Insert 2 base pairs in the DNA coding sequence, this mutation is called ___.

A、specifically label the DNA sequence of interest within a given band.

B、visualize the separated DNA bands in the gel.

C、identify the desired nucleotide sequence by complementary base pairing.

D、denature the DNA sequence of interest.

A、that is the opposite direction of the replication fork

B、that is the only way it can bind to DNA

C、that allows synthesis to resume easily if one base needs to be removed

D、this is the only direction permitted by the double helix

【填空题】AV Clip 21: Exercise May Affect Your DNAAV 21 Exercise May Affect Your DNA.avi Watch the video clip three times and complete the following passage by filling in each blank with the word from the video clip. People who get regular exercise tend to live longer. A new study has some (1)_______ as to why. Researchers in Britain studied more than 2,400 white twins, most toward fraternal, but some are (2)________. They took blood samples from the twins to study their DNA, specially the (3)_________ caps called telomeres that sit on the end of chromosomes to prevent DNA damage. The (4)_________of a person’s telomeres decreases with age. But when doctors studied the twins, they found that the (5)_________of the people who exercise—200 minutes exercise or more per week were longer than those of people who exercised just 60 minutes or less per week. In fact, the telomere size(6)__________ suggest that most active people were (7)__________ten years younger than the least active. Experts recommend adults get at least 30 minutes physical activity each day to help keep their heart, (8)_________and DNA young for years to come.

A、3'-TACCACGGCCGGACTTCAGT-5'

B、3'-TAGGACCCGGGGACTTCAGT-5'

C、3'-ATGGTGCCGGCCTGAAGTCA-5'

D、3'-GAGGCACGGCCGGTCAACAGA-5'

A、Protein production

B、Two new daughter strands

C、Heavy DNA

D、Induced mutations

E、mRNA transcripts

A、a loss of an AT base pair from a gene

B、the addition of methyl groups to cytosines in the promoter region of a gene

C、the substitution of an AT base pair by a GC base pair in a gene as a result of a mistake during DNA replication

D、a deletion that simultaneously removes two genes from the genome

E、None of these examples represents epigenetic changes.

2. Creation of the flag Throughout the process, the maple leaf and the colours red and white have been a recurring, common theme between experts and heraldry enthusiasts. After various discussions over time, there were three final designs to choose from: ·a red ensign with the fleur-de-lis and the Union Jack ; ·a flag with three joined maples leaves in between a blue border; ·and the single leaf design in between a red border. Alan Beddoe, a retired naval captain and heraldic adviser to the Royal Canadian Navy, brought forth the three joined maples leaves. That designed was favoured by heraldist and historian Colonel Fortescue Duguid. Though, it was not the first time the single leaf design was suggested. In 1919, Major General (later the Honourable) Sir Eugene Fiset had recommended the single red maple leaf on a white field as Canada’s emblem. The device had been worn by all Canadian Olympic athletes since 1904. The same design was again proposed for the national flag in 1964 by Dr. George Stanley. John Matheson, Member of Parliament from Ontario and the Prime Minister’s parliamentary secretary, played a critical role in the creation and selection of the Flag. He oversaw and coordinated the research and proposal throughout the process, and presented the single leaf design which is based on a strong sense of Canadian history. The combination of red, white and red first appeared in the General Service Medal issued by Queen Victoria. In 1921, red and white were proclaimed Canada’s national colours by King George V. The final design of the stylized maple leaf was established by Jacques St-Cyr, the precise dimensions of red and white were suggested by George Bist, and the technical description of precise shade of red was defined by Dr. Günter Wyszecki. On a Friday afternoon in the late autumn of 1964, an urgent request came from Prime Minister Lester B. Pearson to the desk of Ken Donovan. Mr. Donovan was then an assistant purchasing director with the Canadian Government Exhibition Commission, which later became a part of the Department of Supply and Services. The Prime Minister wanted prototypes of the proposals for the new flag to take to his residence at Harrington Lake the next morning. There were three proposals: ·a Red Ensign with the fleur-de-lis and the Union Jack; ·a design that included three red maple leaves; and ·a red flag with a single, stylized red maple leaf on a white square. The only design samples in existence were drawings on paper yet Mr. Donovan and his team of designers managed to do the impossible - the flag prototypes were assembled in just a few hours. Graphic artists and silk screeners Jean Desrosiers and John Williams were called in to work on the Friday evening and since no seamstress could be found, the flags were stitched together by the young Joan O’Malley, daughter of Ken Donovan. After a great deal of work, the National Flag of Canada was proclaimed by Her Majesty Queen Elizabeth II on January 28, 1965 and raised for the first time in an inauguration ceremony on Parliament Hill on February 15, 1965. 3. Who played a critical role in the creation and selection of the Flag?

A、Alan Beddoe.

B、Sir Eugene Fiset.

C、John Matheson.

D、Jacques St-Cyr.

A、Bacterial DNA

B、Viral DNA

C、Fungal DNA

D、Viral RNA

A 21-year-old female presents to the physician’s office with complaints of very painful vulvar ulcers. The patient states she has had the symptoms for approximately 3 days, and they are worsening. She says that prior to the ulcerations, there was a burning and tingling sensation of the skin in the same area. She has noted similar symptoms like this before and has been told it is sexually transmitted. On examination you see multiple extremely tender, vesicular (blister-like) lesions on an erythematous (red) base on both labia major of the vulva. She has a moderate amount of tender inguinal lymph nodes bilaterally. The physician uses a swab to sample the ulcer and send it off for diagnostic analysis. 1.What is the most likely diagnosis? 2.If the test is for deoxyribonucleic acid (DNA), what method would be used to amplify the fragments of DNA sampled?

3. Instead of reducing the body's supply of angiotensin II, Angiotensin II receptor blockers(ARBs) block receptors for angiotensin -- a substance that makes blood vessels contract and narrow, as if placing a shield over a lock. This blockade prevents the chemical's artery-tightening effects, and lowers your blood pressure. ARBs can take several weeks to become fully effective. Possible side effects include dizziness, muscle cramps, insomnia, and high levels of potassium. Women should not become pregnant while taking this medication. What does the “chemical” refer to?

A、A. Angiotensin

B、B. ARBs

C、C. Receptors for angiotensin

D、无