Chapter 5 - Biological Macromolecules and Lipids Flashcards
1
Q
What are the four main classes of the most important large molecules found in all living things?
A
Carbohydrates, lipids, proteins and Nucleic acids.
2
Q
As carbohydrates, proteins, and nucleic acids are so large what do we call them?
A
Macromolecules.
3
Q
What does the protein called alcohol dehydrogenase do?
A
Breaks down alcohol in the body
4
Q
What are polymers?
A
A polymer is a long molecule consisting of many similar or identical building blocks linked by covalent bonds, much as a train consists of a chain of cars.
5
Q
What are monomers?
A
The repeating units that serve as the building blocks of a polymer are smaller molecules called monomers. In addition to forming polymers, some monomers have functions of their own.
6
Q
What is the difference between a polymer and a monomer?
A
A monomer is small repeating units which make up what you would call a polymer.
7
Q
How are polymers broken down?
A
Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.
8
Q
What is a dehydration reaction?
A
In chemistry, a dehydration reaction is a conversion that involves the loss of water from the reacting molecule or ion.
9
Q
How are bonds made between monomers?
A
When a bond forms between two monomers, each monomer contributes part of the water molecule that is released during the dehydration reaction: One monomer provides a hydroxyl group (OH), while the other provides a hydrogen (H). This reaction is repeated making a polymer (also called polymerization).
10
Q
How are bonds made between monomers?
A
When a bond forms between two monomers, each monomer contributes part of the water molecule that is released during the dehydration reaction: One monomer provides a hydroxyl group (OH), while the other provides a hydrogen (H). This reaction is repeated making a polymer (also called polymerisation).
11
Q
What is a hydrolysis reaction?
A
In its simplest definition, hydrolysis is a chemical reaction in which water is used to break down the bonds of a particular substance. Hydrolysis means water breakage (from the Greek hydro, water, and lysis, break)
12
Q
What is an example of hydrolysis in our bodies?
A
An example of hydrolysis within our bodies is the process of digestion. The bulk of the organic material in our food is in the form of polymers that are much too large to enter our cells. Within the digestive tract, various enzymes attack the polymers, speeding up hydrolysis. Released monomers are then absorbed into the bloodstream for distribution to all body cells.
13
Q
Other than the formation and breakdown of polymers what other molecule can we use dehydration and hydrolysis reactions for?
A
Lipids
14
Q
What is the term for the simplest carbohydrates?
A
Monosaccharides
15
Q
What are polysaccharides?
A
Carbohydrate macromolecules that are made up of many monosaccharide subunits linked by covalent bonds.
16
Q
What is the most common Monosaccharide?
A
Glucose (C6H12O6)
17
Q
What is the essential parts of the structure of a sugar (Carbohydrate)?
A
The Carbonyl group (C=O) and the multiple hydroxyl groups (-OH)
18
Q
Depending on the location of the Carbonyl group what are the two types of molecule a sugar can be?
A
Aldose (Aldehyde sugar), or a Keytose (Keytone sugar)
19
Q
What type of sugar is glucose?
A
An aldose (Aldehyde sugar)
20
Q
What are things to remember about classifying and naming sugars?
A
Most names for sugars end in -ose. And another criterion for classifying sugars is the size of the carbon skeleton, which ranges from three to seven carbons long. Small differences in the structure is enough to have a complete different sugar.
21
Q
What is a triose?
A
A three-carbon sugar (C3H6O3)
22
Q
What is a pentose?
A
A five-carbon sugar (C5H10O5)
23
Q
What is a Hexose?
A
A six-carbon sugar (C6H12O6)
24
Q
Although it is convenient to draw glucose with a linear car- bon skeleton, this representation is not completely accurate. How would you accurately draw this 6 carbon structure?
A
In aqueous solutions, glucose molecules, as well as most other five- and six-carbon sugars, form rings, because they are the most stable form of these sugars under physiological conditions.
25
What is cellular respiration?
Cellular respiration is the process by which cells in plants and animals break down sugar and turn it into energy, which is then used to perform work at the cellular level.
26
Which Monosaccharide is a major nutrient for cells in terms of cellular respiration?
Glucose
27
Other than being a major nutrient for cells what else does glucose do for the body?
