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Montano1993 [528]
3 years ago
15

Cystic fibrosis is the most common lethal genetic disease in the United States. It strikes one out of every 2,500 people of Euro

pean descent, though it is less common in other groups. Cystic fibrosis is the result of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Over 1,800 different mutations have been identified that can cause cystic fibrosis. People who inherit two recessive CFTR alleles have the disease. Why do certain mutations cause cystic fibrosis?
Biology
1 answer:
IrinaVladis [17]3 years ago
3 0

Answer and explanation:

Cystic fibrosis occurs due to mutations in the CFTR gene, causing deficient ion transport in patients through cell membranes with a reduction in the amount of water from bronchial secretion.

This decrease makes the secretion more adherent to the bronchial walls and compromises the cleaning of these channels, facilitating pulmonary infections.

The disease also causes the blockage of the pancreas ducts, reducing the arrival of digestive enzymes in the intestines.

For an individual to develop cystic fibrosis by mutations, it is necessary to have both chromosomes 7 with the mutated CFTR gene. This means that a person needs to inherit mutated chromosome 7 from his mother and father.

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Biochemical and differential tests can be incorporated into growth media or performed on isolated colonies after they have been
Cloud [144]
<h2>Differential test</h2>

Explanation:

A differential test helps to distinguish that which species lack or have the particular biochemical process,the three differential test media are:

1) Blood agar: Blood Agar is an enriched medium which is used to culture those bacteria or microbes that do not grow easily

  • It is also required to detect and differentiate haemolytic bacteria, especially Streptococcus species
  • It is also a differential media in allowing the detection of hemolysis (destroying the RBC) by cytolytic toxins secreted by some bacteria, such as certain strains of Bacillus, Streptococcus, Enterococcus and Staphylococcus

2) Eosin methylene blue agar (EMB): It is a selective and differential medium used to isolate fecal coliforms

  • Eosin methylene blue are pH indicator dyes which combine to form a dark purple precipitate at low pH; they also serve to inhibit the growth of most Gram positive organisms
  • Sucrose and lactose serve as fermentable carbohydrate sources which encourage the growth of fecal coliforms and provide a means of differentiating them

3) Mannitol Salt Agar (MSA): It is a selective and differential medium

  • The high concentration of salt (7.5%) selects for members of the genus Staphylococcus, since they can tolerate high saline levels
  • Organisms from other genera may grow, but they typically grow very weakly

Three examples of tests which are done on colonies are:

1) Catalase test: Catalase is an enzyme that breaks hydrogen peroxide (H2O2) into H2O and O2

  • Hydrogen  peroxide is often used as a topical disinfectant in wounds, and the bubbling that is seen is due to  the evolution of O2 gas
  • A small amount of growth from the culture is placed onto a clean microscope slide
  • Few drops of H2O2 onto the smear is added
  • A positive result is the rapid evolution of O2 as evidenced by bubbling
  • A negative result is no bubbles or only a few scattered bubbles

2) Indole test: The main requirement for a suitable indole test medium is that it contain

s a sufficient amount of tryptophan

  • Tryptone broth is commonly used
  • The tube of tryptone broth with a small amount of a pure  culture is inoculated
  • Incubation is done at 35°C (+/- 2°C) for 24 to 48 hours
  • To test for indole production, 5 drops of Kovács reagent is directly added to  the tube
  • A positive indole test is indicated by the formation of a pink to red color  in the reagent layer on top of the medium within  seconds of adding the reagent
  • If a culture is indole negative, the reagent layer will remain yellow or be  slightly cloudy

3) Urease test: Urease is a constitutively expressed enzyme that hydrolyzes urea to carbon dioxide and ammonia

  • The urease test identifies those organisms that are capable of hydrolyzing urea to produce ammonia and carbon dioxide
  • Urease test media contain 2% urea and phenol red as a pH indicator
  • An increase in pH due to the production of ammonia results in a color change from yellow (pH 6.8) to bright pink (pH 8.2)
  • Urea broth is a highly buffered medium requiring large quantities of ammonia to raise the pH above 8.0 resulting in a color change
4 0
3 years ago
How is cytokinesis different in plants and animals?
aksik [14]

Answer:

The main difference between plant cell and animal cell cytokinesis is the formation of new cell wall surrounding the daughter cells. Plant cells form a cell plate between the two daughter cells. In animal cells, a cleavage furrow is formed between the two daughter cells.

