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What factor causes the DNA fragments to move in this technique?

DNA is negatively charged, therefore, when an electric current is applied to the gel, DNA will migrate towards the positively charged electrode. Shorter strands of DNA move more quickly through the gel than longer strands resulting in the fragments being arranged in order of size.

What is most likely to occur if an animal population grows larger than the carrying capacity of its environment?

Which statement best describes what is most likely to occur if an animal population grows larger than the carrying capacity of its environment? The birth rate will increase. Both the birth rate and death rate will decrease.

What does natural selection produce changes most quickly in?

Natural selection produces changes most quickly in 1 species with short reproductive cycles.

Which term includes all the activities required to keep an organism alive?

Metabolic activities

When an organism changes and reacts to a stimulus that is the?

A change in an organism’s surroundings that causes the organism to react is called a stimulus (plural stimuli). An organism reacts to a stimulus with a response- an action or change in behavior. Another example is if you are cold, you shiver. The cold is the stimulus while the shivering is the response.

Which processes lead to the greatest variety of genetic combinations?

Fertilization is the process of fusion between male and female gametes; which are haploids and therefore joins to form a diploid zygote and this ensures genetic variation to the fetus as it has received genetic material from two parents.

Which statement concerning production of offspring is correct?

Which statement concerning production of offspring is correct? Production of offspring is necessary for a species to survive, but it is not necessary for an individual to survive.

What will most likely happen if there is a change in the first three subunits on the upper strand of molecule 1?

What will most likely happen if there is a change in the first three subunits on the upper strand of molecule 1? (1) The remaining subunits in molecule 1 will also change. (2) A portion of molecule 2 may be different. (3) Molecule 1 will split apart, triggering an immune response.

What provides new genetic combinations?

Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. Specifically, meiosis creates new combinations of genetic material in each of the four daughter cells. These new combinations result from the exchange of DNA between paired chromosomes.

Is recombination the same as crossing over?

The term used for crossing over is recombination. Recombination can occur between any two genes on a chromosome, the amount of crossing over is a function of how close the genes are to each other on the chromosome.

How many different genetic combinations are there?

There are 8,324,608 possible combinations of 23 chromosome pairs. As a result, two gametes virtually never have exactly the same combination of chromosomes. Each chromosome contains dozens to thousands of different genes.

How do you calculate chromosome combinations?

If you know the haploid number for an organism, you can calculate the number of possible combinations in the gametes. The possible combinations are equal to 2n, where n is the haploid number. For the organism in Figure 9-18, n = 2, so the number of chromosome combinations is 22, or 4.

How does a gamete end up with an extra chromosome?

When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes. But if meiosis doesn’t happen normally, a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy). These problems can cause pregnancy loss. Or they can cause health problems in a child.

What are the chromosome combinations?

The sex chromosomes are referred to as X and Y, and their combination determines a person’s sex. Typically, human females have two X chromosomes while males possess an XY pairing. In the case of humans, this means that parent cells have two chromosomes and gametes have one.

How do crossing over and independent assortment lead to so many different possible combinations of genes?

Crossing-over is the exchange of genetic material between homologous chromosomes. It results in new combinations of genes on each chromosome. When cells divide during meiosis, homologous chromosomes are randomly distributed to daughter cells, and different chromosomes segregate independently of each other.

Why is crossing over and independent assortment important?

Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA. This produces a unique combination of genes in the resulting zygote. Recombination or crossing over occurs during prophase I. The chromosomes now have genes in a unique combination.

How does crossing over lead to genetic variation?

Crossing over is a process that happens between homologous chromosomes in order to increase genetic diversity. During crossing over, part of one chromosome is exchanged with another. Gametes gain the ability to be genetically different from their neighboring gametes after crossing over occurs.

What is crossing over and its significance?

Crossing over is essential for the normal segregation of chromosomes during meiosis. Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the centromere are no longer identical.

Why does crossing over occur between non sister chromatids?

It occurs during meiosis. Crossing over is the exchange of chromosome segments between non-sister chromatids during the production of gametes. The effect is to assort (shuffle) the alleles on parental chromosomes, so that the gametes carry combinations of genes different from either parent.

How many times can crossing over occur?

Crossing over is estimated to occur approximately fifty-five times in meiosis in males, and about seventy-five times in meiosis in females.

What forms when two different chromatids of the same homologous pair cross over?

Crossing over occurs during prophase I of meiosis. It follows the process of synapsis, during which homologous chromosomes pair up to form a bivalent. Non-sister chromatids break at the same point on each homologue. They then exchange alleles to form an X-shaped structure.