learnsmart Flashcards
the plasma membrane is made up of 3 types of lipids. what are they?
cholesterol, phospholipids & glycolipids
which of the following is false regarding the cell membrane?
it is made primarily of cytosol
a type of steroid called __ is scattered within the hydrophobic regions of the phospholipid bilayer, where it strengthens the membrane and stabilizes it at extreme temperatures
cholesterol
forms of passive transport across cell membranes include __
osmosis and diffusion
the 2 major categories of membrane transport are __ transport that requires no energy expenditure and __ transport
passive; active
__ is a passive form of transport
simple diffusion
ion movement through small proteins in the membrane is an example of __ diffusion
channel-mediated
__ is required for osmosis to occur
a selectively permeable membrane
when water moves across a semi-permeable membrane, the pressure it experts is __ pressure
osmotic
the sodium-potassium exchange pump transports __ (number) sodium ions out of the cell for every __ (number) potassium ions it transports into the cell
3 Na+ ions are pumped out of a cell for every 2 K+ ions that are pumped into a cell
the net movement of a substance from high concentration to low is called __
diffusion
K+ movement out of the cell is facilitated by its __ __ gradient but opposed by the __ gradient
chemical concentration
electrical
sodium ions enter the cell through sodium __ channels as they move down their concentration gradient
leak
neurons have a resting membrane potential of __ mv
-70
the __ gradient is dependent on the combination of the __ gradient and the chemical concentration gradient
electrochemical
electrical
which statements characterize organelles?
each type of organelle differs in shape
each type of organelle has a specific function
they are generally located within cells
the synthesis of steroid hormones occurs in the __
smooth er
the primary structure for the processing and packaging of proteins for transport out of the cell is the __
Golgi apparatus
lysomes remove old organelles through a process called __
autophagy
autos- self
phago- to eat
lysomes digest molecular structures of damaged organelles
the organelle that has a double membrane, its own small piece of DNA, and synthesizes ATP is the __
mitochondrion
when a protein is marked for destruction by having a protein called ubiquitin bound to it, the organelle responsible for this removal are __
proteasomes
true or false: cilia and flagella are projections that extend from the surface of some cells
true
which statements characterize microvilli?
they are smaller than cilia
function to increase surface area of plasma membrane
they are microscopic projections of plasma membrane
the 3 major types of membrane junctions are __ junctions, desmosomes and gap junctions
tight
intestinal cells are joined by _ in order to prevent digestive juices from moving between and damaging adjacent cells
tight junctions
gap junctions are bridged by proteins called __
connexons
the nucleus is enclosed by a double membrane structure called the __
nuclear envelope
which statements describe chromosomes?
they contain DNA & proteins
they are more condensed than chromatin
chromatin is composed of __
DNA and proteins
a typical cell has how many nuclei?
1
the relative distributions of K+, which is more concentrated inside the cell and Na+, which is more concentrated outside the cell are the result of the activity of the __
Na+/K+ pump
the plasma membrane also functions in establishing and maintaining an electrochemical gradient at the plasma membrane called the __
resting membrane potential
__ are complex, organized structures inside the cells; they have unique characteristics and shapes
organelles
transport (shuttle) vesicles are produced within a cell by __
rough ER
the 2 types of organelles found in cells are __ -bound and __ -bound
membrane-bound
non-membrane bound
microtubules
move chromosomes during cell division
cilia
move fluid, mucus, and materials over the cell surface
flagellum
propels sperm cells of human male
microvilli
increase membrane surface area for increased absorption and/or secretion
__ is a general function performed by all cells
to obtain nutrients
which of the following describe the general functions of the cell?
- obtain nutrients
- dispose of wastes
- maintain shape of cell
which of the following statements are true regarding integral proteins?
they act as identity markers for the cell
they can act as membrane channels
they can act as receptors
rapid digestion of a cell by its own lysosomes is called __
autolysis
true or false: in transcription a DNA gene is read and copied to produce a newly formed strand of DNA
false
the process by which a DNA gene is copied into RNA
transcription
the 3 functional types of RNA produced during transcription are messenger RNA, transfer RNA and __ RNA
ribosomal
the process that occurs on ribosomes by which a mRNA transcript is read and a nee protein produced is called
translation
which are required for translation?
mRNA, amino acids
tRNA, ribosomes
the primary cellular sites for the production of proteins are the __
ribosomes
in the cell cycle, division of the nucleus is called __
mitosis
in cell division, 1 cell divides to produce 2 identical cells called __
daughter cells
__ proteins provide a means of regulating movement of substances across the plasma membrane
transport
__ cells include all of the cells in the body except sex cells
somatic
much of the internal content of the __ is the genetic material, DNA
nucleus
when a cell is dividing the dna is tightly coiled as..
chromosomes
the 3 components of the cytoplasm of a cell are..
cytosol, organelles, & inclusions
which statements characterize smooth ER?
doesnt have ribosomes attached
can detoxify drugs
stores lipids
the cell division that takes place in somatic cells
mitosis
the microscope that moves an electron beam over the surface of a specimen is the..
scanning electron microscope
the study of cells
cytology
peroxisomes break down harmful substances including
hydrogen peroxide
fatty acid molecules
the __ is a general term for all cellular contents between
cytoplasm
which statement(s) characterizes prophase?
the nuclear envelope disappears
chromatin condenses into chromosomes
it is the 1st stage of mitosis
the cell structure that functions as a gatekeeper to regulate the passage of gases, nutrients, and wastes between the internal and external environments is the __
plasma membrane
