45 terms

Biology Chapter 7: Cell Structure and Function Vocabulary

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Cell
Collection of living matter enclosed by a barrier that separates the cell from its surroundings; basic unit of all forms of life
Cell theory
Idea that all living things are composed of cells, cells are the basic unit of structure and function in living things, and new cells are produced from existing cells
Nucleus
Structure that contains the cells genetic material (DNA) and controls the cells activities
Eukaryotes
Cells that contain nuclei
Prokaryotes
Cells that do not contain nuclei
Organelles
Structures inside a cell that act as tiny organs
Cytoplasm
The area outside of the nucleus
Nuclear envelope
Layer of two membranes that surrounds the nucleus of a cell
Chromatin
Granular material in the nucleus made of DNA bound to protein
Chromosomes
Chromatin condenses to form this; these distinct, threadlike structures contain the genetic information that is passed on from one generation of cells to the next.
Nucleolus
Small dense region inside of the nucleus; ribosomes are made here
Ribosomes
Proteins are assembled on these; small particles of RNA and protein found throughout the cytoplasm; they produce proteins by following coded instructions that come from the nucleus
Endoplasmic reticulum
Internal membrane system
Rough endoplasmic reticulum
Involved in synthesis of proteins; many ribosomes found on its surface
Smooth ER
No ribosomes on the surface; contains collections of enzymes that perform specialized tasks, including the synthesis of membrane lipids and the detoxification of drugs
Golgi apparatus
Function is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.
Lysosomes
Small organelles filled with enzymes; digestion, or breakdown, of lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell; involved in breaking down organelles that have outlived their usefulness; they remove junk
Vacuoles
Saclike structures that store materials such as water, salts, proteins, and carbohydrates
Mitochondria
Organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use
Chloroplasts
Organelles that capture the energy from sunlight and converted into chemical energy in a process called photosynthesis
Cytoskeleton
A network of protein filaments that helps the cell to maintain its shape; this is also involved in movement
Microfilaments
Threadlike structures made of protein called actin; they formed extensive networks in some cells and produce a tough, flexible framework that supports the cell; they also help cells move by assembly and disassembly
Microtubules
Hollow structures made of proteins known as tubulin; they play critical roles in maintaining sell shape; important in cell division, they form a structure known as the mitotic spindle, which helps to separate chromosomes.
Centrioles
Formed from tubulin; located near the nucleus and help to organize cell division; are not found in plant cells
Cell membrane
A thin, flexible barrier that surrounds a cell; regulates what enters and leaves the cell and also provides protection and support
Concentration
The mass of solute in a given volume of solution, or mass/volume
Cell wall
Strong supporting layer around the membrane; provides protection and support
Lipid bilayer
Double layered sheet that gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings
Diffusion
And movement of a substance from an area of higher concentration to an area of lower concentration; does not require energy
Equilibrium
Reached when the concentration of the solute is the same throughout the system
Osmosis
The diffusion of water through a selectively permeable membrane
Isotonic
Same strength
Hypertonic
Above strength
Hypotonic
Below strength
Facilitated diffusion
When protein channels help substances move across the membrane
Active transport
Requires energy
Endocytosis
The process of taking material into the cell by means of infoldings, or pockets, of the cell membrane
Phagocytosis
Extensions of cytoplasm surround a particle and pack packages within a food vacuole, The cell then engulfs it; taking in with the intent to destroy
Pinocytosis
Tiny pockets form along the cell membrane, filled with liquid, and pinch off to form vacuoles with in the cell
Exocytosis
The membrane of the vacuole surrounding the material fuses with the membrane, forcing the contents out of the cell
Cell specialization
Cells throughout an organism can develop in different ways to perform different tasks
Levels of organization in a multicellular organism
Cells, tissues, organs, and organ systems
Tissue
A group of similar cells that perform a particular function
Organ
Many groups of tissues work together to become this
Organ system
A group of organs that work together to perform a specific function