If a pair of homologous chromosomes fails to separate during anaphase of meiosis I, what will be the chromosome number of the four resulting gametes with respect to the normal haploid number (n)?
a) n + 1; n + 1; n - 1; n - 1
b) n + 1; n + 1; n; n
c) n + 1; n - 1; n; n
d) n + 1; n - 1; n - 1; n - 1
Answer:
a) n + 1; n + 1; n - 1; n - 1
Explanation:
Separation of homologous chromosomes occurs during anaphase-I of meiosis. This event reduces the chromosome number from 2n to "n" in the daughter cells. If a pair of homologous chromosomes do not separate during anaphase-I, both the homologous chromosomes of that pair would be present in one daughter cell of the meiosis-I (n+1) while the other daughter cell would lack that chromosome (n-1).
Meiosis-II would maintain this chromosome number. Therefore, two gametes will have one extra chromosome (n+1) while the two gametes would lack one chromosome (n-1).
Answer:
a) n + 1; n + 1; n - 1; n - 1
Explanation:
which part of the central nervous system is used to serve as the main communication link between the body and the brain
Answer: The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord. The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement
Explanation: The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord.
The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement. Like a central computer, it interprets information from our eyes (sight), ears (sound), nose (smell), tongue (taste), and skin (touch), as well as from internal organs such as the stomach.
The spinal cord is the highway for communication between the body and the brain. When the spinal cord is injured, the exchange of information between the brain and other parts of the body is disrupted.
You have a total body concentration of 300 mOsM and total body volume of 3 liters. If you add 0.5 L of a solution containing 150 mosmol of NaCl to the body, what would the new total body concentration be?a) 450 mOsM
b) 300 mOsM
c) 350 mOsM
d) 700 mOsM
Answer:
300 mOsM
Explanation:
The application of osmotic equilibrium comes in.
Using the equation; solute/volume = concentration
S/V =C
In one experiment, Katherine observes that one of her cultured neurons responds to a rapid series of inputs at a single synapse by producing an action potential. In another experiment, she demonstrates that another cell responds to inputs at multiple synapses by producing an action potential. Katherine’s first experiment demonstrates ______________ and her second experiment demonstrates _______________.
Answer:
The answers are "Temporal Summation" and "Spatial Summation".
Explanation:
The experiment explained in the question is performed to observe action potentials and postsynaptic potentials in the neurons and how they affect them to behave differently.
In the first experiment, Temporal Summation is observed which occurs when one presynaptic neuron fires because of the changes in it's axon terminal.
In the second experiment, Spatial Summation is observed which occurs when ,unlike the temporal summation, more than one presynaptic neuron release neurotransmitters to cause the postsynaptic neuron to fire as a result.
I hope this answer helps.
Katherine's first experiment demonstrates temporal summation, while her second experiment demonstrates spatial summation.
Explanation:In her first experiment, Katherine observes that a single synapse of her cultured neuron produces an action potential in response to a rapid series of inputs. This experiment demonstrates temporal summation, where inputs from a single synapse are integrated over time to produce an action potential. In her second experiment, Katherine demonstrates that inputs from multiple synapses can also produce an action potential. This experiment demonstrates spatial summation, where inputs from different synapses are integrated spatially to generate an action potential.
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A technologist in a tissue bank who performed HLA typing by DNA analysis was asked to bank all DNA extracted from specimens received in the laboratory so as to maintain the highest quality of nucleic acid for the longest period. How should the DNA be stored to satisfy this request?
Answer:
I believe the options are:
a) DNase-free water at 22°-25°C
b) DNase-free water at -70°C
c) TE buffer at 2°-8°C
d) Freeze-dried at 22°-25°C
The answer is d) freeze dried at 22°C to 25°C.
Explanation:
As compared to RNA, DNA is a relatively stable biomolecule. It is relatively thermostable. However, DNA is highly susceptible to nuclease and chemical degradation.
