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Cell Biology

More great enzyme animations at McGrawHill Higher Education

▶ Protein Synthesis Animation Video - 2:25 tRNA is joined to the mRNA by a peptide bond. A tRNA moved into the Asite where the codons match the mRNA the Ribosome shifts down by one codon at a time and new amino acids are added one at a time. It cuts off when a stop codon moves into the A site on the mRNA. The mRNA & the amino acid/protein are both released by the ribosome. p-site, A (acceptor) site & E site =Exit

Silent killer... Viewed this way is not scary, indeed it even has something artistic, but behind this innocent appearance hides a killer who kills every year millions of women: it is a cell of breast cancer under the microscope.

Exocytosis is the process by which cells get rid of substances the cell does not need.

Transport Videos

exocytosis - Google Search

Graphics Gallery: An Antibody Molecule

$1 A fun way for students to organize information.

Ice Cream Information Organizer

The light-driven pump uses the energy of absorbed photons of light to transport a solute against its electrochemical gradient. The symporter transports two different solutes in the same direction. It requires the free energy released from the movement of a 2nd solute down its electrochemical gradient. The antiporter transports two solutes in opposite directions across a membrane. The transport of one solute is driven by the coupled transport of a 2nd solute in the opposite direction.

Facilitated diffusion of glucose by the glucose uniporter. The transport of glucose across the plasma membrane can be in either direction, but is mostly into the cell. The glucose uniporter has two states: open to the exterior of the cell (A) and open to the interior of the cell (B). In either state, the glucose uniporter will bind glucose and undergo a conformational change, delivering glucose to the opposite side. The direction of glucose transport is driven by the concentration gradient.

A tRNA molecule showing the region that reads the mRNA (yellow) and the amino acid phenylalanine (blue and red spheres) that the tRNA carries. CREDIT: Patrick O’Donoghue and Dieter Soll, Yale University.

mit_rna_yeast- X-ray structure of a tRNA molecule found in yeast (credit: Yikrazuul/wikipedia)

Deciphering the genetic code - Nirenberg and Matthaei used a test-tube protein synthesis system to determine the amino acids specified by synthetic mRNAs of known codon composition. (Nature Scitable)

Biofilms Spread Through Osmotic Pressure New research at Harvard explains how bacterial biofilms expand to form slimy mats on teeth, pipes, surgical instruments, and crops. Through experiment and mathematical analysis, researchers have shown that the extracellular matrix (ECM), a mesh of proteins and sugars that can form outside bacterial cells, creates osmotic pressure that forces biofilms to swell and spread. The ECM mechanism is so powerful that it can increase the radius of some biofil...

Potassium ions (purple dots) move through an ion channel protein (coiled structure). Image courtesy of Yu Zhou.