Cell Structure

Kathleen & Josiah

" Cells "




cell membrane

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

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cell wall

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

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nucleus

in cells, large structure inside some cells that contains the cell's genetic material, DNA, and controls the cell's activities

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cytoplasm

materials inside the cell membrane- but not including the nucleus

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chromatin

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

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chromosomes

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

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cytoskeleton

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

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ribosomes

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

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endoplasmic reticulum

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

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golgi appratus

stack of membranes in the cell in which enzymes attach carbohydrates and lipids to proteins

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lysosomes

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

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vacuoles

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

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chloroplasts

organelle found in cells of plants and some other organisms that uses energy from sunlight to make energy- rich food molecules by photosynthesis

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mitochondria

cell organelle that releases energy from stored food molecules

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lipid bilayer

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

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concentration

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

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diffusion

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

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selectively permeable

property of biological membranes that allows only certain substances to pass through them

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osmosis

diffusion of water through a selectively permeable membrane

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isotonic

noting or pertaining to a solution containing the same salt concentration as mammalian blood.

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hypertonic

noting a solution of higher osmotic pressure than another solution with which it is compared

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hypotinic

noting a solution of lower osmotic pressure than another solution with which it is compared

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facilitated diffusion

movement of specific molecules across cell membranes through protein channels

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active transport

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


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