Cell cycle and mitosis
In what stage of the cell cycle does DNA replication occur?
The S phase of interphase.
What is the main purpose of meiosis?
To produce haploid gametes for sexual reproduction.
What is the difference between genotype and phenotype?
Genotype is the genetic makeup; phenotype is the observable trait.
Whether an organism with a dominant phenotype is homozygous or heterozygous.
Genes for different traits assort independently during gamete formation.
A cell with 46 chromosomes undergoes meiosis. How many chromosomes will each daughter cell have, and are they genetically identical?
A cell with 46 chromosomes undergoes meiosis. How many chromosomes will each daughter cell have, and are they genetically identical?
What are sister chromatids?
Identical copies of a chromosome connected at the centromere.
How many cells are produced at the end of meiosis, and are they genetically identical?
Four genetically unique haploid cells.
If two heterozygous parents for albinism have a child, what are the chances the child will be albino?
25% chance of being albino.
In a dihybrid cross of YyRr × YyRr, what is the expected phenotype ratio in the F2 generation?
9 yellow round : 3 yellow wrinkled : 3 green round : 1 green wrinkled.
During which phase of mitosis do sister chromatids separate, and what protein previously held them together?
Sister chromatids separate during anaphase, and they were held together by cohesin at the centromere.
During which phase of mitosis do chromosomes align at the metaphase plate?
Metaphase.
During which phase of meiosis do homologous chromosomes separate?
Anaphase I.
What are the possible genotypes for blood type A?
AA or AO.
What is epistasis?
When one gene masks or alters the expression of another gene.
In a dihybrid cross between two heterozygous pea plants (YyRr × YyRr), what is the expected phenotype ratio in the F₂ generation?
9 yellow round : 3 yellow wrinkled : 3 green round : 1 green wrinkled.
What is the main difference between cytokinesis in plant and animal cells?
Animal cells form a cleavage furrow; plant cells form a cell plate.
What is independent assortment, and when does it occur?
The random distribution of homologous chromosomes during metaphase I, increasing genetic diversity.
What type of inheritance results in pink flowers from red and white parents?
Incomplete dominance.
In summer squash, what phenotype results from having at least one dominant W allele?
White fruit, regardless of the Y/y genotype.
A man with type AB blood and a woman with type B blood (whose mother had type O) have children. What are the possible blood types of their children?
Type A, Type B, and Type AB. Type O is not possible.
What is the end product of mitosis?
Two genetically identical daughter cells
What is the difference between meiosis I and meiosis II?
Meiosis I separates homologous chromosomes; meiosis II separates sister chromatids.
What does a testcross help determine?
Whether an organism with a dominant phenotype is homozygous or heterozygous.
What part of meiosis corresponds to Mendel’s principle of independent assortment?
Random alignment of homologs on the metaphase plate during metaphase I.
What is the difference between complete dominance, incomplete dominance, and codominance? Give an example of each.
Complete dominance: One allele completely masks the other (e.g., brown eyes over blue).
Incomplete dominance: Blended phenotype (e.g., red + white flowers = pink).
Codominance: Both alleles are fully expressed (e.g., AB blood type).