Unit 5: Topic 6 - Chromosomal Inheritance

Question 1

What is the law of segregation, and how does it assist in the genetic variation in populations?

Answer 1

When an organism makes gametes, each gamete has a copy of a chromosome from each parent, and each of these copies has different alleles. Since every gene has a different allele, the gamete will randomly inherit one of those alleles. This adds to the probability that the offspring is genetically unique.

Question 2

What is the law of independent assortment, and how does it assist in the genetic variation in populations?

Answer 2

According to the Law of Independent Assortment, genes are assorted randomly in gametes, meaning that the inheritance of a pair of genes is independent of another pair of genes. Independent assortment creates new combinations of alleles, creating many possibilities for genetically different gametes.

Question 3

What is random fertilization, and how does it assist in the genetic variation in populations?

Answer 3

Any of the genetically unique sperm cells can fertilize any of the genetically unique egg cells. This adds to the randomness of the genes/chromosomes in the offspring.

Question 4

What is crossing over/recombination, and how does it assist in the genetic variation in populations?

Answer 4

Homologous chromosomes exchange genetic material, and this results in the chromatids no longer being identical, creating greater genetic variation when eventually, the chromatids will end up in the gametes.

Question 5

What is heredity?

Answer 5

The transmission of genes (the units of heredity) from the parent to the offspring during sexual reproduction. The chromosomal basis of inheritance explains how DNA and RNA, which makes genes, and in turn, chromosomes, create differences and similarities in offspring.

Question 6

What is nondisjunction, and what is an example of it?

Answer 6

Nondisjunction is the failure of chromosomes to separate during meiosis or mitosis and ending up with excess or absence of chromosomes in the cell. The inheritance of a genetic disorder due to nondisjunction is likely. Two examples of conditions due to nondisjunction are trisomy 21 (Down Syndrome) and monosomy X (Turner Syndrome).

Question 7

How can inheritance patterns be used to explain genetic disorders, and what is an example of one?

Answer 7

Inheritance patterns can be used to understand the transmission of genetic disorders from parent to offspring. A disorder is present when an affected, or mutated allele is inherited. The patterns of inheritance include Autosomal dominant, Autosomal recessive, X-linked dominant, X-linked recessive, X-linked, Y-linked, and Mitochondrial Inheritance. Sickle cell anemia is an example of an autosomal recessive disorder. The pedigree charts included in the diagram show how these patterns influence the inheritance of genetic disorders.