Science Team Content Testing Flashcards
Test Deck (177 cards)
2
Q
Testing . . .
A
4 . . 5. . . 6
3
Q
Please define the following term:
Henry’s Law
A
At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.
Pgas=kHc
P= partial pressure of the solute in the gas
kH= constant with dimensions of pressure divided by concentration.
c= concentration of the solute
4
Q
Which gases diffuse in and out of blood during respiration?
A
- Oxygen diffuses into the blood
- Carbon dioxide diffuses out of the blood
5
Q
Please identify and explain the following process depicted by the image:
A
The process depicted is inhalation. When one inhales:
- The diaphragm contracts and moves downward
- The rib cage expands outward
- The lungs expand due to the resulting increase in volume and decrease in pressure of the chest cavity
- Air is drawn in as the decrease in pressure falls below the atmospheric pressure
6
Q
A
The three brain structures that regulate respiration are: 1. Midbrain, 2. Medulla Oblongata, 3. Pons
All three make up the brainstem.
7
Q
Define Macrophage
A
A macrophage is type of white blood cell. Macrophages (Greek for “big eaters”) phagoctyose (engulf and digest) cellular debris and pathogens. They are found throughout the human body as either mobile cells that act throughout the lymphatic system or as stationary/fixed cells that act in high risk areas for microbial infection such as the alveolus of lungs, the liver, the spleen, bone, and connective tissue.
8
Q
Define differential pressure.
A
The difference between pressure inside the lung, called intrapulmonary pressure, and pressure outside the lung, called intrapleural pressure.
9
Q
How is surface tension created in the lungs?
A
The walls of the aveoli are coated with a thin layer of water, and the strong attraction between water molecules creates surface tension
10
Q
What potential problems could this surface tension lead to?
A
When exhalation occurs, the area between aveoli decreases, and therefore increases the strength of the surface tension. This could prevent another expansion of the aveoli (and lungs) and prevent further breathing.
11
Q
What does DNA stand for?
A
Deoxyribonucleic Acid
12
Q
DNA is a polymer of ________, which are held together by ________ bonds.
A
nucleotides; phosphodiester
13
Q
Label the 5’ end and the 3’ end of this single DNA strand.
A
The 3’ end carbon is attached to an -OH group and the 5’ end carbon is attached to a phosphate group.
14
Q
Describe what is meant by the antiparallel nature of DNA.
A
The two strands of DNA that make up the double helix run in opposite directions, one strand with a 5’ -> 3’ orientation and the other with a 3’ -> 5’ orientation.
15
Q
What are the three main parts of a nucleotide?
A
a phosphate group, a 5-carbon sugar, and a nitrogenous base
16
Q
Name the purines and pyrimidines.
A
The purines are adenine and guanine. The pyrimidines are cytosine and thymine.
17
Q
What is the difference in structure between purines and pyrimidines?
A
Purines are two ring structures while pyrimidines are single ring structures.
18
Q
Which nitrogenous base forms hydrogen bonds with adenine?
A
thymine
19
Q
Which nitrogenous base forms hydrogen bonds with guanine?
A
cytosine
20
Q
Which type of bond forms between the nitrogenous bases of two complementary DNA strands?
A
hydrogen bond
21
Q
How many hydrogen bonds form between adenine and thymine?
A
two hydrogen bonds
22
Q
How many hydrogen bonds form between guanine and cytosine?
A
three hydrogen bonds
23
Q
What is the central dogma of molecular biology?
A
DNA is transcribed to RNA which is translated to amino acids that make up a protein.
24
Q
Define DNA helicase.
A
an enzyme responsible for separating the two strands of a DNA double helix needed for initiation of DNA replication
25
What is the name of the enzyme responsible for adding deoxyribonucleotides to a newly created DNA strand during replication?
DNA polymerase
26
What does DNA polymerase require to get started?
DNA polymerase cannot begin adding nucleotides by itself. An RNA primer of approximately 10 ribonucleotides is required to which DNA polymerase can begin adding nucleotides.
27
In what direction does DNA polymerase read the parental strand?
3' -\> 5'
28
In what direction is the new complementary strand created by DNA polymerase?
5' -\> 3'
29
What is the difference between the leading strand and the lagging strand?