The carbon skeleton of glucose serves as raw material for the formation of other types of small organic molecules, such as amino acids and fatty acids.
28
What is a disaccharide?
two monosaccharides joined by a glycosidic linkage, a covalent bond formed between two monosaccharides by a dehydration reaction
29
What is sucrose?
A disaccharide composed of the two monosaccharides Glucose and Fructose
30
How do plants transport carbohydrates?
Generally via the leafs to the plants roots in the form of sucrose
31
What is the sugar present in milk?
Lactose
32
What type of carbohydrate is lactose?
A Disaccharide composed of a glucose molecule joined to a galactose molecule.
33
What must happen too disaccharides to be used as energy?
Disaccharides must be broken down into monosaccharides to be used for energy by organisms
34
What is Lactase?
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness.
35
What is lactose intolerance?
A common condition in humans who lack lactase, the enzyme that breaks down lactose. The sugar is instead broken down by intestinal bacteria, causing formation of gas and subsequent cramping.
36
What are polysaccharides?
Polysaccharides are macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
37
What do polysaccharides do?
Some polysaccharides serve as storage material, hydrolysed as needed to provide sugar for cells. Other polysaccharides serve as building material for structures that protect the cell or the whole organism.
38
What type of polysaccharides do plants store and how does it use this for energy?
Starch, forming starch enables the plant to stockpile surplus glucose. Because glucose is a major cellular fuel, starch represents stored energy. The sugar can later be withdrawn by the plant from this carbohydrate “bank” by hydrolysis, which breaks the bonds between the glucose monomers.
39
What is starch?
A polysaccharide made up of glucose units joined by glycosidic bonds. In plants starch is the main way its plant cells stores energy in the form of glucose.
40
What are plastids?
Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes.
41
Where in a plant is starch stored?
In its Plastids.
42
How is starch released from a plant cells plastids?
Through Hydrolysis. AKA the chemical breakdown of a compound due to a reaction with water.
43
What kind of linkages join the glucose monomers together in starch?
Generally 1-4 linkages (number carbon 1 to number carbon 4)
44
What is the simplest form of starch as its function?
Amylose is important in plant energy storage. Although it is less readily digested than other forms of starch such as amylopectin it is preferred for starch storage in plants due to its helical structure which takes up less space in the cell.
45
Which polysaccharide do animals store for chemical energy?
Glycogen
46
Where is glycogen (Carbohydrate) stored in animals?
Mainly in the liver and muscle cells
47
What happens when a demand of sugar increases in the body?
Hydrolysis of the glycogen stores occurs which releases glucose into the cells.
48
Why is glycogen a good form of carbohydrate storage in the body?
Because it is so extensively branched it has multiple free ends available for hydrolysis therefore it breaks down into glucose easily.
49
Why are low carbohydrate diets not ideal?
Glycogen stores are easily depleted in the body and require regular replenishing (are not long term sources of chemical energy). Therefore without regular servings of carbohydrates the body can become weak and experience fatigue.
50
What are structural polysaccharides?
Any polysaccharide that serves to supply stiffness to a plant or insect.
51
`What is the major component of the tough walls that enclose plant cells?
Cellulose
52
What is the most plentiful organic compound on earth?
Cellulose
53
What is cellulose?
A structural polysaccharide in plants
54
How many linkages join the glucose monomers together in cellulose?
1-4 glycosidic linkages
55
Both starch and cellulose have 1-4 linkages but how do these linkages differ?
Starch can have two different placements of the hydroxyl group (-OH), either below or above carbon number 1. In starch all monomers are in the same orientation (alpha config- with the -OH group below 1st carbon), In cellulose the glucose monomers are in the b config making each glucose monomer opposite to its neighbours. Due to these differences in linkages starch molecules tend to form a helical shape and cellulose molecules tend to form a straight shape
56
What are microfibrils in plants?
A microfibril is a fibre like strand consisting of glycoproteins and cellulose. Cellulose microfibrils are laid down in the inner surface of the primary cell wall. They are a strong building material for plants.
57
Why is it important that cellulose is unbranched?
This allows the molecule to form long and straight chains as a straight chain is ideal for the formation of strong fibers.
58
Can the same enzymes that digest starch in the body by hydrolysing, hydrolyse cellulose and why?
