EXAM 4 Flashcards
(191 cards)
1
Q
In cellular communication, the first step of signaling pathway in which a signaling molecule is detected by a receptor molecule on or in the cell
A
Reception
2
Q
In cell communication the conversion of a signal from outside the cell to a from that can bring about a specific cellular response
A
Transduction
3
Q
In a cellular communication, the change in a specific cellular activity brought about by a transduced signal from outside the cell
A
Response
4
Q
The signaling molecule that binds to a receptor
A
Ligand
5
Q
Referring to a secreted molecule that acts on a neighboring cell
A
Paracrine signaling
6
Q
Signals released from the end of a neuron, diffuse across a short space and bind to a target cell, triggering a response.
A
Synaptic signaling
7
Q
Signaling by secreted chemicals that are formed in specialized endocrine cells, travels in body fluids, and act on specific target cells
A
Hormonal signaling
8
Q
Signal Transduction Pathway diagram (pg216)
A
A: Reception B: Transduction C: Response D: Plasma membrane E: Signaling molecule (Ligand) F: receptor G: relay molecules
9
Q
The enzymes that transfer phosphates from ATP to protein often activating the target protein, a process called phosphorylation
A
Protein kinases
10
Q
The enzymes that remove the phosphates from proteins often deactivating the target protein, a process called dephosphorylation
A
Protein phosphatases
11
Q
A series of chemical reactions during cell signaling mediated by kinases, in which each kinase in turn phosphorylates and activates another
A
Phosphorylation Cascade
12
Q
Signal transduction enzyme cascades can increase the cell’s response by activating products much more than in the preceding step
A
amplification of the signal
13
Q
Different kinds of cells have different collections of proteins and these different proteins allow cells to detect and respond to different signals
A
Specificity of the response
14
Q
For an organism to remain capable of responding to incoming signals, each molecular change in its signaling pathways must last only a short time.
A
termination of the signal
15
Q
Large relay proteins to which other relay proteins are attached that increase the signal transduction efficiency by grouping together different proteins
A
scaffolding proteins
16
Q
A type of programmed cell death, which is brought about by activation of caspase enzymes
A
apoptosis
17
Q
Which of the following best describes hormone signaling
A
Specialized endocrine cells release signal molecules into the circulatory system, permitting distant cells to be affected.
18
Q
The three stages of signal transduction in a cell are
A
signal reception, signal transduction, and cellular response
19
Q
One type of cell signaling is called paracrine signaling. This type of signaling
A
involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid
20
Q
Growth factors often bind to receptors called
A
receptor tyrosine kinases
21
Q
Just after a receptor tyrosine kinase binds to a signal molecule
A
dimerization and phosphorylation occurs
22
Q
A phosphorylation cascade uses ___ as the source of phosphate for signaling.
A
ATP
23
Q
At the end of the Receptor Tyrosine Kinase signaling pathway a transcription factor is turned on. This will directly cause
A
the synthesis of mRNA
24
Q
Signaling through elaborate phosphorylation cascades of several kinases is beneficial to a cell because
A
it amplifies the original signal manyfold
25
The type of protein that terminates signaling through a phosphorylation cascade by performing dephosphorylation is a(n)
phosphatase
26
Apoptosis involves all except which of the following?
lysis of the cell
27
The process of turning genes on and off that ensures the appropriate genes are expressed at the proper times. This process can also help an organism respond to its environment.
Gene regulation
28
A cluster of functionally related genes can be under coordinated control by a single “on-off switch”
Operon
29
A regulatory “switch” that is a segment of DNA usually positioned within the promoter
Operator
30
A protein that can switch off the operon by binding to the operator and blocking RNA polymerase
Repressor (Lac Repressor)
31
A molecule that inactivates the repressor to turn an operon on
Inducer (allolactose)
32
A protein that can increase gene expression for an operon
Activator (CRP)
33
When glucose (a preferred food source of E. coli) is scarce, CRP is activated by this small molecule
Cyclic AMP (cAMP)
34
Lac Operon
```
A: DNA
B: mRNA
C: Proteins
D: Inducer
E: Lacl Repressor
F: Lac Operon
G: Regulatory gene
H: RNA polymerase
I: Operator
```
35
Expression of different genes by cells with the same genome resulting in differences between cell types.
