Answer: B. the 5'-3' orientation of the polynucleotide strand .
The complimentary pairing of DNA molecules ensures 5' 3' and 3'[ 5 ' arrangement for correct pairing of purines and pyrimidine (Adenine E with thymine and cytosine with guanine) in opposite direction. .
RNA only contains five prime and three prime only, but DNA contains both 5'3' and 3'5'.
RNA differs from DNA in the presence of uracil, the sugar molecule, and its various functions. However, both RNA and DNA share the 5'-3' orientation of the polynucleotide strand.
Explanation:The RNA differs from DNA in several ways, including the presence of uracil, the type of sugar molecule it contains, and its various functions. However, the 5'-3' orientation of the polynucleotide strand is a feature that RNA shares with DNA. Both RNA and DNA have this orientation, which describes the direction that the molecules are read and synthesized in cellular processes such as DNA replication and transcription.
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Describe and differentiate between the following heat transfer mechanisms: conduction, convection, radiation and evaporation. In your section on radiation, describe and differentiate between radiative heat transfer between animals and other terrestrial objects, radiative heat transfer between animals, radiative heat transfer between animals and the clear night sky and radiative heat transfer between animals and the sun.
Answer:
Explanation: Radiation is divergence out from a central point, in particular evolution from an ancestral animal or plant group into a variety of new forms.
Ectotherms vs. endotherms
sun is Earth’s principal source of radiative energy. With a surface temperature of
approximately 6000K, the sun’s electromagnetic radiation transmits some of this heat in the
form of infrared radiation to our atmosphere and to varied surfaces on Earth
The ability of the human body to break down the red color in beets is controlled by an autosomal dominant allele. The inability is recessive, detected by red coloration of the urine (we will call this phenotype 'secretor'). If a nonsecretor woman with a secretor father has children with a nonsecretor man who in a previous relationship had a secretor daughter, what is the probability that their first child will be a secretor girl?A)1/2B)1/4C)1/8D)3/8E)1/3
Answer:
c. 1/8
Explanation:
Let's assume that the recessive allele "s" gives the "secretor" phenotype in the homozygous state while the dominant allele "S" is responsible for the "nonsecretor" phenotype.
According to the given information, the nonsecretor woman has a “secretor” father (ss). This makes the woman heterozygous dominant (Ss) for the trait. Likewise, the man has a “secretor” daughter (ss) from the previous relationship. Therefore, the man is also heterozygous dominant (Ss) for the trait.
A cross between two heterozygous dominant parents (Ss x Ss) would produce progeny in following ratio= 3/4 Nonsecretor (1/4 SS and 1/2 Ss): 1/4 Secretor (1/4 ss)
During each reproductive cycle, there are 1/2 chances for a couple to have a girl child (XX x XY= 1/2 XX: 1/2 XY). Therefore, the probability that their first child will be a “secretor girl”= 1/4 x 1/2= 1/8 .
Of the following, which is the most current description of a gene? Of the following, which is the most current description of a gene? a unit of heredity that causes formation of a phenotypic characteristic a DNA sequence that is expressed to form a functional product: either RNA or polypeptide a DNARNA sequence combination that results in an enzymatic product a DNA subunit that codes for a single complete protein a discrete unit of hereditary information that consists of a sequence of amino acids
Answer:
a unit of heredity that causes formation a phenotypic characteristics
A gene is described as a unit of heredity that causes the formation of a phenotypic characteristic. Therefore, option A is correct.
What are genes and their function?Genes are segments of DNA that hold the instructions needed to create a single, usually protein-producing, molecule in your body. These proteins regulate how our body develops and functions; they are also in charge of determining many of our physical traits, like our eye color, blood type, and height.
In the chromosomes, genes that code for a specific character's assigned expression is present in a linear order. They transfer from one generation to another.
Thus, a gene is described as a unit of heredity that causes the formation of a phenotypic characteristic. Therefore, option A is correct.
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The relationship of the genome to an organism is similar to that of the __________ to a population.