NO, because 1: enzymes are reaction specific and 2: it is very rare than your body will have cellulose hydrolysing enzymes
59
What is Chitin?
Chitin is a structural polysaccharide in arthropods (insects, spiders, crustaceans, and related animals) to build their exoskeletons.
60
What is an exoskeleton?
A hard case that surrounds the soft parts of an animal. It is made out of chitin embedded in a layer of proteins, the case is leathery and flexible at first, but becomes hardened when the proteins are chemically linked to each other (as in insects) or encrusted with calcium carbonate (as in crabs)
61
What is the function of chitin in fungi?
Instead of using cellulose, fungi uses chitin as the building material for its cell walls.
62
What are lipids and their functions?
A lipid is a biomolecule that is soluble in nonpolar solvents. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. ... Although the term "lipid" is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides..
63
Do lipids mix well or poorly with water?
poorly
64
Why are lipids hydrophobic?
The hydrophobic behavior of lipids is based on their molecular structure. Although they may have some polar bonds associated with oxygen, lipids consist mostly of hydrocarbon regions.
65
What are 3 important types of lipids?
1. Fats 2. Phospholipids 3. Steroids
66
What are fats?
large molecules constructed from two kinds of smaller molecules called: glycerol and fatty-acids
67
What is glycerol?
Glycerol is an alcohol; each of its three carbons bears a hydroxyl group.
68
What are fatty acids?
A fatty acid has a long carbon skeleton, usually 16 or 18 carbon atoms in length. The carbon at one end of the skeleton is part of a carboxyl group, the functional group that gives these molecules the name fatty acid.
69
Why are fats hydrophobic?
The carbon chain of fatty acids is composed of carbon and hydrogen atoms making the chain non-polar and therefore unable to react with waters polar bonds (Hydrophobic).
70
What is the structure of a fat?
Three fatty acid molecules are each joined to glycerol by an ester linkage, a bond formed by a dehydration reaction between a hydroxyl group and a carboxyl group. The resulting fat, also called a triacylglycerol, thus consists of three fatty acids linked to one glycerol molecule.
71
What is a saturated fatty acid and what is it saturated with?
A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds. If there are no double bonds between carbon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton. Such a structure is said
to be saturated with hydrogen
72
What is an unsaturated fat?
An unsaturated fatty acid has one or more double bonds, with one fewer hydrogen atom on each double-bonded carbon. Nearly every double bond in naturally occurring fatty acids is a cis double bond, which creates a kink in the hydrocarbon chain wherever it occurs.
73
What is the difference between cis and trans?
The difference between the two is that the cis isomer is a polar molecule whereas the trans isomer is non-polar.
74
Are animal fats typically saturated or unsaturated?
Saturated as their flexibility allows the fat molecules to pack together tightly therefore they are solid at room temperature.
75
Are plants typically saturated or unsaturated?
Unsaturated which means they have double or triple bonds. The kinks where the cis double bonds are located prevent the molecules from packing together closely enough to solidify at room temperature. Therefore these fats typically exist as liquids at room temperature.
76
What does hydrogenated vegetable oils mean on food labels?
That unsaturated fats have been synthetically converted to saturated fats by adding hydrogen, allowing them to solidify. Peanut butter, margarine, and many other products are hydrogenated to prevent lipids from separating out in liquid (oil) form.
77
What is cardiovascular disease known as atherosclerosis caused by?
A diet rich in saturated fats
78
What is the cardiovascular disease known as atherosclerosis?
In this condition, deposits called plaques develop within the walls of blood vessels, causing inward bulges that impede blood flow and reduce the resilience of the vessels
79
What type of double bonds in fats contribute to coronary heart disease?
Trans fats (Trans double bonds)
80
What is the major function of fats?
Energy storage
81
True or False? A gram of fat stores more than twice as much energy as a gram of a polysaccharide, such as starch.
True, Fats are great stores of energy
82
Why may plants use a different form of energy storage than animals?
Plants are generally immobile and are able to function with large bulks of energy storage (in the form of starch), animals move around a-lot and therefore require more compact reservoirs of energy storage (such as fat).
83
What are adipose cells?
