Chapter 6- Genetics and Cell Division: Mitosis, Meiosis, and Inheritance

What was significant about Dolly the sheep?

Dolly was the first successfully cloned mammal, identically copied from her mother.

What are the benefits of cloning livestock?

Cloning can produce disease-resistant animals, increase meat production, and eliminate genetic diseases in future generations.

How does sexual reproduction contribute to genetic diversity?

Sexual reproduction generates genetic diversity through the rearrangement of genes and the fusion of sex cells (sperm and egg).

What is fertilization?

Fertilization is the fusion of two sex cells (sperm and egg) into one cell, leading to the potential formation of a functioning human.

What is mitosis?

Mitosis is the process by which most human cells divide, resulting in two identical daughter cells.

What happens during DNA replication before mitosis?

DNA in the nucleus makes a full copy of itself, separating into two strands that serve as templates for new strands.

What are the steps of mitosis?

The steps include Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis, leading to the formation of two identical cells.

What is a zygote?

A zygote is a fertilized cell formed from the union of sperm and egg cells.

How many chromosomes do normal body cells have?

Normal body cells have 46 chromosomes, arranged in 23 pairs.

What is meiosis?

Meiosis is a type of cell division that produces sex cells (gametes) with half the number of chromosomes.

What occurs during Prophase I of meiosis?

During Prophase I, each chromosome pairs with its homologue to form tetrads, initiating genetic recombination.

What is independent assortment in meiosis?

Independent assortment is the random division of homologous pairs into daughter cells, generating genetic diversity.

What is crossing over?

Crossing over is the exchange of genetic material between homologous chromosomes during Prophase I, enhancing genetic diversity.

What is the difference between genotype and phenotype?

Genotype refers to the inherited genetic makeup, while phenotype is how those genes are physically expressed.

What are carriers in genetics?

Carriers are individuals with a single copy of a recessive allele who do not display the associated phenotype but can pass it to offspring.

How do dominant alleles affect recessive alleles?

Dominant alleles can mask the expression of recessive alleles, meaning only one copy of a dominant allele is needed for its phenotype to be expressed.

What is a Punnett square used for?

A Punnett square is used to calculate the probability of inheritance of traits given the genotypes of the parents.

What is the role of the Y chromosome?

The Y chromosome carries genes that provide genetic instructions for male development.

What are sex-linked traits?

Sex-linked traits are characteristics determined by genes located on sex chromosomes, such as red-green color blindness linked to the X chromosome.

What is the term for the union of a sperm and an egg cell?

Fertilization

Most mutations are beneficial to the individual.

False

In a species with 3 pairs of chromosomes how many possible combinations of daughter cells can be formed from meiosis?

8 possible combinations (2³ =8)

From an evolutionary perspective, crossing over…

can be helpful because it can lead to the creation of offspring diversity

Lauren has a single recessive mutation in one of her two copies of chromosomes. this recessive mutation can cause the disease cystic fibrosis. Which statement is true?

If lauren has a child with a partner who does not have the mutation, their children will not have cystic fibrosis.

Javier has an allergy that is inherited in a recessive manner. Which statement is true? 

Both of his parents have at least one copy of the mutation. 

A single copy of a dominant gene is sufficient to cause an associated phenotype

True

If a father’s genotype is Rr, what percent of children will display the dominant phenotype and recessive phenotype?

75% and 25%

The TSPY1 gene is located on the human Y chromosome, which statement is false?

Males have two copies of the TSPY1 gene.