Answer:
Phenotypes
Explanation:
Genome represents the complete set of genetic material of any organism. It includes all the genes and alleles of that particular organism. The same relationship is between the phenotypes and a population.
The variations in genetic allele pair due to the large set of genome that give rise to varied physical characteristics or traits collectively known as phenotype. The larger is the genome size, the higher will be the variability in phenotypes.
The Vocabulary of Nutrition for Children, Adolescents, and Older Adults
In order to understand nutrition-related problems that occur within different age groups, you must first be able to use the vocabulary. Review the sentences below and select the term that best completes the sentence.
Match the words in the left column to the appropriate blanks in the sentences on the right.
picky eating
peak bone mass
life expectancy
obesity
arthritis
bone mineral density (BMD)
food jag
congregate meal
food insecurity
epiphyseal plates
1. ---------------------- usually involves avoidance of new foods, while a---------------------------------- represents a preference for a certain limited number of foods at the exclusion of others.
Answer: 1.Picky eat and food jag.
2.Epiphysial plate 3. Peak bone mass.
4.Obesity. 5. Food insecurity.6.life expectancy.7.anthiritis 8. Congregate meal.
Completion of question.
2. Adolescent bone growth occurs along the -------------------------------------- .
3. In healthy individuals,--------------------------- increases through early adulthood.
4. Rates of ------------------------------------- have doubled in children in the past 30 years.
5. Many older adults experience ------------------------------------- due to factors like limited income, poor health, or impaired mobility.
6. For individuals born around 1900, the ------------------------------ was around 47 years.
7. Severe ---------------------------------------- can impact mobility, making it difficult to obtain and prepare meals.
8. A ------------------------------------------------- can provide nutritious food and socialization for older adults.
Explanation:
In the spinal cord dissection, which of the following structures did you NOT need to dissect in order to view the spinal cord: Select one:a. longissiumus thoracisb. serratus posteriorc. external obliquesd. multifidus
Answer:
External oblique muscle
Explanation:
Suppose the size of a population of marmots is 300. According to genetic drift theory, what is the probability that a newly arisen mutation will become fixed in this population? Select one:a. 1/1200b. 1/100c. 1d. 1/300e. 1/600
Answer:
E. 1/600
Explanation:
Hint:
The probability of fixation of a new neutral mutation is 1/(2N)
Given N as 300
= 1/(2×300)
=1/600
Therefore,
1/600 gives a sure fixation of one allele from the large population
When Gregor Mendel conducted his genetic experiments with pea plants, he observed that a trait’s inheritance pattern was the same regardless of whether the trait was inherited from the maternal or paternal parent. Mendel made these observations by carrying out reciprocal crosses: For example, he first crossed a female plant homozygous for yellow seeds with a male plant homozygous for green seeds, and then crossed a female plant homozygous for green seeds with a male plant homozygous for yellow seeds.
Unlike Mendel, however, Morgan obtained very different results when he carried out reciprocal crosses involving eye color in his fruit flies. The diagram below shows Morgan’s reciprocal cross: He first crossed a homozygous red-eyed female with a white-eyed male, and then crossed a homozygous white-eyed female with a red-eyed male.
The discrepancy between Mendel's and Morgan's results is due to the fact some traits are sex-linked, that is, associated with the sex chromosomes. Mendel's experiments didn't involve sex-linked traits, while Morgan's did. This is why traits inherited from different sex parents produced different results in Morgan's experiments.
Explanation:The observations noted in the question highlight differences between Gregor Mendel and Thomas Hunt Morgan's genetic experiments, involving pea plants and fruit flies, respectively. The discrepancy in results is based on the fact that certain traits (like eye color in Morgan's fruit flies) are sex-linked, meaning they are linked to genes on the sex chromosomes.
Mendel's experiments with pea plants didn't involve sex-linked traits, so results were consistent, whether the traits were inherited from the maternal or paternal parent. However, Morgan's experiment with fruit flies involved a sex-linked trait: eye color. Those traits are found on the X chromosome. Females have two X chromosomes, so a trait can be dominant on one and recessive on the other. Males, having only one X and one Y chromosome, will express the trait present on their single X chromosome. Hence the different results in reciprocal crosses.
