Why is the structure of dna called a double helix?
a.because dna is made of two strands of nucleotides wound together in a spiral.
b.because the number of copies of dna doubles with each round of pcr
c.because two copies of dna are inherited, one each from the mother and father
d.because each of the curved dna subunits appears twice whenever it appears submit for grading save and finish later?

Answers

Answer 1
A- DNA is a double stranded molecule :)

Related Questions

Now is the month of maying" is also called a ________ madrigal.

Answers

Ballet

It was written by Thomas Morley during 1959. The song is in bawdy double entendre. This is considered as a song for dancing during spring. The song is based on the canzonet So ben mi ch'a bon tempo used in 1950. This is one of the most famous English balletts, which is a light dance song that is similar to a madrigal. This forms a key part of Oxfords morning celebration.

A new wastewater treatment plant opens in an area where raw sewage used to be dumped directly into a bay. Which two types of pollution will be reduced the most by the new plant?
A. Toxic and sediment
B. Sediment and bacterial
C. Toxic and nutrient
D. Bacterial and nutrient

Answers

D. Bacterial and nutrient

The correct answer is option D

If a new waste water treatment plant is opened in an area it will be full of bacterial toxin and nutrient.

Sewage usually contains bacteria and nutrients and is directly discharged into the bay.

The bacterial toxin and nutrients can cause different kinds of infection and form algal bloom in water respectively.

Excessive nutrients in water will lead to the growth of algae in the water and will decrease the oxygen content of water in later days.

Which class of glycoconjugates contain both d and l-amino acids?

Answers

I believe peptidoglycans (Murein) contain both d and I-amino acids.

The right answer is B. peptidoglycans.

Peptidoglycan (or murine, or mucocomplex, or mucopeptide) is a component of the bacterial wall maintaining the shape of cells and providing mechanical protection against osmotic pressure. It forms a thin layer in Gram-negative bacteria and a thick layer in Gram-positive bacteria.

It consists of a carbohydrate moiety (= polysaccharide) and a peptide moiety. The polysaccharide is a glycosaminopeptide polymer wherein N-acetylglucosamine (NAG) and N-acetyl-muramic acid (NAM) are linked by beta (1-4) osidic bonds. This bond can be cut off by lysozyme. NAM is a specific compound of bacterial walls. Two polysaccharides are linked by peptide bridges at the level of the NAM, formed by different amino acids: D-alanine, L-alanine, glutamic acid, L-lysine, diaminopimelic acid (lysine analog). Amino acids D are specific for the bacterial wall, they are never found elsewhere.

What word is used to describe the possession of one dominant allele and one recessive allele?

Answers

 The word would be Heterozygous

Heterozygous is the word used to describe the possession of one dominant allele and one recessive allele. For example, in hybrid tall plant (Tt) genes are present. T is dominant gene and its allele t is recessive gene. In heterozygous organisms dominant allele is expressed and recessive allele is unexpressed in phenotype.

In a hypothetical population of 1000 frogs there exists a gene, d, with two alleles (d and d). 280 of the frogs are homozygous dominant (dd), and 220 are homozygous recessive (dd). what is the frequency of heterozygotes in the population?

Answers

To answer this question, subtract from the total population of 1000 the homozygous dominant (DD) frogs of 280 and the homozygous recessive (dd) frogs of 220, and you are left with 500 frogs that by default are heterozygotes (dD). The frequency of these frogs would be 500/1000 = 0.5

Answer:

The frequency of heterozygotes is 0.5

Explanation:

The frequency of heterozygotes can be get from the Weinberg equation:

p + q = 1

The number of individuals = 1000

The frequencies of dominant (DD) = q = 280/1000 = 0.28

The frequencies of recessive (dd) = p = 220/1000 = 0.22

The frequency of heterozygotes is equal to:

q + p = 0.28 + 0.22 = 0.5

During the inflammatory phase of diverticulitis treatment includes antibiotics and a diet that is

Answers

Along with the treatment of antibiotics, a diet that is low in fiber is also advised during the inflammatory phase of diverticulitis. Diverticulitis is the inflammations of abnormal outpouchings in the colon. A low fiber diet will increase the bulk of the stools and make them harder; therefore soft stools will not lodge inside the diverticula and cause more inflammation.

Ms. Green's biology students were studying cellular respiration. One simple organism, yeast, can be used to test the rate of fermentation using different variables. Each group mixed 2 grams of yeast with warm water and placed the mixture into one of five test tubes. The variables can be seen on the graph of student data. Test tube five held only yeast and warm water. The groups used the height of the carbon dioxide bubbles produced in a test tube to determine which group had the highest rate of fermentation. Based on the data collected, what must be added to the yeast in the test tube in order to facilitate fermentation?

