Biology Test: Unit 7 (Cells) Flashcards
What is endocytosis?
The process by which a cell takes material into it’s self by the enfolding of the cell membrane
What is exocytosis?
The process by which a cell releases large amounts of material
What is diffusion?
The process by which molecules tend to move from an area of high concentration to low concentration
What is facilitated diffusion? Does it require energy?
The movement of specific molecules across membranes through protein channels (does not require energy)
What is osmosis? Does it require energy?
The diffusion of water through a selectively permeable membrane (does not require energy)
What is active transport? Does it require energy?
The process of moving material across a cell membrane against a concentration difference (requires energy)
What is an isotonic solution?
When the concentration of two solutions is the same
What is a hypertonic solution?
When comparing two solutions of different concentrations, the solution with a higher concentration of solutes
What is a hypotonic solution?
When comparing two solutions of different concentrations, the solution with a lower concentration of solutes
What is cell theory?
The idea that
- All living things are composed of cells (Theodor Schwann)
- Cells are the basic units of structure and function in living things
- New cells are produced from existing cells (Rudolph Virchow)
What is a prokaryote?
A unicellular organism that lacks a nucleus
What is a eukaryote?
An organism whose cells contain nuclei
What is an organelle?
A specialized structure that performs important cellular functions within a eukaryotic cell. “Little organs.”
What is chromatin?
Granular material visible within the nucleus; consist of DNA bound to proteins
What are chromosomes?
Threadlike structures within the nucleus that contain the genetic information that is passed from one generation of cells to the next
What is a nucleolus?
A small, dense region within most nuclei in which the assembly of proteins begins
What is the nuclear envelope?
A layer of two membranes that surrounds the nucleus of a cell
What is a microtubule?
Hollow tubes of protein cell shape and organelle movement (in cytoskeleton)
What is a microfilament?
Long thin fibers for movement and support (in cytoskeleton)
What is concentration?
The mass of solute in a given volume of solution; mass per volume
What is selective permeability?
Allows CERTAIN molecules to pass through it by diffusion
What are ribosomes?
A small particle in a cell on which proteins are assembled; made of RNA and protein
What is the endoplasmic reticulum?
Smooth / Rough ER; an internal membrane system in cells in which lipid components of the cell membrane are assembled
What is the cytoplasm?
The jelly-like materials that the organelles float in
What are vacuoles?
A cell organelle that stores materials
What is the cell membrane?
A thin barrier around a cell that regulates what goes in and out of the cell
What is the cell wall?
A strong supporting layer around the cell membrane in plants algae, and some bacteria
What is the mitochondria?
A cell organelle that converts chemical energy stored in food into compounds that are more convenient for the cell to use (“power house” of cell)
What are the chloroplasts?
Organelles found in cells of plants and some other organisms that captures energy from sunlight and converts it into chemical energy
What is the cytoskeleton?
A network of protein filaments within some cells that helps the cell maintain shape and is involved in forms of cell movement
What is the golgi apparatus?
A stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum
What are lysosomes?
A cell organelle filled with enzymes needed to break down certain materials in the cell
What is a nucleus?
A structure that contains the cell’s genetic material (DNA) and controls the cell’s activities
What is the order of the levels of organization?
Individual cells, tissues, organs, and organ systems