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Mendel's pea plant experiments showed consistent trait inheritance, while Morgan's fruit fly experiments revealed sex-linked inheritance, leading to different results in reciprocal crosses.
Mendel's observations on pea plants suggested that traits inherited from either parent followed the same patterns.
This was evident through reciprocal crosses, where traits appeared independent of the parent's gender.
However, Morgan's experiments with fruit flies, specifically eye color, revealed a different scenario.
His reciprocal crosses involving red-eyed and white-eyed flies demonstrated sex-linked inheritance, challenging Mendel's generalization.
The difference arose from the presence of sex chromosomes, with the eye color gene located on the X chromosome.
In Mendel's peas, genes were on autosomes, leading to consistent inheritance.
In Morgan's flies, sex linkage introduced complexity. The gender of the parent carrying the trait mattered due to the distinct inheritance of X and Y chromosomes.
This discrepancy highlighted the significance of understanding the nature of genes, their location on chromosomes, and the influence of sex chromosomes on trait inheritance.
Morgan's work contributed to the emerging understanding of sex-linked traits, refining Mendel's principles in light of the complexities associated with sex chromosomes and their impact on inheritance patterns.
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What can the sperm do inside the fallopian tube in order to get as many nutrients as possible?
Final answer:
Once inside the fallopian tube, tubular fluids help carry the sperm toward the secondary oocyte, where the egg releases molecules that allow the sperm to attach and be absorbed for fertilization.
Explanation:
In order to get as many nutrients as possible, once the sperm enters the fallopian tube, tubular fluids help carry them through the tube toward the secondary oocyte at the other end. The secondary oocyte releases molecules that guide the sperm and allow the surface of the egg to attach to the surface of the sperm. The egg can then absorb the sperm, allowing fertilization to occur.
A 68-year old patient with Alzheimer disease was brought to the emergency room by the staff of a local nursing home. He presented as lethargic with a sallow complexion. He had an admission temperature of 102.4F and a respiratory rate of 33/minute. During respiration, the right side of his chest moved better than the left. He showed dense consolidation of the lower lobe of the left lung on physical exam. A sputum sample revealed blood and a greenish color. A chest x-ray showed tight consolidation of the left lung with evidence of formation of cavities in the lung tissue from cytotoxic damage. The patient complained of chills in the exam room, combined with his fever. A smear of his sputum demonstrated no acid-fast bacteria.
Requried:
Diagnose this case study.
Answer:Left Lobar pneumonia
Explanation:
Since the smear test with acid acid fast bacteria is negative,then the test is tuberculosis The respiration, chills,and fever pointed to pneumonia and the consolidation in the left suggested;left lobar.
8. Complementary bases in DNA bond to each other via a. Hydrophobic interactions b. Covalent bonds c. Strong ionic interactions d. Weak H-bonds between partial (+) charge of H and partial (-) charge from the unpaired electron of N or O e. Weak H-bonds between partial (-) charge of H and partial (+) charge from the unpaired electron of N or O
Answer:
Weak H-bonds between partial (+) charge of H and partial (-) charge from the unpaired electron of N or O.
Explanation:
Green plants are the first living organism in a food chain. Where do plants get the energy that they pass along to the primary consumers in their food chains? A. from secondary consumers B. from the Sun C. from other plants D. from decomposersGreen plants are the first living organism in a food chain. Where do plants get the energy that they pass along to the primary consumers in their food chains? A. from secondary consumers B. from the Sun C. from other plants D. from decomposers
Answer:
The sun
Explanation:
They trap the energy with the help of chlorophyll
There are three layers of neurons in the retina.
