C2.0 Flashcards
what is an open system?
exchanges both matter and energy it with the environment
what is a closed system?
exchanges energy but not matter
what is an isolated system?
exchanges neither energy nor matter
what are lipids?
used for energy storage and in cell membranes
(contain glycerol and fatty acids)
fats and oils
phospholipids
what are carbohydrates?
used for energy storage
(contain carbon, hydrogen and oxygen)
sugars and starches
glycogen and cellulose
what are proteins?
used for transport, support, immunity, etc.
(made up of amino acids)
hemoglobin
enzymes
what are nucleic acids?
transfer and expression of genetic information
(made up of nucleotides)
make up our DNA (deoxyribonucleic acid)
major functions of cell organelles:
structure and support control and cell management storage and transport protein production fat production defense energy conversion
cell membrane
acts as a protective barrier
allows for transport of materials into and waste out of the cell
because it’s outer layer has receptor proteins, it is important in cell communication
cell wall
- found only in plants, fungi, bacteria and archaebacteria
a rigid frame that gives plant cells strength and support
is part of what allows plants to grow very tall but remain strong
cytoplasm
a gel-like substance that gives the cell structure
the organelles are suspended in the cytoplasm and can move around through the process of cytoplasmic streaming
stores nutrients until organelles are ready to use them
cytoskeleton
filaments inside the cytoplasm that act like a framework
maintains cell shape and allows for movement of cell parts
similar to the role that your skeleton plays in your body
nucleus
contains DNA, the genetic material of the cell
directs all cellular activities, including mitosis
surrounded by the nuclear envelope
vacuole
membrane-bound structures that store water in plants
turgor pressure makes the plant cell firm ( or turgid )
if the vacuole is not full, the cells become weak and the plant wilts
vesicles
small bubbles with the same structure as the cell membrane
transport substances throughout the cell
Golgi apparatus
flat discs involved in packaging and transport contains enzymes for modifying proteins and lipids
receives the products assembled in the ER and transports them out of the cell
endoplasmic reticulum
series of tubes branching off the nuclear envelope
rough ER
has a grainy appearance due to the attached ribosomes
responsible for synthesizing proteins
ribosomes
granules attached to the ER
take amino acid building blocks and assemble them into proteins
smooth endoplasmic reticulum
has a smooth appearance
takes lipid building blocks and assembles fats ( animal cells ) and oils ( plant cells )
packages macromolecules into vesicles to be shipped to other parts of the cell
lysosomes
membrane-bound sacs containing strong digestive enzymes.
kill invading bacteria and destroy damaged cell organelles.
if a cell malfunction, it’s lysosomes will burst and kill the cell before an infection spreads.
sometimes called suicide sacs
chloroplasts
type of plastid ( organelle used to synthesize and store food )
found only in plants
contain a green pigment called chlorophyll
site of photosynthesis
converts the sun’s energy into glucose and oxygen
mitochondria
site of cellular respiration
carbohydrates that store chemical energy.
converted into usable energy for the cell
cells with higher energy need ( muscle, sperm ) are packed with mitochondria
importance of the cell membrane
structure : contains the cell contents
equilibrium : controls what enters and exits the cell
communication : uses receptor proteins to identify materials and relay messages
protection and defense : recognizes foreign invaders and bars them from entry, or destroys them
transportation : is the barrier through which all materials must pass
fluid mosaic model
the accepted model for
The structure of the cell membrane.
fluid, because the membrane is flexible.
mosaic, because it is a collection of different substances that are held together.
as the name implies, the membrane is made of two layers of days that have phosphates attached.
particles
include any individual molecules of water, nutrients, waste and gases traveling across the membrane.
the particles of a substance are always moving.
how far and how fast they move depends on :
• the relative concentration of that substance on either side of the membrane
• the state of the substance ( solid, liquid of gas )
particle model of matter : solids
have a definite shape and volume.
do not flow or compress readily.
have the least amount of motion, mainly only vibrational.
particle model of matter : liquids
take the shape of their container but have a definite volume.
do not compress readily but flow readily.
have some vibrational, rotational, and translational motion.
particle model of matter : gases
take both the shape and the volume of their container.
highly compressible and flow readily.
have the highest amount of motion, mainly translational.
particle model of matter : four main points
1) all matter is made of particles, but they may be different size and composition
2) the particles are constantly moving, and move least in solids and most in gases. heating particles makes them move faster
3) the particles of matter are attracted to one another or are bonded together
4) particles have spaces between them, and are typically greatest in gases and smallest in solids
concentration gradient
referred to the amounts of a substance dissolved in a solvent, usually water.
a concentration gradient exists when there is a difference in the amount of solute on either side of a membrane.
solutes naturally move down the gradient, which means from an area of high concentration to an area of low concentration.
semi-permeable membranes
the cell membrane is referred to as semi-permeable because it allows some substances to pass through, but not everything.
sometimes called selectively permeable.
diffusion
method of transport for molecules that are fat-soluble of very small molecules.
because these molecules can dissolve or pass right through the barrier, their movement is not restricted by the cell membrane.
diffusion is classified as passive transport because it flows down the concentration gradient.
passive transport
like floating downstream ; it requires an extra energy
osmosis
another form of passive transport.