DNA Storage:
DNA storage methods depend upon the type of sample, the desired quality and for how long the sample needs to be stored.There are four major DNA storage methods:Dried, at room temperature–20°C –80°C –196°C (storage in liquid nitrogen)Freeze drying and storage in liquid nitrogen (-196°C) are the two most effective means to store DNA samples for a long time.For storage at room temperature, DNA samples are dried in a freeze drying machine. Freeze drying removes all the moisture and water from the sample which prevents any hydrolytic reactions.Why is having an extra chromosome 21 tolerable to the point that someone with this condition can survive to maturity? (as compared to having an extra chromosome 2 , for example)
Answer:
This is due to the fact that chromosome 21 is not fundamental to sustain and keep life going.
Chromosome 21 is the second human chromosome to be entirely sequenced. Chromosome 21 seems to consists of 200 to 300 genes that supply instructions for developing and forming proteins. These proteins undergo a variety of unique roles in the body.
Chromosome 21 is majorly involved in brain development at the frontal lobe and the medulla oblingata.
Final answer:
Chromosome 21 is one of the smallest chromosomes with fewer genes, which results in a less severe impact of an extra copy compared to larger chromosomes. This allows individuals with an extra chromosome 21, or Down syndrome, to survive to maturity and lead fulfilling lives with proper assistance despite some intellectual and physical disabilities.
Explanation:
For several reasons, having an extra chromosome 21, known as trisomy 21 or Down syndrome, is more tolerable. Chromosome 21 is one of the smallest chromosomes with fewer genes compared to other chromosomes such as chromosome 2. This reduces the impact of having an extra copy because the gene dosage effect is not as severe as it would be with larger chromosomes that carry more essential genes. The body can somehow manage the extra dose of the genes on chromosome 21, allowing individuals with Down syndrome to survive to maturity and lead fulfilling lives with assistance.
Embryos with extra copies of other chromosomes, or lacking a chromosome (monosomy), usually do not survive because essential genes are either missing or expressed too much, disrupting vital developmental processes. With chromosome 21 being one of the smallest, the impact of the extra genetic material is less damaging, although it still causes various degrees of physical and intellectual disabilities.
Furthermore, individuals with Down syndrome, with proper assistance, can become contributing members of society despite potential mental and physical impairments. The survivability and capabilities of individuals with Down syndrome illustrate that the extra chromosome 21 while presenting challenges, does not preclude a viable and active life.
A relationship in which one organism depends on another for nourishment or some other benefit is specifically known as _____.
Answer: Commensalism
Explanation:
Commensalism is a biological association where two organisms interact and one of the two benefits while the other neither benefits nor get harmed.
A good example is epiphyte growing on Fruit trees. The epiphyte plant benefits by receiving physical support from the tree, while the fruit tree is totally unaffected
Last night in class, Upe asked her instructor about the flow of positive and negative ions into and/or out of a cell. Her instructor told her that the two processes involved in this movement are: A. diffusion and electrostatic pressure. B. glia and microglia. C. agonists and antagonists. D. voluntary and involuntary.
Answer:
Last night in class, Upe asked her instructor about the flow of positive and negative ions into and/or out of a cell. Her instructor told her that the two processes involved in this movement are: A. diffusion and electrostatic pressure. B. glia and microglia. C. agonists and antagonists. D. voluntary and involuntary.
The Answer is option A (diffusion and electrostatic pressure)
Explanation:
How diffusion act on groups of ions:
Ions are diffused when ions move from regions of high concentration to regions of lower concentration.
For Potassium Ion, potassium remains in high concentrations inside the cell, diffusion tends to push Potassium ion outside the cell.
For chloride ion (Cl-), remains in high concentration outside the cell, diffusion pushes it inside the cell.
While, sodium ion (Na+) is more concentrated outside the cell, diffusion pushes sodium ion inside the cell.
