BIO Exam #3 Notes: Mitosis & Meiosis Terminology

Flashcards covering key terms and concepts related to Mitosis and Meiosis as well as transcription and translation processes.

What is a chromatid?

One half of a duplicated chromosome; sister chromatids are identical copies.

What is the role of the centromere?

It is the region of a chromosome where sister chromatids are joined and spindle fibers attach.

What are spindle fibers?

Microtubules that help separate chromosomes during mitosis and meiosis.

Define homologous chromosomes.

Pairs of chromosomes, one from each parent, that are similar in size and gene content.

What happens during crossing over?

Exchange of genetic material between homologous chromosomes during prophase I of meiosis.

What is synapsis?

The pairing of homologous chromosomes during prophase I.

What does diploid (2n) refer to?

A cell with two sets of chromosomes; for example, body cells in humans have 46 chromosomes.

What does haploid (n) mean?

A cell with one set of chromosomes; for example, gametes in humans have 23 chromosomes.

What is independent assortment?

The random distribution of homologous chromosomes during metaphase I of meiosis.

Define cytokinesis.

The division of the cytoplasm, resulting in two daughter cells.

What occurs during interphase?

The cell growth phase where DNA is replicated, including G1, S, and G2 phases.

What happens during prophase?

Chromosomes condense, spindle forms, and the nuclear envelope breaks down.

What is the significance of metaphase?

Chromosomes align at the cell equator.

What occurs during anaphase?

Chromatids (or homologous chromosomes in meiosis I) are pulled to opposite poles.

What happens during telophase?

Nuclear membranes reform, and chromosomes decondense.

What are gametes?

Reproductive cells (sperm or egg) formed via meiosis, each haploid.

What is the purpose of mitosis?

To enable growth, tissue repair, and asexual reproduction by producing genetically identical cells.

What are the stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.

What role do spindle fibers play in mitosis?

They attach to the centromeres of chromosomes and pull sister chromatids apart during anaphase.

What is the result of mitosis in terms of chromosome number and genetic identity?

Two daughter cells, each with the same diploid number of chromosomes and identical genetic information as the parent cell.

What is the difference between mitosis and meiosis?

Mitosis produces identical diploid cells for growth and repair, while meiosis produces genetically diverse haploid gametes for sexual reproduction.

What is crossing over and why is it important?

It increases genetic variation by exchanging DNA between homologous chromosomes and occurs during prophase I of meiosis.

What is nondisjunction?

Failure of chromosomes to separate properly during meiosis, which can lead to genetic disorders.

What is the definition of a gamete?

A reproductive cell produced by meiosis that carries half the number of chromosomes.

What happens during fertilization?

A haploid sperm and haploid egg combine to restore the diploid number (46 chromosomes in humans).

Explain the summary of Mitosis vs. Meiosis.

Mitosis results in 2 identical diploid cells for growth and repair, while meiosis results in 4 unique haploid gametes for sexual reproduction.

What is the role of RNA polymerase?

The enzyme that synthesizes RNA from a DNA template during transcription.

What is alternative splicing?

A process by which different combinations of exons are joined together to produce multiple mRNA variants from one gene.

What happens if the promoter region of a gene is mutated?

The gene will not be transcribed.

What is the function of the 5' cap?

It is a modified guanine nucleotide added to the beginning of mRNA for stability and ribosome recognition.