The leading strand is the newly synthesized strand of DNA being replicated continuously due to the complementary parental strand's 3' -\> 5' direction towards the replication fork. The lagging strand is the newly synthesized strand of DNA that is replicated in a series of fragments (Okazaki fragments) due to the complementary parental strand's 5' -\> 3' direction towards the replication fork.
30
Define **semiconservative** in terms of DNA replication.
The semiconservative nature of replication means that when a new double helix is created, it contains one strand from the original DNA, and one newly synthesized strand.
31
In the Bohr Model, what does the Hydrogen electron orbit?
Nucleus
32
In quantum mechanics, where does the Hydrogen electron exist?
In a spherical probability cloud around the nucleus.
33
In quantum mechanics, what does the principle quantum number, n, define?
The principle quantum number, n, defines what shell the electron is in.
34
As the principle quantum number, n, increases, the energy \_\_\_\_\_\_\_\_\_.
Increases
35
How many electrons per orbital?
2 Electrons
36
How many orbitals are there per shell?
n^2
37
How many electrons per shell?
2n^2
38
Electrons are naturally found in which state?
Ground State
39
To which state does an electron move when it absorbs energy?
Excited State
40
Which is higher in energy, the excited states or the ground state?
Excited States
41
Energy is ______ when a electron moves from excited to ground state.
Released
42
# Define:
Absorption Spectrum
The electromagnetic spectrum, broken by a specific pattern of dark lines or bands, observed when radiation traverses a particular absorbing medium. The absorption pattern is unique and can be used to identify the material.
43
# Define:
Emission Spectrum
The spectrum of bright lines, bands, or continuous radiation characteristic of and determined by a specific emitting substance subjected to a specific kind of excitation.
44
In quantum mechanics, how many orbitals can be found in the s shell?
One orbital.
45
In quantum mechanics, how many orbitals can be found in the p shell?
Three orbitals.
46
In quantum mechanics, how many orbitals can be found in the d shell?
Five orbitals.
47
In quantum mechanics, how many orbitals can be found in the f shell?
Seven orbitals.
48
In quantum mechanics, what does l symbolize?
l is the angular momentum quantum number. l ranges from 0 to n-1.
49
In quantum mechanics,what do the letters s,p,d,f symbolize?
The letters s,p,d,f symbolize the subshells.
50
In quantum mechanics, what is the maximum number of electrons found in an orbital?
Two electrons.
51
In quantum mechanics, for a given shell, higher subshells have ______ energy.
Higher.
52
In quantum mechanics,what does the letter m signify?
The letter m signify's the magnetic quantum number. m ranges from -1 to 1, including 0.
53
In quantum mechanics, what does the letter s signify?
The letter s signify's the spin quantum number. s is either -1/2 or 1/2.
54
In quantum mechanics, what is the shape of the s subshell?
Spherical.
55
In quantum mechanics, subshells are filled by placing electrons in the _____ subshell first.
Lowest.
56
What are the General Characteristics of Fungi?
Fungi are eukariotic chemoheterotrophic organisms that absorb food and nutrients through chitinous cell walls. They can be either unicellular (yeast) or multicellular (mold, mushrooms) and may reproduce either sexually or asexually
57
What are the general functions of the mycelium of fungi?
The mycelium:
- absorbs nutrients
- aids in decomposition of organic matter
- is involved in fungal growth and reproduction
58
Describe the asexual reproductive cycle of fungi
Asexual reproduction occurs in the sporangium found on the cellular walls of reproductive hyphae cells of the mycelium of fungi. Haploid spores (n) are formed in the sporangium by mitotic divisions and then released to germinate on a suitible substrate. Fungi may also undergo budding and fragmentation.
59
Describe the sexual reproductive cycle of fungi
Four distinct stages:
_Plasmogamy:_ the hyphae from two genetically distinct individuals from the same species fuse.
_The heterokaryotic stage:_ the fused hyphae contain two haploid nuclei (n).
_Karyogamy:_ The two haploid nuclei fuse into a diploid zygote (2n).
_Meiosis and Germination:_ the zygote undergoes mieosis and forms haploid spores that will germinate on a suitable substrate
60
Viruses are considered non-living because they...