Answers

I believe the answer is D) a food source

a food source

Both glucose and sucrose are sugars, a food source. The test tubes with boiled water and just water showed no fermentation taking place. The boiling killed the yeast; plain water had no food present.

Explain how this human impact on a forest ecosystem might affect the ability of some species to move to more suitable habitats as earth's climate changes

Answers

The possibility human impact refered to in the statement is deforestation. Deforestation is the widespread removal of trees and other vegetation from forested areas for purposes such as agriculture, road construction and other infrastructural development.

Removing sections of forest can create a disconnect between areas of the forest preventing species from moving and otherwise confining them to smaller regions of the forest.
Final answer:

Human activities that contribute to climate change can significantly affect the ability of various species to move to more suitable habitats. This is due to shifting climates and habitat loss. These environmental disruptions pose a major risk of species extinction.

Explanation:

Human impact on a forest ecosystem, particularly through activities that accelerate climate change, significantly affects the ability of some species to move to more suitable habitats. This is because climate change entails a shifting of colder climates towards the north and south poles, which forces species to move with their adapted climate norms while facing habitat gaps along the way. Habitat loss caused by human activities such as deforestation further exacerbates this problem. For example, the unprecedented contact between polar bears and grizzly bears due to overlapping ranges is a result of these climate shifts.

Additional impacts include changes in regional climates, including rainfall and snowfall patterns, making habitats less hospitable. Global warming also induces the melting and refreezing of the poles and higher elevation mountains—a cycle that has historically provided freshwater to environments—that may result in a shortage of freshwater. As earth's climate changes, these complex ecosystem disruptions threaten various species and potentially catalyze a major trend of species extinction.

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Growing coffee bean plants quickly depletes farming soil of important nutrients. After several years of coffee bean production, the soil will become infertile. Which of the following is a consequence of soil infertility?

Answers

Soil infertility has the consequence of striping the soil of all of its nutrients. This prevents a farmer from growing anything in that area until the soil has had time to repair itself. This causes: -risk of famine - leads to farmers using toxic synthetic fertilizer go promote growthetc. 

Which are limiting nutrients for plant growth?

Answers

The answer would be

d) phosphorus and nitrogen

Answer:

phosphorus and nitrogen

Explanation:

edge

exchange list defines group in terms of

Answers

macronutrient content and types of food.

Hope this helps!

-Payshence xoxo

Which is the purpose of transfer RNA?
A.) to code for protein synthesis
B.) to carry the synthesized genetic information from the nucleus to the ribosomes
C.) to synthesize proteins from RNA
D.) to bring amino acids to the ribosomes to be assembled into proteins.
First, & best answer gets 5 stars.

Answers

to bring amino acids to the ribosomes to be assembled into proteins

Final answer:

The purpose of transfer RNA (tRNA) is to bring amino acids to the ribosomes to be assembled into proteins.

Explanation:

The purpose of transfer RNA is to bring amino acids to the ribosomes to be assembled into proteins. RNA is a type of RNA molecule that carries a specific amino acid and recognizes the corresponding codon in messenger RNA during protein synthesis. By bringing the amino acids to the ribosomes, helps in the process of protein synthesis.

So the correct option is D.

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Which of these is a successful time management strategy

Answers

Where are the answer choices?

The conditions favorable to population screening for pre-symptomatic diagnosis of a given disease include:

Answers

Conditions favorable to population screening for symptomatic diagnosis includes a relatively high prevalence of disease, availability of effective treatment, a screening test with high sensitivity and the presence of a physician that can perform the test. Screening is a technique used in population to detect presence of not yet diagnosed disease in individuals without having signs or symptoms. They are several types of this screening such as universal screening,case findings and others. There are several principles employed by the WHO as a guidelines for practice of screening for diseases. Commonly, there are various programmes employed for screening diseases such as cancer screening, PPd test, screening for metabolic diseases and others.

in an experiment to see if having a nurse come three times to visit the homes of newborn babies reduces doctor visits, what is the independent variable

Answers

An independent variable is a variable that can be changed or controlled. A dependent variable on the other hand is a variable that you cannot control. If you look at your problem, you cannot control doctor visits. In this case, it can be categorized as an effect of the experiment, which is a characteristic of a dependent variable. 

The number of nurse visits however, is the controllable variable. It is the cause of the change in the dependent variable. So your independent variable is the nurse visits. 

Answer:

The nurse visits is the independent variable

Explanation:

What are the relative sizes of oocytes in a dormant follicle, a growing follicle, and a graafian follicle?

