exam 3

What is the process by which bacteria reproduce?

Bacteria reproduce through binary fission.

What type of chromosome do bacteria have?

Bacteria have a circular chromosome.

What initiates replication in bacterial chromosomes?

Replication starts at the origin of the chromosome.

What is the role of the FtsZ protein in bacterial cell division?

FtsZ protein forms a middle septum that allows the cell to divide.

How does the genetic consistency of prokaryotic organisms arise?

Through the clonal reproduction and binary fission process, which ensures each daughter cell gets a complete copy of the chromosome.

What are eukaryotic chromosomes composed of?

Eukaryotic chromosomes are composed of chromatin, which includes 40% DNA and 60% protein.

What is a karyotype?

A karyotype is the particular array of chromosomes in an individual.

What is the diploid number of chromosomes in humans?

Humans are diploid with 46 total chromosomes.

What is chromatin?

Chromatin is a complex of DNA and proteins that make up chromosomes.

What structure allows for the compact packing of DNA in eukaryotic cells?

Nucleosomes facilitate the compact packing of DNA.

What is the primary function of cohesin proteins during cell division?

Cohesin proteins hold sister chromatids together until anaphase.

What are the stages of the eukaryotic cell cycle?

Interphase (G1, S, G2), M phase, and Cytokinesis.

What happens during the G1 phase of the cell cycle?

The cell assesses size, nutrient availability, and DNA integrity.

What occurs during the G2 phase prior to mitosis?

The cell checks for successful DNA replication and DNA damage.

What is the purpose of cytokinesis?

Cytokinesis divides the cytoplasm, resulting in two distinct daughter cells.

What role does the centromere play in mitosis?

The centromere is the point of constriction, serving as the attachment site for the kinetochore.

What distinguishes telophase in the process of mitosis?

Nuclear envelope reforms around the chromatids, and the spindle disassembles.

What is the function of MPF (maturation-promoting factor) in the cell cycle?

MPF induces cell division through phosphorylation.

How do growth factors influence the cell cycle?

Growth factors can override cellular controls that inhibit cell division.

What is the role of p53 in relation to cancer?

p53 is a tumor suppressor gene that monitors DNA integrity and can induce cell death if damage is severe.

What are gametes in sexual reproduction?

Gametes are haploid cells produced through meiosis.

How many rounds of division occur in meiosis?

Meiosis involves two rounds of division, meiosis I and meiosis II.

What is the difference between sister chromatids and homologous chromosomes?

Sister chromatids are identical copies of a single chromosome, while homologous chromosomes are pairs of similar chromosomes from each parent.

What is the significance of synapsis during prophase I of meiosis?

Synapsis is the association of homologous chromosomes, allowing for genetic recombination.

What role does crossing over play in genetic variation?

Crossing over allows for the exchange of genetic material between non-sister chromatids, increasing genetic diversity.

In plant meiosis, how many haploid cells are produced?

Meiosis produces four haploid cells, which may divide mitotically before becoming gametes.

What is the phenotypic ratio expected from a monohybrid cross?

The expected phenotypic ratio is typically 3:1 in the F2 generation.

What defines a dihybrid cross?

A dihybrid cross involves two variations of two traits, exhibiting a phenotypic ratio of 9:3:3:1 in the F2 generation.

What is the principle of independent assortment?

Alleles of different genes assort independently during meiosis.

What is a testcross used for?

A testcross is used to determine the genotype of an individual with an unknown phenotype.

What is pleiotropy?

Pleiotropy refers to a single allele affecting multiple traits or phenotypes.

What is incomplete dominance?

Incomplete dominance is when a heterozygote has a phenotype that is intermediate between the two homozygotes.

What does codominance mean?

Codominance occurs when both alleles of a gene are expressed in the phenotype of the heterozygote.

How do sex-linked traits differ from autosomal traits?

Sex-linked traits are associated with genes found on sex chromosomes and can exhibit different inheritance patterns.

What is dosage compensation?

Dosage compensation is the process ensuring equal expression of genes from sex chromosomes despite different amounts.

How does genomic imprinting affect gene expression?

Genomic imprinting results in the expression of a gene depending on whether it was inherited from the mother or the father.

What is the relationship between recombination frequency and genetic distance?

Recombination frequency is proportional to the genetic distance between loci.

What is the effect of nondisjunction during meiosis?

Nondisjunction can lead to aneuploidy, which is the gain or loss of chromosomes.

What is an example of a recessive genetic disorder?

Cystic fibrosis is an example of a recessive genetic disorder caused by a defect in chloride ion transport.

What type of cells result from meiosis in animals?

In animals, meiosis results in gametes.

What are SNPs (single-nucleotide polymorphisms)?

SNPs are variations at a single base pair in the DNA sequence that can affect genetic traits.

How do mutations in proto-oncogenes contribute to cancer?

Mutations in proto-oncogenes can cause them to become oncogenes, leading to uncontrolled cell growth.

What defines a homozygous genotype?

A homozygous genotype has two identical alleles for a trait.

What does the term 'phenotypic plasticity' refer to?

Phenotypic plasticity is the ability of an organism to change its phenotype in response to environmental conditions.

What is an example of a dominant genetic disorder?

Huntington's disease is an example of a dominant genetic disorder caused by a mutation in the HTT gene.