A researcher studied the development of resistance to antibiotics by bacteria. She studied several antibiotics to determine how long it took for bacteria to develop resistance. She found that, on average, it took eight years for bacteria to develop resistance to an antibiotic. In some cases, bacteria developed resistance to an antibiotic within a year, and none of the antibiotics were still completely effective on bacteria after 30 years.
How is this possible?

Answers

Answer 1

Answer:

See Explanation

Explanation:

Antibiotic resistance is said to have occurred when a given antibiotic drug is no longer effective against the target organisms. This is as a result of genetic mutation in the organism that enable resistance to the drug.

When a drug is being used against a particular organism, the organism gradually develops genetic mutations that helps it to inactivate the antibiotic drug and increase its chances of survival. These traits are passed on to offspring, hence the onset of resistance to antibiotic drugs.

There are different mechanisms of antibiotic resistance which include; Degrading the antibiotic drugs by the use of enzymes secreted by the organism, altering proteins present in the organism upon which the antibiotic drug acts and changing membrane permeability to antibiotic drugs.


Related Questions

i'm working on a lab report on water erosion on edg lol

pls help i'm so behind

is it okay??

Answers

Some facts about Water erosion :

Water erosion is the detachment and removal of soil material by water. The process may be natural or accelerated by human activity. ... Water erosion wears away the earth's surface. Sheet erosion is the more-or-less uniform removal of soil from the surface.

Water and Wind Erosion (cause)

Water erosion is the removal of soil by water and transportation of the eroded materials away from the point of removal. Water action due to rain erodes the soil and causes activities like gully, rill, and stream erosion leading to the downstream effects of flooding and sedimentation.

Looks pretty good to me!

A probability of 1/4 is equal to a probability of 75%

True or False

Answers

False the probability of 1/4 isn’t equal to 75%

Give two differences between the structure of bacterial cells and the structure of plant cells.

Answers

Answer:

The plant cell is a eukaryotic cell whereas a bacterial cell is a prokaryotic cell. ... Bacterial cells lack membrane-bound organelles, and their genome is arranged into the nucleoid. The main difference between plant cell and bacterial cell is their structure and function

What codes for RNA
plz help

Answers

Answer: DNA

Explanation:

please help me in biology! I will give brainliest.​

Answers

Answer:

1. logistic population growth

2. 72

3. week 2 and weeks 4 - 10

4. 2.78%

5. 12

Give five example molecules​

Answers

These are the five examples for the molecules with the clear definition.

What does aerobic respiration require?

Answers

Answer:

Aerobic respiration requires oxygen.

Based on the living things in the pyramid, please tell me what examples would fit into these categories:
Primary Producers, primary consumers, secondary consumers, and tertiary consumers.

Answers

Answer:

Primary producer = Oak tree leaves

Primary consumer = Caterpillars

Secondary consumer = Blue j a y s

Tertiary consumers = Hawk

Explanation:

An energy pyramid is a graph which shows how energy is transferred or flows from one trophic level to the next. Organisms which occupy the same level in the food chain within an ecosystem belong to the same trophic level.

The shape of an an energy pyramid is a pyramid indicating that the number of living things as well as the amount of energy flow decreases as one goes from one lower trophic level to the next higher level.

At the base of the pyramid are the primary producers which use energy of the sunlight to manufacture their own food. Example is the Oak tree.

The next higher level is the primary consumers who feed directly on the primary producers. For example caterpillars.

The next higher level is the secondary consumers who feed on the primary consumers. For example the Blue j a y s.

The highest levelin the pyramid is the tertiary consumers who feed on the secondary consumers. For example, the hawk.

Which type of selection would be caused by this bird species ?

Answers

Answer:

Directional Selection

Explanation:

Which is the BEST example of a community responding to an external factor?

Answers

Plants and animals thrive on the forest floor after the fall of a white pine causes an opening in the canopy. Many species of raptors fly alongside each other during the autumn migration to warmer climates.

Which property of lights helps in the formation of shadows

Answers

The expansion of light as it dims down and cannot completely processe through a object

:

The reflection and rectilinear propagation of light helps in the formation of shadows. The property that light neither can pass through an opaque object nor can bend to a large extent by itself leads to shadow formation.

Explanation:

#Hope_it_helps

Which step of cell division is the end of the cycle where 2 daughter cell have separated?
A Interphase
B. Anaphase
C. Metaphase
D. Cytokinesis​

Answers

Answer:

D

Explanation:

im pretty sure its cytokinesis

Answer:

D.

Explanation:

3 ways in which our atmosphere is not like a greenhouse
( HELP ME PLEASE)!!!!

Answers

Answer:

1.) The atmosphere is an open system, with heat energy always escaping to space. Unlike the glass it absorbs 95% of the UV in the creation of ozone. This sounds insignificant, but one scientist argues variation in the 5 percent is the cause of warming.

