Anatomy and Physiology Cell Basics Quiz

A cell is the smallest functional unit of life, capable of carrying out all necessary life functions independently. Tissues are made up of cells, organs are made up of tissues, and organisms are made up of organ systems composed of organs.

The correct answer includes the key components of a cell that are essential for its structure and function. The incorrect answers either do not represent the basic parts of a cell or are specific organelles within a cell.

The plasma membrane plays a crucial role in maintaining the cell's internal environment and regulating the movement of substances in and out of the cell.

The extracellular matrix is the most abundant extracellular material in connective tissue, providing structural support and strength to the cells. Collagen, elastin, and fibrin are also important components of the extracellular matrix but are not the most abundant.

The plasma membrane consists of a lipid bilayer made up of phospholipids, glycolipids, and cholesterol, not proteins, carbohydrates, or nucleic acids.

Phospholipids have a polar 'head' that is hydrophilic and a nonpolar 'tail' that is hydrophobic, causing them to line up with the heads facing towards the extracellular and intracellular fluids and the tails facing away from the fluid.

Membrane proteins can be classified into integral proteins, which are embedded within the membrane, and peripheral proteins, which are not directly attached to the membrane but interact with integral proteins.

Membrane proteins serve various functions in the cell, but their primary purpose is to facilitate communication with the external environment by allowing the passage of molecules in and out of the cell.

Integral proteins are firmly inserted in the membrane with both hydrophobic and hydrophilic regions, exhibiting various functions such as channels, carriers, enzymes, and receptors for signal transduction. The incorrect answers provide inaccurate characteristics that do not align with the nature of integral proteins.

Glucose requires a phosphate group to enter a cell through facilitated diffusion facilitated by glucose transport proteins like GLUT1. The addition of a phosphate group to glucose traps it inside the cell preventing it from diffusing back out.

Glycocalyx is a carbohydrate-rich area on the cell surface that helps cells recognize each other and allows the immune system to distinguish 'self' from 'nonself'.

Cell junctions play crucial roles in maintaining tissue integrity and facilitating communication between cells. The correct types of cell junctions are tight junctions, desmosomes, and gap junctions.

Tight junctions are specialized connections between cells that play a crucial role in creating barriers in tissues to control the passage of ions, water, and other molecules. They are not gaps that allow free movement of substances, nor are they specific to plant cells only. Additionally, tight junctions are not hormones. The correct answer highlights the impermeable nature of these junctions and provides examples of where they are typically found.

Desmosome junctions are specialized structures in animal cells that provide strong adhesion between cells while still allowing some flexibility to prevent tissue damage.

Gap junctions are specialized intercellular connections that allow for direct communication between neighboring cells by forming channels that allow small molecules and ions to pass through. These junctions play a crucial role in allowing electrical signals to propagate quickly between cells, such as in the heart and smooth muscle.

Substances can move across the membrane through different processes, with passive and active processes being the two main ways. Simple diffusion, facilitated diffusion, and osmosis are specific types of passive processes that involve different mechanisms for substance movement.

Passive transport does not require energy input from the cell and includes processes like diffusion and filtration. Active transport, osmosis, and facilitated diffusion are not types of passive transport.

Diffusion is the process of molecules or ions moving from areas of high concentration to areas of low concentration, not the other way around.

Diffusion is the movement of molecules from areas of high concentration to areas of low concentration, driven by collisions between molecules. The factors affecting the speed of diffusion include the size of molecules and temperature. The incorrect answers provided do not accurately describe the process of diffusion.

When a plasma membrane is damaged, it disrupts the normal selective permeability function, allowing substances to freely cross the membrane. This disrupts concentration gradients and can lead to various issues like loss of essential fluids, proteins, and ions in certain medical conditions like burns.

The correct answer explains the types of molecules that can passively diffuse through the plasma membrane based on their characteristics. Polar and charged molecules would not be able to passively diffuse through the nonpolar lipid core, and only very large molecules lack the ability to pass through membrane channels. Additionally, molecules that are actively pumped across the membrane require energy as opposed to passively diffusing.

Carrier mediated facilitated diffusion involves integral proteins that facilitate the movement of specific molecules by changing shape. It is distinct from simple diffusion, active transport, and utilizing ATP for moving molecules against their concentration gradient.

Channel-mediated facilitated diffusion involves the use of specific channels formed by transmembrane proteins to allow the passage of ions or water down their concentration gradient. It is a passive process and requires the presence of the channels to facilitate the movement of molecules.

Osmosis specifically refers to the movement of a solvent through a selectively permeable membrane.