Cell Communication and Response

Cell(s)

Smallest Unit of life

Protein(s)

Made of amino acids that perform many jobs

Gene(s)

Instructions for a protein. 1 gene = 1 protein

constitutively active

When the gene that makes a protein is always on. For essential proteins that are always needed. (Hemoglobin or ATP Synthase- you always need oxygen and ATP)

Gene Regulation

Turning on and off of specific genes (transcription) in response to changes in cells internal and external environment

Cell- Cell Communication

Extra Cellular communication between cells. Often trigger signal transduction.

ligand receptor

substance that binds (only sometimes a protein); receptacle for binding, key to a lock (SHAPE!!)

Signal Transduction

Intracellular communication. A multi-step process where signals are passed from protein to protein inside the cell that eventually arrive at the nucleus to start or stop transcription (gene expression)

Water

Most common molecule in a cell (Up to 70% of mass)

Hydrolysis

A chemical process that splits a molecule by adding water.

Phosphate

Second most common molecule in cells (ATP, membranes, nucleic acids)

Phosphorylation

the addition of a phosphate group to a molecule (Often proteins to change shape and turn activity on or off)

Transcription Factor

A regulatory protein that binds to DNA and affects transcription (turn on or off) of specific genes.

Promoter

specific region of a gene where RNA polymerase can bind and begin transcription

repressor

A protein that binds to an operator and physically blocks RNA polymerase from binding to a promoter site

operon

group of genes that work together (Transcribed together)

2 vs 38 ATP

Bacteria are only able to perform glycolysis so they only make 2 molecules of ATP per sugar molecule.

post-transcriptional modification

the modifications that occur to an mRNA transcript before it is exported from the nucleus as mature mRNA. Include: splicing of introns, addition of 5' cap, addition on poly-A-tail and rearranging of exons

Intron

sequence of DNA that is not involved in coding for a protein (Removed from mRNA before leaving nucleus)

Exons

Coding segments of eukaryotic DNA. (Will be translated)

pre-mRNA

a form of messenger RNA that contains both introns and exons and has no cap or tail.

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

exocytosis

release of substances out a cell by the fusion of a vesicle with the membrane.

Endocytosis

A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane. Vesicle is formed.

post-translational modification

Changes to the new protein that may be critical to its final function, like folding, phosphorylating glycosylating, or methylating

Methyl

CH3

Glyco

Prefix meaning sugar

Ubiquitination

The process of adding ubiquitin chains to a protein targeted for degradation.