The exchange of respiratory gases in a cell takes place through the:
lungs
vacuoles
stoma
cell membrane
cell membrane mostly consists of
carbohydrates and lipids
carbohydrates and nucleic acid
protein and carbohydrates
protein and lipids
in cells, the selectivity of the cell membrane is closely associated with the maintenance of:
homeostasis
plasmolysis
phagocytosis
pinocytosis
During which process do molecules move from a region of higher concentration to a region of lower concentration?
diffusion
active transport
cyclosis
circulation
Osmosis is a physical process most closely associated with the life function of:
absorption
respiration
locomotion
reproduction
Normally, the process of osmosis, the net flow of water molecules into or out of the cell depends on the difference in the:
concentration of water molecules inside and outside the cell
concentration of enzyme on either side of the cell membrane
rate of molecular motion on either side of the cell membrane
rate of movement of insoluble molecules inside the cell
If red blood cells are placed in distilled water, they will eventually be destroyed. Which process is most likely to be the chief cause of this destruction?
hydrolysis
dehydration synthesis
osomosis
The destruction of all ATP (energy) molecules in a cell would interfere most immediately with the process of:
gas exchange
osmosis
Active transport of certain proteins from a cell's environment into the cell is most closely associated with the:
cell wall
ribosome
nuclolus
Sodium ions are "pumped" from a region of lower concentration to a region of higher concentration in the nerve cells of humans. This process is an example of:
passive transport
during which process is ATP not essential?
active tranport
The process of osmosis would explain the net movement of water into a cell if the percentage of:
water was 90% inside the cell and 95% outside the cell
water was 95% inside the cell and 90% outside the cell
protein was 30% inside the cell and 35% outside the cell
water and protein was equal inside and outside the cell
Freshwater protozoa may be distinguished from many marine protozoa by the fact that the freshwater species contain:
plasma membranes
contractile vacuoles
chromosomes
cytoplasm
An important role of the cell membrane is to:
store materials
change the rate of which chemical reactions occur
constructs proteins for the cells
maintain homeostasis
the cell membrane is said to be selectively permeable because it
is ultra thin and flexible
composed of lipids and proteins
allows only certain molecules to move through it
allows all molecules to pass through it, but only very slowly
what happens during diffusion?
molecules move automatically from an area of higher concentration to an area of lower concentration
molecules are pumped from an area of lower concentration to an area of higher concentration
an enzyme joins with a particular molecule
a catalyst speeds up the rate if a chemical reaction
during passive transport
the cell uses energy to move molecules across the cell membrane
molecules loves across the cell membrane without the use of energy
the cell uses energy to break chemical bonds
chemical bonds are broken without the use of energy
a plant cell shrinks when placed in salt water due to the movement of
salt molecules in the cell
water molecules out of the cell
salt molecules out of the cell
water molecules in the cell
placing limp celery in water will make the celery stalk firm again due to
gravity
a catalyst
the organelle that stores water for the cell is the
chloroplast
vacuole
lysosomes
golgi complex
a red blood cell placed in distilled (100%) water will swell and burst due to the diffusion of
salt out of the cell
salt into the cell
water out of the cell
water into the cell
some single-celled organisms live in fresh water (100% water) lakes. what problem do they encounter on a daily basis?
water is diffusing through their cell membrane and they may burst if it is not removed
water is diffusing out of their cell membrane and may shrivel up and die if water is not pumped back into the cell
both a and b
they do not encounter any problems living in the freshwater lake
human blood cells placed in a 2% salt solution appear to shrink, but those placed in a 0.4% salt solution burst. which statement best supports these observations?
salt causes cell walls to swell
salt is actively transported across the cell membranes
the nucelus does not regulate water balance in a cell
osmosis may be occur in either direction across the cell membrane
which process would include a net movement of sugar molecules through a membrane from a region of lower concentration to a region of higher concentration
In the human body, potassium is small and can pass easily through the cell membrane. potassium is constantly diffusing out of the cell. however, there is always a higher concentration of potassium inside cells and a lower concentration outside of the cells. what process is responsible for maintaining this concentration gradient?
when a cell uses energy to move materials across the cell membrane, the process is known as
the net movement of molecules across the cell membrane is dependent upon the
selectivity of the cell membrane
selectivity of the cell wall
neither a or b
a process that requires energy by cell and is used to engulf large macro-molecules is called
endocytosis
exocytosis
what happens during active transport
substances are moved from areas of high concentration to areas of low concentration with the use of energy
substances are moved from areas of low concentration to areas of high concentration without the use of energy
substances are moved from areas of high concentration to areas of low concentration without the use of energy
substances are moved from areas of low concentration to areas of high concentration with the use of energy
the sodium-potassium pump of a cell is located in
a protein molecule of the cell membrane
a lipid molecule of the cell membrane
an ATP molecule of the cell membrane
an ADP molecule of the cell membrane
in the cytoplasm
