1
Q
What are the four major classes of biomolecules?
A
- Proteins
- Nucleic acids
- Lipids
- Carbohydrates
2
Q
What is the first reason why a carbohydrate is considered an important biomolecule?
A
Energy stores (starch in plants, glycogen in animals), fuels and metabolic intermediates
3
Q
What is the second reason carbohydrates are considered important biomolecules?
A
Important structural elements of nucleic acids, cell walls
4
Q
What is the third reason why carbohydrates are considered important biomolecules?
A
Covalently linked to many proteins (glycoproteins) and lipids (glycolipids) at organelle and cell surfaces
–important for interactions (increased interactions with water)
5
Q
The majority of carbohydrates are what type of functional groups and why do those groups matter?
A
- Polyhydroxyl aldehydes
- Ketones
Matters because carbonyl and hydroxyl groups dominates
6
Q
What is a monosaccharide and what does it consist of?
A
- A carbohydrate
- Aldose and ketose sugars
- Various isomers
7
Q
What is a monosaccharide used for and give example
A
Identify the anomeric carbon and the reducing end
Ex: glucose (blood sugar)
8
Q
What is a disaccharide and give an example
A
- Carbohydrate
- Two sugars are joined by an O-glycosidic bond (often involves one or more anomeric carbons)
Ex: sucrose (table sugar)
9
Q
What is a polysaccharide and give examples
A
- Carbohydrate
Ex: glycogen, starch, cellulose, glycosylated proteins
10
Q
What suffic is added to a molecule that is a carbohydrate
A
”–ose” like ketose or aldose
11
Q
When naming monosaccharides, what does tri, tert, and pent refer to?
A
Indicates the number of carbons
Ex: aldotriose or ketotriose
12
Q
What is an aldose
A
- Contains an aldehyde group at 3-6 C atoms with multiple asymmetric centers
13
Q
What is an enantiomer?
A
Non superimposable mirror images of each other such as D- or L- glucose
–perfect mirror images such as D vs L
14
Q
How do you determine the enatiomeric configuration for an aldehyde group?
A
The asymmetric C center furthest from the aldehyde group determines D or L configuration
15
Q
What is an epimer?
A
Isomers differing at a single asymmetric center
–are diastereomers
–includes isomers that are anomers
16
Q
What is a ketose?
A
Contains a keto group on one end of 3-6 C atoms with multiple asymmetric centers
17
Q
What is a diastereomer?
A
Isomers with variations in asymmetric carbon(s) but are not mirror images
18
Q
What are the two types of cyclized monosaccharides and their differences?
A
- Pyranose (6 membered ring)
–2 possible anomeric forms (alpha, beta) - Furanose (5 membered ring)
19
Q
What is a hemiacetal?
A
When molecules containing a hydroxyl group and a carbonyl group cyclize to form
20
Q
How does an aqueous solution affect a ring structure?
A
The ring can open and close, the open chain and ringer anomers are in equilibrium with each other
21
Q
What is the difference between an alpha anomer and a beta anomer?
A
Alpha (OH is pointed down on anomeric carbon)
Beta (OH pointed up on anomeric carbon)
22
Q
What is an anomeric carbon essentially?
A
It’s the carbonyl C from the open chain that is covalently bonded to two different oxygen atoms in the ring form
–> an ether oxygen and an alcohol group
23
Q
What are some common monosaccharides and what functional group do they form?
A
- D glucose
- D ribose
- 2 deoxyribose
–all form various polysaccharides or exist as the carbohydrate component of various biomolecules
–Each of these three are a ring form of aldoses
24
Q
What is the reducing end of a carbohydrate?
A
- Has a free OH on the anomeric carbon
–free OH group can easily reduce Cu++ due to free aldehyde group in open chain form but only if the OH was free and not involved with any other bond
25
When can it not be a reducing end?
If the anomeric C is involved in a glycosidic bond to something, it will not have a the free reactive OH and it can not be a reducing end
26
If all aldoses and ketoses have an anomeric C, will it also always have a reducing end?
No, not all will have a reducing end. Just some
27
What are some additional things to note about disaccharides?
