Homeostasis, Cell Structure and Function Flashcards
what is homeostasis?
the process of maintaining balance in an organism’s internal environment
what is a fundamental idea of modern biology?
cell theory
what are some examples of homeostasis?
maintaining healthy blood pressure, and volume of body water
what are the three principles of cell theory?
all living organisms are composed of one or more cells, cells are the basic unit of structure for all living organisms, cells arise only form previous cells and pass their genetic material onto their daughter cells.
what occurs when cells pass copies of their genetic material onto daughter cells?
what do all cells have in common?
all cells have a plasma membrane
a plasma membrane is a special boundary that does what?
helps control what enters and leaves the cell
why do most cells break down molecules?
to generate energy
what are the two basic kinds of cells?
prokaryotic and eukaryotic
which cell contains a nulceus?
eukaryotic cells
what are specialized structures that perform specific instructions?
organelles
what is a type of organelle found in a eukaryotic cell?
a nuclues
what does a nuclues contain?
genetic material
which cells do not have a nulcues?
prokaryotic cells
what leads us to believe prokayotic cells to be the first on earth?
their simplicity
what theory proposes that a symbiotic relationship formed between two prokaryotic cells?
the endosymbiont theory
what did the symbiotic relationship between the prokaryotic cells lead to?
the creation of the eukaryotic cell
what is the process of maintaining balance in an organism’s environment?
homeostasis
what is selective permeablility?
being able to allow or not allow something to pass through
when and how much of various substances enter and leave a cell depends on what?
the plasma membrane
what are two layers of phospholipids arranged in a way that allows the cell to exist in a watery environment?
a phospholipid bilayer
hydrophobic?
does not like water, the tail
hydrophilic?
likes water, head
hydrophilic?
likes water, head
the bilayer keeps the internal and external environments separate how?
the polar heads face the outside and non-polar tails areon the inside
small uncharged molecules pass through the membrane easier why?
because non-polar dissoles water
what role do transport proteins serve in a plasma membrane?
to move waste materials and/or needed substances
what molecules move among the plasma membrane?
carbohydrates, cholestro, proteins
polar substances dissolve in ___?
polar substances
non-polar substances dissolve in ___?
non-polar substances
what are the three roles of proteins in a plasma membrane?
recept, transport, and support
what does it mean to be a receptor?
receptors transmit signals to the inside of the cell
what does it mean to be a supporter?
a supporter gives the membrane structure and strength
what does it mean to be a transporter?
to form channels to move substances through the membrane
what role does cholesterol play in a plasma membrane?
it contributes to the fluidity and prevents the tails from sticking together, also non-polar
what roles do carbohydrates play in a plasma membrane?
they define the cell’s characteristics and help the cell identify chemical signals
what does the condenser on a microscope do?
concentrate the light
what does the iris diaphragm do on a microscope?
controls the amount of light
what feature on a microscope allows you to move the specimen?
the X-Y stage movement knobs
what do vacuoles store?
food, enzymes, and waste
why don’t plant cells burst?
plant cells have a cell wall
centrioles are made up of what?
microtubules
what is the function of centrioles?
to pull apart DNA
why do mitochondrion have folded membranes?
to have multiple reactions on its higher surface area
mitochondria is needed for what process?
cellular respiration
chloroplasts are needed for what process?
photosynthesis
compare and contrast cilia vs flagella
cilia have hair like attachments and several of them, flagella have few longer attachments that move in a whip like movement. they are both microtubules
what is the diffusion of water across a selectively permeable membrane?
osmosis
because of osmosis what happens to water molecules?
water molecules will move to the side of the cell with the greater solute concentration
because of osmosis what happens to water molecules?
water molecules will move to the side of the cell with the greater solute concentration
the net movement of water to the side with the greater solute concentration continues until what is reached?
dynamic equilibrium
true or false?
Facilitated diffusion requires no additional input of energy because the particles are moving from an area of high concentration to an area of lower concentration.
false, diffusion and facilitated diffusion are also known as passive transport because neither process requires additional energy input.
all the chemical processes of the cell take place directly in?
the cytoplasm of the cell
what is the semifluid material enclosed by a plasma membrane?
cytoplasm
all chemical processes take place in cytoplasm in what type of cell?
prokaryotes
all chemical processes take place in the organelles inside the cytoplasm of what type of cell?
eukaryotes
what is a supporting network of long, thin protein fibers that form a framework for the cell and proved an anchor for the organelles?
cytoskeleton
what are long, hollow protein cylinders that form a rigid skeleton for the cell and assist in moving substances within the cell?
microtubules
what are thin protein threads that help give the cell shape and enable the part of the entire cell to move?
microfilaments
a nucleus is surrounded by what?
a nuclear enelope, nucleolus
which organelle contains most of the cell’s DNA?
the nucleus
which organelles manufacture proteins?
ribosomes
where are ribosomes produced?
inside the nucleus
what is a membrane system of folded sacs and interconnected channels that serves as the site for protein and lipid synthesis?
endoplasmic reticulum
what is a flattened stack of membranes that modifies, sorts, and packages proteins?
golgi apparatus
Proteins are packaged into sacs called what?
vesicles
which organelle can fuse to the plasma membrane and release the proteins to the environment?
vesicles
How are lysosomes important to the immune system?
they get rid of harmful bacteria and viruses
this organelle is like an energy generator
mitochondria
How is a cell wall different than a classroom wall?
Cell walls are permeable; classroom walls are impermeable, meaning substances cannot pass through. Everything that enters and leaves a plant cell must be able to pass through a cell wall.
