of water molecules present, higher or lower water potential?
The greater the number of water molecules present, the higher (less negative) the water potential
89
Pure water has a water potential of what?
Zero
90
Phospholipids are similar to lipids except that what?
Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule
91
Fatty acid molecules do what to water?
Fatty acid molecules repel water
92
Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are what?
hydrophilic
93
Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.
Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.
A phospholipid is therefore made up of what?
phospholipid is therefore made up of 2 parts, a:
1. Hydrophilic 'head'
2. Hydrophobic 'tail'
94
Molecules that have 2 ends (poles) that behave differently in this way are said to be what?
Molecules that have 2 ends (poles) that behave differently in this way are said to be polar
95
An amphipathic molecule is?
An amphipathic molecule is a molecule that has both:
1. Polar
2. Non-polar
regions
96
Phospholipids are amphipathic molecules.
They have a what head?
Phospholipids have a hydrophilic head
97
Proteins are usually what molecules?
Very large
98
What are amino acids?
Amino acids are the basic monomer units that combine to make up a polymer called a polypeptide
99
Polypeptides can be combined to do what?
Polypeptides can be combined to form proteins
100
Every amino acid has a central carbon atom to which are attached what?
Every amino acid has a central carbon atom to which are attached 4 different chemical groups:
1. The amino group
2. The carboxyl group
3. A hydrogen atom
4. R (side) group
101
Every amino acid has a central carbon atom to which are attached 4 different chemical groups - the amino group, the carboxyl group, a hydrogen atom and the R (side) group.
The amino group is -what?
The amino group is -NH2
102
Every amino acid has a central carbon atom to which are attached 4 different chemical groups - the amino group, the carboxyl group, a hydrogen atom and the R (side) group.
The carboxyl group is -what?
The carboxyl group is -COOH
103
Every amino acid has a central carbon atom to which are attached 4 different chemical groups - the amino group, the carboxyl group, a hydrogen atom and the R (side) group.
What is the R (side) group?
The R (side) group is a variety of different chemical groups.
Each amino acid has a different R group
104
Through a series of condensation reactions, many amino acid monomers can be joined together in a process called polymerisation.
What is a polypeptide?
A polypeptide is the resulting chain of many hundreds of amino acids
105
As polypeptides have many (usually hundreds) of the 20 naturally occurring amino acids joined in different sequences, it follows that there is an almost limitless number of possible what?
Combinations
Therefore types of primary protein structure
106
the primary structure of a protein that determines its what?
Shape and function
107
It is the primary structure of a protein that determines its shape and therefore its function.
A change in just what can lead to a change in what?
A change in just a single amino acid in this primary sequence can lead to a change in the shape of the protein
108
A change in just a single amino acid in this primary sequence can lead to a change in the shape of the protein and may stop what?
1. Can lead to a change in the shape of the protein
| 2. May stop it carrying out its function
109
The a-helices of the secondary protein structure can be twisted and folded even more to give the complex and often specific 3-D structure of each protein, known as the tertiary structure.
This structure is maintained by a number of different bonds.
Where the bonds occur depends on the primary structure of the protein.
These bonds include what?
These bonds include:
1. Disulfide bridges
2. Ionic bonds
3. Hydrogen bonds
110
Describe disulfide bridges
Disulfide bridges are:
1. Fairly strong
2. Therefore not easily broken
111
Ionic bonds are formed between where?
Ionic bonds are formed between any:
1. Carboyxl
2. Amino
groups that are not involved in forming peptide bonds
112
Ionic bonds are weaker than what?
Ionic bonds are weaker than disulfide bridges
113
Ionic bonds are weaker than disulfide bridges and are easily broken by what?
Ionic bonds are:
1. Weaker than disulfide bridges
2. Easily broken by changes in pH
114
Hydrogen bonds are what, but what?
Hydrogen bonds are:
1. Numerous
,but
2. Easily broken
115
It is the 3-D shape of a protein that is important when it comes to how it functions.
It makes each protein distinctive and allows it to recognise, and be recognised by, other molecules.
The protein can then do what?
The protein can then interact with those other molecules in a very specific way