Differential Gene Expression
36
Distal gene regulation control elements in eukaryotic cells that may be far away from a gene or even located in an intron
Enhancers
37
The developmental process that irreversibly commits a cell to becoming a particular cell type
Determination
38
The process by which cells become specialized in structure and function
Cell Differentiation
39
Normal cellular genes that are responsible for normal cell growth and division that can be mutated to increase cell division and cause cancer
Proto-oncogenes
40
Cancer-causing mutated genes that promote excess cell division like mutated ras
Oncogenes
41
Genes that prevent uncontrolled cell growth that can be mutated to contribute to cancer like p53
tumor-suppressor gene
42
The idea that multiple mutations are generally needed to cause full-fledged cancer; thus the incidence increases with age
Multi step model of cancer
43
The type of gene that produces repressor and activator proteins
Regulatory gene (lacl)
44
In bacteria, a set of genes that is controlled as a single unit is called a(n)
operon
45
The LacI repressor protein blocks transcription of the lac operon by binding to which of these?
the operator
46
For the lac operon, the repressor protein is deactivated when the ___ is present inside the cell increasing the amount of lac operon transcription .
inducer
47
Which of these turns on a eukaryotic gene by binding to an enhancer?
Activator
48
In both prokaryotes and eukaryotes, which of the following is an important part of gene regulation?
controlling the attachment on RNA polymerase to the promoter
49
All of the different types of cells in a person come from the one cell created by fertilization; the fusion of an egg cell with a sperm cell. Amazingly, almost all of the cells in us have all of the DNA that was in that original cell but are cells become very different from one another. What process below makes our cells distinct even though they have the same genes?
differential gene expression
50
The process that makes cells become more specialized in structure and function like muscle cells is called
cell differentiation
51
As people get older their risk of cancer increases because
the longer we live, the more mutations accumulate
52
Cancer is caused by changes in specific types of genes. Which of the genetic changes below is most likely to cause cancer in a person?
mutations in proto-oncogenes and inactivation of a tumor suppressor gene
53
In breast cells the receptor tyrosine kinase HER2 is expressed and responds to growth factors causing cell division. A new therapeutic called Herceptin binds to HER2 and inhibits signaling. Herceptin should be used to treat breast cancer under which of these circumstances?
If patient's cancer cells have high levels of HER2
54
The branch of biology concerned with classifying and naming organisms
Taxonomy
55
Remains or traces of organisms from the past, usually found in sedimentary rock
Fossils
56
The study of fossils, that was largely developed by French scientist Georges Cuvier
Paleontology
57
Favorable inherited traits for the environment a species live in
Adaptations
58
A process in which individuals with favorable inherited traits are more likely to survive and reproduce
Natural selection
59
The process in which humans have modified other species by selecting and breeding individuals with desired traits.
Artificial selections
60
Argument for Natural selection:
Individuals in a population___ identical in their heritable characteristics
Organisms produce _____ offspring than the environment can support
Individuals that are more suited to their environment tend to leave ____ offspring than other individuals
Over time, ____ traits accumulate in the population
Vary
More
More
Favorable
61
Similarity between organisms resulting from common ancestry
Homology
62
Remnants of features that served important functions in the organisms ancestors
Vestigial traits
63
Is the evolution of similar, or analogous, features in distantly related groups
Convergent Evolution
64
Depiction of the hypothesis about the relationships among different groups and show that homolgies form nested patterns
Evolutionary trees
65
The history of life on earth written in the remains of organisms that is evidence of the extinction of species, and changes within groups over time
Fossil record
66
The geographic distribution of species, provides evidence of evolution
Bio geography
67
Layers of sedimentary rock that can contain fossils
Strata
68
Charles Darwin made important contributions to our understanding of how populations evolve but he did not discover everything. Of the statements below, which is correct about Darwin's contributions?