- Lack organelles and a cytoplasm
- Do not respond to external stimuli
- Do not grow by increasing in size
- Are unable to undergo metabolic functions and instead replicate using the host's metabolic machinery
61
The capsid region of a virus may contain either _____ or _____ but not both.
DNA; RNA
62
Identify the following:
The image depicts a typical **bacteriophage**, with a capsid head region containing either single stranded or double stranded DNA or RNA and a protien tail region.
63
Compared to bacteria and animal cells viruses are _______ in size and additionally lack both a _______ and \_\_\_\_\_\_\_\_.
significantly smaller; cytoplasm; organelles
64
# Define:
Bacteriophage
A bacteriophage is a virus that infects bacteria recognizable by its distinct capsid head region and protien tail.
65
# Define:
Viral Envelope
A **viral envelope** is a bilayer lipid membrane that contains both viral and host protiens, encloses the capsid of some viruses, and plays a role in infection and pathogenisis.
66
Viruses can be classified in four general catergories based on whether they have…
DNA: **ssDNA** (single stranded) or **dsDNA** (double stranded)
RNA: **ssRNA** (single stranded) or **dsRNA** (double stranded)
67
A virus cannot perform its own metabolic functions, therefore it must ________ in order to reproduce.
utilize the metabolic machinery of the host cell
68
The six general stages in the viral life cycle are:
Adsorption
Penetration
Uncoating
Synthesis
Assembly
Release
69
Describe what occurs during the **adsorption stage** of the viral life cycle
During the adsorption stage the virus attaches itself to the membrane of a host cell. Viral attachment protiens recognize specific receptors on the outside of the cell, therefore only cells that have the appropriate receptors are suceptible to viral attack.
70
Identify the process occurring in the image below:
The image depicts the **adsorption stage** of the life cycle of an HIV virion. HIV is in the process of attaching to the CD4 receptor on the plasma membrane of a T-cell.
71
Describe what occurs during the **penetration stage** of the viral life cycle
During the penetration stage the virus infiltrates the host cell. Enveloped viruses may either fuse directly with the plasma membrane or enter using an endosome. Non-enveloped viruses may either cross the plasma membrane directly or be taken in by an endosome.
72
Define
Retrovirus
A retrovirus is an **RNA virus**, that uses the enzyme **reverse transcriptase** to transcribe viral RNA into DNA.
73
What is reverse transcriptase?
Reverse transcriptase is an enzyme used by retroviruses to convert their two RNA strands into DNA
74
Although many viruses exit from host cells by lysis, retroviruses belong to the category of viruses that do not and undergo _______ instead.
Why is this method utilized?
budding
Retroviruses, like other enveloped viruses, bud from the host cell in order to obtain the glycoprotien viral envelope from the host plasma membrane.
75
Write the orbital diagram for the element Flourine.
76
In quantum mechanics, what is the conventional notation for electronic structure?
77
# Define:
Aufbau's Principle
Aufbau's Principle:
shells / subshells of lower energy get filled first.
For example, 1s fills first, then 2s, then 2p ...etc. Review the exact order of energies because later on, the d subshells get filled after the s.
78
# Define:
Hund's Rule
Hund's Rule:
when you fill a subshell with more than 1 orbital (p, d, f), you first fill each orbital with a single electron and with the same spin
The reason for Hund's rule is that electron-electron repulsion in doubly occupied orbitals make them higher in energy than singly occupied orbitals.
79
# Define:
Pauli's Exclusion Principle
Pauli Exclusion Principle:
Two electrons in the same orbital must be of different spins.
80
What occurs during the transcription stage of the retroviral life cycle?
During the transcription stage, the provirus is transcribed by host RNA polymerase forming mRNA and retroviral RNA molecules. The mRNA is then translated by the host's metabolic machinery into glycoprotien and capsid components. The RNA and components are then assembled into capsids
81
The higher the effective nuclear charge for an electron, the _____ the ionization energy.
Higher
82
Alkali Metals have [number] valence electrons and [high/low] ionization energy.
Alkali Metals have _one_ valence electrons and _low_ ionization energy.
83
Halogens have _number_ valence electrons and _high/low_ electron affinity.
Halogens have _seven_ valence electrons and _high_ electron affinity.
84
Alkaline earth metals have _number_ valence electrons and _high/low_ ionizations energy.
