20 terms

7.2 - Cell Structure

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Terms in this set (...)

cytoplasm
the portion of the cell outside of the nucleus
2 main parts of the cell?
nucleus & cytoplasm
organelle
"little organs" - cell structures that act like specialized organs and have specific functions
vacuole
large, saclike, membrane enclosed structures (STORAGE)

types:
- central vacuole (plants)
- contractile vacuole (animals & unicellular org.)
lysosome
small organelles filled with enzymes (CLEANUP)
- in plant and animal cells
- responsible for preventing certain diseases
(prevents buildup of "bad stuff")
cytoskeleton
protein filaments that help shape & organize eukaryotic cells (SHAPE + STRUCTURE)
- transport materials within the cell
- in certain organisms (cell flagella & cilia), they can
move the entire cell

makeup:
- microfilaments
- microtubules
centriole
helps organize cell division
- in animal cells only
- located near the nucleus
- formed from tubulin (microtubule?)
ribosome
small particles of RNA and protein found throughout the cytoplasm
- in all cells
- produce proteins by coded DNA instructions

(the more protein synthesis needed = more ribosomes present)
endoplasmic reticulum
the internal membrane system (ER) in eukaryotic cells
- lipids of cell membranes & materials to be exported are assembled here

types:
- "smooth ER"
- "rough ER" --> protein synthesis, ribosomes on
surface
Golgi aparatus
the next stop for proteins after the rough ER
- sorts proteins from rough E.R. for storage or
secretion purposes and ships them out in vesticles
chloroplast
biological representation of solar power plants
- in plants and some other organisms
- converts energy from the sun into chemical energy
stored as food
- 2 membranes surround chloroplasts (inside is a
membrane with chlorophyll)
mitochondrion
the powerhouse of the cell
- in almost all eukaryotic cells, both plant and animal
- converts chemical energy from food into energy for
cells to easily use
cell wall
a strong supporting layer around the cell membrane
- in most cells and prokaryotic cells)
- animals cells do NOT have a cell wall
- support, shape, and protect the cell
- most are porous enough to let CO2, H2O, etc.
through
- provide strength against gravity

note: ALL cells have CELL MEMBRANES
NOT all cells have CELL WALLS
lipid bilayer
the double-layered sheet in almost all cell membranes
- in mostly all cells b/c all cells have a cell membrane
(not in ones whose membrane doesn't have a lipid
bilayer)
- gives cell membranes a flexible structure that forms
a strong barrier between all of its surrounding
selectively permiable
the property in which some substances can pass through the cell membrane and others cannot
- if something is too large or too charged, the
membrane is impermeable to it
- most biological membranes are selectively
permeable
What is the role of the cell nucleus?
The nucleus contains nearly all the cell's DNA and, with it, the coded instructions for making proteins and other important molecules.
What are the functions of vacuoles, lysosomes, and the cytoskeleton?
vacuoles:
- store materials like water, salts, proteins, and carbs

lysosomes:
- break down lipids, carbs, and proteins into smaller
molecules for cells to use
- break down organisms that are no longer useful, i.e.
"junk"

cytoskeleton:
- helps cell maintain its shape and is involved in
movement
What organelles help make and transport proteins?
ribosomes: proteins are assembled

rough ER: proteins that will be released from the cell and membrane proteins designed for specific locations are made

Golgi apparatus: modifies, sorts, and packages proteins, etc. from the E.R. for storage or release from the cell and ships them out in vesticles
What are the functions of chloroplasts and mitochondria?
chloroplasts: capture the energy from sunlight and convert it into food that contains chemical energy through photosynthesis

mitochondria: convert chemical energy stored in food into compounds that are more convenient for the cell to use
What is the function of the cell membrane?
cell membrane:
1) regulates what enters and leaves the cell
2) protects and supports the cell