Тhe axons of which of these neuron layers form the optic nerves?
a. rod cells
b. bipolar cells
c. cone cells
d. ganglion cells
Answer:
d. ganglion cells
Explanation:
There are 10 ten layers of retina from outermost to innermost:
Layer of retinal pigment epithelium ( this is the outermost layer of retina)Layers of rods and cones (this is the layer of photoreceptors i.e. the cells that are responsible for vision)External Limiting membrane (also known as Outer limiting membrane, it is a network like structure))Outer Nuclear Layer (this layer contains the nuclei of rods and cones i.e. photoreceptors)Outer plexiform Layer (this layer contains synapses of rods and cones i.e. photoreceptors with dendrites of bipolar cells)Inner Nuclear Layer (this layer contains nuclei of bipolar cells)Inner plexiform Layer (this layer contains synapses of bipolar cells with dendrites of ganglion cells)Ganglion cell layer (this layer contains nuclei of ganglion cells)Nerve fiber layer (this layer contains axons of ganglion cells, it is these axons that form the optic nerve)Internal limiting membrane (this layer lies next to the vitreous body which is a jelly-like, transparent substance that fills the space between the retina and the lens)QUESTION:
a. rod cells
This is the incorrect answer choice as the axons of rods synapse with dendrites of bipolar cells in outer plexiform layer.
b. bipolar cells
This is the incorrect answer choice as the axons of bipolar cells synapse with dendrites of ganglion cells in inner plexiform layer.
c. cone cells
This is the incorrect answer choice as the axons of cones synapse with dendrites of bipolar cells in outer plexiform layer.
d. ganglion cells
This is the correct answer choice as axons of ganglion cells form the fibers of optic nerve (Cranial Nerve II/ CNII).
True/False
A microphyll is a simple leaf with only one vasuclar bundle.
Answer:
true
Explanation:
microphyll leaves are small leaves with an unbranched vein (simplevascular system) running through the center
Answer:
True
Explanation:
In plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein. Few of plants with microphyll leaves exist today.
In the root of which of the following are the xylems and phloems arranged in a ring? (A) Gymnosperms.(B) Eudicots.(C) All plants.(D) Monocots.
Answer:
Eudicots
Explanation:
The make up like 75% of flowering plants. Their vascular tissues (xylem and phloem are arranged in a ring like structure
In the root of **eudicots**, the xylem and phloem tissues are arranged in a ring. This type of arrangement is known as the **"vascular cambium"** or **"vascular cylinder."** The corect option is B.
Eudicots, also known as dicotyledonous plants, are one of the two major groups of flowering plants (angiosperms).
1. **Eudicots:** Eudicots are a diverse group of flowering plants that typically have two cotyledons (seed leaves) and exhibit various characteristics, including the arrangement of vascular tissues in their roots. In eudicot roots, the vascular tissues, which include xylem (responsible for water and mineral transport) and phloem (responsible for nutrient transport), are arranged in a distinct ring.
2. **Monocots:** Monocots, the other major group of flowering plants, have only one cotyledon. In monocot roots, the arrangement of vascular tissues is scattered rather than forming a distinct ring. The xylem and phloem are typically arranged in bundles that are scattered throughout the root cross-section.
3. **Gymnosperms:** Gymnosperms, which include conifers and other seed-bearing plants, also have vascular tissues in their roots, but the arrangement can vary. Some gymnosperms have vascular tissues arranged in a more complex manner, rather than a simple ring.
4. **All Plants:** While all plants have vascular tissues (xylem and phloem) responsible for transportation, the arrangement of these tissues in the root can differ based on the plant's evolutionary lineage.
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Check ALL of the following that are possible consequences of reassortment in viruses. A. Reassortment can be used by researchers in the lab to produce "live attenuated" vaccines. B. Reassortment can lead to the evolution of new strains of influenza. C. Reassortment can recombine genetic elements from different influenza strains.
Answer:
All options are correct.
Explanation:
Viruses can be considered in the border line between the living and non living organisms. The viruses behaves like non living outside the host and once enter in the host starts reproducing and acts as living organisms.
Reassortments is the formation of the new genetic material in the host. This reassortment ability can be used by the scientists for the vaccine preparation. This reassortment are responsible for the evolution of new strains as well as can form new genetic material from the different strains of virus.
Thus, all given options are correct.