osmosis is similar to diffusion, except deals solely with the movement of water molecules.
osmosis occurs when there is a solute concentration different, but the membrane is not permeable to the solute.
water molecules move through the membrane and also pass through channel proteins called aquaporins.
because the solute is not free to move particles of water will move until the relative concentrations are equal on either side of the membrane.
tonicity
refers to the concentration of the solutes outside the cell, relative to the concentration inside the cell
(3 types)
isotonic solution
concentration inside and outside the cell is equal water is flowing in at the same rate as it is flowing out
cell will appear normal and healthy
• animal cells will appear normal
• plant cells will appear slightly limp due to a lack of turgor pressure
hypotonic
the concentration of solutes outside the cell is lower than inside the cell
(hypo = lower)
- in an effort to find equilibrium, water will flow from the extra cellular fluid (ECF) into the cell
- the cell becomes bloated and overfull and can eventually rupture
- water is flowing in the cell faster than out
• animal cells with appear swollen, and may burst
• plant cells will appear turgid, and the plant will appear healthy
hypertonic
the concentration of solutes outside the cell is higher than inside the cell
(hyper = higher)
in an effort to find equilibrium, water will flow from the cell into the ECF.
the cell becomes shrivelled, and dried up.
water is flowing out of the cell faster than in.
• animal cells will appear shrivelled, and may die
• plant cells will pull away from the rigid cell wall (called plasmolysis) will appear wilted and limp
facilitated diffusion
diffusion that is helped along by proteins embedded in the cell membrane
still a form of passive transport
for substances that are water-soluble
channel proteins
shaped like tubes.
hydrophilic and charged.
form tunnels through the membrane through which the water-soluble molecules can pass (usually small charged ions)
carrier proteins
hydrophobic
attach to larger molecules that can’t fit through the protein channels (glucose)
the protein will attach to the molecule on the outside of the cell, then roll over or change shape to deposit the molecule inside the cell
active transport
cell moved molecules against the concentration gradient.
requires extra work and energy by the cell (like swimming upstream)
pump molecules from an area of low to high concentration
the energy supplies to carry out this task is produced in the mitochondria
created through the process of cellular respiration, this energy is packaged into a substance called ATP (adenosine triphosphate)
endocytosis
when molecules are too big to fit through the membrane, a vesicles forms around the solute. this process requires ATP
exocytosis
when the cell needs to rid itself of a large waster product, a vesicles formed by the Golgi apparatus surrounds the molecule and transports it to the membrane and gets released into the ECF
recognition proteins
on the outside of the cell membrane, there are sugar and protein complexes (glycoproteins) called recognition proteins
like a lock and key mechanism
receptor proteins
blind the substance and physically move it across the membrane by endocytosis
eg : new pain relievers that treat migraines instead of providing overall pain relief
viruses
gain access to the cell by mimicking the shape of a harmless substance
cancer
comment treatments for cancer do not target only the cancerous cells, but target healthy cells as well
liposomes
a form of medication that surround a fluid-filled sac with a phospholipid bilayer. this mimics a vesicles produced by the cell : the medicine is able to dissolve directly through the cell membrane. liposome medication is able to deliver the medication much quicker
hormones
chemical messages produced by one part of the body that act on another part
insulin
produced by the pancreas, and acts on all body cells to tell them to pick up glucose for cellular respiration
dialysis : dialysis treatments
used by patients who have malfunctioning kidneys
peritoneal dialysis
a catheter is inserted into the abdominal cavity.
a sterile fluid is pumped into the cavity.
the concentration of waste in the blood is much higher than in the dialysate fluid.
nutrients from the fluid diffuse into the blood, and waster diffuses out.
the “dirty” fluid is pumped back out of the body and disposed of.
hemodialysis
a patients blood is physically removed from the body, cleaned using dialysate fluid, and returned to the body.
this procedure is much more invasive and requires the patient to be in the hospital.
what is a system
a set of interconnected parts
AP : membranes in the cell
• the cell membrane and other internal membranes help with cellular processes by:
- keeping the cell separate from the outside environment (extra cellular fluid)
- keeping parts of the cell separate from each other
• this minimizes competing interactions and increases space for reactions to take place
- for example, amino acids from the nucleus are used to build proteins in the rough endoplasmic reticulum just off the nucleus
• organisms that lack these membranes (prokaryotes like archaea and bacteria) often rely on a cell wall which serves to:
- protect cell from outside environment
- regulate materials that transfer in and out of the cell
• these organisms are smaller in size with simple cellular processes
AP : feedback mechanisms
• organisms can respond to their environment through their behaviour and/or their physiology
• this can be accomplished through feedback mechanisms
- positive feedback is a response to the environment that increases the result
- negative feedback is a response to the environment that reduces the result
• positive feedback mechanisms amplify the response
- when fruits are ready to ripen or respond to an injury they release ethylene :
- starch into sugar
- chlorophyll changes into other pigments
- pectin breaks down so fruit softens
• negative feedback mechanisms reduce the response
- temperature regulations in humans
what is surface area?
the surface area of a cell refers to the total area of the outside of the cell membrane
- to calculate surface area, add up the area of all sides of the cell
what is cell volume?
the volume of a cell refers to the volume of the contents of the cell
- to calculate volume, multiply the dimensions of the sides
