![briseidam6683](/avatars/25026.jpg)
briseidam6683
20.09.2020 •
Biology
Which of the following statements regarding restriction enzymes is NOT true?
A) Most restriction enzymes recognize sequences of 20-25 bp in length.
B) Bacteria can add methyl groups to their DNA to prevent digestion by endogenous restriction enzymes.
C) Most restriction enzymes recognize palindromic sequences in host DNA.
D) Restriction enzymes may produce either sticky or blunt ends when digesting host DNA.
Solved
Show answers
More tips
- F Family and Home What Kind of Wedding to have After 11 Years of Marriage?...
- C Computers and Internet How to Top Up Your Skype Account Without Losing Money?...
- H Health and Medicine How does childbirth happen: everything future mothers need to know...
- H Health and Medicine What Are the Best Vitamins? A Scientific View on Vitamin Supplements...
- A Auto and Moto How to Deregister a Car in Moscow?...
- A Auto and Moto What Is the Cost of Customs Clearance for a Car in Russia?...
- A Auto and Moto How to choose the right drive for your BMW...
- H Health and Medicine 10 Tips for Avoiding Vitamin Deficiency...
- L Leisure and Entertainment Mysteries of the Name Vyacheslav Dobrynin...
- H Health and Medicine What makes Graves’ disease dangerous?...
Answers on questions: Biology
- B Biology How can scientists use the fossil record in sedimentary rock to learn which species lived at different times in earth s history?...
- B Biology Where would you expect the air pressure to be greatest in a valley?...
- B Biology How many dogs are in the river...
- B Biology Explain any patterns or trends displayed by the group 1 stars...
- B Biology Which blood vessels supply oxygenated systemic blood to the lung tissue?...
- B Biology Which of the following organisms do not belong to the phylum chordata? a. whale b. earthworm c. lizard d. snake...
- B Biology Which two organisms are most closely related, based on the tree above?...
- B Biology Which consumer or producer has the most biomass...
- B Biology In finding nemo, in what ways does dory merlin and how does merlin dory? (what is their symbiotic relationship)...
- B Biology 1. Compare the distances between each of the inner planets to the distances between the outer planets. ...
Ответ:
The correct option is option A
Explanation:
Restriction enzymes are endocleases that cleave DNA fragment (of usually four, five or six nucleotide long) at specific sites to produce blunt or sticky ends. They recognize palindromic sequences of host DNA when cleaving the specific sites. The sequences below (on complementary strands) give an example of a palindromic sequences.
5'-CCC║GGG-3'
3'-GGG║CCC-5'
As can be seen above, when read from 5' to 3', the two sequences are the same despite being on opposing strands. And when cut between the guanine (G) and cytosine (C) (as shown above), it produces a blunt end. But when cut as shown below produces a sticky end.
5'- G║AATTC -3'
3'- CTTAA║G -5'
The explanation above shows options C and D are right while option A is wrong (hence the correct option).
Also, bacteria prevent their own DNA from been digested by restriction enzymes by adding methyl group to their restriction sites which prevents restriction enzymes from recognizing restriction sites of their DNA; this generally makes bacterial DNA to be highly methylated. This explanation makes option B right also.
Ответ:
Mix scraps of meat (the older, the better) with something sweet. Lots of people swear by using rotten fish or shrimp, which probably work best because they smell so much. Bait for Fruit Flies: Use fruit (the riper, the better), apple cider vinegar, fruit juice, syrup, wine, beer, or any combination