Alkaline earth metals have_ two _valence electrons and _low_ ionizations energy.
85
Noble Gases have _number_ valence electrons and _high/low_ electron affinity and _high/low_ ionization energy.
Noble Gases have _eight_ valence electrons and _low_ electron affinity and _high_ ionization energy.
86
Why do transition metals have high conductivity?
Transition metals have a "sea of mobile electrons": free flowing (loosely bound) outer d electrons.
87
# Define:
Representative Element
Representative elements include the s block and the p block of the periodic table because they have no free flowing (loosely bound) outer d electrons.
88
What are the main chemical differences between metals and nonmetals?
_Metals_
1. Likes to lose electrons to gain a + oxidation state (good reducing agent).
2. Lower electronegativity - partially positive in a covalent bond with non-metal.
3. Forms basic oxides.
_Non-metals_
1. Likes to gain electrons to form a - oxidation state (good oxidizing agent).
2. Higher electronegativity - partially negative in a covalent bond with metal.
3. Forms acidic oxides.
89
# Define:
Oxygen Group
The group (column) that contains oxygen.
90
What are the main physical differences between metals and nonmetals?
_Metals_
1. Good conductor of heat and electricity
2. Malleable, ductile, luster, solid at room temp(except Hg)
_Non-metals_
1. Poor conductor of heat and electricity
2. Solid, liquid, or gas at room temp. Brittle if solid and without luster.
91
Which element is the most similar to Oxygen?
Sulfur
92
# Define:
Electron Affinity
Electron affinity is the amount of energy released when an atom gains an electron.
93
# Define:
Electronegativity
Electronegativity is how much an atom hordes electrons in a covalent bond.
94
Which enzyme is responsible for making repairs during DNA replication?
DNA polymerase proofreads as it adds nucleotides to new DNA strands. When a mismatched nucleotide is detected, DNA polymerase re replaces it with the correct nucleotide.
95
What is recombinant DNA?
DNA whose two DNA strands have been artificially recombined.
96
A __________ enzyme cuts a DNA strand at a specific nucleotide sequence that is usually palindromic.
restriction
97
Define sticky ends.
Sticky ends are complementary single stranded ends created by a restriction enzyme cut. A restriction enzyme will often cut a strand unevenly, creating sticky ends that can form base pairs with any DNA molecule that has a complementary sticky end.
98
_________ ends are those caused by a restriction enzyme that cuts a DNA strand straight across, leaving no uneven ends that can hybridize.
Blunt
99
Define hybridization.
Hybridization is the process by which separated strands of DNA will spontaneously bond with either their original complementary partner or any other complementary strand.
100
Which three kinds of double stranded combinations can be made from hybridization?
* DNA-DNA
* DNA-RNA
* RNA-RNA
101
Name the four main steps of the gene cloning process.
1. Cut human DNA and plasmid DNA with the same restriction enzyme.
2. Insert human DNA restriction fragment into plasmid by mixing them together.
3. Seal with DNA ligase.
4. Insert plasmid into bacteria, where replication occurs.
102
What use does an antibiotic resistant gene have during gene cloning?
Since the cloning process is not perfect, some bacteria will not have the desired plasmid. To get rid of this bacteria, an antibiotic resistant gene is necessary in desired plasmids. Bacteria that do not have the appropriate plasmid will be killed upon contact with the antibiotic, leaving only desired clones.
103
Which two specific genes must a bacterial plasmid contain to eliminate undesirable bacteria in the gene cloning process?
The lacZ gene and an antibiotic resistance gene
104
When active, what does the lacZ gene do?
An active lacZ gene allows bacteria to break down the sugar X-gal. When placed on a medium with X-gal, the active lacZ gene is indicated by blue.
105
What purpose does an inactivated lacZ gene have in the gene cloning process?
An inactivated lacZ gene containing the desired DNA fragment cannot break down the sugar X-gal. When the cloned bacteria is put on a medium with X-gal, the inactive lacZ gene does not change color (like active lacZ gene would).
106
The ________ gene allows for detection of desired DNA fragments while an _________ \_\_\_\_\_\_\_\_\_\_\_\_ gene allows for detection of desired vectors.
lacZ; antibiotic resistance
107
What does PCR stand for?