How electrostatic pressure act on groups of ions:
Electrostatic pressure is a surface charge that experiences a force in the presence of an electric field and can be described as the force on two ions with similar charge and the force of two ions with opposite charge.
For Potassium ion, the positive charge of Potassium ion is attracted to the negative charge inside the cell, hence, electrostatic pressure pushes Potassium ion inside the cell.
For chloride ion (Cl-), since the negative charge of chloride ion is attracted to the positive charge outside the cell, electrostatic pressure pushes chloride ion outside the cell.
For Sodium ion (Na+), since the positive charge of sodium is attracted to the negative charge inside the cell, electrostatic pressure pushes sodium ion inside the cell. But, sodium ion cannot permeate the cell membrane and remains in high concentration outside the cell.
Students use a microscope to look for structures present in four different cells. The students placed an X for each structure that was viewed for each cell on the table shown.
Which cell that was viewed is most likely a prokaryote?
A. Cell W
B. Cell X
C. Cell Y
D. Cell Z
Cell X is likely a prokaryotic cell. Option B) is the correct answer.
Explanation:
The prokaryotic cells are present in unicellular organisms such as bacteria and lack Nucleus in it. The cell X is not filled with x-mark in the nucleus.The prokaryotic cells consist of the cell membrane, cell wall and a genetic material composed of DNA. All these are marked with x-mark for cell X.Chloroplasts are not present in prokaryotic cells and the space for it is left blank in cell X without the x-mark.This information clearly shows that prokaryotic cell structure is viewed likely in cell X.The cell that is most likely a prokaryote is Cell X.
Hence, the correct option is B.
Prokaryotic cells are characterized by the following features:
They do not have a nucleus.
They have a cell wall.
They may have chloroplasts.
They have DNA that is not enclosed in a nucleus.
Cell X has a cell wall, chloroplasts, and DNA. However, it does not have a nucleus. This means that Cell X is most likely a prokaryotic cell.
Cell W has a nucleus, so it is not a prokaryote.
Cell Y has a nucleus and chloroplasts, so it is also not a prokaryote.
Cell Z has a nucleus, but it does not have chloroplasts. This means that Cell Z could be either a prokaryote or a eukaryote.
However, since Cell X is more likely to be a prokaryote based on the information given, Cell Z is less likely to be a prokaryote.
Therefore, The cell that is most likely a prokaryote is Cell X.
Hence, the correct option is B.
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If intelligence is determined primarily by heredity, which pair should show the highest correlation between IQ scores?
Answer:
The options
a) fraternal twins
b) identical twins
c) brothers and sisters
d) parents and children
The CORRECT ANSWER IS b)
b) identical twins
Explanation:
Identical twins both acquire identical genetic material. Therefore, if intelligence is basically controlled by heredity, you would foresee identical twins to possess the biggest correlation between IQ scores since they share 100 percent of the same genes
Answer:
the answer would be B, I got it right on edge :)
Explanation:
Convergent evolution is said to have occurred if the mouse species on two islands with similar habitats are found to have similar characteristics even though they originated from different species that did not have these characteristics.A. TrueB. false
Answer:
True
Explanation:
When two or more distantly related species develop some structural or functional similarities since they are found in the same environmental conditions, the process is called convergent evolution. Here, the developed similarities may not be present in the ancestors of these species. For example, the presence of wings in birds (Aves) and bats (mammals) represents convergent evolution. Therefore, the presence of similar features in two different species of mouse due to similar habitat conditions represent convergent evolution.
Answer:
True
Explanation:
When two species of an organism habituating in two different locations with similar environmental conditions possess similar characteristics are said to evolve through convergence.
Such species have homologous structures due to which they have similar internal skeletal structure but their function and looks vary.
For example – wings of bat and limbs of human beings are homologous structure but their function and look are different from each other.
Hence, the given statement is true
"You begin an experiment with two populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.f., they are clones). You grow these populations in flasks on a lab bench under identical conditions with sufficient resources for the survival of all individuals. What process will introduce genetic variation into these populations?"