Lying three layers deep under the skin, the adipose tissue is composed of a loose collection of specialised cells, called adipocytes, embedded in a mesh of collagen fibers. Its main role in the body is function as a fuel tank for the storage of lipids and triglycerides.
84
Where do animals tend to stock their long-term food reserves?
In their adipose cells.
85
Other than proving a home to energy storage in animals what do adipose cells do?
They provide cushions to the body's vital organs such as the kidneys and they also provide a layer of insulation under the body's skin.
86
What are phospholipids?
Phospholipids are a class of lipids that are a major component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. This bilayer provides a barrier around the cell which only lets in certain molecules like carbondioxide and oxygen necessary for cellular respiration. During digestive process phospholipid form clusters to help move vitamins, nutrients and fat containing molecules through the body.
87
What type of lipid could cells not exist without?
Phospholipids
88
What are Phospholipids made up of?
A phospholipid has a hydrophilic (polar) head and two hydrophobic (non-polar) tails.
89
How are Phospholipids similar in structure to fats?
A phospholipid is similar to a fat molecule in that it only has two fatty acids attached to glycerol rather than three.
90
True or false? When phospholipids are taken away from water they self-assemble into a double-layered sheet called a “bilayer”
False. When phospholipids are added to water, they self-assemble into a double-layered sheet called a “bilayer”
91
Which way are phospholipids arranged in its bilayer at the surface of a cell?
The hydrophilic heads of the molecules are on the outside of the bilayer, in contact with the aqueous solutions inside and outside of the cell. The hydrophobic tails point toward the interior of the bilayer, away from the water.
92
True or False? the existence of cells depends on the properties of phospholipids.
True
93
What are steroids?
Steroids are lipids characterised by a carbon skeleton consisting of four fused rings. Steroids have two principal biological functions: as important components of cell membranes which alter membrane fluidity; and as signalling molecules.
94
How are different steroids distinguished?
By the particular chemical groups attached to this ensemble of rings
95
What is Cholesterol?
A type of steroid which is a crucial molecule in animals. It is a common component of animal cell membranes and is also the precursor from which other steroids, such as the vertebrate sex hormones, are synthesised (formed).
96
What are vertebrates?
an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
97
Where is Cholesterol synthesised in vertebrates?
It is synthesised in the liver and obtained by diet.
98
What is atherosclerosis?
Atherosclerosis refers to the buildup of fats, cholesterol and other substances in and on your artery walls (plaque), which can restrict blood flow.
99
True or False? without proteins organisms would not be able to function.
True
100
What are enzymes?
Chemical agents that selectively speed up chemical reactions without being consumed in the reaction.
101
How many amino acids make up ALL proteins?
20 Amino acids
102
What is the bond between amino acids called?
Peptide bonds
103
What is a polymer of amino acid called?
A polypeptide
104
What is a protein?
A protein is a biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific three-dimensional structure.
105
What are amino acids?
Amino acids are organic compounds that contain amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, although other elements are found in the side chains of certain amino acids.
106
What are defensive proteins?
Proteins which provide protection against disease
| Example: Antibodies inactivate and help destroy viruses and bacteria.
107
What are hormonal proteins?
The provide the coordination of an organism‘s activities. For Example: Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration.
108
What are receptor proteins?
Receptor proteins are the response of cell to chemical stimuli Example: Receptors built into the membrane of a nerve cell detect signalling molecules released by other nerve cells.
109
Are non-polar side chains in proteins hydrophobic or hydrophilic?
They are hydrophobic
110
Are polar side chains in proteins hydrophobic or hydrophilic?
They are hydrophilic
111
What type of charge do acidic amino acid side chains have?
Side chains are generally negative in charge due to the presence of a carboxyl group. (Notice that all amino acids have carboxyl groups and amino groups; the terms acidic and basic in this context refer only to groups in the side chains.)
112
What type of charge do basic amino acid side chains have?
Basic amino acids that have amino groups in their side chains that are generally positive in charge. (Notice that all amino acids have carboxyl groups and amino groups; the terms acidic and basic in this context refer only to groups in the side chains.)
113
Are acidic and basic side chains hydrophobic or hydrophilic?
Because they are charged, acidic and basic side chains are hydrophilic
114
How are peptide bonds formed?
Through dehydration reactions (The loss of a water molecule) which link the carboxyl group of one amino acid to the amino group of the next.