He proposed natural selection as the mechanism of evolution
69
Which of the following people below was the first scientist to recognize that evolutionary change explains patterns in fossils and the match of organisms to their environments but incorrectly proposed that the mechanism for evolution was the use and disuse of traits.
Lamarck
70
Darwin incorporated which of these ideas from Malthus into his mechanism of natural selection?
populations tend to increase at a faster rate than their food supply normally allows
71
Before Darwin published On the Origin of Species most biologists thought that animals and plants never changed and each species was independent and unrelated to any other species. However, during the time that Darwin lived, observations of fossils and homologous structures in living organisms showing underlying similarities specifically suggested to biologists that ___ .
dissimilar organisms might have evolved from a distant, common ancestor
72
You can summarize the scientific theory of evolution as
an overarching explanation, supported by much evidence, for how populations change overtime
73
Darwin developed the mechanism of natural selection to explain how evolution happens. Which of the options below best describes the mechanism of natural selection?
Organisms better adapted to their immediate environment are most likely to survive and reproduce
74
The mechanism of natural selection relies on ___ to determine which traits will be successful.
the environment
75
Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection?
Genetic frequencies within the population change.
Poorly adapted individuals have decreased survivorship.
A change occurs in the environment.
Well-adapted individuals leave more offspring than do poorly adapted individuals.
3-2-4-1
76
On an island, a species of rabbit has two fur colors, tan and gray. One population of rabbits lives on the western side of the island where there are gray rocky beaches and another rabbit population lives on the eastern side of the island where there are tan sandy beaches. A species of falcon on the island is constantly hunting the rabbits. On this island, natural selection will cause which of the following to occur?
Since tan rabbits blend better with the sandy beaches and gray rabbits blend better with the rocky beaches, the amount of tan rabbits will increase on the east side of the island and the number of gray rabbits will increase on the west side of the island.
77
Mosquitoes transmit many diseases including malaria. The pesticide DDT has been used for decades to reduce the number of mosquitoes but now it is much less effective that it used to be because ___.
many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics
78
Homologous structures like the wings of an eagle and the wings of a hummingbird provide evidence for which of these?
common ancestry
79
Which of the following pairs of traits is an example of convergent evolution?
the wings of a dragonfly and the wings of a hawk
80
In dolphin flippers, the bones are homologous to the bones in the ___ of a cat.
front limbs
81
Which of these is the strongest evidence that all life on Earth is related back to a single common ancestor?
All organism use essentially the same genetic code
82
The finches on the Galapagos islands are more similar to the finches of South America than to finches anywhere else in the world. This type of evidence for common ancestry comes from
bio geography
83
Microevolution states which of the following?
populations are the units of evolution
84
A natural population can be described as
a group of individuals of the same species occupying a given area that interbreed
85
Which of the following is the only source for new gene variations in a population?
mutation
86
What is the term for all copies of every type of allele at every locus in all members of the population?
gene pool
87
When analyzing the population genetics of a single gene with 2 alleles the Hardy-Weinberg theorem states that p + q = 1. The 1 in this equations represents ___.
the sum of the frequencies of both alleles in a gene pool
88
In the Hardy-Weinberg formula, 2pq represents _____.
the frequency of heterozygous individuals in the gene pool
89
If the frequency of a dominant allele is 0.2, what is the frequency of the recessive allele?
0.80
90
The presence of freckles is due to a dominant allele. 16% of the individuals in a particular population lack freckles. Use the Hardy-Weinberg formula to calculate the percentage of individuals in this population who are homozygous dominant for freckles
36%
91
Which of the following conditions not required for Hardy-Weinberg equilibrium?
non-random mating
92
The mechanism of evolution called genetic drift is caused by
chance events
93
Of the options below, which describes gene flow the best?
Wind blows pollen from one population of plants to another, and cross-fertilization occurs.
94
Genetic drift has the greatest impact on the allele frequencies of a population when _____
the population size is small
95
A small number of birds of the same species migrate from an island to found a population on a newly formed volcanic island. The population grows to the point where it consists of as many individuals as the population on the original island. Which of the following statements is most likely to apply to this population of birds on the newly formed volcanic island?
