Biology Puzzle Masters please enter, Biology Questions, Masters please enter

1 b a as in the case of DNA replication but not in the sister chromatids and c as in the separation of the sister chromatids but not in the doubling of the DNA.

d, such as before and during subtract 1 and metaphase, the DNA is duplicated but the chromosomes are not doubled.

2 b Because the transport of k ions is by the sodium and potassium pump (a protein carrier, the carrier of active transport), when it transports k ions into the cell, at the same time, k ions are also transported to the outside of the cell along the concentration (the larger the intracellular concentration, the faster the transport), when the carrier is normal, the concentration of k ions is 3000 times that of the culture medium to reach equilibrium, if the movement of the carrier on the membrane is inhibited, the outward speed is smaller, and the concentration required to reach the equilibrium is less than 3,000 times, and the intracellular concentration decreases

I think the answer is problematic, since the concentration of k ions drops immediately, it should be a sudden process, and the cell membrane becomes fully permeable.

Select C, five bases indicate that there is both DNA and RNA. The 8 nucleotides are 4 deoxynucleotides and 4 ribonucleotides. DNA is a double-stranded structure, and RNA is a single-stranded structure, so 4 nucleotide strands can only be 1 DNA and 2 RNAs.

Option C has three nucleic acid molecules and 4 nucleotide chains, so one double strand and three single strands, the double strands must be DNA, with a total of five bases and 8 nucleotides after analysis. So the other three must have two nucleotide strands, and the other two must be RNA

1. A Reason AAB can be cultivated by using the haploid AB of the first plant

2. There is an error in the second question: the female mouse and the female mouse are crossed, the idea is that the gene mutation and the offspring are all wild and mutated must be dominant, if on the X chromosome, when the mutant male mouse and the wild female mouse are crossed, the female mouse is all mutated, and the male mouse is all wild, otherwise autosome.

3. b Just remember that polyploid metabolism is vigorous, adaptable to the environment, and it is manifested as disease resistance, drought resistance, cold tolerance, and wide distribution.

4. D. The sex ratio of the population is generally divided into three types: male and female equivalent: characterized by the fact that the number of females and males is approximately equal. This type is more common in higher animals.

Females and males: Characterized by a significant number of females than males. This type is commonly found in artificially controlled populations and groups of animals such as bees and elephant seals, where hundreds of male bees, one queen bee and hundreds of thousands of worker bees are all females.

2) Female and male polymorphism: It is characterized by a significant number of males than females. This type is rare.

Such as domestic termites and other animals that operate social sexual life. If bees only look at individuals with reproductive ability, they can also be regarded as female and male polymorphic.

a Favorable mutations are retained and the original gene pool must be changed b Migration and migration strengthen gene exchange c Small population The base is small.

5. b No need to explain, just remember.

6. (1) A35% calculates 39% 2+20% A65% calculates 30% 2+%50

2）aa20%*20%=4% aa50%*50%=25% a35% a65%

3) The genotype tends to be heterozygous and the population tends to be stable.

7. d The environment determines the direction of natural selection.

Water. Free diffusion of sodium ions. Active transportation.

2.Protein.

3.There is no figure ?..It's trapezoidal.

4.Distribution of inorganic salt ions on both sides of the cell membrane.

1. Free diffusion, active transportation.

2. Protein.

3. Proportional graphics.

4. Ions enter and exit the cell.

1.free diffusion; Active transportation.

2.Proteins (trypsin is what breaks down proteins, so. 3.Proportional graphic resembles a ground segment.

4.Changes in the amount and location of ions inside and outside the cell.