Answers

Final answer:

The size of oocytes varies among the dormant, growing, and mature Graafian follicles during development. Dormant follicles contain the smallest oocytes, whereas the growing follicles have larger oocytes as granulosa cells proliferate. The mature Graafian follicles house the largest oocytes, which are ready for ovulation.

Explanation:

The question refers to the relative sizes of oocytes during different stages of follicular development in the human ovary, known as folliculogenesis. Oocytes are found within ovarian follicles, and their size and development change as the follicle matures.

Primordial Follicle: In a dormant, or primordial follicle, the oocyte is relatively small and arrested in the first meiotic prophase. This is the initial stage of development.


Growing Follicle (Primary and Secondary Follicles): Next, the follicle enters the growing phase, which encompasses primary and secondary follicle stages. During this phase, the oocyte grows in size gradually. First, primary follicles with a single layer of granulosa cells form and as these cells proliferate, secondary follicles develop with multiple layers of granulosa cells and a maturing oocyte which has secreted the zona pellucida, a critical structure for fertilization. The oocyte here remains a primary oocyte.

Graafian Follicle (Tertiary Follicle): At the final stage of maturation before ovulation is the Graafian follicle, also known as the tertiary or antral follicle. It is much larger compared to the previous stages. A large antrum is formed, the oocyte has grown substantially in size and gains several layers of granulosa cells. This stage ends with the rupture of the follicle and release of the secondary oocyte during ovulation.

It is important to inspect tina's mouth thoroughly because oral cancers are most commonly found:

Answers

The most common type of cancer in the oral cavity is squamous cell carcinoma and the most common area of the oral cavity that is affected by cancers are the lips and tongue. A systematic physical examination of the oral cavity must be done to differentiate a benign lesion to a potentially malignant ones.

When traits inherited from both parents are expressed, the alleles are said to have
A. homozygous recessive alleles.
B. polygenic inheritance.
C. incomplete dominance.
D. mutations.

Answers

I think C. incomplete dominance is the answer to your question

Answer:

B. polygenic inheritance.

Explanation:

Polygenic inheritance occurs when several pairs of genes interact to determine a trait, each with an additive effect on the other. That is, in this type of inheritance the characteristics of both parents are expressed in the offspring. Thanks to this type of interaction there is a very wide variety of phenotypes and genotypes for some characteristics. The interaction of these phenotypes with the environment further increases this variation, such as skin color and height, etc.

which is a drawback to using incineration to dispose of toxic materials? A. fire is a thermal pollutant B. the smoke that results is toxic C. the ashes that result are toxic D. some toxins will not burn

Answers

The answer is the ashes that result are toxic.

Two equal body masses are accelerated, but body a's acceleration one-fourth of body b's. what is the force of body b on body a

Answers

body b will have a force 4 times stronger than body a, causing body b to reverse the direction of body a

Final answer:

The force of body B on body A is equal in magnitude and opposite in direction to the force of body A on body B, according to Newton's Third Law of Motion, regardless of their difference in acceleration.

Explanation:

The question relates to Newton's Second Law of Motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration (F=ma). Given that body A's acceleration is one-fourth of body B's acceleration, and assuming they have equal masses, we can deduce that the force acting on body A is also one-fourth of the force acting on body B due to their proportional relationship as outlined in Newton's Second Law. However, according to Newton's Third Law of Motion, for every action, there's an equal and opposite reaction. Therefore, the force of body B on body A is equal in magnitude and opposite in direction to the force of body A on body B.

This means, regardless of the difference in acceleration between bodies A and B, the force exerted by body B on body A will be equal to the force exerted by body A on body B, maintaining equality in force magnitudes between the two bodies but in opposing directions.

What are some of the human activities that threaten the world's largest surviving regions of rain forest?

Answers

One human activity would be deforestation to make space for recreation or housing. 

Rainforests are the forests growing in the areas of high rainfall which receive rainfall approximately 175-200 cm in a year. Almost half of the rain forests have been destroyed due to the human demand of arable land and wood. The logging interest is for cutting the rain forests for timber, mining operations cut down forests completely to dig mines. Hydroelectric projects destroy large stretches of rain forest by flooding. Road building is another big problem. The destruction of rainforests is also affecting the overall world climate. Current rates of deforestation is 6 million hectares per year and is a major concern threatening the world’s largest surviving regions of rainforests.

The law of segregation states that allele pairs separate during gamete formation. How then do we have two alleles for a trait?