Answer:
Horizontal method of gene transfer
Explanation:
Bacteria divide by binary fission which produces the exact copy of the daughter cells with the same genetic material but they do exhibit variation in their genetic material.
The process that is responsible to introduce the genetic variation is the mechanisms of horizontal methods of DNA transfer which involves the transformation, transduction and conjugation.
These methods of gene transfer are considered by the biologist as the primitive methods of sexual reproduction.
Thus, Horizontal method of gene transfer is the correct answer.
Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type of medium would be referred to as a(n):______
a) enrichment culture.
b) differential and enrichment culture.
c) selective and differential medium.
d) selective median.
Answer:
C) Selective and differential medium.
Explanation:
Selective Medium:
A media contains specific ingredients which are required to promote the growth of microorganism and inhibit the other microorganisms to grow is called selective medium.
Differential Medium:
A media contains specific ingredients which differentiate the same group organisms or closely related organisms is called differential medium.
NaCl is used in media to promote the growth of Staphylococcus aureus and inhibit the growth of other gram positive and negative bacteria.
A yellow halo color shows the bacterial fermentation of sugar which will distinguish Staphylococcus aureus with other strains.
So, it will be selective and differential medium which will allow to grow Staphylococcus aureus and differentiate with other bacteria.
Who was the first african american to be on a u.S. Postage stamp
Answer:
Booker T. Washington
Explanation:
The first African American to be on a U.S postage stamp is known as Booker T. Washington.
Booker T. Washington lived between April 5, 1856 – November 14, 1915. He served in the capacity as an adviser to many American presidents. An orator and educator that excelled and prospered the national cause of the black race in multi-racial America.
He was self educated American slave.
At the time when white heroes were predominantly featured on the postage stamp, Booker T. Washington broke through the ranks in 1940s.
Consider the Color locus. At this locus there are two alleles - red and green. The red allele is dominant to the green allele. If the selection coefficient against the green/green homozygote is 0.30, what it the fitness of the green/green homozygote?
Answer:
0.7
Explanation:
Using Hardy-Weinberg equation of genetic variation being constant when disturbing factors such has mutation and others are removed.
p² + pq + q² = 1 and p + q = 1
where p² is the frequency of the homozygous dominant genotype (RR) and q² is the frequency of the homozygous recessive genotype (rr) and 2pq is the frequency of heterozygous genotype (Rr). p represent the frequency of "R" and q represent "g". since the coefficient against the green/green homozygote is 0.30 then
the fitness of the green/green homozygote = 1 - 0.3 = 0.7
Heartbeat, digestion, respiration, and elimination of wastes are carried out by organ systems close to the central axis. These functions, close to the center of the body, operate or are ready to operate when the child is born. What principle of development does this represent?
Explanation:
This is the principle of proximodistal development that additionally depicts the bearing of advancement. This implies that the spinal string creates before external parts of the body. The child arms create before the hands also, the hands and feet create before the fingers and toes. Finger and toe muscles (utilized in fine engine ability) are the last to create in physical development.Proximodistal development is the changes of growth in child to operate the body when the child ready to operate after birth.Hence, the proximodistal development represent the changes in these functions.
Many conditions other than those that attack the brain tissue directly can also produce symptoms of neurocognitive disorder. These can be either medical conditions or other types of mental disorders. One cause of neurocognitive disorder is the severe interruption of blood flow to the brain known as a?
Answer:
The neuro cognitive disorder of blood flow to the brain is called as dementia.
Explanation:
When mental function decreases due to mental diseases,the term is called dementia in medical terminology.
There are several causes of dementia are-
Brain injury which is caused by trauma.Intra cerebral hemorrhage,blood clot in the brainBreathing problem like hypoxia.Cardiovascular problems like TIA, Stroke,heart infection etc.Alzheimer disease,Huntington disease,HIV,any injury in brain.Pick disease etcA person who is ______ perceives themself as a member of a different gender from the one assigned at birth.