1. Bonds can be alpha or beta and are numbered for the participating C atom from each sugar
2. Most carbohydrates have both a reducing and non reducing end (not all)
28
Most carbohydrates have both reducing and non reducing end. What is an exception?
Sucrose -- it's a non reducing sugar
--Both anomeric (carbonyl) carbon atoms are in glycosidic linkage to each other ("head to head")
29
What types of glycosidic bonds should you be familiar with?
1. Sucrose
alpha Glucose (1-->2) beta Fructose
2. Lactose
Beta Galactose (1-->4) alpha glucose
3. Maltose
alpha Glucose (1-->4) alpha glucose
**all three are dissaccharides
30
Where are the three familiar glycosidic bonds hydrolyzed and by what?
Hydrolyzed by sucrase, lactase, and maltase (enzymes) in intestinal microvilli
31
What causes lactose intolerance?
Lack of lactase enzyme
32
What is the importance of polysaccharides?
Glycogen, starch, and dextran are important mobilizable stores of glucose
33
What are important things to note about glycogen and starch?
1. The alpha-1,4 linked main chain tends to coil into a hollow helix
2. Glycogen has a branch about every 10 glucose units; starch has fewer branches at about every 30 units
34
What happens when glycogen and starch are mobilized?
They're hydrolyzed by enzymes that work from the man non-reducing ends
--there is only one non reducing end (but no reducing because it is bound to a protein)
35
What's a type of polysaccharide in plants and how does it differ from other polysaccharides?
Cellulose
1. It is an unbranched beta-1,4 linked chain
2. The chains are straight (favors its structural role)
3. H bonds within and between adjacent chains, making it strong and water insoluble
36
What are amino sugars?
When an Amine group replaces the OH group
37
What are the common amino sugars found in nature?
1. D-glucosamine
2. D-mannosamine
3. D-galactosamine
38
What is N-Acetyl-D-glucosamine?
A component of many polysaccharides, including chitin, the hard shell like exoskeleton of crustaceans and shellfish
39
What are glycoproteins?
Carbohydrates attached to integral membrane proteins and many secreted proteins (decreases hydrophobicity)
**either N-linked to Asparagine or O-linked to Serine or threonine
40
What is glycosylation?
The addition of sugars to oxygen or nitrogen
41
What is Erythropoietin (EPO)?
1. Glycoprotein found in serum
2. Secreted by kidneys
3. Stimulates production of red blood cells
42
What is EPO commonly used for?
1. Recombinant EPO used to treat anemias
2. Endurance athletes take EPO to increase oxygen carrying capacity
43
What is another example of glycoprotein?
Human blood types -- short carboydrate chains are attached to proteins (Forming glycoproteins) on the surface of red blood cells
44
Are lipids water insoluble or water soluble biomolecules?
Insoluble
45
What are several functions of lipids?
1. Fuel
2. Energy stores
3. Signal molecules
4. Membrane components
46
Lipids are...
Amphipathic -- mainly hydrophobic with a hydrophilic region
47
What are the 3 types of membrane lipids?
1. Phospholipids
2. Glycolipids
3. Cholesterol
48
What are fatty acids?
1. Major constituent of membrane lipids
2. Long hydrocarbon chains with a terminal carboxyl group (C-1 carbon)
3. Exists in saturated, unsaturated cis/trans forms
49
What are the hydrophilic and hydrophobic parts of a fatty acid?
1. The C-1 carbon (COO-) is hydrophilic
2. The rest of the chain is hydrophobic
50
What is a saturated fatty acid
A fatty acid that contains the maximum number of hydrogens
51
What are unsaturated fatty acids?
Naturally occurring double bonds in fatty acids
--they're almost always cis
--gives the chain a bend
52
What are the two "ends" of a fatty acid and how are they different?
1. Delta C end (C-1) --> polar end
2. Omega C end --> nonpolar, hydrophobic end (at the end of the chain)
53
In regards to fatty acid nomenclature, what does 18:1 (cis-triangle9) mean?