Polymerase Chain Reaction
108
Why is PCR more beneficial than simply gene cloning?
PCR is a much faster method of cloning.
109
What are the four main steps of PCR that can be repeated for several cycles?
1. Target DNA is denatured to separate the double stranded DNA template.
2. Many copies of two complementary DNA primers are mixed.
3. The solution is cooled so primers can hybridize with the single stranded templates.
4. Heat resistance polymerase is added to extend the primers.
110
Which three items must be mixed for PCR to take place?
target DNA, two RNA primers, and a heat resistance polymerase
111
What is the unit for rate and the rate constant, k?
* rate= Molarity/seconds (M/s)
* k= depends on the overall order of the reaction. k multiplied by the concentration of the reactants must have the same unit as rate
112
What is the difference between order of a reaction and overall order?
If Rate=k[A]m[B]n,
* order of reaction: the power to which the concentration of a species is raised in the rate law [m,n]
* overall order: the sum of the individual orders, or the exponents of the concentration variables in the rate law [ m+n]
113
What happens if the slow step in a multi-step reaction is not first?
An integrated rate law must be written.
114
Identify the different parts of a rate law:
Rate=K[A]m[B]n
for the reaction: 2A + B→C
* k= rate constant
* [A] and [B]= concentrations of the reactants, A and B
* m and n = order of reaction
115
Why do many reaction rates decrease over time?
Reactions occur as reactant molecules collide. Over time, in a reaction, the concentration of reactants decreases as they are consumed. Therefore, the number of collisions decreases and so the rate of reaction decreases.
116
Define: overall rate order
The sum of all exponents of the concentration variables in the rate law. A reaction can have an overall rate order of zero, one, or two.
117
In a zero order reaction, the rate is __________ of the reactant concentration.
Independent
118
Why is a rate law an empirical law?
Because the rate law for a reaction is experimentally determined and cannot be generally inferred from the chemical equation for the reaction. Therefore, the order of a reaction cannot be inferred from coefficients in the chemical reaction.
119
What does a negative reaction order imply?
A negative order implies that the concentration of the species appears in the denominator of the rate law. Therefore, increasing the concentration of that species,which is usually a product, slows down the reaction because the species participates in a reverse reaction.
120
121
Define: Half-life
The half-life is the time needed for a substance's concentration to fall to one-half its initial value. The greater the value of the rate constant, k, the shorter the half-life of the reaction.
122
Define: Integrate rate law
The integrated rate law gives the concentration of reactants or products at any time after the start of the reaction. The integrate rate law is different for each order of reaction.
123
Define: Reaction mechanism
A reaction mechanism is a sequence of elementary reactions describing the changes that are believed to take place as reactants are transformed into products.
124
# Define an intermediate and identify it in the reaction below:
Step 1: O3→O2+O
Step 2: O+O3→O2+O2
A reaction intermediate is a species that plays a role in a reaction, but does not appear in the overall chemical equation. An intermediate goes from being a products to a reactant.
The intermediate would be O.
125
Define: Molecularity
Molecularity is the number of reactant molecules taking part in a specified elementary reaction. Elementary reactions are classified according to their molecularity. A reaction can be unimolecular, bimolecule, or termolecular.
126
The rate law for an _________ reaction can be written from its chemical equation, but not for an ____________ reaction.
elementary; overall
127
How is the equilibrium constant related to the rate constant?
The equilibrium constant, K, for an elementary reaction, is equal to the ratio of its forward and reverse rate constants.
K=k/k'
128
As temperature is increased, the reaction rate _______ because the \_\_\_\_\_\_\_\_\_\_of the rate law also increases.
increases; rate constant(k)
129
According to the Arrhenius equation, the higher the activation energy, Ea, the \_\_\_\_\_\_(more/less) dependent the rate constant is on temperature.
More
130
# Define the equation:
An equation that predicts the value of the rate constant at one temperature from its value at another temperature.
ln(k'/k)=Ea/R (1/T - 1/T')
131
Explain: Collision theory of reaction
The collision theory of reactions states that a reaction may take place only when two molecules collide with a kinetic energy at least equal to a minimum value, Emin, or otherwise they will simply bounce again.