Hormones come in three categories. BLANK circulate in the blood and act at sites distant from their origin; BLANK pass through ducts; and BLANK act on their local tissue environment.
Paracrines
Exocrines
Endocrines
Answer:
ENDOCRINES circulate in the blood and act at sites distant from their origin;
EXOCRINES pass through ducts;
and PARACRINES act on their local tissue environment.
Explanation:
Exocrines are known for producing external secretions that are released through a duct, usually into the digestive system or the skin
Endocrine are known for producing internal secretions called HORMONES that are transported around the body by the bloodstream. They are also called ductless glands.
Paracrines are known for producing hormones that act on his immediate location or producing gland
Base your answer to the following question on the statement below and on your knowledge of biology. Some internal environmental factors may interfere with the ability of an enzyme to function efficiently. Identify two internal environmental factors that directly influence the rate of enzyme action.
Answer:
Temperature & Presence of any inhibitors or activators.
Explanation:
Temperature: Although a higher temperature increases the rate of reaction, enzymes denature after a specific temperature. At different temperatures, the different enzyme works. So, for getting a particular function from an enzyme, proper temperature is needed. If adequate temperature won't present or temperature will fluctuate, the enzyme won't be able to work effectively.
Presence of any inhibitors or activators: When any inhibitors will present during an enzymatic reaction, the enzyme won't be able to work effectively. And if any activators will present, it will completely change the work efficiency of any enzyme.
A new screening test for Lyme disease is developed for use in the general population. The sensitivity and specificity of the new test are 60% and 70%, respectively. Three hundred people are screened at a clinic during the first year the new test is implemented. (Assume the true prevalence of Lyme disease among clinic attendees is 10%.) Calculate the following values:The predictive value of a positive test is:
A. 33.0%
B. 18.2%
C. 94.0%
D. 22.2%
E. 6.0%
Answer:
The predictive value of a positive test is:
B. 18.2%
Explanation:
Multiple couples living in a small village in the eastern African lowlands, all of whom are heterozygous for the HbS allele, have 500 children among them. Of these children, 139 are homozygous for HbA, 279 are heterozygous for HbS, and 82 suffer from sickle cell disease. Are these data statistically significant? Explain using a chi-square statistical analysis test.
Answer:
Significant
Explanation:
Please see the attachment
Final answer:
A chi-square statistical analysis can be used to determine whether the genotype frequencies of children born to heterozygous parents in an African village (HbSA) differ significantly from expected ratios. The analysis compares observed and expected frequencies of HbAA, HbAS, and HbSS to assess statistical significance, informing on the persistence of the HbS allele due to heterozygote advantage in malaria-endemic areas.
Explanation:
To determine whether the observed frequencies of the genotypes are statistically significant, we can use a chi-square statistical analysis. The expected genotype frequencies in the children can be calculated based on the Mendelian inheritance given that both parents are heterozygous (HbSA).
For heterozygous parents, the expected genotypic ratio would be 1 HbAA:2 HbAS:1 HbSS.
Expected number of children for each genotype based on 500 offspring:
HbAA = 500 / 4 = 125HbAS = 500 / 2 = 250HbSS = 500 / 4 = 125The chi-square test formula is:
χ² = Σ[(observed - expected)² / expected]
Applying the observed frequencies:
For HbAA: (139 - 125)² / 125For HbAS: (279 - 250)² / 250For HbSS: (82 - 125)² / 125The sum of these values is the chi-square statistic. Comparing this value with the critical value from the chi-square distribution table for 2 degrees of freedom (since there are three categories - AA, AS, SS - and one degree of freedom is lost) will determine if the difference between observed and expected is statistically significant. If the calculated chi-square value is higher than the critical value, the null hypothesis (no difference between observed and expected) is rejected, indicating that the observed frequencies are not due to chance alone.
The persistence of the HbS allele is explained by the heterozygote advantage in malaria-endemic regions. Heterozygous individuals (HbAS) are more resistant to malaria compared to homozygous HbAA, maintaining the allele in the population despite the disadvantages to homozygous HbSS individuals. This form of selection is known as balancing selection, illustrating how heterozygotes can have a selective advantage in certain environments, which helps explain the continued presence of the HbS allele in modern populations.