115
What is it called when peptide bonds are formed over and over again to form a molecule?
A polypeptide. A polymer of many amino acids linked by peptide bonds.
116
What is the N-Terminus of the polypeptide backbone?
The N-Terminus is where the free amino acid group sits on the polypeptide backbone
117
What is the C-Terminus of the polypeptide backbone?
The C-Terminus is where the free carboxyl group sits on the polypeptide backbone
118
A functional protein is not just a polypeptide chain, but.... continue this sentence.
one or more polypeptides precisely twisted, folded, and coiled into a molecule of unique shape.
119
What determines what three-dimensional structure the protein will have under normal cellular conditions?
The amino acid sequence of each polypeptide
120
What is the simplest structure of a protein?
The sequence of the amino acids.
121
What is a functional protein?
A functional protein is not just a polypeptide chain, but one or more poly- peptides precisely twisted, folded, and coiled into a molecule of unique shape, which can be shown in several different types of models.
122
What are globular proteins?
Globular proteins are spherical proteins and are one of the common protein types. Globular proteins are somewhat water-soluble,
123
What are fibrous proteins?
Fibrous proteins are generally composed of long and narrow strands and have a structural role (they are something). These proteins form long fibres that serve a structural role in the human body.
124
What are antibodies?
An antibody, also known as an immunoglobulin, is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses
125
What are endorphin molecules?
Endorphins, molecules produced by the pituitary and hypothalamus glands to produce pain relief and a sense of well-being. Receptors are specific protein molecules that are configured to bind to opiates
126
What are morphine molecules?
A manufactured drug, which is a receptor proteins on the surface of brain cells in humans, producing euphoria and relieving pain.
127
True or False? Morphine, heroin, and other opiate drugs are able to mimic endorphins
True, they all have a shape similar to that of endorphins and can thus fit into and bind to endorphin receptors in the brain. This fit is very specific, something like a lock and key
128
What are the 3 computer generated structural models of proteins?
1: Space filling model, 2: Ribbon model, 3: Wireframe model
129
What is the space filling model?
Shows all the atoms of the protein (except hydrogen), emphasising the overall globular shape.
130
What is the Ribbon model?
Shows only the backbone of the polypeptide, emphasising how it folds and coils to form a 3-D shape
131
What is the Wireframe model?
Shows the backbone of the polypeptide chain with side chains (R groups) extending from it
132
What are the four levels of protein structure?
Primary, secondary, tertiary, & quaternary.
133
When does the 4th structure of protein arise (quaternary)?
when a protein consists of two or more polypeptide chains.
134
What is the primary structure of proteins?
A linear chain of amino acids
135
What is transthyretin?
A globular blood protein that transports vitamin A and one of the thyroid hormones throughout the body. Transthyretin is made up of four identical polypeptide chains, each composed of 127 amino acids.
136
What dictates the secondary and tertiary structure of proteins?
The chemical nature of the backbone and the side chains (R groups) of the amino acids along the polypeptide.
137
What is the secondary structure of proteins?
A structure with regions stabilized by hydrogen bonds between atoms of the polypeptide backbone. (A structure with coils and folds)
138
What causes the coils and folds in the secondary structure of proteins?
The hydrogen bonds between the repeating constituents of the polypeptide backbone (not the amino acid side chains)
139
How can hydrogen bonds form between the repeating constituents of the polypeptide backbone?
The oxygen atoms have a partial negative charge, and the hydrogen atoms attached to the nitrogens have a partial positive charge, therefore, hydrogen bonds can form between these atoms. Individually, these hydrogen bonds are weak, but because they are repeated many times over a relatively long region of the polypeptide chain, they can support a particular shape for that part of the protein.
140
What is the a (alpha) helix?
The a helix is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located three or four residues earlier along the protein sequence. (A delicate coil held together by hydrogen bonding between every fourth amino acid)
141
What is the β pleated sheet?
The Beta-pleated sheet is a series of anti-parallel chains of covalently-linked amino acids, with adjacent chains linked by hydrogen bonds. The regular folding of each amino acid chain leads to a regular pleated pattern across chains.
142
What is the tertiary structure of proteins?
