Anatomy & Physiology 1: Chapter 3 - Cellular Structure and Function Quiz

This question addresses the prevalence and ancient nature of unicellular organisms, specifically bacteria, on Earth. While there are many multicellular organisms like plants, the majority of Earth's residents are unicellular. Viruses, although abundant, are not considered ancient in the same way as bacteria. Algae, while also ancient, are not the most abundant or prevalent organisms on Earth.

Cellular activity can be both individual, as each cell functions on its own, and collective, as cells work together to form tissues and organs to carry out specific functions in the body.

Cell activity is mainly controlled by sub-cellular structures such as organelles, which play specific roles in the functioning of the cell.

Membrane proteins are specifically designed to interact with the hydrophobic environment of the cell membrane, allowing them to perform functions such as transport of molecules, signal transduction, and cell recognition.

Passive transport refers to the movement of biochemicals and substances across the cell membrane without the use of energy.

Passive transport is the movement of molecules across a cell membrane without the need for energy input. The four main types of passive transport are osmosis, simple diffusion, facilitated diffusion, and filtration. Active transport, endocytosis, and exocytosis require energy input from the cell to transport molecules across the cell membrane.

Osmosis specifically refers to the movement of water, not minerals, gases, or proteins, across a partially permeable membrane.

Facilitated diffusion is a passive process where molecules or ions move across the membrane with the help of specific proteins, unlike active transport where energy is required. It is different from simple diffusion as it involves the use of transport proteins.

Exocytosis is the process of moving substances out of a cell through the fusion of vesicles with the cell membrane. Therefore, the correct answer is 'out'.

Endocytosis is the process by which cells take in substances from outside the cell by engulfing them in a vesicle.

Endocytosis is the process by which cells absorb material from outside the cell by engulfing it with their cell membrane. The correct types of endocytosis are phagocytosis, pinocytosis, and transcytosis as mentioned in the answers. The incorrect answers provided do not describe the process of endocytosis and its specific functions.

Membrane potential refers to the electrical potential difference between the interior and exterior of a cell. It is not related to the rate of cell division, specific cell types, or physical size of a cell.

Sodium (Na) is primarily responsible for maintaining a positive charge outside of the cell through active transport mechanisms. Potassium (K), calcium (Ca), and chloride (Cl) also play key roles in cell function but do not contribute significantly to the positive charge on the outside of the cell membrane.

Large proteins have a net negative charge inside cells, contributing to the overall negative charge of the cell. Cholesterol molecules, carbohydrates, and nucleic acids do not typically play a significant role in generating the net negative charge inside cells.

Cell communication involves various methods such as direct contact signaling, electrical signaling, and chemical signaling. Mechanical, visual, and thermal signaling are not typical methods of cell communication.

An isotonic solution has the same solute concentration as inside cells, allowing water to move freely in and out without changing the cell's size or shape. Hypotonic and hypertonic solutions have different solute concentrations leading to water movement that alters cell size. Isotonic solutions do not dehydrate cells.

In a hypertonic solution, cells will lose water due to osmosis and shrink/shrivel because the external solution has a higher solute concentration than inside the cells, leading to water leaving the cells to try to balance the concentration levels.

In a hypotonic solution, cells take on water due to a lower solute concentration outside the cell compared to inside, leading to bloating and potential bursting. The other incorrect options do not accurately describe the effects of a hypotonic solution on cells.

The correct answer includes light, transmission electron, and scanning electron microscopes, which are the most common types used for different applications in microscopy.

The cell theory states that cells are the basic structural and functional unit of all living organisms, and new cells can only arise from pre-existing cells.

The correct answer is 'cellular' because life is fundamentally based on the existence and functioning of cells, which are considered the basic unit of life.

The human body is composed of approximately 70 trillion cells.

The Fluid Mosaic Model describes the cell membrane as a fluid structure with various molecules such as phospholipids, proteins, and carbohydrates arranged in a mosaic pattern. This model accounts for the dynamic nature of the cell membrane and its ability to regulate the movement of molecules.

Membrane junctions refer to specific types of cell junctions that play important roles in cell adhesion, communication, and signaling. The correct types of membrane junctions are tight junctions, adherens junctions, gap junctions, and desmosomes.

Membrane transport refers to the movement of ions, small molecules, and macromolecules across the cell membrane through various mechanisms such as passive diffusion, facilitated diffusion, active transport, and endocytosis.

Simple diffusion involves the passive movement of substances along the concentration gradient, from high to low concentration, without the need for energy input or a carrier molecule. It occurs across a semipermeable membrane, such as the phospholipid bilayer of cells.

Active transport is a process that requires energy to move molecules across membranes against the concentration gradient, unlike passive transport which does not require energy and moves substances with the concentration gradient.

The Na/K pump is responsible for maintaining the right concentrations of sodium and potassium ions inside and outside the cell, which is essential for various cellular functions.

Vesicular transport involves the formation of vesicles to move large particles across a membrane, different from the other types of transport mentioned.