Answer:
Transgender.
Explanation:
Transgender is defined as a term that includes ways that people’s gender identities can be different from the sex they were assigned at birth. Transgender people have a gender identity or gender expression that differs from their sex assigned at birth. Some transgender people who desire medical assistance to transition from one sex to another identify as transsexual
Skeletal muscle is _____.
a. "voluntary" because its contraction is deliberate
b. classified as a subtype of cardiac muscle
c. also known as smooth muscle
d. "involuntary" muscle and its movement is not deliberate
e. made up of cells with a single nucleus
Answer:
it should be A
Explanation:
Answer: Option A
Voluntary because its contraction is delibrate
Explanation:
Skeletal muscles are voluntary muscles that are controlled by the somatic nervous system (SNS). They are mostly found in the muscles and are muscles that are attached to bones. Attachment to bones is done by tendons which is made up of many bundles of collagen fibers. Contraction of skeletal muscles are deliberate i.e. voluntary and they are also involved in movement.
Which directly contribute to sea levels rising?
Explanation:
he two major causes of global sea level rise are thermal expansion caused by warming of the ocean (since water expands as it warms) and increased melting of land-based ice, such as glaciers and ice sheets. ... In urban settings, rising seas threaten infrastructure necessary for local jobs and regional industries.
What directly contributes to sea levels rising is:
Melting of land iceIncreasing temperature in ocean waters.
Why are sea levels rising?
There are two major causes for sea levels to be rising during the last years. The first one is the melting land ice present in glaciers and lands. As these ices melt, the water goes to the ocean, increasing its levels.
The second direct cause is the increasing temperature of the ocean. In other words, the temperature of the Earth is increasing, so the oceans get warmer, and as a result, the water in them expands.
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You have spent time working with a population of beetles. Sexually mature males range in size from 2-6 cm in length. You realize that the females only mate with males that measure less than 3 cm long. If you measured allele frequencies at a single gene (locus) that contributes to overall length, would you expect this population to be in H-W equilibrium from one generation to the next?
Answer:
Option B, No
Explanation:
Complete question is as follows -
You have spent time working with a population of beetles. Sexually mature males range in size from 2-6 cm in length. You realize that the females only mate with males that measure less than 3 cm long. If you measured allele frequencies at a single gene (locus) that contributes to overall length, would you expect this population to be in H-W equilibrium from one generation to the next?
Select one:
a. Yes
b. No
Solution -
No, because Hardy Weinberg’s equilibrium theory is not applicable in practical scenario as it assumes that H-W equilibrium persists from one generation to the other only when these is no disturbing factor . These disturbing factors include – natural selection, non-random mating, genetic drift, gene flow and mutations. Since this theory works only in an idealized state where no such disturbances occur, it is very difficult to say that the beetle population can remain in H-W equilibrium. Also the females in the beetle population are selecting the males for mating thereby exhibiting sexual selection. Hence, H-W equilibrium will not be applicable.
Hence, option B
Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about fifteen million years ago. Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time.
Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes _____.
A) polyphyletic
B) paraphyletic
C) monophyletic
D) into a new order
Answer:
The correct option is B) paraphyletic
Explanation:
A clade can be described as a monophyletic group which comprises of different organisms which have an ancestor in common and all its linear descents.
A paraphyletic group can be described as a group of organisms that have descended from the same evolutionary organism or ancestor groups, but it might comprise of one or more of the descendants.
Removing humans from the great ape clade results in a paraphyletic group as this group would then consist of an ancestral species and some, but not all, of its descendants.
Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade would make phylogenetic tree of the great apes paraphyletic. A paraphyletic group consists of an ancestral species and some, but not all, of its descendants. As humans share a common ancestor with chimps, gorillas, and orangutans, removing humans from the group creates a grouping that includes some but not all descendants of that common ancestor. This exclusion breaks the completeness of the monophyletic group (which includes all descendants), therefore, the correct answer to the question is:
B) paraphyletic
Which is true concerning muscle tissue? Select one: a. cuboidal shape enhances function b. highly cellular and well vascularized c. contains contractile units made of collagen d. is a single-celled tissue
The true statement about muscle tissue is that it is highly cellular and well vascularized. There are three types of muscle tissue: skeletal, cardiac, and smooth, all of which are highly cellular, well vascularized and have excitability, enabling movement and force generation.
Explanation:Concerning muscle tissue, the true statement is: b. highly cellular and well vascularized. This relates to the nature of muscle tissue, which is indeed highly cellular and well vascularized, allowing it to perform its functions of movement and force generation. Muscle cells, or myocytes, are derived from the mesoderm and their numbers remain relatively constant throughout life. These cells are characterised by their excitability; they respond to a stimulus and are contractile, meaning they can shorten and generate a pulling force.
There are three types of muscle tissue in the body - skeletal muscle, cardiac muscle, and smooth muscle. These all have properties in common, such as the ability to change their electrical states and send an electrical wave (or action potential) along the membrane. This property is known as excitability.
The forms of muscle tissue show different characteristics: skeletal muscle cells appear striated with many nuclei along the membranes; cardiac muscle cells appear striated with a single nucleus; smooth muscle cells have a single nucleus with no visible striations. These differences help them perform their different functions within the body.
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What theory of hearing contends that areas of the basilar membrane are highly specialized, with each area responding to a different frequency?
Answer: Place theory
Explanation:
Place theory is a theory of hearing that affirms that, the areas of the basilar membrane are highly specialized, with each area responding to a different frequency. Our awareness of sound depends on where each component frequency produces vibrations along the basilar membrane. By this theory, the pitch of a sound, such as a human voice or a musical tone, is determined by the places where the membrane vibrates, based on frequencies corresponding to the tonotopic organization of the primary auditory neurons.
The Place Theory of hearing contends that each area of the basilar membrane is specialized, resonating and responding to specific frequencies.
Explanation:The theory of hearing that posits specialized areas of the basilar membrane, each responding to a different frequency, is known as the Place Theory. According to the Place Theory, specific parts of the basilar membrane resonate and respond to certain frequencies while ignoring others. Each segment corresponds to a specific pitch or frequency, which allows for the perception of different sounds. For example, high frequency sounds vibrate the base of the cochlea, closer to the middle ear, while low frequency sounds vibrate the apex, closer to the center of the cochlea.
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The blood leaving the aorta reaches the circle of Willis, a collection of arteries that supplies blood to the brain. Assume that it takes 600 ms for blood to reach the circle of Willis and that its average velocity is reduced to 61 cm/s. What is the average acceleration experienced by the blood?
Answer:
Option D
Explanation:
Please see the attached image for initial velocity and the options for this question are
A.−67.0 cm/s2
B.−0.670 cm/s2
C.0.670 cm/s2
D.67.0 cm/s2
Solution
Acceleration is the rate of change of velocity or speed.
Mathematically it can be represented as
[tex]da = \frac{dv}{dt}[/tex]
where a represents the acceleration, v represents the velocity and t represents the time taken.
Given
time is equal to [tex]600[/tex] ms
or
[tex]0.6[/tex] seconds
Substituting the given values in above equation we get
[tex]a = \frac{101-61}{0.6} \\= 66.67 \frac{m}{s^2}[/tex]
Hence, option D is correct
The average acceleration of blood reaching the circle of Willis, with average velocity of 61 cm/s over 600 ms, is calculated using the formula for acceleration and found to be 101.67 cm/s^2.
Explanation:The question involves computing the average acceleration experienced by the blood as it travels from the aorta to the circle of Willis. To find the acceleration, we can use the formula a = (v_f - v_i)/t, where v_f is the final velocity, v_i is the initial velocity (assumed to be zero if not given), and t is the time taken.
