Cell Structure and Function Vocabulary

Honors Bio with Dr. Kohler - Test Date 11/2/26

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 units of structure and function in living things, and new cells are produced from existing cells

nucleus

structure that contains the cell’s genetic material (DNA) and controls the cell’s activities

eukaryote

organism whose cells contain nuclei

prokaryote

unicellular organism lacking a nucleus

organelle

specialized structure that performs important cellular functions within a eukaryotic cell

cytoplasm

material inside the cell membrane - not including the nucleus

nuclear envelope

layer of two membranes (double membrane) that surrounds the nucleus of a cell

chromatin

granular material visible within the nucleus; consists of DNA tightly coiled around proteins

chromosome

threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next

nucleolus

small, dense region within most nuclei in which the assembly of proteins begins

ribosome

small particle in the cell on which proteins are assembled; made of RNA and protein

endoplasmic reticulum

internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified

golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell

vacuole

cell organelle that stores materials such as water, salts, proteins, and carbohydrates

mitochondrion

cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use

chloroplast

organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy

cytoskeleton

network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement

centriole

one of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope

cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

cell wall

strong supporting layer around the cell membrane in plants, algae, and some bacteria

lipid bilayer

double-layered sheet that forms the core of nearly all cell membranes

concentration

the mass of solute in a given volume of solution, or mass/volume

diffusion

process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

equilibrium

when the concentration of a solute is the same throughout a solution

osmosis

diffusion of water through a selectively permeable membrane

isotonic

when the concentration of two solutions is the same

hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

hypotonic

when comparing two solutions, the solution with the lesser concentration of solutes

facilitated diffusion

movement of specific molecules across cell membranes through protein channels

active transport

energy-requiring process that moves material across a cell membrane against a concentration difference

endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

phagocytosis

process in which extensions of cytoplasm surround and engulf large particles and take them into the cell

pinocytosis

process by which a cell takes in liquid from the surrounding environment

exocytosis

process by which a cell releases large amounts of material

cell specialization

the process in which cells develop in different ways to perform different tasks

tissue

group of similar cells that perform a particular function

organ

group of tissues that work together to perform closely related functions

organ system

group of organs that work together to perform a specific function