The new island population exhibits less genetic variation than the old island population.
96
Which of the following allows for gene flow between populations?
migration
97
A sudden change in the environment, such as a fire or flood, that drastically reduces the size of a population leading to changes in allele frequencies is called __
the bottleneck effect
98
Students that are new to the theory of evolution by natural selection are often surprised that the process can produce an organism with greater relative fitness because mutations are random changes. Which statement explains how greater relative fitness evolves even though mutations are random?
mutation is random but natural selection causes adaptive mutations to accumulate over time
99
Relative fitness is best described as
reproductive success
100
Birds with longer and shorter wings survive in a region that has many severe storms more successfully than other birds in the same population with average-sized wings. This illustrates _
disruptive selection
101
A population of squirrels is preyed on by small hawks. Only the smallest squirrels can escape into burrows. After several generations, the squirrels in the area tend to be very small. What process is responsible for this outcome?
directional selection
102
Adult male peacocks have colored feathers and compete for female mates. The coloration of the male feathers is best explained as the result of ________, and specifically of ________.
sexual selection; intrasexual selection
103
Which of the following represents evolutionary change above the species level like the origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery?
macroevolution
104
According to the Biological Species Concept, two individuals would be considered part of separate species if they
cannot interbreed
105
Unfortunately, the biological species concept is not useful for all organisms. It cannot be applied to which of the organisms below?
bacteria that only reproduce asexually
106
We can use the morphological species concept to describe a fossil species based on
its body shape
107
Reproductive isolation that happens before mating is called ___.
a prezygotic barrier
108
Two species of frogs in the same pond mate but do not produce viable fertile offspring because the sperm of each species cannot fertilize the eggs of the other species. The reproductive barrier between them is an example of
gametic isolation
109
Which of the following best describes sympatric speciation?
It is the appearance of a new species in the same area as the parent population.
110
Speciation that occurs when a population is divided into geographically isolated subpopulations preventing gene flow is called
allopatric speciation
111
Although very rare, some plants species have been documented to arise in a single generation
if a polyploidy event creates a reproductive barrier.
112
If a new species of plant is to be produced by means of allopolyploidy from two parental species that are 2n = 10 and 2n = 14, how many chromosomes would you expect in the somatic cells of the new species?
24
113
Which of the following is the best definition of a hybrid zone?
an area where mating occurs between members of two closely related species, producing viable offspring
114
Which of these describes the way that speciation between two populations is slowed down by hybrid zones
incomplete reproduction isolation
115
A pattern of evolution in which species diverge from one another more slowly and steadily over time fits the ______ model of speciation
gradualistic
116
You are examining the fossil record and notice that through time there are abrupt changes resulting in speciation followed by long periods of no change. The model for the tempo of speciation that best fits this description is
punctuated equilibrium
117
The Hardy-Weinberg equation can be used to test whether evolution is occurring in a population. Let's use the Hardy-Weinberg equation to investigate the evolution of the population below. In particular, the Hardy-Weinberg equation makes it possible to predict the genetic make up of the next generation of a population like Mendelian genetics is used to predict the genetics of children for two parents.
An example population has 700 individuals: 85 of genotype AA, 320 of genotype Aa, and 295 of genotype aa. The first step in this process is to determine the gene pool of our population by counting up the number of each allele, A and a.
Total # of A alleles 85(2)+1(320)= 490
total # of a alleles: 910
total #: 490+910=1400
what is the frequency of A:490/1400= 0.35
frequency of a: 0.65
p^2+2pq+q^2
predicted AA genotype frequency p^2: 0.1225
Aa 2pq: 0.455
aa q^2: 0.4255
```
Next gen 10000 : 500AA; 4500 Aa, 5000 aa
(multiply 10000 with frequency)
AA: 1225
Aa: 4550
aa: 4225
```
Evolution?
Yes the number of AA individuals is lower and the number of aa individuals higher than predicted
118
The Hardy-Weinberg equation ( p2 + 2pq + q2 = 1) can be used in several ways to investigate population genetics. In the problem below we will use the Hardy-Weinberg equation in a slightly different way to investigate the frequency of a human disease and the allele that causes it.
