1- Introduction To Biology Flashcards
(177 cards)
1
Q
What are the five steps in the scientific method?
A
1) Observation
2) Hypothesis
3) Prediction
4) Experimentation
5) Hypothesis supported or falsified
2
Q
What important factor needs to be met in the experimentation stage of the scientific method?
A
Only one variable of interest can be altered at a time
3
Q
What is the treatment variable in the experimentation stage?
A
What you will change in the experiment to show its effect and test the prediction of your hypothesis.
4
Q
What is a positive control experiment and what does it permit?
A
An experiment in which you know the positive outcome.
This permits the scientist to verify that their setup is working fine and will produce predictable results.
5
Q
What is a negative control experiment and what does it permit?
A
An experiment in which you know the negative outcome.
This permits the scientist to verify that their setup is working fine and will produce predictable negative results.
6
Q
What can be done to ensure that the results of the experiment are not a fluke?
A
Repeating the experiment several times
7
Q
What is a theory?
A
A highly successful hypothesis that was not falsified by any experiments. It is a body of interconnected concepts, supported by scientific reasoning and a lot of experimental evidence.
8
Q
What was the goal of Pasteur’s experiment?
A
To falsify the hypothesis of spontaneous generation
9
Q
What are the characteristics of all living organisms? (7)
A
1) Cellular organization
2) Ordered complexity
3) Sensitivity to the environment
4) Growth, development, and reproduction
5) Energy utilization
6) Homeostasis
7) Evolutionary adaption
10
Q
What is cellular organization?
A
-All organisms are made of cells
-All cells come from pre-existing cells
11
Q
What is ordered complexity?
A
All living things are both complex and highly ordered
12
Q
What is sensitivity to environment?
A
All organisms respond to stimuli
13
Q
What is growth, development, and reproduction?
A
All organisms are capable of growing and reproducing, and they all possess hereditary molecules that are passed to their offspring, ensuring that the offspring are of the same species.
14
Q
What is energy utilization?
A
All organisms take in energy and use it to perform many kinds of work. Every muscle in your body is powered with energy you obtain from what you eat.
15
Q
What is homeostasis?
A
All organisms maintain relatively constant internal conditions that are different from their environment.
16
Q
What is evolutionary adaption?
A
-All organisms interact with other organisms and the nonliving environment in ways that influence their survival.
-Only the organisms that survive can reproduce and pass their traits that permit their survival to the next generation.
-Therefore, after multiple generations, the specie evolves the best adaption to their environment.
17
Q
Why are viruses not considered to be alive?
A
-No cell organization (no cell)
-No sensitivity to the environment
-No growth, development, and reproduction without a host
-No energy utilization
-No homeostasis
18
Q
What is ‘basic research’?
A
Basic research is intended to extend the boundaries of what we know.
19
Q
What is ‘applied research’?
A
-Research where its foundation is provided by basic research
-May involve the manufacture of goods such as food additives or drugs
20
Q
What is the most complex chemical system on Earth?
A
The living system
21
Q
What is the first level of hierarchical organization?
A
The cellular level
22
Q
What are the components of the cellular level?
A
- Atoms
- Molecules
- Organelles
-Cell
23
Q
What is an organelle?
A
A complex biological molecule assembled into tiny structures within membrane-bounded units we call cells.
24
Q
What is the basic unit of life?
A
A cell
25
What is a cell?
The basic unit of life which can be composed of single cells (bacteria) or multi-cellular (animas, plants).
26
What is the second level of hierarchical organization?
The organismal level
27
What are the components of the organismal level?
-Tissues
-Organs
-Organ systems
28
Define ‘tissues’
Groups of similar cells that act as a functional unit
29
Define ‘organs’
Structures composed of several different tissues that act as a structural and functional unit
30
Define ‘organ systems’
Group of organs into organ systems that have a function
31
What is the third level of hierarchical organization?