18 carbons, 1 double bond, double bond starts on C-9 and the double bond is cis
54
What is the importance of an omega 3 fatty acid?
Protects against heart disease and cannot be synthesized -- must be obtained from the diet
55
What are some physiological roles of fatty acids?
1. Building blocks of membrane lipids: phospholipids and glycolipids
2. Covalent modification on many membrane proteins (lipoproteins)
3. Derivates serve as hormones and intracellular secondary messengers
4. Fuel molecules storing excess energy
56
What is an example of a fatty acid that fuels molecules storing excess energy
Triacylglycerols (also called neutral fats or triglycerides) -- storage lipids
--where R1, R2, and R3 are fatty acids covalently bonded to a glycerol core by a terminal carboxyl
--also serve as insulation and padding
57
Lipids are classified into how many classes and what are they?
1. Triacylglycerols
2. Waxes
3. Phosphoacylglycerols
4. Sphingolipids
5. Glycolipids
6. Sterols
58
How are triacylglycerols formed?
Formed by a process called esterification of long fatty chain fatty acids and glycerol
Carboxylic acid + alcohol --> ester + water
59
Describe waxes
1. Coat plant stems, fruit
2. Found on skin, fur
3. Formed by a process called esterification of long chain fatty acids and long chain alcohols
Carboxylic acid + alcohol --> ester + water
60
What does a phosphoacylglycerol consist of?
Consists of glycerol (3 carbons) covalently linked to two fatty acids [nonpolar, hydrophobic end] (by their C-1 carbon) and to a polar non-fat component, phosphate linked to an alcohol
61
What are some additional facts about phosphoacylglycerols?
1. Abundant in all membranes
2. Are built on a 3 carbon molecule, glycerol
3. Polar end formed from a phosphoester linkage between phosphate adn the hydroxyl of glycerol
4. Fatty acids are covalently linked to glycerol through esterification
62
What are some examples of common phosphoglycerides?
1. Phosphatidyl serine
2. Phosphatidyl ethanolamine
3. Phosphatidyl choline
4. Phosphatidyl inositol
63
What doe spingolipids consist of?
Consist of sphingosine (an amino alcohol) covalently linked to one fatty acid (at the C2 carbon) and to a phosphate attached polar group
--fatty acid attached to amine group
--polar group attached to hydroxyl group farthest from the chain
64
What are some additional things to note about sphingo lipids?
1. The phosphoric acid component is esterified to the amino alcohol
2. Found in cell membranes
65
What is an example of a spingolipid?
1. Spingomyelin -- makes up the white matter of the myelin sheath that surrounds the nerve cells
66
What do glycolipids consist of?
Contain a carbyohydrate -- there is a sugar (glucose or galactose) instead of a phosphate ester at the polar end of the lipid
--Contains a sphingosine core
67
Where are glycolipids found?
They are always on the extracellular membrane surface (recall membranes are asymmetric)
68
What are steroid?
Molecules derived from cholesterol
--structurally different from phospholipids and glycolipids but fits beside them in membranes and has roles in membrane structure
69
What are some additional things to note about steroid?
1. The -OH is the polar end
2. Serves a precursor for the synthesis of the steroid hormones (i.e estrogen, testosterone) and bile acids
3. Cholesterol is also amphipathic
70
What are some functions of a membrane?
1. Barrier that define cells and divide cells into compartments
2. Contain specific channels and pumps to traffic in/out
3. Contain receptors to detect external signals (and may generate signals)
4. Are sites of some energy metabolism
5. High selective permeability
6. Controls flow of information between cells
71
What are some features of membranes?
1. Sheet like
2. Lipid bilayer (two layers of lipids with polar heads facing outwards)
3. Decorated with other biomolecules: lipids and proteins, with some carbohydrates attached on a surface
4. Are noncovalent assemblies -- assemble and are then held together by noncovalent interactions
5. Specific jobs done by various proteins -- mostly held in the membrane by noncovalent interactions
6. Asymmetric -- each side of membrane is different
7. Electricall polarized (negative inside membrane)
72
What are the noncovalent interactions of the lipid bilayer?