For a pair of genes with alleles: A (dominant) a (recessive) at the first locus; and B (dominant) b (recessive) at the second locus, that operate in a duplicate dominant epistatic manner, what proportion of offspring from a doubly-heterozygous mating are expected to show the recessive phenotype? A. 0.5. B. 1 (it's dominant). C. 15/16. D. 9/16. E. 1/16.
Answer:
E. 1/16
Explanation:
In a duplicate dominant epistasis, when one locus presents a dominant genotype and the other presents a recessive genotype, the dominant one hides the effective of the recessive gene. Therefore, a recessive phenotype will only be observed when both genes are recessive homozygous (aabb).
Assuming a doubly-heterozygous mating (AaBb x AaBb), the probability that both genes are recessive homozygous is:
[tex]P=\frac{1}{2}*\frac{1}{2}*\frac{1}{2}*\frac{1}{2}\\P =\frac{1}{16}[/tex]
1/16 of offspring are expected to show the recessive phenotype.
Which of the following taste sensations is incorrectly matched to the chemicals that produce it? (A) salty-metal ions(B) sour-acids (C) umami-triglycerides and fatty acids(D) sweet-organic substances such as sugar and some lead salts(E) bitter-alkaloids
Option (C) umami - triglycerides and fatty acids is the incorrect match. The umami taste is associated with amino acids like glutamate, not triglycerides and fatty acids.
The question asks which of the following taste sensations is incorrectly matched to the chemicals that produce it. The taste sensations and their corresponding chemical triggers are as follows:
salty - metal ionssour - acidsumami - triglycerides and fatty acidssweet - organic substances such as sugar and some lead saltsbitter - alkaloidsFrom the provided choices, option (C) umami - triglycerides and fatty acids is incorrectly matched. The umami taste is actually associated with amino acids like glutamate and nucleotides, which are found in high concentrations in foods like meat broths and some cheeses, rather than triglycerides and fatty acids. Recent research suggests there might be a separate taste for fats or lipids, which could be where the confusion arises.
Body color in a fish is controlled by one gene with two alleles. Homozygotes for one allele and heterozygotes are bright red, whereas homozygotes for the other allele are brown. You collect 100 individuals from a population and count 84 red individuals and 16 brown individuals. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of the recessive allele
Final answer:
The frequency of the recessive allele in a fish population where 16 out of 100 individuals display the recessive phenotype is 0.4, calculated using the Hardy-Weinberg principle.
Explanation:
To calculate the frequency of the recessive allele using the Hardy-Weinberg principle, we must first designate the allele frequencies as p for the dominant allele and q for the recessive allele. In the observed fish population with individuals displaying two phenotypes (bright red and brown), we know that brown coloration is the recessive phenotype, which means those individuals are homozygous recessive (qq). Given that there are 16 brown (recessive phenotype) individuals out of 100, we can say that q² (the frequency of the homozygous recessive genotype) is 0.16. To find the frequency of the recessive allele (q), we take the square root of 0.16, giving us q = 0.4. Therefore, the frequency of the recessive allele in the population is 0.4.
In order to save the northern spotted owl, _______ was banned on much of the old-growth forest in the Pacific Northwest where the owl lives.
Answer:
Logging
Explanation:
The basic and essential ban on logging in much of the old-growth forest in the Pacific Northwest where the owl lives was to help save the northern spotted owl.
Originally a marine species, stickleback fish now live in both marine and freshwater environments. Marine sticklebacks have pelvic spines that protect them from marine predators. Freshwater sticklebacks do not have pelvic spines, which reduces their likelihood of being caught by freshwater predators that can grasp onto these spines. The lack of spines in freshwater sticklebacks results from a heritable mutation that modifies the function of the Pitx1gene. This mutation occurred:
a.
in the mRNA that is transcribed from the Pitx1 gene in pelvic cells.
b.
in the regulatory region of the Pitx1 gene.
c.
in the coding region of the Pitx1 gene.
d.
in the cells of the pelvis of freshwater sticklebacks.