The population level
32
Define ‘population’
Group of organisms of the same species living in the same space
33
Define ‘ecosystem’
Populations of organisms interact with each other and their physical environment
34
Define ‘biosphere’
The entire planet can be thought of as an ecosystem that we call the biosphere
35
*What are emergent properties?
- Result from interaction of components
- Cannot be deduced by looking at parts themselves
36
What are the core concepts of biology?
1) Chemical and physical laws
2) Structure determines function
3) Energy transformations
4) Information transactions
5) Evolution
37
Explain “Life is subject to chemical and physical laws”
- living systems operate according to known chemical and physical principles
- biological systems are the ultimate application of some very complex chemistry
38
Explain “Structure determines function”
- a unifying theme in biology is the relationship between structure and function
- the proper functioning of molecules, of cells and of tissues and organs depends on their structure
-When we know the function of a particular structure, we can infer the function of similar structures found in different contexts, such as in different organisms.
39
Explain “Living systems transform energy and matter”
-all life constantly requires energy
-the majority of energy on Earth comes from our Sun
-the basic nature of life constantly transforms energy and matter
40
Give examples to “living systems depend on information transactions”
Example:
-Life is coded by Deoxyribonucleic Acid (DNA)
-sequence of 4 nucleotides encode cell’s information
-gene: discrete unit of information (ex: code for a specific protein)
-genome: entire set of DNA instructions
-continuity of life depends on transmission of DNA to the offspring.
41
What are the four nucleotides?
A- Adenine
T- Thymine
G- Guanine
C- Cytosine
42
Explain “Living systems depend on information transactions”
Cells are able to process information about their environment, both internal and external
-cells in multicellular organisms must coordinate with each other
43
Explain “Evolution explains unity and diversity of life”
-All organisms today descended from one simple creature living about 3.5 billion years ago
-Some of the characteristics of that primitive organism have been preserved through evolutionary history into the present
-Underlying unity in biochemistry and genetics hint that all life come from the same origin.
44
Prove that ‘’evolution explains unity and diversity for life’’ with the assistance of stromatolite
-Stromatolite found dating back to 3.4 billion years
-Modern living stromatolites in Shark Bay, Western Australia.
-Some of the characteristics of that primitive organism have been preserved through evolutionary history into the present.
-Phylogenetic study have shown that all organisms are link in the tree of life from a common ancestor about 3.5 billion years ago!
45
What are stromatolite?
-Stromatolite are a mat of Cyanobacteria that traps fine-grained sediment
-Fossilized stromatolite is the preserve layers of sediment containing fossilized cyanobacteria.
46
What book did Charles Darwin make and what does it discuss
‘’On the Origin of Species’
-gives an explanation on how organisms have changed over time and acquired diversity of new forms
47
What did Charles Darwin envision?
-all species were descended from a single common ancestor and that the history of life could be depicted as a branching tree (each twig represents existing species)
48
Who is the ‘’father of modern taxonomy’’ and why is he nicknamed this?
Carl Linnaeus
-Wrote the book Systema Naturae which expanded the systematic and universal way of classifying living things
49
What is taxonomy?
Taxonomy is the science of classifying living things
50
How do you write the scientific name of an organism?
-The first word is the genus to which the organism belongs (capitalized)
-The second word refers to the particular species (not capitalized)
-Whole name written in italics (bc Latin)
51
What is the taxonomic system in order?
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
52
What are the domains?
1) Bacteria (prokaryote)
2)Archaea (prokaryote)
3)Eukarya (eukaryote)
53
What are prokaryotes?
1) Prokaryotic DNA is not contained within a membrane-bound nucleus
2) The DNA in Prokaryotic cells is circular
3) Prokaryotic cell wall composition is biochemically different than eukaryotic cells
4) The size of prokaryotic cells is considerably smaller than eukaryotic cells
(I.e: DNA is just floating around)
54
What are eukaryotes?
DNA is contained within a membrane-bound nucleus
55
What are the kingdoms?