Bilayers are noncovalent structures stabilized by all 4 noncovalent interactions
1. Hydrophobic (biggest effect)
2. Van der Waals attraction between lipid tails
3. Electrostatic/hydrogen bends between polar head groups and with water
73
What affect do unsaturated fatty acids have on noncovalent bonds?
Disrupt the non covalent interactions, especially the Van der Waals attraction between lipid tails
74
How does the cis double bond affect melting point and fluidity?
Interferes with FA stacking in membranes, decreases rigidity, decrease melting point and increasing fluidity
Increase: cis double bond, fluidity
Decrease: rigidity and melting point
75
What additional things are there to note about cis unsaturation?
1. This configuration has the greatest impact on membrane fluidity
2. Cis is naturally occuring in dietary fats
**especially important in microorganisms where fatty acid composition is dynamic and adaptable to habit/climate
76
What is the fluid mosaic?
1. Essential to membrane function and cell survival
2. Lipids and many proteins diffuse in the plane of the membrane (a 2 D solution)
77
What are some additional things to note about the fluid mosaic>
1. Lipids move at ~2 micrometer/sec
2. Proteins vary greatly in mobility -- some are anchored to intracellular structures
3. Membrane proteins typically don't flip flop; lipids do so very slowly (membrane asymmetry is long lasting)
--lateral diffusion = rapid
--transverse diffusion (flip flop) = slow
78
How is it possible for membranes to be asymmetric?
Absence of flip flop diffusion makes it possible for membranes to be asymmetric
79
What does an asymmetric membrane entail?
1. Different lipid compositions on inside and outside
2. Different peripheral proteins and different ends of integral proteins on inside and outside
3. Carbohydrates (glycolipids) only found on the outside of plasma membranes, phosphorylation sites on the inside
80
Why are membrane proteins important?
1. Account for 18-75% of the membrane and are responsible for much of the membrane activity (i.e. pumps, gated channels, receptors, enzymes)
2. Proteins associate with membranes in three different ways -- peripheral, integral, anchored
81
What are integral proteins?
1. Membrane spanning proteins with nonpolar amino acids contacting the fatty acid tails ("inside out" compared to aqueous, soluble proteins)
2. Hydrophobic interacitons beetween hydrophobic amino acids of the protein and the fatty acyl chains of the bilayer interior
**essentially channel inserted inside bilayer
82
What are peripheral proteins?
1. Bind to surface of integral or anchored proteins
2. Some interaction with polar heads of membrane lipids
3. Associations via ionic interactions and hydrogen bonds between charged and polar side chains of the protein and polar head groups of membrane lipids
83
What are anchored proteins?
Attached to the membrane without cross it
84
How does aspirin work?
1. Cox enzyme substrate is a fatty acid (arachiodonic acid) that comes to the enzyme through the hydrophobic membrane
2. Aspirin inhibits cox enzyme by transferring an acetyl group to Ser530 (irreversible inhibitor, covalent modification of enzyme active site)
85
What is an example of an anchor protein
Prostaglandin H2 synthase (COX enzyme)
--produces prostglandic H2 which mediates: inflammation, regulates gastric acid secretion, fever, platelet function, etc
86
What is simple diffusion?
Molecules which can pass directly through the membrane, down their concentration gradient
--molecules spontaneously move from region of high concentration to one of lower concentration (2nd law thermo)
87
What are the few molecules that can pass through the lipid bilayer through simple diffusion?
1. Oxygen
2. Water
3. Lipophilic molecules (cholesterol, estrogen, testpsterone, etc)
88
How does facilitated diffusion work?
1. Specific protein channels (membrane proteins) allow polar molecules and ions pass through membranes
2. Channels have a hydrophobic surface with interacts with the fatty acid chains and cholesterol in the lipid bilayer
3. Channel is lined with hydrophilic amino acids
4. Also known as passive transport
**facilitated = needs channel protein
89
What is active transport?
The movement of molecules or ions against its concentration gradient
--requires energy from another source
--membrane proteins which perform this function are called protein pumps
90
What is an example of active transport?
