AP Biology - Unit 4

G-Protein-Linked Receptors

A cell membrane protein receptor that is very common with a diversity of functions, but only result in single pathway responses.

Tyrosine Kinases

A cell membrane protein receptor that produces a multiple pathway response and regulates/coordinates many cell functions.

Ion Channels

Open or close when ligands bind to a receptor.

Intracellular Receptors

A cell membrane protein receptor that target proteins inside the cell. These must be hydrophobic to pass into the cell.

Steps of Cell Communication

Reception, Transduction and Response

Reception

When a single molecule (ligand) bonds to a receptor protein on the cell's surface.

Transduction

The step of cell communication when the information is sent through the cell. It is initiated by conformational change of the receptor protein and is eventually turned into a cellular response. Multistep pathways can amplify a signal.

Response

This is what the cell signaling results in, which causes either regulation of cytoplasmic activities or transcription.

Quorum Sensing

The process by which bacteria determine the population density of their species in a local area by sending out ligands. Once the concentration of these ligands reach a certain point, the bacteria all respond simultaneously.

Cell-to-Cell Communication

When cells that are touching communicate by surface receptors directly giving information to the cytoplasm it is directly connected to.

Local Signaling

Communication of cells when they are close together, but not touching.

Long Distance Signaling

Communication of cells that are far apart. These ligands must use hormones to travel through the blood stream to get to their destination.

Prophase

Chromosomes begin to coil, centrioles move to opposite poles, the spindle fibers begin to coil, the nuclear membrane dissolves and the nuclear membrane disappears.

Metaphase

The chromosomes begin to line up along the equator of the cell.

Anaphase

The spindle fibers connect to the chromosomes and pull them to the opposite poles of the cell.

Telophase

The nucleus reforms, the spindle fibers disintegrate, and the DNA uncoils. This is basically the opposite of Prophase.

Cytokinesis

The cytoplasm splits in two as a cleavage furrow forms and the cell splits into two.

Cancerous Cell

Most cells enter G0 once they sense that there is no need for more cells, but these cells continue to reproduce rapidly with no mind to how many cells are present, thus creating a tumor. If these cells enter the blood stream, they can be transported all over the body.

Centromeres

Area where the chromatids of a chromosome are attached at the center.

Chromatids

These are the tightly coiled pieces of DNA that connect at the centromere to create chromosomes.

G1 Phase

This is the first growth phase of the cell, in which the cell grows. The cell can also enter G0 here if needed.

G0 Phase

This is the resting phase of the cell cycle that a cell enters if it does not need to split into two because there are already enough cells.

S Phase

A part of Interphase in which the DNA replicates and is organized into chromosomes as it wraps around histone proteins which form into chromatin and connect to make chromosomes.

G2 Phase

This is the second growth phase of the cell cycle in which the cell grows again and prepares for division by producing more organelles.