Given that the average velocity when it reaches the circle of Willis is 61 cm/s and assuming the initial velocity is 0 (since we are calculating the average acceleration from rest), and the time taken is 600 ms or 0.6 seconds, we can calculate the acceleration as follows:
a = (61 cm/s - 0) / 0.6 s
a = 101.67 cm/s2
The average acceleration experienced by the blood is 101.67 cm/s2. This value is positive, indicating that the blood is speeding up as it travels to the circle of Willis.
Question: Laboratory 1: Tools For Scientific Inquiry Questions For Review 1. A Group Of Students Hypothesizes That The Amount Of Alcohol Produced On Depends On The Amount Of Glucose Supplied To The Yeast. They Want To Use 5%, 10%, 15%, 20%, 25%, And 30% Glucose Solutions. A. What Is The Independent Variable? B. What Is The Dependent Variable? C. What Control ...
Answer:
The independent variable is the amount of glucose being supplied and the dependent variable is the amount of alcohol being produced.
An independent variable can be described as the variable which is being changes in a scientific experiment so that its effects can be studies.
The dependent variable can be described as the variable which is under study and which gets affected by the changes in the independent variable.
The control that can be designed for this experiment can be another experiment in which the amount of glucose is kept constant in each of the yeasts.
The fruit fly Drosophila melanogaster has an allele that confers resistance to DDT and similar insecticides. Laboratory strains of D. melanogaster have been established from flies collected in the wild in the 1930s (before the widespread use of insecticides) and the 1960s (after 20 years of DDT use). Lab strains established in the 1930s have no alleles for DDT resistance. In lab strains established in the 1960s, the frequency of the DDT-resistance allele is 37%. Which statement is correct?
A) Alleles for DDT resistance arose by mutation during the period of DDT use because of selection for pesticide resistance.
B) The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.
C) Resistance to DDT evolved in some fruit flies in order to allow them to survive.
Answer:
The answer is option "B"
Explanation:
DNA is comprised of a set of genes that dictates a given trait. The genes themselves are comprised of alleles that allow for variations and differences in the trait that the concerned gene is responsible for. In the case of D. Melanogaster, there is an allele that allows for resistance to pesticides such as DDT. The two samples that are referred to in the question are differentiated on the basis of the amount of time that has lapsed since the start of significant DDT usage. So at the time when widespread DDT usage was not in place, the sample showed no DDT resistant alleles. With the passage of time in which DDT usage grew, the resultant effect as evidenced from the later sample indicated a significantly higher percentage of DDT resistant allele. This means that the ability of this species of fruit flies to survive, referred to as their evolutionary fitness, increased only after use of DDT increased. This means that DDT resistance trait changed as a natural response to the introduction of a different climate thereby allowing subsequent offspring of fruit flies to boast of higher numbers of alleles that have DDT resistance capacities thus allowing them to survive.
For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?
A) Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long.
B) There is no radioactive isotope of nitrogen.
C) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive.
D) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
Answer:
D) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
Explanation:
Alfred Hershey and Martha Chase carried out an experiment by employing the sulfur labeled proteins and phosphorous labeled DNA of the phage. These phages were permitted to infect bacteria. It was noted that the DNA had entrance to the bacterial cells and was thought to be the genetic material. The offspring of the phages that were marked with radioactive phosphorus was still marked although the offspring of the phages marked with radioactive sulfur were unmarked. This proved that DNA and not protein can be labeled as genetic material. When students employed the use of radioactive nitrogen in lieu of radioactive phosphorous, and could not obtain the required results due to nitrogen being found in proteins and DNA as nitrogen bases. Therefore, the radioactivity could not differentiate between DNA and proteins.
In view of this, the right answer is
D.
'Amino acids (and thus proteins) also have nitrogen atoms. Thus, the radioactivity would not distinguish between DNA and proteins.'
