How can we help?

You can also find more resources in our Help Center.

48 terms

Cells

science
STUDY
PLAY
light microscope
enables us to see the overall shape and structure of a cell
passes visible light through a specimen
can study living cells, cell, tissues that have been stained
can only magnify about 1000 times
total magnification
a times b
ocular times objective
magnification
the increase in the apparent size of an object
resolution
a measure of the clarity of the image
electron microscope
uses a beam of electrons rather than light
greater resolution than LM and can magnify up to 100,000 times
cant be used with living specimens
small cell- surface areas
small cell has greater ratio of surface area to volume than a large cell of the same shape
surface area- cell membrane
volume- cytoplasm
cell increases in size..
its volume increases faster than its surface area
cells are more efficient when they are small
prokaryotic cells definiton
simpler than eukaryotic cells
have no nucleus
bacteria, archae
eukaryotic cells defintion
protists plants animals fungi
have a nucleus and other membrane bound organelles
all cells share common feautures
plasma membrane- makes proteins
DNA
ribosomes
prokaryotic cells
no real nucleus
DNA is coiled into a nucleoid region in the cytoplasm
cytoplasm includes ribosomes
plasma membrane
cell wall
eukaryotic cells
larger and partitioned into functional compartments called organelles
have a true nucleus
animal cells
no cell wall
contain centrioles and lysosomes
may have flagella
can have tiny vacuoles (bubble filled with water)
plant cells
have both plasma membrane and rigid cellulose cell wall
have large central vacuole and chloroplasts
lack centrioles, lysosomes, and flagella
have mitochondria( takes glucose converts it to atp)
nucleus
cells genetic control center and contains DNA
controls cellular activities
separated from the cytoplasm by the nuclear envelope
nuclear envelope
nuclear pores in the envelope control flow of materials in and out
ribosomes are synthesized in the nucleolus (dark circles inside nucleus)
endomembrane
many cell organelles connected through this
a series of membranous organelles
endoplasmic reticulum
continuous network of flattened sacs and tubes
smooth endoplasmic reticulum
lacks attached ribosomes
makes lipids
proccesses materials such as toxins and drugs in liver cells
rough endoplasmic reticulum
studded with ribosomes
manufactures membranes
modifies and packages proteins
golgi apparatus
a stack of flattened membranous sacs that finishes, sorts, ware houses, and ships cell products
UPS of cell
lysosomes
sacs of enzymes that form from the gogi apparatus
function in digestion within a cell
destroy bacteria that have been ingested into white blood cells
recycle damaged organelles
abnormal lysosomes can cause fatal diseases
vacuoles
function in the general maintenance of the cell (storing water)
plant cells contain large center vacuole
some protists have contractile vacuoles that pump excess water out of a cell
chloroplasts
convert solar energy to chemical energy
found in plants and are the sites of photosynthesis
photosynthesis
sunlight+water+CO2 to glucose and oxygen
mitochondria
harvest chemical energy from food
found in nearly all eukaryotic cells
carry out cellular respiration
convert the chemical energy in food to ATP for cellular work
cellular respiration
oxygen+glucose to CO2+H2O+36 ATP
ATP is adenosine triphosphate
cytoskeleton
network of three types of protein fibers that provides structure for the cell
1. microfilaments (thin)
2. intermediate filaments (medium)
3. microtubules (thickest)
cilia and flagella move when microtubules bend
move whole cells or materials across the cell surface
plant cell walls
made largely of cellulose (carb)
provide protection and support
connect by plasmodesmata- channels through the wall
animal cell membranes
embedded in an extracellular matrix that binds cells together in tissues
connected by cell junctions
membrane structure and function
plasma membrane forms a boundary between a living cell and its sorroundings
shows selective permeability only allowing certain things to enter and leave the cell
phospholipids
are the main structural components of membranes
1 polar phosphate group attached to hydrophilic glycerol head
2 nonpolar fatty acids, hydrophobic tails
phospholipids in membrane
form a bilayer that is selectively permeable
small nonpolar lipid
soluble molecules pass through- polar molecules not soluble in lipids and do not pass though
difusion
the movement of molecules from an area of high concentration to an area of low concentration
passive transport
across membranes occurs when a molecule diffuses down a concentration gradent (from high to low concentration)
small nonpolar molecules
such as O2 and CO2 diffuse easily across the phospholipid bilayer of a membrane
facilitated difusion
transport proteins help substances difuse down a concentration gradient (move from higher to lower concentration)
osmoregulation
the control of water balance
isotonic solution
solute concentration is the same in both solutions you are comparing
hypotonic solution
has more water and less solute than the solution you are comparing it to (dilute)
hypertonic solution
had more solute and less water than the solution you are comparing it to (concentrated)
animal cell what solution is best?
isotonic is best
water comes out of cell at the same rate it is coming in
plant cell what solution is best?
hypotonic solution causes cell to poof up making the plant stay upright
plasmolysis
where cell membrane pulls away from the cell wall causing plant to wilt
Active transport
requires energy to move solutes against a concentration gradient (from low to high concentration) allows to stock pile solutes for later on
requires ATP (source of energy) and transport proteins
exocytosis
a vesicle of large waste may fuse with the membrane and expel its contents outside the cell
endocytosis
extensions of the cytoplasm move out to sorround large materials the cell needs
1. pinocytosis- engulfing liquids
2.phagocytosis- engulfing solids