132
If the forward reaction is endothermic, the activation energy is higher for the _______ reaction than for the \_\_\_\_\_\_\_\_reaction.
forward; reverse
133
Explain: Transition state theory
The transition state theory states that a reaction takes place only if two molecules acquire enough energy, perhaps from surrounding solvent, to form an activated complex and cross an energy barrier.
134
Define: Activated complex
The activated complex is an arrangement of the two molecules that can either go on to form products or fall apart again and return to being reactants. During the activated complex, new bods only partly form.
135
What is the difference between a homogeneous and heterogeneous catalyst?
* homogeneous catalyst: a catalyst in the same phase as the reactants of the reaction
* heterogeneous catalyst: a catalyst in a different phase than the reactants
136
Explain: Induced-fit mechanism
In the induced-fit mechanism, the enzyme molecule adjusts its shape to accommodate the incoming substrate molecule.
137
Define: Law of Mass Action
The law of mass action states that at equilibrium, the composition of the reaction mixture can be expressed in terms of an equilibrium constant,K.
138
Define: Le Chatelier's Principle
Le Chatelier's Principle states that when a stress is applied to a system in dynamic equlibrium, the equilibrium tends to adjust to minimize the effect of the stress.
139
Define
Virion
140
Describe what occurs during the uncoating stage of the viral life cycle
During the uncoating stage proteolytic enzymes, found in the cytoplasm of the host cell, remove the capsid from the nucleic acid of the virus. This stage always occurs in the cytoplasm of the host cell.
141
The uncoating stage of the viral life cycle occurs in the…
cytoplasm of the host cell
142
The eclipse period occurs between what two stages of the viral life cycle?
uncoating and maturation stages
143
# Define:
eclipse period
The period between the end of the uncoating and the beginning of the maturation stages in the viral life cycle in which no intact infectious virions are seen within the host cell.
144
Describe what occurs during the protien synthesis stage of the viral life cycle
During the protien synthesis stage viral nucleic acids and protiens are replicated and viral parts are synthesized using the metabolic machinery of host cell (ie. ribosomes, tRNA, mitochondria, golgi apparati, enzymes, etc). The virus is not infectious as this stage occurs during the eclipse period.
145
Where does the protien synthesis stage occur in most DNA viruses? How about RNA viruses?
DNA viruses: mostly occurs in the nucleus of the host cell
RNA viruses: only occurs in the cytoplasm of the host cell
146
Describe what occurs during the maturation stage of the viral life cycle
During the maturation stage viral parts, such as the capsid, completed during the protien synthesis stage, are assembled around the replicated viral genome. The exact assembly process differs for enveloped and non-enveloped viruses.
147
What happens during the maturation stage of enveloped viruses?
During the maturation stage a capsid is formed around the viral genome and viral envelope glycoprotiens are transported to and embedded in the plasma membrane of the host cell
148
Compared to events occurring during the maturation stage of enveloped viruses, what DOES NOT happen during the maturation of non-enveloped viruses?
The maturation of non-enveloped viruses does not involve the transport of glycoprotiens to the cytoplasmic membrane of the host cell, a process that occurs during the maturation of enveloped viruses.
149
What happens during the maturation stage of non-enveloped viruses?
During the maturation stage a capsid is formed around the viral genome
150
Describe what occurs during the release stage of the viral life cycle
During this release stage the newly replicated assembled viruses exit the cell. Typically, non-enveloped viruses are released by lysis and enveloped viruses exit by budding from the cytoplasmic membrane of the host cell.
151
Compare the lytic and lysogenic viral life cycles
Lytic cycle: results in the immediate production of virulent (infectious) viruses. Occurs in both eukaryotes and prokaryotes
Lysogenic cycle: viruses lie latent within host cells and are passed on in subsequent cell divisions until the lytic cycle is triggered at a later time. Occurs mostly in bacteria/prokaryotes
152
Define
Lysis
The degeneration of the cytoplasmic membrane of a cell often due to viral, enzemic or osmotic mechanisms. Can be thought of as "cell bursting"
153
What are the five major steps in the retrovirus life cycle?
1. Fusion
2. Reverse Transcription
3. Integration
4. Transcription
5. Budding
(\*\* these steps are related to the stages of general viral life cycle)
154
Describe what occurs during the fusion step in the retroviral life cycle.