Phenylketonuria (PKU) is a recessive human metabolic disease. We will use the Hardy-Weinberg equation to investigate the why this disease continues to occur in humans.
The occurrence of PKU is the United States population is 1 child born with PKU per 10,000 births.
0. 0001
0. 01
0. 9
0. 18
119
A change in allele frequencies (evolution) in a population over generations
Microevolution
120
A localized group of individuals capable of interbreeding and producing fertile offspring
Population
121
All the alleles for all loci in a population
Gene pool
122
The proportion of each allele in a population
Allele frequency
123
Hardy-Weinberg equilibrium equation for population genetics
p^2+2pq+q^2
124
The frequency of the homozygous genotypes
p^2 and q^2
125
The frequency of the heterozygous genotypes
2pq
126
How allele frequencies generally fluctuate unpredictably from one generation to the next
Genetic drift
127
Genetic drift that occurs when a few individuals become isolated from a larger population
Founder effect
128
Genetic drift that occurs when there is a sudden reduction in population size due to a change in the environment
Bottleneck effect
129
The movement of alleles among populations
gene flow
130
The mechanism of evolution that consistently results in adaptive evolution
natural selection
131
Mechanisms of evolutionary change
| Gen 1
```
14
6
20
0.7
0.3
```
132
Mechanisms of evolutionary change
| Gen 2
```
10
10
20
0.5
0.5
```
133
Comparing the allele frequencies in Generation 1 and Generation 2, is evolution occurring in this population?
If evolution is occurring, what mechanism of evolution is causing the change in allele frequency?
Yes p and q change from gen 1 to gen 2
Genetic drift
134
Modes of natural selection
```
original pop
evolved pop
directional selection
disruptive selection
stabilizing selection
```
135
The pattern of natural selection that favors individuals at one end of the phenotypic range
directional selection
136
The pattern of natural selection that favors individuals at both extremes of the phenotypic range
disruptive selection
137
The pattern of natural selection that favors intermediate variants and acts against extreme phenotypes
stabilizing selection
138
Natural selection that selects for mating success traits
sexual selection
139
Marked differences between the sexes in secondary sexual characteristics that results from sexual selection
sexual dimorphism
140
Competition among individuals of one sex (often males) for mates of the opposite sex
intrasexual selection
141
Often called mate choice, a selection that occurs when individuals of one sex (usually females) are choosy in selecting their mates
intersexual selection
142
Microevolution states which of the following?
populations are the units of evolution
143
a natural population can be described as:
a group of individuals of the same species occupying a given area that interbreed
144
Which of the following is the only source for new gene variations in a population
mutation
145
What is the term for all copies of every type of allele at every locus in all members of the population
gene pool
146
When analyzing the population genetics of a single gene w (2) alleles the H-W theorem states that p+q=1 the 1 in this equation represents?
the sum of the frequencies of both alleles in a gene pool
147
In the H-W formula 2pq represents
the frequency of heterozygous individuals in a gene pool
148
if the frequency of a dominant allele is 0.2 what is the frequency of the recessive allele
0.80
149
the presence of freckles is due to a dominant allele 16% of the individuals in a particular population lack freckles. use the H-W formula to calculate the % of individuals in this population who are homozygous dominant for freckles
36%
150
Which of the following conditions not required for H-W equilibrium
non-random mating
151
The mechanism of evolution called genetic drift is caused by
chance events
152
of the options below, which describes gene flow the best
wind blows pollen from one population of plants to another, and cross fertilization occurs
153
genetic drift has the greatest impact on the allele frequencies of a population when
the population size is small
154
a small # of birds of the same species migrate from an island to found a population on a newly formed volcanic island. the population grows to the point where it consists of as many individuals as the population on the original island. which of the following statements is most likely to apply to this population of birds on the newly formed volcanic island?
the new island population exhibits less genetic variation than the old island population
155
which of the following allows for gene flow btwn populations
migration
156
a sudden change in environment that drastically reduces the size of a population leading to changed in allele frequencies is called
the bottleneck effect
157
Students that are new to the theory of evolution by natural selection are often surprised that the process can produce an organism with greater relative fitness because mutations are random changes. Which statement explains how greater relative fitness evolves even though mutations are random?
