unit 3 and 4 cc6

Protein sorting and transport

Ribosomes

Rough ER and smooth ER

<p>Ribosomal RNA (rRNA)</p> Signup and view all the answers

<p>Ribosomal proteins</p> Signup and view all the answers

<p>Synthesis of proteins</p> Signup and view all the answers

<p>Smooth ER</p> Signup and view all the answers

<p>Both in the cytoplasm and the rough endoplasmic reticulum (ER)</p> Signup and view all the answers

<p>Two subunits: the large subunit and the small subunit</p> Signup and view all the answers

<p>Membrane of the ER</p> Signup and view all the answers

<p>Studded with ribosomes</p> Signup and view all the answers

<p>Endoplasmic reticulum (ER)</p> Signup and view all the answers

<p>Signal sequences are short amino acid sequences located at the N-terminus of proteins. They are recognized by a protein called the signal recognition particle (SRP) and are involved in transporting proteins to the ER membrane.</p> Signup and view all the answers

<p>The translocon is a protein responsible for inserting proteins into the ER membrane.</p> Signup and view all the answers

<p>Once proteins are inserted into the ER membrane, they begin to fold into their three-dimensional structures.</p> Signup and view all the answers

<p>The ER contains enzymes that help to process proteins, remove signal sequences, and add carbohydrates to proteins (glycosylation).</p> Signup and view all the answers

<p>The smooth ER is responsible for the synthesis of lipids, including phospholipids and cholesterol.</p> Signup and view all the answers

<p>Transport vesicles are small membrane-bound sacs that bud off from the ER membrane and carry proteins and lipids to their destinations in the cell.</p> Signup and view all the answers

<p>The Golgi apparatus is responsible for the modification, sorting, and export of proteins.</p> Signup and view all the answers

<p>Protein glycosylation is the process of adding carbohydrates to proteins. Carbohydrates are important for the proper folding and function of proteins, cell-to-cell recognition, and immune defense.</p> Signup and view all the answers

<p>Proteins are sorted in the Golgi apparatus by specific proteins called sorting receptors, which bind to specific carbohydrates on the surface of proteins and direct them to the correct transport vesicles.</p> Signup and view all the answers

<p>Lysosomes are organelles that contain enzymes that break down cellular debris and foreign material. They contain acidic enzymes that can break down proteins, lipids, carbohydrates, and nucleic acids.</p> Signup and view all the answers

<p>Lysosomes are formed from transport vesicles that bud off from the Golgi apparatus.</p> Signup and view all the answers

<p>Cholesterol is a molecule that helps to stabilize cell membranes.</p> Signup and view all the answers

<p>Ion channel-linked receptors are transmembrane proteins that have an ion channel pore. When a signaling molecule binds to an ion channel-linked receptor, it opens the ion channel pore, allowing ions to flow into or out of the cell.</p> Signup and view all the answers

<p>Cell surface receptors have a variety of functions, including receiving and transmitting signals, regulating cellular processes such as cell growth, differentiation, metabolism, and apoptosis, and providing information about the environment to the cell.</p> Signup and view all the answers

<p>Nuclear receptors are located in the nucleus of the cell and bind to DNA to regulate gene expression. Cytoplasmic receptors are located in the cytoplasm of the cell and bind to signaling molecules to activate signaling pathways.</p> Signup and view all the answers

<p>The steps in the cAMP pathway include: 1. A signaling molecule binds to a G protein-coupled receptor (GPCR) on the cell surface. 2. The activated GPCR activates a heterotrimeric G protein. 3. The activated G protein activates adenylate cyclase, an enzyme that converts ATP to cAMP. 4. cAMP activates protein kinase A (PKA), a serine/threonine kinase. 5. PKA phosphorylates other proteins, initiating a signaling cascade.</p> Signup and view all the answers

<p>The cAMP pathway is regulated by factors such as the concentration of signaling molecules, the activity of adenylate cyclase, and the activity of phosphodiesterase.</p> Signup and view all the answers

<p>The cAMP pathway is important for the proper functioning of many different cell types, including cells in the nervous system, endocrine system, and immune system. It is involved in a variety of cellular processes, including cell growth, differentiation, and metabolism.</p> Signup and view all the answers

<p>Cell signaling is the process by which cells communicate with each other. This communication is essential for the proper functioning of cells and organisms because it allows cells to coordinate their activities and respond to changes in their environment.</p> Signup and view all the answers

<p>Signaling molecules are molecules released by cells to communicate with other cells. They communicate by binding to specific receptors on the surface of target cells.</p> Signup and view all the answers

<p>Cell signaling can occur over short or long distances and can be classified into autocrine, juxtacrine, paracrine, endocrine, and neurocrine signaling. These differ based on the distance over which the signaling occurs and the method of communication.</p> Signup and view all the answers

<p>Receptors are proteins located on the cell membrane or inside the cell. They bind to signaling molecules and initiate a cellular response.</p> Signup and view all the answers

<p>GPCRs are transmembrane proteins coupled to heterotrimeric G proteins. When a signaling molecule binds to a GPCR, it activates the G protein, which then activates a downstream signaling pathway.</p> Signup and view all the answers

<p>TKs are transmembrane proteins with a tyrosine kinase domain. When a signaling molecule binds to a TK, it activates the tyrosine kinase domain, which then phosphorylates other proteins, initiating a signaling cascade.</p> Signup and view all the answers

<p>The main types of signaling molecules include hormones, neurotransmitters, growth factors, and cytokines. Examples of hormones are insulin and adrenaline, neurotransmitters include dopamine and serotonin, growth factors such as epidermal growth factor (EGF), and cytokines like interleukins and interferons.</p> Signup and view all the answers

<p>G proteins are activated by GPCRs and play a crucial role in transmitting signals from the cell surface to the inside of the cell, initiating various cellular responses.</p> Signup and view all the answers

<p>TKs initiate cellular responses by phosphorylating other proteins, while GPCRs activate downstream signaling pathways through G proteins.</p> Signup and view all the answers

<p>Signaling molecules play a vital role in coordinating cellular activities, regulating physiological processes, and responding to external stimuli, which are essential for the proper functioning and survival of cells and organisms.</p> Signup and view all the answers

<p>Autocrine signaling involves a cell signaling itself. An example is the secretion of growth factors by cancer cells to promote their own growth and proliferation.</p> Signup and view all the answers

<p>Juxtacrine signaling involves direct contact between adjacent cells, while paracrine signaling involves the release of signaling molecules that act on nearby cells. Both play crucial roles in coordinating cellular activities and responses.</p> Signup and view all the answers