Intro to Genetics: Cell Division

Flashcards covering key vocabulary terms related to cell division, genetics, mitosis, and meiosis from the lecture notes.

2nd law of thermodynamics

States that every energy transfer involves some loss of energy.

Energy forms

Kinetic and potential energy.

Prokaryotic DNA

Single, double-stranded DNA molecules, formed in a loop; may contain plasmids.

Eukaryotic DNA

Consist of several double-stranded DNA molecules. Number of chromosomes depends on the species.

Cell Division

Process by which cells make more cells for growth, development, and to heal wounds.

Diploid (2n)

Cells that have both sets of chromosomes, typical of somatic (body) cells.

Haploid (n)

Cells that have only 1 set (half) of chromosomes, typical of sex cells.

Homologous chromosomes

Pairs of chromosomes that are the same shape, code for the same traits, and have similar banding patterns. Humans have 23 pairs.

Histone

Proteins around which DNA is wrapped to form nucleosomes in eukaryotic chromosomes.

Nucleosomes

DNA wrapped around histones.

Chromatin fiber

Nucleosomes coiled together.

Duplicated chromosome

Consists of a p arm, q arm, centromere, and telomere; formed from condensed chromatin.

Cell Cycle

The life cycle of a cell, consisting of Interphase (G1, S, G2) and Mitotic phase (Mitosis, Cytokinesis).

Interphase

More than 90% of the life of a cell is spent in this phase, involving cell growth, DNA replication, and organelle replication.

G1 phase

Stage of interphase characterized by cell growth, development, and protein production (longest stage).

S phase

"Synthesis" stage of interphase where DNA replication occurs.

G2 phase

Stage of interphase where organelles are replicated (shortest stage).

Mitosis

The division of the nucleus which results in two completely identical copies of chromosomes packaged into two new nuclei.

Prophase

Stage of mitosis where chromosomes condense and become visible, spindle fibers emerge, and the nuclear envelope breaks down.

Prometaphase

Stage of mitosis where chromosomes continue to condense, kinetochores appear at centromeres, and mitotic spindle microtubules attach to kinetochores.

Metaphase

Stage of mitosis where chromosomes are lined up at the metaphase plate, with each sister chromatid attached to a spindle fiber from opposite poles.

Anaphase

Stage of mitosis where centromeres split, sister chromatids (now called chromosomes) are pulled toward opposite poles, and spindle fibers elongate the cell.

Telophase

Stage of mitosis where chromosomes arrive at opposite poles, decondense, nuclear envelope reforms, and the mitotic spindle breaks down.

Cytokinesis

Division of the cytoplasm, occurring after telophase of mitosis, pinching apart the original cell into two daughter cells via a cleavage furrow.

G1 Checkpoint

Cell cycle checkpoint to verify DNA is not damaged.

G2 Checkpoint

Cell cycle checkpoint to ensure DNA is replicated properly.

M Checkpoint (spindle assembly checkpoint)

Cell cycle checkpoint to check for alignment of chromosomes.

Apoptosis

Programmed cell death, if any cell cycle checks fail.

Neoplasm

Abnormal growth of cells.

Benign

Non-cancerous.

Malignant

Cancerous.

Cancer

Cellular growth disorder resulting from mutation of genes that regulate the cell cycle, characterized by lack of differentiation, abnormal nuclei, tumor formation, metastasis, and angiogenesis.

Metastasis

Malignant growths that occur a distance from the primary site of cancer.

P53 gene

Known as the 'guardian of the genome,' it normally functions to control the cell cycle but is mutated in over 50% of all human cancers.

HeLa Cells

An immortalized cell line used in scientific research, derived from cervical cancer cells of Henrietta Lacks.

Asexual reproduction

Reproduction involving only one parent, producing offspring genetically identical to the parent.

Sexual reproduction

Reproduction involving sperm and egg from two parents combining, producing offspring genetically different from one another and from the parents.

Gametogenesis

The production of gametes.

Gametes

Specialized male and female reproductive cells (sperm and egg).

Meiosis

Specialized form of cell division to produce gametes, occurring only in gonads (testes in males, ovaries in females), reducing the number of chromosomes by half.

Meiosis I

The first phase of meiotic division, which separates homologous pairs into two separate cells.

Meiosis II

The second phase of meiotic division, which separates the sister chromatids in each cell to produce four haploid cells.

Prophase I (Meiosis)

Stage of Meiosis I where the nuclear envelope breaks down, microtubules assemble, chromosomes condense, and crossing over may occur.

Crossing over

Exchange of genetic information between homologous chromosomes during Prophase I, which may produce new combinations.

Metaphase I (Meiosis)

Stage of Meiosis I where homologous pairs line up at the equator, with random alignment resulting in genetically diverse gametes.

Random alignment

Arbitrary arrangement of members of homologous pairs to face a pole during Metaphase I, contributing to genetic diversity.

Anaphase I (Meiosis)

Stage of Meiosis I where microtubules shorten and homologous pairs separate.

Telophase I (Meiosis)

Stage of Meiosis I where the nuclear envelope reforms around chromosomes, followed by cytokinesis partitioning DNA into haploid daughter cells.