anatomy: ch.2 pt.1 over cells

what are cells measured in and what is it equal to when compared to cm?

measured in um (micrometers) and 1cm=10,000um

what are the 3 basic parts that MOST human body cells have?

plasma membrane, cytoplasm, and nucleus

what is the cell membrane?

an extremely thin outer border of a cell that separates the intracellular and extracellular fluid compartments

what type of bilayer does the plasma membrane have and what key features does it have?

a phospholipid bilayer. it has selective permeability and is always expanding and contracting

what are the two general types of membrane transport?

passive transport and active transport

what is passive transport and is ATP required?

materials move down the concentration gradient (high to low) and no ATP is required

what is active transport and does it require ATP?

materials move against the concentration gradient (low to high) and it requires ATP

what are the three types of passive transport?

simple diffusion, osmosis, and facilitated diffusion

what type of molecules is simple diffusion used for?

small, nonpolar molecules moving from high to low

what is osmosis?

diffusion of water

what type of molecules is facilitated diffusion used for and what helps them move across the membrane?

large molecules moving from high to low. (Think you need a KEY to unlock the door.) transport proteins help move molecules across membranes

what is a type of active transport?

bulk transportation

what are the two types of bulk transport and what do they do?

exocytosis: materials are packaged into vesicles and secretes out of the cell when vesicles fuse with the plasma membrane. endocytosis: materials are taken into the cell then packaged into vesicles

what are the two forms of endocytosis?

phagocytosis and pinocytosis

what is phagocytosis?

nonspecific uptake of particles by formation of membrane extensions (pseudopodia) that surround and engulf particles

what is pinocytosis?

nonspecific uptake of cellular fluid

what is considered the cytoplasm?

if it is inside the cell and not part of the nucleus, it is part of the cytoplasm

what are 3 parts of the cytoplasm?

cytosol, inclusions, and organelles

what is cytosol?

fluid containing water and many smaller dissolved molecules

what are inclusions?

they are chemicals such as pigments, nutrients, and protein crystals

what are organelles?

tiny little organs within the cell that all perform a specific function

what organelles are membrane-bound?

ER, golgi apparatus, lysosomes, peroxisomes, and mitochondria

what organelles are non-membrane-bound?

ribosomes, cytoskeleton, centrosomes, centrioles, cilia, flagella, microvilli

what are the enclosed spaces between the folds of the ER called?

cisternae

what is a function of the smooth ER and what makes it smooth?

detoxification of drugs, alcohol, poison, It is smooth because it has a lack of ribosomes

what is one purpose of the rough ER and why is it rough?

modifies the proteins and packages them into transport vesicles, rough because attachment of ribosomes

what is a function of the golgi apparatus?

recieves material from the ER for modification, sorting and packaging, sends it out (like UPS)

what are lysosomes generated by and what is their function?

generated by golgi apparatus (compartment to carry), will digest and remove waste products within the cell

how are perioxisomes made and what do they do?

sacs formed by pinching off from RER (smaller than lysosomes), detoxify harmful molecules in the cell (abundant in liver cells)

what is the purpose of the mitochondria, what is a key component of it, and what are the gaps in it called?

generates ATP, has a double layer and the gaps in it are called cristae

what is the purpose of ribosomes?

responsible for protein synthesis

what is the cytoskeleton and what is its purpose?

proteins organized in the cytosol as solid filaments or hallow tubes, gives structure (steel beams in building)

what are three cytoskeleton components?

microfilaments, intermediate filaments, and microtubules

where is the centrosome located and what does it have attached to it?

adjacent to nucleus, has pair of centrioles

what is the purpose of a centriole?

helps with cell division

what is the purpose of cilia?

fine hairs on exposed surfaces of certain cells that help to move objects across their surface

what is the purpose of flagella and how do they differ from cilia?

whip-like tails (on sperm), longer than cilia

what is microvilli and what is its purpose?

tiny projections from plasma membrane, role is to increase surface area for membrane transport