1) Archaeae
2) Bacteria
3) Fungi
4) Plantae
5) Animalia
6) Protists (wtv doesn’t fit in the other kingdoms)
56
What are the 4 pillars of biological classification that you need to know?
1) Domain
2) Kingdom
3) Genus
4) Species
57
What is the origin of biomolecules?
-Hadean Earth was a hot mass of molten rock abt 4.5 billion yrs ago
-Hadean Earth was pummeled by asteroids, which could potentially vaporize entire oceans
-As it cooled, much of the water vapor present in Earth’s atmosphere condensed into liquid water that accumulated on the surface in chemically rich oceans.
58
What are the most abundant elements found in living organisms in substantial amounts? (12)
1) Oxygen
2) Carbon
3) Hydrogen
4) Nitrogen
5) Calcium
6) Phosphorus
7) Potassium
8) Sulfur
9) Sodium
10) Chlorine
11) Magnesium
12) and trace amounts of some others
59
What are the four elements that make up 96.3% of human body weight?
1) Carbon
2) Hydrogen
3) Oxygen
4) Nitrogen
60
What are atoms composed of?
-Protons
-Neutrons
-Electrons
61
What are the three kinds bonds that atoms (in molecules or compounds) are held together with?
1) Ionic bonds
2) Covalent bonds
3) Hydrogen bonds
62
What are ionic bonds?
-formed by the attraction of oppositely charged ions
-gain or loss of electrons forms ions
63
What are covalent bonds
-forms when atoms share 2 or more valence electrons
-results in no net charge, satisfies octet rule, no unpaid electrons
-strength of covalent bond depends on the number of shared electrons
64
How does electronegativity work for covalent bonds?
-atom’s affinity for electrons
-differences in electronegativity dictate how electrons are distributed in covalent bonds
-determines polarity
65
How are hydrogen bonds formed and are they weak or strong?
-Cohesion (polarity of water allows water molecules to be attracted to one another)
-Attraction produces hydrogen bonds
-Each individual bond is weak but together can make enormous effects
66
What is responsible for many of water’s important physical properties?
Hydrogen bonds
67
What are the properties of water? (7)
1) Water cohesion/adhesion
2)Water has a high specific heat
3)Water has a high heat of vaporization
4)Solid water is less dense than liquid water
5) Water is a good solvent
6) Water organizes nonpolar molecules
7)Water can form ions
68
Explain ‘’water cohesion’’ and what it’s responsible for
-Cohesion permit water to be liquid at room temperature and not a gas
-Cohesion is responsible for water tension
69
What is water adhesion responsible for?
-Adhesion of water molecules is responsible for the capillary action, where the adhesion of water can go up a tube made of polar molecules giants gravity
(Plants use this capillarity action to transport water in the stems)
70
How much energy (cal) does water need to change into gas?
586 calories
71
Why is it important that water has a high specific heat?
The heat generated by the chemical reaction inside cells would destroy the cells if not for the absorption of this heat by the water within them.
72
Why do humans sweat? (High heat of vaporization)
The evaporation of water from a surface causes cooling of that surface. Sweating is a way to dispose of excess heat.
73
Why is it important that solid water is less dense than liquid water?
Life could not exist in a lake during winter if ice sank to the bottom of the
74
Water is good at dissolving what kind of molecules?
Polar molecules and ions
75
What does water form to prevent the solute from reforming salt crystals?
Hydration shells
76
What does water cause hydrophobic molecules to do?
Aggregate or assume specific shapes
77
What are organic molecules and hydrocarbons?
Organic molecules: molecules that contain carbon atoms (except CO2)
Hydrocarbons: molecules consisting only of carbon and hydrogen
78
What are functional groups and what are their characteristics?
They are specific molecular groups that bond to carbon-hydrogen cores
-Each group has unique chemical properties
-The different functional groups will interact between each other in a molecule, in addition to the environment, creating the 3D structure of the functioning bio-molecules
79
Which functional groups are polar and why?
Hydroxyl and carbonyl groups because of the electronegativity of their oxygen atoms
80
Which functional group is SLIGHTLY polar?