During fusion glycoprotiens on the retroviral envelope interact with specific protiens on the plasma membrane of the host cell, enabling the envelope to fuse (combine) with the plasma membrane
155
In the retroviral life cycle, which step follows fusion? Describe what occurs during this step.
Reverse transcription; during this step the retrovirus enters the cytoplasm where it's two ss-RNA strands are transcribed and synthesized into one ds-DNA by the enzyme reverse transcriptase.
156
What occurs during the integration step of the retroviral life cycle?
The newly formed viral ds-DNA is transported into the nucleus where it is integrated with host DNA forming a viral-host DNA hybrid called a provirus
157
In the integration stage of the retroviral life cycle a viral-host DNA hybrid called a ________ is formed
provirus
158
What occurs during the transcription stage of the retroviral life cycle?
During the transcription stage, the provirus is transcribed by host RNA polymerase forming mRNA and retroviral RNA molecules. The mRNA is then translated by the host's metabolic machinery into glycoprotien and capsid components. The RNA and components are then assembled into capsids
159
Although many viruses exit from host cells by lysis, retroviruses belong to the category of viruses that do not and undergo _______ instead. Why is this method utilized?
Retroviruses undergo budding
Retroviruses, like other enveloped viruses, bud from the host cell in order to obtain the glycoprotien viral envelope from the host plasma membrane.
160
What occurs during the budding stage of the retroviral life cycle?
During the budding stage the assembled retroviral capsids interact with viral glycoprotiens on the plasma membrane of the host cell causing it to bud and pinch off, releasing enveloped retroviral virions.
161
Define
transduction
Transduction a form of genetic recombination in which bacterial DNA is transferred from one bacterium to another by a bacteriophage that accidentally obtained chromasomal host DNA within its capsid.
162
Name the process shown below:
Transduction
163
Define
Prokaryote
A prokaryote is an organism that lacks a membrane bound nucleus and is further characterized by a nucleiod, cell wall and membrane, cytoplasm, flagella,and ribosomes. Two domains of prokaryotes exhist: bacteria (Eubacteria) and archaea
164
Lacking a nuclear membrane, bacteria are _______ organisms that have their single circular chromosome and RNA centered in the ________ region instead
prokaryotic; nucleiod
165
As bacteria do not undergo mitosis they must lack a \_\_\_\_\_\_\_\_.
mitotic apparatus
166
Bacteria have a _______ in the nucleoid region, as a result their genes are expressed only once and they are therefore considered to be \_\_\_\_\_\_\_.
singlular circular chromosome; haploid
167
Compared to organelles found in a eukaryotic animal cell, what organelles does a prokaryotic bacteria cell lack?
A prokaryotic bacteria cell lacks a nucleus, mitochondria, golgi apparatus, lysosomes and an endoplasmic reticulum
168
If bacteria lack mitochondria and other organelles responsible for metabolism in eukaryotic animal cells then how do they generate energy?
Bacteria gain energy from either photosynthesis, chemotropy or by ingesting organic matter. As they lack metabolic organelles many biochemical reactions are carried out across membranes through the use of proton pumps and other concentration gradients.
169
Classify the following types of bacteria:
A) bacilli, rod shaped
B) spirilli, spiral shaped
C) cocci, spheric or elliptical
170
What do the terms gram-positive bacteria and gram-negative bacteria mean?
Gram-positive and gram-negative are classifiations of bacteria made on the basis of whether or not their cell walls react to a dye called Gram stain. Gram-positive bacteria retain the stain and gram-negative do not.
171
Which quantum number defines electron shell?
n
172
As you move from Ne to Na, what happens to the effective nuclear charge?
The effective nuclear charge decreases from Ne to Na due to shielding.
173
Size [increase/decrease] as you go down a column.
Size [increase/decrease] as you go across (to the right of) a row.
Size _increases_ as you go down a column.
Size _decreases_ as you go across (to the right of) a row
174
# Define:
Electronegativity
A chemical property that describes the ability of an atom (or, more rarely, a functional group) to attract electrons (or electron density) towards itself.
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Which element is the most electronegative?
Fluorine
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# Define:
Electron Affinity
Electron Affinity is the energy change when an electron is added to the neutral species to form a negative ion.
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