unit 3 and 4 cc6

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What are the essential processes for the proper functioning of cells?

Protein sorting and transport

Where are proteins synthesized?

Ribosomes

What are the two main types of endoplasmic reticulum (ER)?

Rough ER and smooth ER

What is responsible for catalyzing the formation of peptide bonds in ribosomes?

Ribosomal RNA (rRNA) Signup and view all the answers

What is responsible for binding to the mRNA and ensuring that the correct amino acids are added to the growing polypeptide chain in ribosomes?

Ribosomal proteins Signup and view all the answers

What is the main function of rough endoplasmic reticulum (ER)?

Synthesis of proteins Signup and view all the answers

What is responsible for the synthesis of lipids in the cell?

Smooth ER Signup and view all the answers

Where are ribosomes found in the cell?

Both in the cytoplasm and the rough endoplasmic reticulum (ER) Signup and view all the answers

What is the composition of ribosomes?

Two subunits: the large subunit and the small subunit Signup and view all the answers

What are the proteins inserted into during their synthesis in the rough endoplasmic reticulum (ER)?

Membrane of the ER Signup and view all the answers

What does the rough endoplasmic reticulum (ER) look like under a microscope?

Studded with ribosomes Signup and view all the answers

What are responsible for the folding and processing of proteins in the cell?

Endoplasmic reticulum (ER) Signup and view all the answers

What are signal sequences and how are they involved in targeting proteins to the ER?

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. Signup and view all the answers

What is the role of the translocon in the ER?

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

Describe the process of protein folding in the ER.

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

What are some of the functions of the enzymes found in the ER?

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

What is the function of the smooth ER?

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

Explain the role of transport vesicles in the export of proteins and lipids from the ER.

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. Signup and view all the answers

What is the Golgi apparatus responsible for?

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

What is protein glycosylation and why is it important?

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. Signup and view all the answers

How are proteins sorted in the Golgi apparatus?

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. Signup and view all the answers

What are lysosomes and what do they contain?

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. Signup and view all the answers

Where are transport vesicles that form lysosomes derived from?

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

What is the function of cholesterol in the cell membranes?

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

Explain the function of ion channel-linked receptors and how they are activated.

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. Signup and view all the answers

What are the functions of cell surface receptors?

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. Signup and view all the answers

Differentiate between nuclear receptors and cytoplasmic receptors. Where are they located and what do they bind to?

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. Signup and view all the answers

Describe the steps in the cAMP pathway.

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. Signup and view all the answers

What factors regulate the cAMP pathway?

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

Why is the cAMP pathway important?

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. Signup and view all the answers

What is cell signaling and why is it essential for cells and organisms?

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. Signup and view all the answers

What are signaling molecules and how do they communicate with other cells?

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. Signup and view all the answers

What are the different types of cell signaling and how do they differ?

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. Signup and view all the answers

What are receptors and where are they located?

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

What are G protein-coupled receptors (GPCRs) and how do they function in cell signaling?

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. Signup and view all the answers

What are tyrosine kinase-linked receptors (TKs) and how do they initiate signaling?

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. Signup and view all the answers

What are the main types of signaling molecules, and give examples of each type?

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. Signup and view all the answers

Explain the role of G proteins in cell signaling.

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. Signup and view all the answers

How do tyrosine kinase-linked receptors (TKs) differ from G protein-coupled receptors (GPCRs) in initiating cellular responses?

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

What are the functions of signaling molecules in cell communication, and why are they important?

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. Signup and view all the answers

Describe the process of cell communication in autocrine signaling and provide an example of an autocrine signaling molecule.

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. Signup and view all the answers

Compare and contrast the roles of juxtacrine and paracrine signaling in cell communication.

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. Signup and view all the answers