Describe how the structure of a virus aids in its ability to infect cells.
Answer:
Capsid proteins interlock with a receptor site on the host cell.
The capsid protein and host cell receptor interlock like a puzzle piece.
Viruses vary in shape to attack the various types of receptors on cells.
The shapes of viruses include polyhedral, helical, enveloped, and complex.
Once the virus attaches to the host cell, it invades the cell and hijacks the DNA of the cell
The structure of a virus aids in its ability to infect cells by attacking the receptors and attaching to the host cells.
What is Virus?This is defined as a small infectious agent which can replicate only inside the cells of another organism. Its structure infect cells through the following:
Capsid proteins interlock with a receptor site on the host cell.The capsid protein and host cell receptor interlock.Viruses vary in shape to attack the various types of receptors on cellsThe virus attaches to the host cell, it invades the cell and hijacks the DNA of the cell.Read more about Virus here https://brainly.com/question/8146080
When comparing liver cells and kidney cells within an organism, many differences can be observed and documented. Which of following is not a difference between liver cells and kidney cells in the same animal?
Choose one:
A. The different cells have different roles in the body.
B. The different cells are generated during the animal's development.
C. The different cells produce different proteins.
D. The different cells express different genes.
E. The different cells have different DNA.
Liver cells and kidney cells in the same animal have different roles in the body and produce different proteins. However, they have the same DNA.
When comparing liver cells and kidney cells within an organism, several differences can be observed. While liver cells and kidney cells have different roles in the body and produce different proteins, one similarity between them is that they have the same DNA. Genes are sections of DNA that provide instructions for the production of proteins, and both liver cells and kidney cells express different genes to carry out their distinct functions.
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Match the following terms and definitions 1. gene alternate forms for a specific gene 2. allele a genetic characteristic of the individual 3. trait a portion of DNA which codes a specific heredity trait 4. chromosome a thread-like molecule in the nucleus composed of DNA chromosome a genetic characteristic of the individual
Answer:
1. Allele - alternate forms for a specific gene
2. Trait - a genetic characteristic of the individual
3. Gene - a portion of DNA which codes a specific heredity trait
4. Chromosome - a thread-like molecule in the nucleus composed of DNA
Explanation:
1. An allele is the variant form of a gene. According to Mendel, an organism receives two forms of a gene from each parent. This forms are called ALLELES.
2. A trait is a particular characteristics of an individual determined by its genetic content. In other words, genes determine characteristics or attribute an individual possesses, this attribute is the TRAIT.
3. A gene is a sequence of nucleotides present on the DNA molecule that codes for certain products (proteins) and pass on traits to offsprings. The gene is a segment of the DNA that holds the genetic information.
4. CHROMOSOMES are visible structures in the nucleus (eukaryotes) or cytoplasm (prokaryotes) formed by the wrapping up of histone proteins around DNA molecule. It is the form in which the genetic material is passed on.
The term gene is a portion of DNA that codes a specific heredity trait, Allele refers to alternate forms for a specific gene, Trait means a genetic characteristic of an individual, and Chromosome is a thread-like molecule in the nucleus composed of DNA. Each term has a key role in genetic inheritance.
Explanation:The correct matching for the terms to their definitions are: 1. Gene should be matched with a 'portion of DNA which codes a specific heredity trait', 2. Allele can be defined as 'alternate forms for a specific gene', 3. Trait should be connected with 'a genetic characteristic of an individual', and 4. Chromosome could be best described as 'a thread-like molecule in the nucleus composed of DNA'
Gene is a unit of heredity which is transferred from a parent to offspring. Alleles are different versions of the same gene, each individual organism has two alleles for each gene - one from each parent. A trait is a characteristic that an organism can pass on to its offspring while a chromosome is a long thread-like grouping of genes, where each chromosome consists of DNA coiled and supercoiled around histones.
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