mutation is random but natural selection causes adaptive mutations to accumulate overtime
158
Relative fitness is best described as
reproductive success
159
birds with longer and shorter wings survive in a region that has many severe storms more successfully than other birds in the same population with average-sized wings. this illustrates
disruptive selection
160
A population of squirrels is preyed on by small hawks. Only the smallest squirrels can escape into burrows. After several generations, the squirrels in the area tend to be very small. What process is responsible for this outcome?
directional selection
161
Adult male peacocks have colored feathers and compete for female mates. The coloration of the male feathers is best explained as the result of ________, and specifically of ________.
sexual selection; intrasexual selection
162
The origin of new species also know as “the mystery of mysteries”.
Speciation
163
Broad patterns of evolutionary change above the species level that is the cumulative effect of many speciation and extinction events
Macroevolution
164
The general term for the existence of biological factors (barriers) that impede two species from reproducing
Reproductive Isolation
165
The offspring of crosses between two different species
Hybrids
166
The type of reproductive barrier that blocks fertilization from occurring
Prezygotic barrier
167
The type of reproductive barrier that prevents the hybrid zygote from developing into a viable, fertile adult. This type of barrier sometimes results in hybrids.
postzygotic barrier
168
A species model that states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring and they do not breed successfully with other populations
The biological species concept
169
Reproductive barriers
```
Presygotic barriers
mating attempt
fertilization
postzygotic barriers
fertilization
viable and fertile offspring
```
170
Speciation that occurs when gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations
allopatric speciation
171
Speciation that takes place in geographically overlapping populations through genetic changes (polyploidy), habitat differentiation, or sexual selection
sympatric speciation
172
The general term for the presence of extra sets of chromosomes due to accidents during cell division
polyploidy
173
A species with more than two chromosome sets, derived from one species
autopolyploid
174
A species with multiple sets of chromosomes derived from different species
allopolyploid
175
A model of evolution with periods of apparent stasis punctuated by sudden change during the evolutionary history of species
punctuated equilibrium
176
A model of evolution which theorizes that most speciation is slow, uniform and gradual during the evolutionary history of species
gradualism
177
Which of the following represents evolutionary change above the species level like the origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery?
macroevolution
178
According to the Biological Species Concept, two individuals would be considered part of separate species if they
cannot interbreed
179
Unfortunately, the biological species concept is not useful for all organisms. It cannot be applied to which of the organisms below?
bacteria that only reproduce asexually
180
We can use the morphological species concept to describe a fossil species based on
its body shape
181
Reproductive isolation that happens before mating is called ___.
prezygotic barrier
182
Of the options below, which one is a postzygotic barrier?
the production of sterile hybrids
183
Two species of frogs in the same pond mate but do not produce viable fertile offspring because the sperm of each species cannot fertilize the eggs of the other species. The reproductive barrier between them is an example of _____.
gametic isolation
184
Which of the following best describes sympatric speciation?
it is the appearance of a new species in the same area as the parent population
185
Speciation that occurs when a population is divided into geographically isolated subpopulations preventing gene flow is called ___.
allopatric speciation
186
Although very rare, some plants species have been documented to arise in a single generation
if a polyploidy event creates a reproductive barrier
187
If a new species of plant is to be produced by means of allopolyploidy from two parental species that are 2n = 10 and 2n = 14, how many chromosomes would you expect in the somatic cells of the new species?
24
188
Which of the following is the best definition of a hybrid zone?
an area where mating occurs between members of two closely related species, producing viable offspring
189
Which of these describes the way that speciation between two populations is slowed down by hybrid zones?
incomplete reproductive isolation
190
A pattern of evolution in which species diverge from one another more slowly and steadily over time fits the ______ model of speciation.
gradualistic
191
You are examining the fossil record and notice that through time there are abrupt changes resulting in speciation followed by long periods of no change. The model for the tempo of speciation that best fits this description is ___.
punctuated equilibrium