Na+K+ pump of animal cells )ion pump
--Plasma membrane with this pump generates ion concentration gradients
--3 Na out/2K in
--energy input from ATP hydrolysis to form Na ion gradient
--Na can repeatedly enter/exit cell
91
What are cotransporters?
A type of active transport -- thermodynamically unfavorable flow of one molecule up its concentration gradient is coupled to the favorable flop of a different molecule down its concentration gradient
92
What are the two types of cotransporters and whats the difference?
1. Antiporter -- opposite directions
2. Symporter -- same direction
93
What is an example of a cotransporter?
Lactose Permease of E.coli -- H+ gradient across membrane, high concentration on outside of cell. H+ gradient drives uptake of lactose against its concentration gradient using a symporter
94
What is signal transduction?
A cell needs to respond to changes in extracellular signals to help the organism adjust to changing conditions
--it begins with signal to a receptor and ends with a change in cellular function
95
What are the key features of signal transduction?
1. Release of primary messenger
2. Reception of the primary messenger
3. Delivery of the message inside the cell by a second messenger
4. Activation of effectors that directly alter the physiological response
5. Termination of signal
96
What is an example of releasing primary messenger?
A wound, digested meal triggers the release of a hormone, neurotransmitter, etc.
97
What does reception of the primary messenger involve?
Most primary messengers don't enter the cell --> they bind to receptor, which transmit the info to the inside of the cell
--the interaction of primary messenger (ligand) with a receptor results in a change in conformation
98
What does the delivery of the message inside the cell involve?
Small molecules relay info from receptor ligand complexes
--Second messengers can amplify the signal
99
What is the point of activation of effectors?
Ultimate effect of a signaling pathway is to activate (or inhibit) a pump, enzyme, transcription factor
100
What does termination of signal mean?
After the cell has completed a response to a signal, it must have a way of turning off the initial signal
101
What are some examples of second messengers?
1. cAMP, cGMP
2. Calcium ion
3. Inositol 1,4,5-triphosphate (IP3)
4. Diacylglycerol (DAG)
102
What are G-protein coupled receptors?
1. Also known as seven transmembrane receptors (7TM)
2. Integral plasma membrane protein
3. Contains 7 alpha helical transmembrane regions
--approx 1000 known GPCRs
--more than 50% of therapeutic drugs target this class of receptirs
103
Where is the n terminus and c terminus of a GPCR?
1. N terminus -- extracellular
2. C terminus -- intracellular
104
What do GPCRs mainly do?
Bind to a variety of signal molecules (i.e hormones, tastants, neurotransmitters)
105
What are some examples of signal molecules?
1. Photons
2. Histamine
3. Serotonin
5. Epinephrine
106
What is epinephrine
1. A neurotransmitter
2. Part of the "flight/flight" response
3. Relaxes muscles in the airway
4. Dilates pupils
5. Stimulates glycolysis in the muscle
107
What makes something a G protein?
A receptor is a G protein coupled when it binds to a G protein on its cytoplasmic surface
--It is a G protein because it binds a guanyl nucleotides
--3 subunits (alpha, beta, gamma)
108
What is the importance of the alpha subunit in a G protein?
Binds to GDP and GTP
109
What happens when G protein binds with epinephrine?
Causes a conformational change in the beta-adrenergic receptor, including the cytoplasmic loops
110
What are the main results of conformational change?
1. Release of GDP and binding of GTP
2. Release of the G protein and dissociation of the alpha subunit from the beta-gamma subunits
111
What is the significance of the subunit bound to the GTP?
It is now considered "on" and becomes the molecule that will continue the ephinephrine signal on the inside of the cell
112
What's an important thing to note about a single binding of a primary messenger?
Single binding of a primary messenger to its receptor can generate many signaling molecules, amplifying the response
113
What does releasing the GTP bound G protein do?
Allows for binding of another GDP bound G protein -- this can repeat over and over
114
What is adenylate cyclase?
