AP Biology Unit Four Flashcards

Signal transduction 

This is the process when a cell receives a signal from outside and converts this signal into an internal response. This process involves a series of molecular events.

Ligand

These are molecules that bind to and interact with other molecules. These are usually protein receptors to start a biological response.

Receptor protein

These are protein molecules that bind to ligands

Target cell

This is a cell that has specific receptors on its surface. This allows it to respond to a specific signal.

Protein modification

This is the process of changing proteins after they have been translated from mRNA.

Phosphorylation cascade

This is a series of protein kinases that sequentially phosphorylate each other. This amplifies a signal and causes a cellular response.

Cellular response

This is the way a cell responds to stimuli or signals in its environment.

G protein-coupled receptor 

These are a large family of cell-surface proteins that act as receptors for a lot of different types of signaling molecules.

Amplification

This is the process of creating many copies of a specific DNA or RNA sequence.

Second messenger

These are molecules that transmit signals from a cell surface receptor to intracellular targets.

Cyclic AMP (cAMP)

This is a second messenger molecule that plats a role in the signal transduction pathways. It is an intracellular signal that passes information from extracellular signals to start a specific cellular response.

Gene expression

This is the process where the information that is encoded in a gene is used to create a functional product, which is ususally a protein.

Apoptosis

A programmed form of cell death

Positive feedback mechanism

This amplifies a response, driving a process further away from a set set point instead of counteracting the change.

Negative feedback 

The negative feedback loop counteract changes from a set point, promoting stability and homeostasis.

Homeostasis

This is the body’s ability to maintain a stable internal environment even if there are external changes. Homeostasis maintained through mechanics like negative and positive feedback loops.

Cell cycle

This is a series of growth, DNA replication, and division processes that leas to the creation of two new, identical daughter cells.

Interphase (G0, G1, S, G2)

This is the period in the cell cycle when a cell is not actively dividing.

G0 phase

This is a phase in the cell cycle when the cell is not actively dividing or preparing to divide and can exit the cycle

G1 Phase

The cell grows in size

S phase

DNA is replicated

G2 phase

The cell continues to grow

Mitosis

This is when a single cell divides into two identical daughter cells.

Prophase

This is the first stage of mitosis when the chromation condenses into visible chromosomes and the nuclear envelope starts to break down.

Metaphase

This is a stage in mitosis when chromosomes that are duplicated and condensed are lined up along the center of the cell.

Anaphase

This is when sister chromatids seperate and move to opposite poles of the cell.

Telophase

This is the last step of mitosis when the chromosomes arrive at opposite poles, decondense back into chromatin, and when the nuclear envelope reforms around each set of chromosomes.

Cytokinesis

This is the process of cell division when the cytoplasm of a parent cell splits into two daughter cells.

Cyclins

This is a family of regulatory proteins that are needed for controlling the cell cycle.

Cyclin dependent kinases 

These are protein kinases that need a cyclin, which provides domains needed for enzyme activity.