2.) There are no winds in a greenhouse. In the greenhouse and in the atmosphere energy is partly transferred from the heated surfaces through collision between air molecules (conduction). However, in the atmosphere a large portion of that heat is transported vertically by rising air currents (convection), and also horizontally by advection or commonly wind. There are no winds in a greenhouse.

3.) Heat reduction in a greenhouse requires a physical change with a vent to let LW escape or a screen to block SW entering. Clouds are nature’s screen. However, they can block SW and LW, such that we have little idea how clouds work to modify temperatures

Explanation:

The basic idea of a greenhouse is that sunlight or shortwave (SW) energy passes through the glass and heats surfaces. The surfaces radiate that heat as longwave (LW) energy or sensible heat (heat you can feel). LW cannot pass through the glass, so is trapped and raises the temperature in the greenhouse; the glass acts like a one-way valve. A greenhouse is a closed system because the heat cannot escape unless artificially changed by opening vents or blocking sunlight. The glass supposedly represents the entire atmosphere. It also blocks 100 percent of the ultraviolet (UV) portion of the sunlight.

Where do hurricanes most always start?
a) over tropical oceans
b) over tropical land
c) over attic oceans

Answers

a) over tropical oceans

59:14 Organisms that live in the tundra have developed unique adaptations that aid in their survival. Ursus maritimus has a variety of adaptations which enable it to survive in the tundra. It is the largest terrestrial carnivore, but it is also an excellent swimmer that spends much of its time in and near the water hunting its favorite food. It has large paws with small bumps to provide traction as it walks across the ice. Its fur is helpful as camouflage during the winter months, but not as helpful during the summer. Which organism has the adaptations described that enable it to survive in the tundra

Answers

Answer:

Polar bear.

Explanation:

Polar bear is the organism that has the adaptations which enable it to survive in the tundra. the polar bear has white skin and fur on all its body which helps it to camouflage in the ice and to prevent the loss of heat from its body. The polar bear catch its favourite food in the water which is the fish that provide high nutrition to the polar bear. It is a good swimmer and have large paws with small bumps that helps it to provide support while walking on the ice. The scientific name of polar bear is Ursus maritimus whose features are described in the question.

3. Label the parts of the digestive system on the image below by typing in the organ name next to the corresponding letter.

Answers

Answer:

A. Salivary Gland (I believe)

B. Esophagus

C. Liver

D. Stomach

E. Pancreas

F. Small intestine

G. Large Intestine

Critically explain three aspects of growth​

Answers

-toddler.

-childish.

- teenager.

-adult.

- older (over 50 years)

autism

What are the 4 steps of mitosis? What occurs during each?

Answers

Explanation:

There are four stages of mitosis: prophase, metaphase, anaphase and telophase.1) Prophase: chromatin into chromosomes, the nuclear envelope break down, chromosomes attach to spindle fibres by their centromeres 2) Metaphase: chromosomes line up along the metaphase plate (centre of the cell) 3) Anaphase: sister chromatids are pulled to opposite poles of the cell 4) Telophase: nuclear envelope reforms, chromosomes unfold into chromatin, cytokinesis can begin The order of the stages of mitosis can be remembered using the mnemonic PMAT.

Brainiest will be mark, if correctly answered.

No link!!!! I can’t open it!!!!

The process of upwelling occurs as a result of which of the following?

A. warmer, less dense deep water that floats to the surface

B. surface waves that mix surface and deep water

C. cooler dense water rises to the surface, replacing warmer water

D. sunlight that warms deep water that rises to the surface

Answers

Answer:

The answer you are looking for is A

Explanation:

Answer:

A

Explanation:

brainliest please?

A mutation in a gene results in an animal that cannot make a protein that allows muscles to contract which of these is most likely to happen

Answers

Answer:

it will get weaker give water

Explanation:

feed it bread

A heritable change in a person's genetic makeup is referred to as a mutation. Changes can be substantial or negligible. Chromosomes or chromosome parts may be lost, added, duplicated, or rearranged in significant alterations. Thus, option B is correct.

What mutation in a gene results in an animal?

High-energy sources like radiation or chemicals in the environment can both result in mutations. They may also emerge on their own during DNA replication. The two main kinds of mutations are chromosomal abnormalities and point mutations.

Mutations can alter an organism's phenotype, which is its outward appearance, or they can have an impact on the way DNA encodes the genetic information (genotype). When mutations happen, they might kill an organism completely or only partially.

The likelihood that a gene mutation will cause an animal to be unable to produce the protein necessary for muscles to contract is that the animal will perish before producing any progeny.

Therefore, The animal will die before having any offspring.

Learn more about mutation here:

https://brainly.com/question/17130462

#SPJ5

The above given question is incomplete. The complete question is given below:

A mutation in a gene results in an animal that cannot make a protein that allows muscles to contract. Which of these is most likely to happen? * A. The gene will eventually be found in all animals of the species. B. The animal will die before having any offspring. C. The gene will change back to the normal form. D. The animal will pass this gene on to many offspring.

