unit 3 test Flashcards
Cell theory
1.all living things are composed of 1 or more cell
2.cell is the basic unit of life
3.all new cells arise from existing cells
prokaryotic cell
unicellular organism that lacks a nucleus or any other membrane bound organelle
-smaller
-cell membrane
eukaryotic cell
cell that has a membrane bound nucleus and other membrane bound organelles
-larger
-cell membrane
both prokaryotic cells and eukaryotic cells have..
-plasma membrane/ cell membrane
-cytoplasm
-DNA
-ribosomes
macromolecule
also known as polymers, made up of monomers; carbohydrates, proteins, lipids, nucleic acids/DNA & RNA
carbohydrates
-primary source of energy
-carbon, hydrogen, & oxygen
1:2:1
-monomer : monosaccharides/ simple sugars
lipids
-help move and store energy
-carbon, hydrogen, & oxygen
-monomers: fatty acids and glycerol
-hydrophobic
protein
-“building block”
-nitrogen, carbon, hydrogen, & oxygen
-monomer: amino acids
nucleic acids
-store and transmit hereditary or genetic info
-carbon, hydrogen, oxygen, nitrogen, & phosphorus
-monomer: nucleotides
-ribonucleic acid (RNA) : contains sugar ribose
-deoxyribonucleic acid (DNA) : contains sugar deoxyribose
components of cell membrane
-bilayer of phospholipids
-proteins
-carbohydrates
plasma membrane
only allow certain substances to enter and leave the cell to prevent harmful material from entering and important material from leaving
selectively permeable
only allows certain material to pass or leave (plasma membrane)
passive transport
when substances more from an area of high concentration to an area of of low concentration naturally without energy
-diffusion
-facilitated diffusion
-osmosis
diffusion
general movement where substances move from an area of high to low concentration
concentration gradient
a physical space in which there is a different concentration of a single substance
facilitated transport/ diffusion
substances moving across the plasma membrane with the help of proteins
osmosis
movement of free water molecules through a semipermeable membrane according to the waters concentration gradient across the membrane
-tonicity
-osmolarity
-hypertonic solution
-hypotonic solution
-isotonic solution
tonicity
the amount of solute in a solution
osmolarity
the measure of tonicity or total amount of solute dissolved in a specific amount of solution
hypotonic solution
extracellular solution has a higher concentration of water but lower concentration of solute than the cell does.
-water flows into the cell
-cell swells
hypertonic solution
extracellular solution has a lower concentration of water but higher concentration of solute than the cell does.
-water flows out of the cell
-cell shrivels
isotonic solution
extracellular solution has a the same concentration of water and solute than the cell does.
-water flows into and out of the cell
-cell stays the same
active transport
requires the use of the cells energy in the form of ATP. moves substances against us concentration gradient
electrochemical gradient
a combined gradient of concentration and electrical charge that affects ion movement across a membrane
Na+
sodium
-electrical gradient drives Na+ into cell
K+
potassium
-electrical gradient drives K+ into the cell
-concentration gradient drives K+ out of cell
cell interior (electrochemical gradient)
-negatively charged compared to extracellular fluid
-higher K+ concentration, lower Na+ concentration compared to outside
primary active transport
directly used ATP to move substances, e.g., sodium-potassium pump
sodium potassium pump
moves K+ into cells and N-+ out, creating concentration and charge differences across the membrane
endocytosis
cellular process of engulfing external substances to bring them into the cell
exocytosis
cellular process where materials inside a cell are packaged into vesicles and released into the extracellular space