Sulfhydryl
81
Which functional group is nonpolar?
Methyl
82
Which functional groups are acidic and why?
Carboxyl & phosphate groups
-can release H+ in solution (those groups will negatively charge in aqueous solution)
83
Which functional group is basic and why?
Amino groups
-can accept H+ and form NH3+, since they can remove H+ from solutions, they are basic. (This group will positively charge in aqueous solutions)
84
Which type of bond can be created between acidic and basic functional groups?
Ionic bonds
85
What are isomers?
Molecules with the same molecular or empirical formula
86
What are structural isomers?
They differ in structure of carbon skeleton
87
What are stereoisomers?
They have the same carbon skeleton but differ in how the groups attached to this skeleton are arranged in space
88
What are enantiomers?
-Carbon bound to 4 different molecules
-Chiral molecule: mirror image (Dextro:right & Levo:left)
89
How many versions of the two possible enantiomers do living systems tend to produce
Only a single version
90
What are monomers and polymers?
Monomer: basic structural unit of polymers (carbohydrate, amino acid and nucleic acids)
Polymers: molecule made up of a large number of identical or similar units (monomers) attached by covalent bonds
91
Does dehydration occur during the synthesis or degradation of polymers?
Synthesis (formation of large molecules by the removal of water)
92
What is hydrolysis?
The breakdown of large molecules by the addition of water (used in the degradation of polymers)
93
How are polymers formed?
Monomers are joined together
94
Explain the synthesis of polymers
-Dehydration occurs to form large molecules by removing water
-Monomers are then joined to form polymers
95
What are macromolecules?
Thousands of atoms united by covalent bonds
96
What are the macromolecules called?
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
97
What are some characteristics of carbohydrates?
-Molecules with a 1:2:1 ratio of carbon, hydrogen, oxygen
-Empirical formula C1nH2nO1n
-C—H covalent bonds holds energy and thus carbohydrates can be used to store energy
98
What are monosaccharides?
Monosaccharide: one sugar
-Is a monomer of carbohydrate which is 3 to 7 carbons long.
-The majority of monosaccharides have 5 to 6 carbons and have a cyclic form in aqueous solutions.
-Monosaccharides (especially glucose) are an essential source of energy for cells during the processes of respiration and fermentation
99
What are disaccharides?
Two monosaccharides linked together
100
How does the synthesis of disaccharides occur?
-by dehydration (reaction between 2 hydroxyl groups) which makes it possible to make a covalent bond (called **glycosidic bond**).
101
What is the difference between how glucose is transported in humans and in plants?
In humans: transported as **monosaccharides**
In plants (and other organisms): **converted to disaccharides before being transported within the organism**
(note: In such a form, it is less readily metabolized during transport and enzymes that can hydrolyze glucose is only present in the tissue that uses glucose)
102
What are examples of disaccharides?
-Lactose (is of animal origin. It is only made by mammary glands of mammals)
-Maltose (created in the seeds of plants as they break down their stored energy in order to sprout)
103
What are oligosaccharides?
Small chains of about three to ten monosaccharides linked together
104
What is the function of oligosaccharides?
-Found on cell surfaces acting as identification markers (ex: blood types are the presence of different oligosaccharides at the surface of the red blood cells)
105
What are polysaccharides?
Long chains of more than ten monosaccharides linked together
106
What is the function of polysaccharides?
-Energy storage (plants use starch & animals use glycogen)
-Structural Support (plants use cellulose & arthropods and fungi use chitin
107
What are the two types of cyclic molecules that glucose can form?
-Alpha isomers
-Beta isomers
108
What is the polymer that beta glucose forms?
Cellulose
109
Why **can’t** you digest cellulose?
We don’t have the enzyme needed to break the **beta glycosidic bond** of cellulose. Therefore, we can’t digest it and access the glucose sugar.
110
How are polysaccharides’ monomers linked together?