1. Enzyme that converts ATP to cyclic AMP (cAMP)
2. Is an integral membrane protein containing 12 helices
3. Contains 2 cytoplasmic domains; the catalytic part of the enzyme
115
What is the result of amplifying the signal by adenylate cyclase?
the binding of GTP to adenylate cyclase (or the binding of epinephrine to GPCR) increases the intracellular concentration of cAMP
116
What does cAMP do?
Cyclic AMP activates protein Kinase A (PKA)
117
What is a kinase?
An enzyme that phosphorylates proteins
118
What is protein kinase A specifically?
A multipurpose kinase, reversibly activated by binding of cAMP
Activates many proteins by phosphorylation
119
How is protein kinase A regulated?
Regulated by structural change induced by cAMP binding
120
Does the activation of PKA by cAMP amplify the signal? Why?
NO -- for every 4 cAMP molecules, 2 molecules of catalytic PKA are activated so no amplification of the response
121
What is the effect of epinephrine in liver cells?
Increase glucose synthesis during exercise
122
How is the signal turned off?
1. An enzyme can be deactivated
2. Dissociated of the ligand from the receptor
123
What is an example of an enzyme being deactivated and its process?
Ex: Adenylate cyclase
Alpha subunit has intrinsic GTPase activity (convert GTP to GDP)
This releases the alpha subunit from adenylate cyclase
Alpha subunit reforms an inactive heterotrimer with beta-gamma
Results on signal transduction pathway being "turned off"
124
What is a result of a defect in signal transduction pathways? Give example
Many diseases, especially cancer, are result of defects in signal transduction pathways
Ex: cholera toxin
125
What is cholera and how is it caused?
A large volume loss of electrolytes and fluid from intestines caused by cholera toxin. It's secreted by the intestinal bacterium vibrio cholerae
Mainly comes from contaminated water supply
126
What is the significance of intestinal epithelial cells?
Intestinal cells regulate the uptake and release of water and electrolytes from the lumen of the intestine
127
Sometimes the body needs to get rid of water and electrolytes. How will it do that?
A GPCR is activated and eventually activated PKA phosphorylates a chloride channel which causes it to open
128
What does the concentration gradient of the lumen of the intestine look like?
1. Chloride moves down its concentration gradient out of the cell
2. Sodium and water move into the lumen for charge and osmolar equilibrium
129
How many domains does cholera toxin have and what is the significance of one of them?
1. Two
2. the A domain (has enzymatic activity) enters the cell and covalently modifies the GTP bound G protein alpha subunit
--this modification traps the alpha subunit into the active conformation
130
What are karyotypes?
1. Exact copies of DNA inside most cells within your body
2. 46 chromosomes inside each cell
3. Basis for inheritance/blueprint of the organism
131
What is the composition of DNA?
A linear polymer of 4 different units each consisting of the same sugar-phosphate group and one of 4 different bases attached: A, C, G, T
132
What are the groups that the nucleotide bases are classified as and in what group?
1. Purines: A, G
2. Pyrimidines: C, T
133
What are nucleotides?
1. Monomers (i.e mononucleotides that form the strands of DNA)
2. 4 difference nucleotides in DNA
134
What are the four nucleotides in DNA?
1. 5'-dATP
2. 5'-dCTP
3. 5'-dGTP
4.5'-dTTP
135
How is the DNA strand formed?
1. Nucleotides linked by covalent bonds form a sugar phosphate DNA backbone (phosphate, sugar, phosphate, sugar, etc.)
--3',5' phosphodiester covalent linkage between nucleotides
2. The order of nitrogenous bases in the DNA strand is the DNA sequence
136
How does DNA have polarity?
DNA chains have directionality (polarity) with 5'-phosphate and 3'-OH ends
137
How are the two strands that form a double helix stabilized?
Stabilized by non-covalent interaction: hydrogen bonds form between two complementary DNA strands
**sequence of bases on one strand is restricted
138
Which base pair has the highest/strongest energy: AT or GC?
GC because it has 3 hydrogen bonds
**AT only has 2 hydrogen bonds
139
Are the bases inside the double helix hydrophobic or hydrophilic?
Hydrophobic
140
Are the phosphate ribose backbone on the outside hydrophobic or hydrophilic?
Hydrophilic
141
What are telomeres?
