Asexual Reproduction and Cell Division Flashcards

Flashcards to review key vocabulary and concepts related to asexual reproduction, cell division, and the cell cycle.

Cell Theory

All cells derive from other cells by division.

Zygote

a fertilized egg, the first cell of a new organism, formed when a sperm cell and an egg cell combine (diploid)

Cell Division

Method of reproduction for single-cell organisms using cell division.

Cell Cycle

Process by which cells regulate cell division.

Tumorigenesis

Uncontrollable cell growth due to failure of cell cycle regulation.

Cell Cycle

Series of biochemical and structural events involving growth, replication, and division of a cell.

Cell Cycle - Before Division

The cell grows larger, organelles double, and DNA is replicated.

Two Major Stages of the Cell Cycle

Interphase and Mitosis (Mitotic phase)

Interphase

Most of the cell cycle is spent in this phase, 95% of the time.

G1 Phase

Recovery from the previous division; cell doubles its organelles; accumulates raw material.

S Phase

DNA replication (synthesis); chromosomes become 2 identical bound chromatids; centrosome is also duplicated.

G2 Phase

Between DNA replication and the onset of mitosis; cell synthesizes proteins necessary for division.

Mitosis (karyokinesis)

Nuclear division; daughter chromosomes distributed to two daughter nuclei.

Cytokinesis

Cytoplasm division; results in two genetically identical daughter cells.

Mitosis

Nuclear division of somatic cells.

Five Phases of Mitosis

Prophase, Prometaphase, Metaphase, Anaphase, Telophase.

Cell Status Before Mitosis

DNA has been duplicated, chromosomes unwound, centrosomes duplicated.

Centrosome (MTOC)

Microtubule-organizing center found near the nuclei of animal cells.

Chromatin

Compacted form of DNA associated with histone proteins.

Condensins

Proteins that help condense chromosomes during prophase.

Kinetochore

Protein structure that attracts and binds mitotic spindle microtubules.

Metaphase Plate

Imaginary plane midway between the two poles of a dividing cell.

Cohesin

Proteins that degrade during anaphase to allow sister chromatids to separate.

Telophase

Two separate "daughter" nuclei begin to form. Chromosomes begin to decondense.

Cytokinesis in Animal Cells

Cleavage furrow forms out of actin filaments and pinches the cell into two.

Cytokinesis in Plant Cells

A new cell wall forms between the daughter cells with the help of vesicles of the Golgi apparatus, + proteins + glucose

Mitotic Spindle

Made of microtubules, anchored by two centrosomes.

G0 Phase

Inactive state some cells enter, can be temporary or permanent.

External Signals Controlling Cell Cycle

Growth factors, hormones received at the plasma membrane.

Internal Signals

Family of proteins (cyclins & Cdks) that control the cell cycle.

G1 Checkpoint

The integrity of the DNA, cell size and protein reserves are assessed.

G2 Checkpoint

Proper chromosome & centrosome duplication is assessed.

M Checkpoint

Attachment of each kinetochore to spindle fiber is assessed.

Proto-oncogenes (Positive Regulators)

Proteins that promote the cell cycle.

Tumor Suppressors (Negative Regulators)

Proteins that restrain the cell cycle.

Positive Regulators of the Cell Cycle

Cyclins and Cyclin-dependent kinases (Cdks)

Negative Regulators of the Cell Cycle

Retinoblastoma protein (Rb), p53, and p21

Proto-oncogenes

Normal genes, but when mutated become oncogenes, causing cancer

Tumor suppressor genes

Usually, they are the negative regulators of the cell cycle.

Binary Fission

Mitosis of bacteria resulting in two genetically identical offspring.

FtsZ Protein

Protein vital in prokaryotic cytokinesis; similar to tubulin and actin.