★ ap bio : cell structure and function

i gen dont know if this is finished or not but ima post it.. i comes frm a study guide frm my ap bio teacher

prokaryote

a microscopic single-cell organism that *doesn’t* have a nucleus; examples include bacteria

eukaryote

a microscopic multicellular organism that has a nucleus and membrane-bound organelles in the cytoplasm; examples include plants + animals

plasma membrane

forms the boundary for a cell; is **selectively permeable** + made of phospholipids, proteins + carbs

endoplasmic reticulum (er)

network of membranous sacs and tubes; active in membrane synthesis + other synthetic/metabolic processes

cell wall

protects plant + helps maintain shape

nuclear envelope

a double membrane that surrounds the nucleus- it has pore structures that regulates what enters and leaves the nucleus

chromatin

the complex DNA and protein housed in the nucleus that forms chromosones

nucleolus

the region of the nucleus where ribosomal RNA is synthesized and complexes with proteins to form ribosomal subunits

ribosomes

the site of protein synthesis that is composed of rRNA; found in eukaryotes and prokaryotes

golgi apparatus

the warehouse of proteins-- each protein from the ER are received, sorted, folded, modified if needed, and shipped

lysosomes

membrane-bound sacs of hydrolytic enzymes that digest large molecules

vacuoles

large vesicles that perform a variety of functions in different kinds of cells

central vacuoles

a prominent organelle in older plant cells that can make up 80% of volume of the cell

mitochondria

the site of cellular respiration (the powerhouse of the cell)

chloroplast

the site of photosynthesis

endosymbiont theory

a theory where the mitochondria and chloroplast descended from prokaryotes and were engulfed by ancestors of eukaryotes-- **evidence** includes having their own DNA, double membrane structure, and being able to reproduce independently

cristae

the inner folding of the *mitochondria*-- they increase the surface area, which enhances the productivity of cellular respiration

cytoskeleton

a network of protein fibers that runs throughout the cytoplasm-- responsible for support, mobility, and regulation in some biochemical activities

microtubules

the largest protein fiber that makes up the cytoskeleton; made of protein tubulin + shape and support cell

microfilaments (actin filaments)

a protein fiber that makes up the cytoskeleton that are composed of the protein actin-- functions in smaller-scale support

intermediate filaments

a protein fiber that makes up the cytoskeleton; similar to microfilaments but are important in maintaining shape of the call and fixing position of certain organelles

transport protein

a protein that can transport certain *hydrophilic* substances into the plasma membrane

aquaporin

a special transport protein for water

passive transport

where a substance travels from a high concentration to a low concentration-- it requires **no energy**

passive diffusion

a type of passive transport; where hydrophobic substances can easily pass thru the membrane (this is because of the **hydrophobic** tails in the bilayer)

omosis

the diffusion of water across a selectively permeable membrane

isotonic solution

where water crosses at the same rate in both directions of the membrane

hypertonic solution

where the cell loses water to its surroundings