Answers

A gamete is the organisms sex cell. In humans, female gametes are the eggs cells, and male gametes are the spermatozoon. Because of the law of segregation, each gamete carries one allele for a trait, insted of a pair.
However, during sexual reproduction the female gamete and the male gamete come together to form an embryo with the complet pair of alleles for each trait.

In summary, we have two alleles for a trait because one came from our mother and the other came from our father. 

Answer:

its a

Explanation:

An object is dropped on Earth from a height of 15 m. How long did it take for the object to reach the ground?

Answers

you take 15 and divide it by 9.82 (gravity ) and then you have your time which is 1.5

Answer:

1.2 seconds

Explanation:

(2 x 15/9.8)

Trees are able to transport water hundreds of feet up from the roots because of

Answers

the dual action of capillary "sucking" within its xylem, and the loss of water at leaves surface, both of which pulls water upwards

To reduce the likelihood of back pain, use a safe ______ technique. A. Lifting B. Sitting C. Standing D. Lying

Answers

The correct answer is A. Lifting

Answer: Lifting

Explanation:

To reduce the back pain you must know how to lift the objects in a proper position. This is necessary to reduce the effect of the weight of the object.

Bending and uplifting the object in a wrong position can affect your back in a very bad way. So, it is important to keep your posture appropriate while lifting.

Lifting in a wrong position can increase the chances of back injury or back pain.

what 3 animals be affected if owls were removed from the food chain

Answers

I think mice , birds , snakes ( I pretty sure they eat mice , I know their a member of the bird family and I'm guessing snakes

Answer:

Rabbits, mice, and snakes will probably increase since one of their predators is gone.

____ on the blood determine a person’s blood type.

Answers

Ans.

A blood type or blood group of a person is determined by the antigen present on the surface of blood cell of that person. The antigen present on the cell surface may a carbohydrate, glycolipid, protein, or glycoprotein molecule. Humans show four blood groups, which are A, B, AB, and O on the basis of antigen present in their red blood cells.

Thus, the blank can be filled as 'antigens.'

Final answer:

Blood types are determined by the presence or absence of antigens on the surface of red blood cells. The ABO blood type system and Rh blood group are examples of antigen systems used to classify blood types.

Explanation:

Blood types are determined by the presence or absence of different proteins called antigens found on the surface of red blood cells.

For example, the ABO blood type system is based on the presence of two antigens, A and B, on the red blood cells. Individuals can have blood types A, B, AB, or O, depending on the combination of antigens they have. The Rh blood group is another antigen system, with individuals being either Rh positive or Rh negative based on the presence or absence of the Rh antigen.

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Part a when an ectopic pacemaker leads to an extrasystole, the ______.

Answers

When the ectopic pacemaker leads to an extrasystole, the ventricles seem to contract before the atria contracts.

When an ectopic pacemaker leads to an extrasystole, the electrical signals that control the heartbeat originate from a different location than the sinoatrial (SA) node. This can cause a premature contraction, known as an extrasystole, which is an extra heartbeat that occurs outside the normal rhythm.



Here's a step-by-step explanation:

1. Normally, the SA node, located in the right atrium of the heart, acts as the natural pacemaker. It generates electrical signals that initiate each heartbeat.

2. However, in some cases, an ectopic pacemaker may become active. An ectopic pacemaker is an abnormal region of the heart that can generate electrical signals independently of the SA node.

3. When an ectopic pacemaker becomes active, it can initiate an extrasystole. This means that an additional electrical signal is generated, causing an extra contraction of the heart muscle.

4. The extrasystole usually occurs earlier than the next expected heartbeat, disrupting the normal rhythm of the heart.

5. The origin of the extrasystole can vary, depending on the specific location of the ectopic pacemaker. For example, if the ectopic pacemaker is located in the ventricles, the extrasystole will be known as a ventricular extrasystole. If it originates in the atria, it will be called an atrial extrasystole.

6. Extrasystoles can be identified on an electrocardiogram (ECG) as abnormal or premature beats that deviate from the regular pattern.

In summary, when an ectopic pacemaker leads to an extrasystole, the electrical signals that control the heartbeat come from a different location than the SA node, causing an extra contraction of the heart outside the normal rhythm.

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A client with angina is preparing to go home with a prescription for nifedipine, a calcium channel blocker. what should the client be taught?

Answers

The client should be advised not to take the drugs with grapefruit. This is because grapefruit increases the absorption of the drug in the blood. This results to an increase in the level of serum. In this condition the monitoring of blood should be frequent.

Nearsightedness, farsightedness, and astigmatism are all caused by an abnormally shaped retina.
a. True
b. False

Answers

B false because it the cornea
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