Explanation:

Have a great day!

7 0
2 years ago
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Humans and dogs often have a relationship in which the dog provides protection and companionship in return for food and shelter.
evablogger [386]
 The bond between humans and dogs has lasted thousands of years and has even shaped the way our brains have developed. Our canine companions affect us in a surprising amount of ways, from boosting our immune systems to staving off dementia. With everything that dogs do for us, it’s no wonder they’ve been nicknamed “man’s best friend”.   Our history with dogs goes farther back than our history with domesticated livestock, including sheep and cows. Evidence has been found that supports dogs and humans living together as far back as 13,000 years. Initially, packs of wolves would follow humans, looking for food scraps. At some point the friendlier wolves approached the humans, who in turn took them in as companions. The bond was mutually beneficial in that humans could provide shelter and protection, and wolves could help bring down prey. Friendly wolves were bred with other friendly wolves, to eventually become dogs. What’s interesting about this, is that dogs evolved alongside humans, so they are able to connect with us on a deeper level than many animals today.  



While it is interesting to note the evolution from wolf to dog, the effect dogs have had on humanity could be considered just as fascinating. Recent research has found that looking into a dog’s eyes activates the same hormonal response that bonds us to human babies. Scientists at Azabu University in Japan brought in 30 dog owners and a few wolf owners for the experiment. Owners were asked to stare into the eyes of the animals for a set period of time, with urine samples collected from all participants before and after the study. The result was that the dogs who stared the longest into their owner’s eyes experienced a 130 percent rise in oxytocin levels (a chemical associated with the feeling of happiness), with the owners experiencing a 300 percent rise in oxytocin. None of the wolf-owner duos experienced an increase in oxytocin. This could explain why we feel so attached to our furry companions, even going to far as to treat them like children.

Today, as it was thousands of years ago, dogs are not just companions. Service dogs, therapy dogs, herding, and police dogs are everywhere in Western society, with new positions evolving constantly. More than 2,300 reading education assistance dogs around the country are helping children to improve their literacy skills by simply being present. Children who are uncomfortable reading aloud to people are able to practice with a nonjudgmental companion, and are more likely to practice words they do not immediately recognize. In one study, children who read to dogs over the course of 10 weeks exhibited a 12 percent improvement in reading skills, while those who did not read to a dog showed no improvement

Dogs can have a huge impact on the development of children, both physically and mentally. A 2012 report in the journal Pediatrics states that children who grow up in home with a pet are less likely to get sick than children who live pet-free. Researchers believe that by exposing children to pet dander and other microbes brought in from outside, children’s immune systems get an early boost in development. This early exposure helps them fend off illness later on in life, and results in less use of antibiotics that could cause bacterial resistance.

Another study found that children who owned a dog were more empathetic and pro-social compared to children who grew up without a dog in the house. Children also reported higher levels of positivity about their home and family when they had a strong bond with the dog. Children can greatly benefit from the love given and received by four-legged family members who provide unconditional comfort.

The benefits boosted by our furry friends can be observed in both children and adults alike. Dog owners, on average, have lower blood pressure, lower cholesterol levels, fewer hearts attacks, and suffer from less medical problems on average. This could be in part because dog owners typically take their dogs on walks, which is part of a healthy lifestyle. Dogs also encourage humans to be more social. Studies have found that 40% of people reported making friends much easier as the result of owning a dog. And you know that happy feeling you get at the end of a long work day when you see your furry friend? People who own dogs have the lowest response to stress. It really does seem like dogs make us better people.

4 0
3 years ago
Read 2 more answers
Mitosis or Meiosis?<br> I make diploid cells.___________
madreJ [45]
Mitosis. Meiosis creates haploid cells.
7 0
3 years ago
Quincy and Leon are comparing sponges and cnidarians. Quincy says that spicules in sponges are similar to stinging cells in cnid
Gennadij [26K]

Answer:

Quincy is correct, because both spicules and stinging cells can be used to protect against predators.

Explanation:

its right on the quiz

4 0
3 years ago
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