Organism solves not just the answer, but every option where it is wrong.

A restriction endonuclease recognizes only one specific segment of deoxynucleotide. (6 deoxynucleotides to form the recognition sequence).

To produce transgenic disease-resistant rice, gene gun method, pollen tube channel method, and Agrobacterium transformation method can be used. (No E. coli anything).

Resistance genes on the vector facilitate the selection of cells containing recombinant DNA. (Correct).

In genetic engineering, exogenous genes can be obtained directly from the gene pool; The marker gene is conducive to the screening of the target gene. (Marker genes have nothing to do with expression).

The cultivation of genetically modified plants takes advantage of the totipotency of cells. (Yes, plant tissue culture is used in the second half of the cultivation of transgenic plants, a process that takes advantage of the totipotency of plant cells.)

New species of organisms cannot be cultivated using genetic engineering. (New species should have reproductive isolation, while genetic engineering is only modified on gene fragments, not reproductive isolation).

Correct, choose B and ask again if you don't understand it, you will have to reply. Thank you.

1 Only one specific deoxynucleotide sequence can be recognized.

2 E. coli should be Agrobacterium.

3 pairs. 4 Gene Library.

5 Not right or not quite right.

There are many ways to transgenetize, if the foreign gene is introduced into callus or mesophyll cells, and the cells carrying the foreign gene are cultivated into plants through redifferentiation, the totipotency of plant cells is used, such as the gene gun method or the leaf disc method.

There are also methods that do not use tissue culture for transgenesis, such as pollen tube channel method, which does not use cell totipotency.

6 Genetic engineering often modifies only a very small number or one gene of an organism, so that it only breeds a new species of organism, which cannot be a species.

Online answer B says 3,5 yes.

a. There is no new base self-cause. All.

It turns out that there is bai in the genotype.

b. There are two divisions of du

Each division yields two different gametes, zhi

There are four possible DAOs, but it can only choose one of them.

Not to mention that it may be a secondary oocyte of one; The first polar body 0 species) c, I didn't say gender, why it must be oocyte.

It's 1 3. It has been determined that it is a girl, so it doesn't matter if there is a probability of having a boy or a girl. gave birth to a girl and must be right-handed, so don't worry about the probability that she is left-handed.

Now to calculate, both parents are rr, then the right-handed girl has an rr probability of 1 3, an rr probability of 2 3, and she marries a left-handed man, rr, and the probability of having a left-handed child is obviously 1 3.

It's 1 2Because the female genotype of F1 may be RR or RR, the RRXRR chance is 0 and RRXRR is 1:1, so the total probability is 0+1 2 1 2

The answer is 1 3.

The girl has been determined to be right-handed, so there are only two cases, RR and RR, where 2 3 is RR and 1 3 is RR

To make the offspring appear left-handed, then 2 3 * (1 2) = 1 3

The probability of a girl bb is 1 3 bb is 2 3 (known to be a girl, 1 2 is not necessary), so the probability of having a left-handed child is 1 3.

It's purely a matter of probability, and I don't know what the current middle school biology teaches is useless.

1.Red-eyed female Drosophila is dominantly homozygous.

The red-eyed female flies in the experiment are known to be dominantly homozygous, and the inheritance of this eye color is with the X chromosome. It is assumed that the allele that controls eye color is b. b then the red-eyed female in experiment 1 is xbxb, the white-eyed is xb, the genotype of y's offspring is xbxb and xby, so all are red-eyed

Sorry, we didn't talk about that wing, so we don't know how.