-Unbranched chain linkage occurs between the carbon 1(C-1) of the glucose molecule and the C-4 of another, making them at 1->4 linkages.
-Branched chain linkage occurs between the carbon 1 (C-1) of one glucose molecule and the C-6 of another, making them at 1->6 linkages.
111
What are lipids?
-loosely defined group of molecules with one main chemical characteristic
-Insoluble in water
-High proportion of nonpolar C—H bonds causes the molecule to be hydrophobic
-Do not form polymers
-Good source of energy due to high C to H with 9 kcal per g compared to carbohydrate 4 kcal per g.
112
What are the 3 families of lipids?
1) Triglycerides
2) Phospholipids
3) Steroids
113
What are triglycerides?
Lipid family composed of one glycerol and three fatty acids.
114
Differences between saturated and unsaturated triglycerides
Saturated:
-No double bonds between carbon
-Higher melting point, animal origin
Unsaturated:
-One or more double bonds
-Low melting point, plant origin
115
What are monounsaturated and polyunsaturated triglycerides
Monounsaturated: Fatty acids with one double bond
Polyunsaturated: Fatty acids with more than one double bond
116
What are cis and trans fatty acids?
Cis fatty acid:
-most naturally occurring unsaturated fatty acids have double bonds with a cis configuration
Trans fatty acid:
-fats that are partially hydrogenated (not natural)
-linked to elevated levels of low-density lipoprotein (LDL) ‘’bad cholestorol’’ and lowered levels of high-density lipoprotein (HDL) ‘’good cholesterol). (This condition is thought to be associated with an increased risk for coronary heart disease)
117
What are phospholipids?
The molecule that composes the membranes of the cell (outer and inner membranes)
118
What are phospholipids composed of? (And explain their characteristics)
1) Phosphate group: The charged polar ‘’head’’ usually had a charged organic molecule linked to it, such as choline, ethanolamine, or the amino acid serine. It’s **hydrophilic**!
2)Glycerol: 3-carbon alcohol, in which each carbon bears a hydroxyl group (—OH). Glycerol forms the backbone of the phospholipid molecule.
3) Fatty acids: Two fatty acids (hydrocarbon chains) attached to the glycerol backbone. The nonpolar ‘’tails’’ (—CH) make the fatty **hydrophobic** (afraid of water)
119
Phospholipids are amphipathic, which means…
They are both hydrophilic and hydrophobic
Lipid head loves water (hydrophilic)
Lipid tail is scared of water (hydrophobic)
120
What are micelles?
Lipid molecules orient with polar (hydrophilic) heads toward water and nonpolar (hydrophobic) tails away from water
121
Due to its amphipathic property, phospholipids can create…
Bilayers
122
How does the saturation of fatty acids affect its structure?
Saturated fatty acids have no double bonds and make the tail of the phospholipids straight
Unsaturated fatty acids have double bonds between carbon atoms, which bend/kink in the fatty acids tails.
As a result, there is less packing between the fatty acid tails. This makes the plasma membrane fluid
123
What are steroids?
They are composed of 4 carbon rings
124
What is the function of steroids?
-Chemical signalling (hormones)
-Have an impact on fluidity of plasma membrane
125
What affects plasma membrane fluidity?
-Presence of cholesterol (high cholesterol makes it less fluid)
-Temperature (at body temp. Lower membrane fluidity, at lower temp. increase membrane fluidity (so that it doesn’t solidify))
126
When β glucose forms a polymer, it creates…
Cellulose
127
Name some characteristics of fatty acids
- The hydrocarbon chains of fatty acids vary in length (most common are even-numbered chains of 14-20 carbons)
- The three fatty acids of a triglyceride are often very different from one another
- The many C-H bonds of fats serve as a form of long-term energy storage
128
What are the different functions of nucleic acids?
- Storing genetic information (DNA)
- Structural/catalytic function (r-RNA)
- Directing the synthesis of proteins (m-RNA, t-RNA)
- Serves as energy reaction molecules (ATP, NAD, FAD)
129
What are the 3 types of nucleic acids?