Long series of repeating (TTAGGG)n groups protect the ends of the chromosome from damage
142
What are centromeres?
Duplicated chromosomes bound at the center
143
What are genes and what percentage of DNA do they make up?
Protein coding portion of DNA (~2%)
144
What is the percentage of non coding DNA?
~98%
145
What is a DNA polymerase?
An enzyme that takes instruction from templates to replicate
146
What does DNA polymerase do?
Catalyze the formation of polynucleotides by the formation of covalent bonds between deoxy-mononucleotides with some requirements
147
What are the requirements for DNA polyermase to catalyze formation of polynucleotides
1. Substrate: dATP, dCTP, dGTP, dTTP
2. Mg++
3. A DNA template (single or double stranded)
4. Polynucleotide primer with 3'OH
5. New strand is formed in a 5' to 3' direction
148
In vivo, rather than a polynucleotide primer with an 3'OH, what is needed instead?
An RNA primer
149
How does the primer strand attach itself to the phosphate?
The free 3' OH of existing strand attacks the first phosphate of a new monomer, forming a phosphate diester bond
150
How is it possible for the primer strand to attach to the phosphate?
1. Coupling to another reaction
Energy released by DNA polymerase is hydrolyzed by pryophosphatase -- provides more energy to make DNA polymerization exergonic (releasing energy -- favorable)
151
In terms of base pair matching, how accurate is it and what happens if there is an error?
1. High fidelity so pretty accurate
2. Wrong base added, proof reading site on DNA polymerase hydrolyzes it off then tries again
152
What is the order of the flow of genetic info?
DNA --> transcription --> RNA --> translation --> protein
153
What does the RNA polymerase require?
1. Like DNA, four nucleotide triphosphates
2. Mg++
3. Template (does not require primer)
154
What is the result of the RNA polymerase "reading" the template?
Polymerizes the "message or mRNA" synthesis of the message, mRNA in 5 to 3 direction
155
What are important "players" in transcription?
1. Template DNA
2. RNA polymerization
3. Four NTPS
4. Mg
156
What is generated through transcription by RNA polymerase?
1. tRNA
2. rRNA
3. mRNA
4. snRNA (small nuclear)
5. miRNA (micro)
157
What is the genetic code?
Translation dictionary for RNA to amino acids
158
How are amino acids encoded and what is it called?
Encoded by groups of three nucleotides (codons)
159
Is there any overlapping or gaps between codons on the mRNA?
No
160
What is the start codon and how many stop codons?
1. Met - start codon
2. 3 stop codons
161
What should be noted about translation?
1. Occurs on ribosome (made of protein and rRNA)
2. Requires mRNA template
3. Translation start site (typically AUG codon in the mRNA)
4. Requires tRNA adaptor molecules representing 20 amino acids
5. Peptide bonds are formed between amino acids
6. Synthesis of protein
162
What's an important distinction between peptide bonds and phosphodiester bonds?
1. Phosphodiester is between nitrogenous bases
2. Peptide bonds are between amino acids
163
What is tRNA?
an adaptor between the mRNA codon and the amino acid
164
What is an anticodon?
A sequence on the tRNA and complementary to the codon (NOT a sequence found on genetic code tables)
165
What's an important thing to note about codons?
Codons are sequences on mRNA not tRNA
166
Is there a tRNA for stop codons?
Nope. They have a protein called release factors that recognize the stop codons
OSU
flashcards
Decks in class (24)
# Cards
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IDS30
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IDS 230
-
Ch 1-3 Microbio70
-
Ch 4-5 Microbio49
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Lab Practical 1 Prep71
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Micro Exam 2109
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Lecture 694
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Lab Practical 2117
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Exam 3 Microbio123
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Animal Bio exam 346
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Exam 4 Micro85
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Bio Practical 395
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Bio Final1
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Micro final91
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Micro Final Sec 2120
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Micro Final Sec 473
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Micro Final Sec 648
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Biochem Exam 1105
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Biochem 2126
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Biochem 3166
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Biochem 4177
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Glycolysis1
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Pathways1
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Biochem 418
