true because they are driven by the ATP made by the light-dependent reactions. Both systems shut down in the dark. The light-independent reactions can last a little longer if there is ATP remaining in the chloroplast.
appear; disappear
im not 100% sure if thats what is being asked, but they fit and are true
Answer:
isotonic solution
Explanation:
this means the inside and outside of the solute are the same
Analyze the human karyotype and give two examples of pairs of metacentric chromosomes, two examples of telocentric pairs, and two examples of acrocentric pairs.
Answer: The test that is conducted to evaluate and identity the shape,size and number of chromosomes in cells of organism is called the Karyotype.
Metacentic chromosomes are X - shaped chromosomes. They have centromere at the middle, which makes the arms of the chromosomes equal in length. Therefore any type of chromosomes with equal length of arms is said to be Metacentic. Thus chromosomes on position 1,13, 16 , 19 and 20 are examples.
When a pair of chromosomes showed a regular segregation at anaphase of meiosis, they are said to be telocentric. They are type of chromosomes in which the centromere are located at the terminal ends of the chromosomes, with the telemeres extending from theses ends.Hence during segregation, the ends of telocentric chromosomes are orientated towards the poles of the cells. example is the alphabets ''i'' shaped chromosomes in mice and 29 pairs autosomes in Angora goats.
When the centromere is located in such a way that one arm lenght of a chromosomes is longer than the other, then this is called acrocentric. Example is chromosome 21 of down syndrome.others are 13, 14, 15, 22, and Y-chromosomes.
Explanation:
Answer:
Over time, a series of random occurrences can cause an allele to become more or less common in a population. This is called Genetic drift.
When a population is severely reduced by an environmental disaster such as a fire, the result is a Bottleneck effect due to the reduced genetic diversity of the survivors.
The Founder effect can occur if a small group of organisms migrates to a new location and becomes isolated from the rest of the population.
Explanation:
Genetic drift is an evolutive force. It is the random change that occurs in the allelic frequency of a population through generations. Its effects are harder in a small-sized population, meaning that the magnitude of this change is inversely related to the size of the original population.
Genetic drift results in some alleles loss -including the beneficial ones-, while some other alleles get fixated. Low-frequency alleles are the most likely to be lost. The changes produced by genetic drift accumulate in time and results in a loss of genetic variability within a population.
Genetic drift affects a population and reduces its size dramatically due to a disaster or pressure -bottleneck effect- or because of a population split -founder effect-. The bottleneck effect most likely affects smaller populations.
- <u>The bottleneck effect</u> -a case of genetic drift-, mostly affects smaller populations after the occurrence of a natural disaster or some human action -such as extensive hunting, for instance-. These events might act as a pressure that reduces significantly the number of individuals in a population. In these situations, some alleles are lost, and the survivors have a different genetic charge than the one of the original population. There might be a reduced genetic variability, with a possibility of developing a peculiar allelic component. If the survivors in the population carried or developed a mutation, probably this mutation passed from generation to generation.
- <u>Founder effect</u> refers to the origin of a new population from only a few individuals that are coming from a bigger-sized population. These founder individuals, which are carrying some of the genes of the original population, settle down in a new area and reproduce. The new and small population might or might not be genetically representative of the original one. Some rare alleles might be exceeded or might be lost by complete. Consequently, when the small population increases in size, it will have a genetically different composition from the original one. In these situations, genetic variability is reduced, and there exists the possibility of developing a peculiar allelic composition. When the number of individuals that originated the new population is low, the founder effect will be very extreme because the genetic drift effects are inversely proportional to the original number of individuals.