Chapter 2 - Cells Flashcards
Define a system in the context of body organization.
A system is a group of organs that work together for a common purpose.
For example, the respiratory system supplies oxygen and removes carbon dioxide from the blood.
What is an organ?
An organ is normally made up of two or more types of tissues that work together.
For example, the stomach is an organ with epithelial tissue on the inside and muscular tissue in the wall.
Define tissues.
Tissues are groups of similar cells that carry out a common function.
What are cells?
Cells are the lowest structural level and are specialized to carry out different functions.
For example, muscle cells can shorten in length, and red blood cells transport oxygen.
How do all body systems work together?
All body systems work together to meet the needs of a functioning organism.
What is the function of the cell membrane?
The cell membrane separates the internal and external environment and determines which substances can enter or exit the cell.
What is the structure of the cell membrane?
The cell membrane is composed of a phospholipid bilayer, membrane proteins, and cholesterol.
What does ‘differentially permeable’ mean?
Differentially permeable refers to the ability of a cell membrane to only allow certain particles to pass through.
Define passive transport process.
Passive transport is the movement of substances through the cell membrane requiring no energy.
What is simple diffusion?
Simple diffusion is a passive process driven by the concentration gradient, resulting from the random movement of ions and molecules.
What is facilitated diffusion?
Facilitated diffusion involves carrier proteins allowing large molecules to be transported across the membrane without energy.
Define osmosis.
Osmosis is the diffusion of water across a differentially permeable membrane.
What is active transport?
Active transport is the movement of molecules from low concentration to high concentration, requiring energy.
What is vesicular transport?
Vesicular transport is the movement of substances across the cell membrane in membranous sacs called vesicles, requiring energy.
What is endocytosis?
Endocytosis is the process of taking liquids or solids into the cell by folding the cell membrane around a particle.
What is exocytosis?
Exocytosis is when the contents of a vesicle are passed to the outside of the cell.
What is the difference between phagocytosis and pinocytosis?
Phagocytosis is the process of taking solids into the cell, while pinocytosis involves taking liquids.
What are the types of tissues?
The four types of tissues are epithelial, connective, muscular, and nervous tissue.
What is the function of epithelial tissue?
Epithelial tissue covers or lines organs and consists of closely joined cells.
What is the function of connective tissue?
Connective tissue provides support for the body and holds body parts together.
What is the function of muscular tissue?
Muscular tissue consists of muscle fibers that can contract to become shorter.
What is the function of nervous tissue?
Nervous tissue is made up of neurons that carry messages throughout the body.
What is pinocytosis?
Pinocytosis is the process of taking liquids into the cell.
What is phagocytosis?
Phagocytosis is when a vesicle contains a solid.
What happens during exocytosis?
The vesicle formed inside the cell migrates to the cell membrane, and the contents are pushed out into the extracellular fluid.
What are some examples of materials expelled during exocytosis?
Waste products or products made by the cell, such as carbon dioxide and hormones.
How does a cell’s size and shape affect diffusion?
A cell with a small surface area but a large volume cannot support itself due to insufficient surface to absorb nutrients and remove waste.
What is the importance of surface area to volume ratio in cells?
Cells must have a large surface area to volume ratio to effectively absorb nutrients and remove wastes via diffusion.
How do concentration gradients affect the rate of diffusion?
The greater the difference in concentration, the steeper the diffusion gradient and the faster the rate of diffusion.
How does the chemical nature of materials affect their movement across a membrane?
larger molecules are unable to diffuse directly through the cell membrane and must use facilitaed diffusion.