Answer: option c - in the coding region of the Pitx1 gene
Explanation:
Note that there is LACK OF SPINE, not the presence of defective spine; so, an heritable mutation must have occurred in the coding region of pix1 gene of freshwater sticklebacks resulting in absolute LACK OF SPINE
Final answer:
The lack of pelvic spines in freshwater sticklebacks is due to a mutation in the regulatory region of the Pitx1 gene, specifically in an enhancer sequence upstream of the gene's exons, which affects gene expression in the pelvic area.
Explanation:
The mutation that resulted in freshwater sticklebacks lacking pelvic spines, compared to their marine counterparts, occurred in the regulatory region of the Pitx1 gene. This finding was reported in a significant study published in the Nature journal on April 15, 2004. The mutation affects a noncoding region, specifically an enhancer sequence upstream of the Pitx1 gene exons. This enhancer, when unmutated, activates the Pitx1 gene in the developing pelvic area, leading to the development of spines. However, in freshwater sticklebacks, a mutation in this regulatory region prevents the expression of Pitx1 in the pelvic region, thereby inhibiting the growth of pelvic spines. This adaptation likely offers a survival advantage in freshwater environments where being spineless decreases the likelihood of predation from certain types of predators.
Some people have freckles, and some people do not have freckles. If a child has freckles, at least one parent has freckles. However, the child may have a sibling that does not have freckles. Which statement best describes the presence of freckles? Freckles are not determined by DNA. There are two alleles for freckles. There is no dominant allele for freckles. Freckles are determined by two genes instead of by one.
The statement that correctly describes the presence of freckles is there are two alleles for freckles, hence option B is correct.
What is alleles?An allele is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution.
Small, brownish to reddish dots on your skin are known as freckles. They frequently appear on your face, neck, back, upper chest, hands, and arms, as well as other sun-exposed places. Even though freckles are typically not harmful, it is always a good idea to keep an eye out for any changes.
Therefore, the statement that correctly describes the presence of freckles is there are two alleles for freckles, hence option B is correct.
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A student is performing a Gram stain of a mixed culture of both E. coli and S. aureus and he forgets to decolorize with ethanol. What should his slide look like? A. Both are colorless because the ethanol is needed for the cells to absorb the stains B. The E.coli should appear red/pink and the S aureus should appear blue/purple. C. Both the E. coliand the S. aureus should appear blue/purple. D. Both the E. coliand the S. aureus should appear red/pink.
Answer:
Correct option is C.
Explanation:
Gram staining is a technique of separation of the bacteria based on the cell wall composition. Steps involved in gram staining are:
1) Primary stain application which is known as crystal voilet, it stains all cells purple/blue.
2) Mordant stain application which is known as iodine solution, is added, and form crystal iodine complex, all cells continue to stain blue/purple.
3) Decoloration step, in this step, we can differentiate gram negative or gram positive bacteria. So, decolorizing agent such as ethanol or acetone extracts blue color from thin walled peptidoglycan layer gram negative bacteria, and gram positive bacteria remain blue/purple because it contains thick walled peptidoglycan layer.
4) Counterstain application in this step safranin red dye stain the gram negative decolorized cells red/pink, and gram positive bacteria remain same blue.
So, if a student is performing a Gram stain of a mixed culture of both E. coli and S. aureus, and he forgets to decolorize with ethanol Both the bacteria should appear blue/purple color.
In Drosophila, normal eyes are brick red in color. Homozygotes for recessive alleles at the brownlocus (bw/bw) have brown eyes. Homozygotes for recessive alleles at the cinnabar locus (cn/cn) have bright red eyes. The two genes interact: bw/bw; cn/cn have white eyes. If a pure-breeding brown is crossed to a pure-breeding cinnabar fly, color eyes will the F1 have and what proportion of the F2 will be white?
A.brown, 3/16
B.brick red, 9/16
C.bright red, 3/16
D.brick red, 1/16
E.answers not shown in those given here.