What is speciation? What are the causes of speciation? How does isolation lead to speciation?NO LINKS PLEASE

Answers

The biological species concept tells us that organisms belong to the same species if they can breed to produce fertile and viable offspring. Speciation is therefore the development of reproductive isolation between individuals of an original population.

This can occur in 2 different ways:

1. Allopatric speciation. This is when speciation occurs due to some sort of geographic barrier separates a population into 2 groups. These two groups can then undergo genetic divergence, where each group grows increasingly dissimilar genetically due to random mutations and natural selection acting separately in each group, or from processes such as genetic drift. It is important to recognize that the lack of gene flow between these two groups contributes to the genetic divergence of the groups. Genetic divergence can lead to prezygotic and post-zygotic barriers which prevent production of fertile/viable offspring between the 2 groups. Each of these populations now represents a new species, whose gene pools are completely separate from one another.

2. Sympatric speciation. This is when speciation occurs without the presence of any sort of physical/geographical barriers. Truthfully, this is a much less common occurence. However, it is thought that sympatric speciation can occur as a result of strong divergent selection. Sympatric speciation may also occur as a result of a polyploid individual being introduced into a diploid population.

Isolation leads to speciation by preventing gene flow between 2 groups of an original population, allowing genetic differences between the groups to accumulate over time (via natural selection, genetic drift, etc.). Over time, the accumulation of these genetic differences may result in reproductive isolation between the 2 groups, causing these two groups to be committed to separate evolutionary paths.

Answer: So, how might speciation happen?

Explanation:

Speciation describes a situation where a population in a species becomes so different that it can no longer successfully interbreed with other populations of the ‘same’ species.

What is adaptation? What are the two types of adaptation? Give an example each.

Answers

Answer:

adapting can be learning from your environment and ways to survive etc.

Adapting can also go to sexual reproduction to survive diseases unlike asexual reproduction.

An adaptation is a trait which increases the relative fitness of an individual. The fitness of an individual has 3 components: 1. Probability of survival to reproductive age. 2. Probability of attracting a mate. 3. Average number of offspring. Any trait which increases the fitness of an individual by positively impacting one of these three aspects is considered an adaptation.

There are 2 types of adaptation: physical and behavioral. These are self-explanatory. Physical adaptations could include things like adaptations to morphology or physiology of an organism. Behavioral adaptations are adaptations to, well . . . behavior :)

Você sabe de onde vem á água da sua casa?

Answers

Answer:

No se compa

Explanation:

no se compa no seconpa

Which statement best describes the composition of genetic material?

A. Genes and chromosomes are made of DNA
B. Genes and chromosomes are made of RNA
C. Genes are composed of DNA; chromosomes are composed of RNA
D. Genes are composed of RNA; chromosomes are composed of DNA

Answers

71/6 is the answer tho. Or 11.8333... or 11 and 5/6 (I said this first!!)

Btw, the answer is B

Brainliest?? ;D

In a certain ecosystem, there is a large number of rabbits which graze upon grass. Rabbits are herbivores, which means they only eat plant material. Later, a population of wolves is introduced into this ecosystem. Wolves are carnivores, which means they only eat meat.

How will the introduction of wolves into this ecosystem affect the other organisms?
A.
The change will be helpful to the rabbits and the grass.
B.
The change will be harmful to the rabbits but helpful to the grass.
C.
The change will be helpful to the rabbits but harmful to the grass.
D.
The change will be harmful to the rabbits and the grass.

Answers

Answer:

b

Explanation:

8. What adaptation helps desert plants keep animals away?

Answers

Answer:

Well there are pr ick les, and some may have other adaptations

Explanation:

Select the correct answer.
Which item is made from a synthetic material?
a. cotton pants
b. leather jacket
c. frying pan
d. wicker basket

Answers

A Leather jacket bdheueugenwudhe

Answer:

B is the wrong answer the other guy is wrong

Explanation:

i did the test just now and it was wrong

A man lifts weights and exercises until he is very muscular. He works out
with the hope that his children will also be very strong. A problem with his
idea is that:
characteristics that are acquired during one's lifetime cannot be passed on to
offspring
not all offspring want these new characteristics
these characteristics may make the offspring less likely to survive
offspring are born weak

Answers

Answer:

This man hasn't been taught genetics.

Explanation:

That's not how they work-

A. Characteristics that are acquired during ones lifetime cannot be passed on to offspring

_____ occurs when a species is not able to adapt to changing environmental conditions, not able to successfully reproduce, and dies out.​

Answers

Explanation:

Extinction occurs when a species is not able to adapt to changing environmental conditions,not able to successfully reproduce and dies out.

Which statement describes characteristics of planarians?

Answers

They live in freshwater, are free-living, and reproduce sexually and asexually.

Most planarians are found in freshwater. Since they reproduce through fission, they reproduce asexually. However, since they are heteromorphic, they also reproduce sexually.

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