1) DNA
2) Ribonucleic acid
3) Energy reaction
130
What are the types of ribonucleic acid (RNA)
-Messenger ribonucleic acid(m-RNA)
-Transfer ribonucleic acid (t-RNA)
-Ribosomal ribonucleic acid (r-RNA)
131
What are the types of energy reaction nucleic acids?
-Adenosine triphosphate (ATP)
-Nicotinamide adenine dinucleotide (NAD)
-Flavin adenine dinucleotide (FAD)
132
What are nucleic acids monomers and polymers called?
Monomers: nucleotides
Polymers: nucleic acids
133
What is the structure of a nucleic acid?
- Phosphate group
- Pentose sugar (Ribose: OH in C-2 (RNA) or Deoxyribose: H in C-2 (DNA))
- Nitrogenous base
134
Characteristics of the nucleic acids backbone
-Phosphate group + sugar
-Linked together by phosphodiester bonds
- Links are made on carbon C-5 and C-3 of the sugar. This gives the direction of the DNA 5’ to 3’.
135
How is the synthesis of DNA polymer (polynucleotide) done?
By polymerase enzyme which adds nucleotides, one by one,only to the free hydroxyl 3’ end (OH) of a growing DNA strand (5’-> 3’)
136
Nitrogenous bases include:
-Purines: Adenine (A) and Guanine (G)
-Pyrimidines: Cytosine (C), Thymine (T) and Uracil (U (only In RNA))
137
What is the function of DNA?
Store the genetic information (ex.: to make protein)
138
What is a double helix?
Two polynucleotide strands connected by hydrogen bonds
139
What are the complementary base-paring rules?
-Adenine (A) with Thymine (T) (2x H bonds)
-Guanine (G) with Cytosine (C) (3x H bonds)
140
What is DNA’s secondary structure?
The double helix
141
What is the difference between RNA and DNA
-RNA contains ribose sugar instead of deoxyribose
-Includes to the base uracil instead of thymine
-Is a single polynucleotide strand
142
What are the functions of RNA within the cell?
1) Messenger RNA (m-RNA): transfers information from DNA to ribosome
2) Ribosomal RNA (r-RNA): structural part of the ribosome and have catalytic function
3) Transfer RNA (t-RNA): carries amino acids to the ribosome
143
What is Ribosomal RNA?
The structural part of the ribosome and has catalytic functions
144
What are the subunits of ribosome composed of?
Proteins and rRNA
145
What is Adenosine triphosphate (ATP)
The primary energy currency of the cell
146
What is nicotinamide adenine dinucleotide (NAD)
Electron carriers for many cellular reactions
147
What is flavin adenine dinucleotide (FAD)
Electron carriers for many cellular reactions
148
What are the characteristics of amino acids?
-Organic molecule
-Has an amino group
-Has a carboxyl group
-Single hydrogen
-Has a central alpha carbon where there is a side chain (R).
149
What allows for the formation of different amino acids?
The presence of different side chains (R), with different functional groups
150
How many common amino acids are there?
20
151
What are the characteristics of non-polar amino acids?
-Often have R groups that contain methyl as a functional group
-Hydrophobic and thus arrange themselves away from water in aqueous solutions
152
What are the characteristics of polar uncharged amino acids?
-Have R groups that contain oxygen under a hydroxyl or carbonyl functional group
- Tend to make hydrogen bonds between electronegative elements (such as oxygen) and hydrogen
- Are hydrophilic
153
What are the characteristics of charged amino acids?
-Have R groups that contain acids or bases that can ionize
- Charged R group of amino acids can interact and create ionic bonds with each other
154
What are the characteristics of aromatic amino acids?
-Have R groups that contain an organic (carbon) ring with alternating single and double bonds These are non-polar
-Non-polar amino acids are hydrophobic and thus in aqueous solutions they tend to arrange themselves away from water molecules
155
What is special about the amino acid methionine
Is often the first amino acid in a chain of amino acids
156
What is special about the amino acids Proline and Cysteine?