Three-dimensional shape stabilised by interactions between side chains. tertiary structure is the overall shape of a polypeptide resulting from interactions between the side chains (R groups) of the various amino acids.
143
What is one type of interaction that contributes to the tertiary structure?
A hydrophobic interaction
144
What are hydrophobic interactions in protein folding caused by?
amino acids with hydrophobic (nonpolar) side chains usually end up in clusters at the core of the protein, out of contact with water. Thus, a “hydrophobic interaction” is actually caused by the exclusion of nonpolar substances by water molecules.
145
Which interactions help stabilize the tertiary structure?
Van der waals interactions and hydrogen bonds
146
What are disulfide bridges?
Covalent bonds which further reinforce the tertiary shape of a protein. Disulfide bridges form where two cysteine monomers, which have sulfhydryl groups (—SH) on their side chains are brought close together by the folding of the protein.
147
What is the quaternary structure of proteins?
The association of two or more polypeptides (some proteins only).
148
What is collagen?
Collagen is the most abundant protein in your body. which is a fibrous protein that has three identical helical polypeptides intertwined into a larger triple helix, giving the long fibers great strength. This suits collagen fibers to their function as the girders of connective tissue in skin, bone, tendons, ligaments, and other body parts. (Collagen ac- counts for 40% of the protein in a human body.)
149
What is Hemoglobin?
The oxygen-binding protein of red blood cells. It consists of four polypeptide subunits, two of one kind (α) and two of another kind (β). Both α and β subunits consist primarily of α-helical secondary structure. Each subunit has a nonpolypeptide component, called heme, with an iron atom that binds oxygen.
150
What is sickle-cell disease?
An inherited blood disorder, is caused by the substitution of one amino acid (valine) for the normal one (glutamic acid) at the position of the sixth amino acid in the primary structure of hemoglobin. . Normal red blood cells are disk-shaped, but in sickle-cell disease, the abnormal hemoglobin molecules tend to aggregate into chains, deforming some of the cells into a sickle shape
151
What can be dangerous about sickle cell disease?
The cells can clog with tiny blood vessels, impeding blood flow. The toll taken on such patients is a dramatic example of how a simple change in protein structure can have devastating effects on protein function.
152
What are the key factors determining protein structure?
1: The protein structure is being synthesized in the crowded environment within a cell, aided by other proteins and also 2: The physical and chemical conditions of the protein’s environment impact its shape.
153
What would happen if in a protein structure, the pH, salt concentration, temperature, or other aspects of its environment are altered?
The weak chemical bonds and interactions within a protein may be destroyed, causing the protein to unravel and lose its native shape, a change called denaturation
154
What is denaturation?
The process that causes a protein to lose its shape is known as denaturation. Denaturation is usually caused by external stress on the protein, such as solvents, inorganic salts, exposure to acids or bases, and by heat.
155
What happens to a protein after denaturation?
The denatured protein is biologically inactive.
156
True or False? Most proteins become denatured if they are transferred from an aqueous environment to a non-polar solvent.
True
157
Why can excessively high fevers can be fatal?
As proteins in the blood tend to denature at very high body temperatures.
158
What familiar diseases are associated with the misfolding of proteins in the cell?
cystic fibrosis, Alzheimer’s, Parkinson’s, and mad cow disease
159
What is X-ray crystallography?
The method most commonly used to determine the 3-D structure of a protein, it depends on the diffraction of an X-ray beam by the atoms of a crystallised molecule. Using this technique, scientists can build a 3-D model that shows the exact position of every atom in a protein molecule.
160
What are Nuclear magnetic resonance (NMR)
| spectroscopy and bioinformatics?
They are complementary approaches to understanding protein structure and function
161
Why is the structure of some proteins difficult to determine?
A growing body of biochemical research has revealed that a significant number of proteins, or regions of proteins, do not have a distinct 3-D structure until they interact with a target protein or other molecule.
162
What are Nucleic acids?
Nucleic acids are polymers made of monomers called nucleotides. They store, transmit, and help express hereditary information
163
What is the amino acid sequence of a polypeptide is programmed by?
A discrete unit of inheritance known as a gene
164
What are the two types of nucleic acids?
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA),
165
What do nucleic acids allow living organisms to do?
to reproduce their complex components from one generation to the next
166
What is gene expression?
