Chapter 4 Cell Structure And Function Holt

Front 1

cell

Back 1

the smallest unit that can carry on all the processes of life.

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cell theory

Back 2

All living organisms are composed of one or more cells
Cells are the basic units of structure and function in an organism
Cells come only from the reproduction of exsisting cells.

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plasma membrane (cell membrane)

Back 3

covers a cell's surface and acts as a barrier between the inside and the outside of a cell

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cytoplasm

Back 4

the region of the cell that is within the plasma membrane and the includes the fluid, the cytoskeleton and all of the organelles (except the nucleus)

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cytosol

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the part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not the membrane bound organelles.

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nucleus

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the control center of the cell. A membrane bound organelle that contains the DNA. most functions in a eukaryotic cell controlled by this.

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prokaryotes

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are organisms that lack a membrane bound nucleus and membrane bound organelles

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eukaryotes

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organisms made of one or more cells that have a nucleus and membrane bound organelles

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organelles

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well defined, intracellular bodies that perform a specific function for the cell. (like tiny organs)

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tissue

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a group of similar cells and their products that carry out a specific function

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organs

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groups of tissues and their products that perform a particular job in a organism

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organ system

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a group of organs that accomplish relate tasks.

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phospholipid bilayer

Back 13

the foundation of the cell membrane. the phosphlipids line up so that their heads point outward toward the water and their tails point inward away from water

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chromosomes

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structures in the nucleus made up of DNA and protein

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nuclear envelope

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made up of two phospholipid bilayers that covers the nucleus

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nucleolus

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the site where DNA is concentrated when it is in the process of making ribosomal RNA

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Ribosomes

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are organelles made of protein and RNA the direct protein synthesis in the cytoplasm.

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mitocondria

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the power house of the cell. tiny organelles that transfer enery from organic molecules to ATP. (has own DNA)

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Endoplasmic Reticulum
(ER)

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a system of membranous tubes and sacs caled cisternae.

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Golgi apparatus

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another system of flattened membranous sac. responsible for packaging and shipping the proteins.

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lysosomes

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are vesicles that bud from the golgi apparatus and contain digestive enzymes

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cytoskeleton

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a network of thin tubes and filaments that crisscrosses the cytosol. they give shape to the cell and are used as internal tracks.

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microtubules

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hollow tubes made of a protein called tubilin

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cilia

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a hairlike structure that extends from the surface of a cell where they help in movement. short and present in large numbers

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flagella

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extends from the surface of a cell where they help in movement. longer and usually few in number (like the tail in a sperm cell)

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centrioles

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consist of two short cylinders of microtubules are right agles to each other and are situated in the cytoplasm near the nuclear envelope

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cell wall

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a rigid layer that lies outside the cell's plasma membrane made of cellulose a stiff matrix of proteins and carbohydrates

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central vacuole

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a large fluid filled organelle that stores water and enzymes, metabolic wastes, and other materials.

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plastids

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are organelles that, like mitocondria, are surrounded by a double membrane and contain their own DNA

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chloroplasts

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use light energy to make carbohydrates fro carbon dioxide and water.

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thylakoids

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a system of flattened, membranous sacs in chloroplasts

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chlorophyll

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inside the thylakoids are the main molecule that absorbs light and captures light energy for the cell