Answer:
answer is d
Explanation:
THe answer is D because this is dihybrid cross and we cross bwbw RR( normal red eye gene) x RR cncn. The F1 progeny has R in all locus of these genes so all will be R as heterozygous. When F1 progeny crossed, the 1/4 of bw cross and 1/4 of cn cross habe bwbw/cncn and will be white. So it will be 1/4x1/4 = 1/16
Following a flood, migration from neighboring populations alters genotypic frequencies of a population of river-bottom midges. Assuming that the conditions for Hardy–Weinberg subsequently are met, how many generations of random mating are required to restore the genotypic frequencies to Hardy–Weinberg equilibrium?(A) Between 3 and 10(B) Between 11 and 20(C) 2(D) 1(E) More than 20
Answer: D
Explanation: Hardy-Weinberg (H-W) principle assumes the following;
1. Random mating
2. No migration
3. No selection
4. No mutation
5. Large population
When genotype frequencies in a population deviate from H-W principle, it takes only one (1) generation of random mating to H-W equilibrium if the above assumptions hold, that the frequencies in males and females are equal and that the locus is autosomal.
In the case of different allele frequencies between the sexes, it will take two (2) generations of random mating to H-W equilibrium.
Also, it will take multiple generations to attain equilibrium for sex-linked loci because one sex has two copies of the gene and the other sex has only one.
Final answer:
Migration after a flood can disrupt the genotypic frequencies of a population. In order to restore the genotypic frequencies to Hardy-Weinberg equilibrium, multiple generations of random mating will be needed. The exact number of generations required will depend on the extent of the frequency changes.
Explanation:
In this scenario, migration from neighboring populations alters the genotypic frequencies of a population of river-bottom midges after a flood. To restore the genotypic frequencies to Hardy-Weinberg equilibrium, random mating is required.
The Hardy-Weinberg equilibrium principle states that, under certain conditions, the allele and genotype frequencies in a population remain constant from generation to generation in the absence of evolutionary forces. These conditions include no mutation, no migration, a large population size, random mating, and no natural selection.
In this case, since migration has disrupted the genotypic frequencies, random mating over multiple generations will be needed to restore the frequencies to Hardy-Weinberg equilibrium. The number of generations required depends on the extent of the genotypic frequency changes and can vary. However, it is likely to take more than 20 generations of random mating to restore the genotypic frequencies to equilibrium.
Which lipoprotein contains the highest percentage of cholesterol?
Answer: low-density lipoproteins (LDL)
Explanation:
Low-density lipoprotein is the major carrier of cholesterol in blood. The loss of triacylglycerols convert Very low-density lipoproteins (VLDL) to low-density lipoproteins (LDL), thus making LDL the lipoprotein with the highest percentage of cholesterol.
Low-Density Lipoprotein (LDL) is the type of lipoprotein that contains the highest percentage of cholesterol. Although chylomicrons do carry cholesterol, they are not the lipoprotein with the highest percentage.
Explanation:The type of lipoprotein that contains the highest percentage of cholesterol is Low-Density Lipoprotein (LDL), often referred to as 'bad cholesterol'. However, it's necessary to understand that lipoproteins are complex particles composed of multiple types of lipids, including cholesterol, as well as proteins. Each type of lipoprotein carries different proportions of these components, with LDL carrying the greatest proportion of cholesterol.
A chylomicron, as described in your question, is one type of lipoprotein. It is large, water-soluble, and transports triglycerides, cholesterol, and other lipids from the intestine, through the lymphatic system, and into the bloodstream. Triglycerides within chylomicrons are broken down into free fatty acids and glycerol that can be used for energy or stored in adipose tissue. The remaining chylomicron remnants are taken up by liver cells, which combine them with proteins to form other lipoproteins that transport cholesterol in the blood.
In summary, while chylomicrons and other lipoproteins do contain cholesterol, it is the Low-Density Lipoprotein (LDL) that carries the greatest proportion of cholesterol.
Learn more about Lipoproteins and Cholesterol here:https://brainly.com/question/35632643
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