Biology Exam Review: Cell Division, Mendelian Inheritance, and Viruses

These flashcards cover key concepts related to cell division, genetics, inheritance patterns, and viruses, providing a comprehensive review for exam preparation.

What is a karyotype?

A karyotype shows the number, size, and form of chromosomes in an actively dividing cell.

How many pairs of chromosomes do humans have?

Humans have 23 pairs of chromosomes.

What is interphase?

Interphase is the phase of the cell cycle during which the chromosomes are decondensed, replicated, and found in the nucleus.

What are the stages of the cell cycle?

The stages of the cell cycle include G1, S, G2 (interphase), and mitosis.

What are sister chromatids?

Sister chromatids are pairs of identical chromosomes joined at a central point called the centromere.

What occurs during prophase?

During prophase, chromosomes condense and the nuclear membrane begins to dissociate into vesicles.

What is the role of the mitotic spindle?

The mitotic spindle ensures that each daughter cell will obtain the correct numbers and types of chromosomes.

Define cytokinesis.

Cytokinesis is the process where the cell divides into two daughter cells immediately following mitosis.

What distinguishes meiosis from mitosis?

Meiosis involves two rounds of division and produces four haploid cells, while mitosis produces two diploid cells.

What is crossing over and when does it occur?

Crossing over is the physical exchange of genetic material between homologous chromosomes that occurs during prophase I of meiosis.

What are the Mendelian ratios observed in the F2 generation?

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

What does the pedigree analysis help researchers study?

Pedigree analysis helps to trace the inheritance of genetic traits through generations within a family.

What is the significance of plasmids in bacteria?

Plasmids are small, circular DNA molecules that may confer growth advantages, such as antibiotic resistance, to bacteria.

What is the process of transformation in bacteria?

Transformation is the uptake of free DNA from the environment by a bacterial cell.

What is aneuploidy?

Aneuploidy is the presence of an abnormal number of chromosomes in a cell.

What are the main components of a virus?

A virus consists of nucleic acid enclosed in a protein coat, with some having an envelope derived from the host cell.

Explain the concept of genetic diversity in bacteria.

Genetic diversity in bacteria arises from mutations and genetic transfer through processes such as transformation, conjugation, and transduction.

What is incomplete dominance?

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

What is the role of the environment in determining phenotype?

The environment provides the nutrients and energy necessary for the expression of the genotype, affecting the resulting phenotype.

What is the law of segregation?

The law of segregation states that the two alleles for a trait segregate from each other during the formation of gametes.

How can the phenotype be influenced by multiple genes?

Traits influenced by multiple genes are referred to as polygenic traits, resulting in continuous variation.

What defines a diploid organism?

A diploid organism has two sets of chromosomes, one from each parent, totaling 46 chromosomes in humans.