DNA directs RNA synthesis and, through RNA, controls protein synthesis.
167
In gene expression, other than DNA what is needed for correct operation?
Proteins
168
What is messenger RNA?
mRNA is created during transcription. During the transcription process, a single strand of DNA is decoded by RNA polymerase, and mRNA is synthesised. The mRNA molecule interacts with the cell’s protein-synthesizing machinery to direct production of a polypeptide, which folds into all or part of a protein.
169
What are polynucleotides?
A polynucleotide molecule is a biopolymer composed of 13 or more nucleotide monomers covalently bonded in a chain. DNA and RNA are examples of polynucleotides with distinct biological function.
170
What are nucleotide, in general, is composed of?
It is composed of three parts: a five-carbon sugar (a pentose), a nitrogen-containing (nitrogenous) base, and one to three phosphate groups
171
What is a nucleoside?
Nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase and a five-carbon sugar ribose
172
Why are nitrogenous bases called nitrogenous bases?
They are called nitrogenous bases because the nitrogen atoms tend to take up H+ from solution, thus acting as bases.
173
What are the two families of nitrogenous bases?
Purines and pyrimidines
174
What is a pyrimidine?
A pyrimidine has only one six-membered ring of carbon and nitrogen atoms. In DNA the pyrimidines are cytosine and thymine, in RNA uracil replaces thymine.
175
What are Purines?
Purines are larger, with a six-membered ring fused to a five-membered ring (Double rings). The purines are adenine (A) and guanine (G)
176
What is the sugar used in DNA?
deoxyribose
177
What is the sugar used in RNA?
ribose
178
What is the difference between deoxyribose and ribose?
The only difference between these two sugars is that deoxyribose lacks an oxygen atom on the second carbon in the ring, hence the name deoxyribose.
179
What reaction is used to link nucleotides into a polynucleotide?
A dehydration reaction (The loss of a water molecule)
180
In the polynucleotide, what are adjacent nucleotides are joined by?
A phosphodiester linkage
181
What is the sugar-phosphate backbone?
The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule
182
Which end of the DNA strand has has a phosphate attached?
The 5' end
183
Which end of the DNA strand has has a hydroxyl group attached?
The 3' end
184
Which bonds hold the nitrogenous bases of each strand of DNA together?
Hydrogen bonds
185
What is the role of tRNA?
The job of tRNA is to read the message of nucleic acids, or nucleotides, and translate it into proteins, or amino acids
186
Do the two strands of DNA run in the same direction or the opposite?
They run in different directions. This arrangement is referred to as antiparallel,
187
What does it mean by complementary within the two strands of DNA?
When they say that the strands are complementary to each other, they mean that if one strand contains Adenine, Gunine and cytosine so on the other strand there will Thymine bond with Adenine, Cytosine with Gunanine and Gunanine with Cytosine.
188
Which feature makes it possible to generate two identical copies of each DNA molecule in a cell that is preparing to divide?
The complementary strands of DNA (A-T, C-G)
189
Do RNA molecules exist as double strands or as single strands?
Single strands
190
Can base pairing occur in the single strand of RNA?
Yes, It occurs between regions of two RNA molecules or even between two stretches of nucleotides in the same RNA molecule through coiling.
191
Why is base pairing good for an RNA molecule?
It allows it to take on the particular three-dimensional shape necessary for its function
192
Which base pair is not present in RNA and what is it replaced with?
Thymine (T), and it is replaced with Uracil (U).
193
What was the the Human Genome Project?
The Human Genome Project was an international research effort to determine the sequence of the human genome and identify the genes that it contains
194
What does burgeoned mean?
To begin to grow or increase rapidly; flourish.
195
What is bioinformatics?
The science of collecting and analysing complex biological data such as genetic codes.
196
What is the approach called genomics?
Genomics, in contrast, is the study of the entirety of an organism's genes – called the genome. Using high-performance computing and math techniques known as bioinformatics, genomics researchers analyze enormous amounts of DNA-sequence data to find variations that affect health, disease or drug response.
197
What is the approach called proteomics?
Proteomics is the large-scale study of proteins. Proteins are vital parts of living organisms, with many functions.
198
True or False? Sequences of genes and their protein products document the hereditary background of an organism.
True