Proline: causes kinks in chains
Cysteine: links chains together
157
What is special about the amino acid cysteine?
-Contains a R group with a sulfhydryl functional group, which links chains together to make disulfide bridges
158
What are monomers and polymers of amino acids?
Monomers: amino acids
Polymers: polypeptides composed of monomers of unbranched amino
159
What are proteins made up of?
One or more polypeptides
-They can only be called a protein if the polypeptides have a function
160
True or false? The combination of 20 different amino acids is enough to make almost all the proteins in an organism?
True
161
How are amino acids joined?
Dehydration synthesis
162
How are peptide bonds formed?
Between the amino end and carboxyl end of two adjacent amino acids
163
What are the four levels of structure for amino acids?
1) Primary structure: sequence of amino acids
2) Secondary structure: interaction of atoms in the peptide backbone
3) Tertiary structure: 3D structures form by the interaction between the side chains (R) of the other amino acids and also with the environment
4) Quartenary structure: arrangement of two or more polypeptide chains in a functional protein
164
What are characteristics of the secondary structure of amino acids?
-Hydrogen bonds between amino acids of the backbone (not the R groups)
-Only the H from the amine and O atoms from the carbonyl groups of the backbone participate in the Hydrogen bonds
165
What are the two structures of interaction of atoms in the peptide backbone?
-Alpha helix: coiled spiral
-Beta pleated sheet: planar structure
166
What are beta pleated sheets always composed of?
A minimum of 2 or more beta pleated strands
167
One polypeptide with a _________ structure can form a functioning protein.
Tertiary
168
What are motifs?
The similar structures of dissimilar proteins (a.k.a super-secondary structure)
169
What are the 3 different motifs?
1) Beta-Alpha-Beta motif
2) Helix-turn-helix
3) Beta barrel
170
What is the beta-alpha-beta motif?
Creates a fold or crease at the core of nucleotide-binding sites in a wide variety of proteins
171
What is the helix-turn-helix motif?
Consists of two alpha helices separated by a bend. This motif is important because many proteins use it to bind to the DNA double helix
172
What is the beta barrel motif?
Beta sheet folded around to form a tube. Are involved in membrane transport
173
What are motifs useful for?
Determining the function of unknown protein
174
What are domains for amino acids?
-Functional units within a larger structure
-Substructure within the tertiary structure of a protein
-Most proteins are made up of multiple domains that perform different parts of the protein’s function. In many cases, these domains can be physically separated
175
What are the protein functions? (6)
1) Enzyme catalysis - biological catalysts that facilitate specific chemical reactions
2) Defence - proteins use their shapes to ‘’recognize’’ foreign microbes and cancer cells. These cell-surface receptors form the core of the body’s immune systems
3) Transport - A variety of proteins transport small molecules and ions
4) Support - protein fibres play structural roles. These fibres include keratin in hair, fibrin in blood clots, and collagen
5) Motion - Muscles contract through to sliding motion f two protein filaments: actin and myosin
6) Regulation - Small proteins called hormones serve as intercellular messengers in animals
176
What environmental factors can change the structure and function of proteins?
-Temperature: since the function of a protein depends on is 3D shape, the function of the protein will be altered if it is outside its nominal temperature range
-pH: affects ionic bonds and hydrogen bonds and thus have an impact on the structure of the protein
-Denaturation Protein: When environmental conditions exceed the limitations of a protein, the secondary, tertiary and quaternary bonds are broken. If the change is extreme, denaturation results from degradation of these bonds, the protein will no longer function and the damage is permanent
177
What is keratin and what is its characteristics?
-Structural protein for hair, wool, feathers, nails, scales, hooves, horns, skin
-Very strong and water insoluble
-Long alpha helix with hydrophobic amino acids
-Disulfide bonds, more S-S bonds the harder the structure
-Permanent wave (perm), is made by the reduction of disulfide bonds and generation of new disulfide bonds
