cells - the living units (exam 1) Flashcards
what are the three parts of the cell theory
1.) structural/functional unit 2.) all life is made of cells 3.) cells come from preexisting cells
what are the 3 variabilities to cells
size, shape, and function
what are the 3 structures of cells
membrane, cytoplasm nucleus
where does most of the weight of the membrane come from
proteins
what is an integral protein
a protein that goes all the way through the membrane
what is a peripheral protein
on the edge of the membrane
what are the functions of proteins in the membrane (7)
transport, receptor, attachment, enzyme, joining cells, recognition
what do glycoproteins do
attach to proteins
what do glycolipids do
attach to fats
what is the cell’s outer surface called
glycocalyx
what is a tight cell junction
the fusion of two cell membrane proteins to prevent movement between cells (prevents things from getting in between the cells)
what do desmosomes do
fuse protein plates together/hold cells together
how do skin cells shed
the breaking down of desmosomes
what are desmosomes made of
linker proteins
what is a gap junction
a large group of channels that line with adjacent cells to electrochemically couple cells
what are microvilli and what do they do
finger-like projections that act to increase surface area
what do cilia do
provide motion in order to move mucus
describe a selectively permeable barrier
a barrier that only allows certain things to get through
describe passive mechanisms
not using energy to cross the membrane
what is filtration
using hydrostatic pressure (fluid pressure) to move molecules
what is diffusion
the movement of molecules from an area of higher concentration to lower concentration
what does the kinetic energy of molecules mean
molecules are in constant motion
what are the factors that affect the rate of diffusion (4)
temperature, concentration gradient, solubility, molecular size/weight
how does temperature effect that rate of diffusion
higher temperature –> more kinetic energy –> faster diffusion
how does molecular size/weight affect the rate of diffusion
smaller molecules –> faster diffusion
how does molecular concentration affect the rate of diffusion
greater the difference in concentration –> increase in collisions –> faster diffusion
give three examples of lipid soluble solutes
O2, CO2, alcohol
what is facilitated/carrier-mediated diffusion
diffusion with the help of carrier proteins
what is channel-mediated diffusion
diffusion with protein channels that is specific to what is let through the membrane
what is osmosis (3 parts to the definition)
diffusion of water through selectively permeable membrane
what is dialysis (3 parts to the definition)
diffusion of solute through a selectively permeable membrane
in osmosis when does volume increase
when there is higher osmolarity
when does water follow the solute
osmosis
what happens to a cell in an isotonic solution
nothing changes because the concentration is the same both inside and out of the cell
what happens to a cell in a hypertonic solution
water moves out of the cell because there are more solutes outside the cell. this causes the cell to shrivel up (crenation)
what happens to a cell in a hypotonic solution
water goes into the cell because there are more solutes inside the cell. this causes the cell to grow, and possibly burst
describe active mechanisms
requiring energy to cross the membrane
what is primary active transport
an ion going against its concentration gradient
what is the biggest user of energy in the body
the sodium potassium pump
what are the 3 simplified steps to the sodium-potassium pump
1.) a solute binds to a membrane protein
2.) ATP phosphorylates
3.) protein changes shape, the ion pumps
what are the products of 1 ATP pump in the sodium-potassium pump
3 sodium ions out of the cell
2 potassium ions into the cell
what does the sodium-potassium pump set up
a concentration gradient across all cell membranes
what does symport of Na+ mean
Na+ and a solute move in the same direction
what does antiport of Na+ mean
Na+ and solute move in different directions
describe endocytosis
into cell movement
describe phagocytosis
eat cell movement (solids)
describe pinocytosis
drink cell movement (liquids)
how does mediated endocytosis work
specific protein receptors on the cell surface engulf specific substances
describe exocytosis
out of the cell movement (solids/liquids)
what is the electro-chemical gradient set up by
a sodium-potassium ATP pump
what does membrane potential describe
voltage/charge
what is the charge of the inside of a cell
negative
where is sodium found, where is potassium found
sodium –> outside a cell
potassium –> inside a cell
what is a ligand
a chemical that binds to a protein receptor
what do ligands do
binds and opens ion channels to cause ions to diffuse across the membrane
what does the G-protein receptor make
a second messenger inside the cell
what energy molecule do G-proteins use
GTP
what is the most common 2nd messenger
cAMP
what do electrically-gated ion channels cause
action potentials along neurons/muscle cells
what is an action potential
a moving electrical charge
what are the 3 parts of the cytoplasm
cytosol, inclusions, organelles
what is not included in the cytoplasm
the nucleus
what is cytosol
the cell solution (water and solutes)
what are inclusions
areas that store energy molecules and waste
what are organelles
the organs of the cell
where do you get the mitochondria from
mom
how is DNA found in the mitochondria
in a DNA ring/loop
what is the function of the mitochondria
convert energy (food + O2 –> CO2 + H2O + energy)
what is the continuous network of membranes in the ER used for
partition and transport
is the smooth er more or less common than the rough er
less common
what does the smooth er do (4)
metabolize fat, make membrane, stores calcium in muscles, and houses special liver enzymes
what does the rough er do (2)
the ribosomes make proteins and the proteins are exported
what are ribosomes made of
RNA and protein
what are the two types of ribosomes
bound and free
what are bound ribosomes
make proteins used for export on the rough er
what are free ribosomes
make proteins for the cell’s use
what is the golgi apparatus
a stack of membrane discs
what does the golgi apparatus do
modifies and packages proteins from the rough er usually for export
what does cis face mean for the golgi apparatus function
receiving
what does trans face mean for the golgi apparatus function
shipping
what does the peroxisome do
eliminate oxidative chemicals
what is peroxide
a damaging chemical formed during metabolism (H2O2)
what do lysosomes do
break apart
what does the membrane sac of acid hydrolase enzymes do
use water to break apart
what are actin filaments involved in
movement
what are myosin filaments involved in
muscle cells
what do intermediate filaments do
bracing (skeletal) fibers that give form/shape to the cell
what does polymerization mean
adding many pieces
what does de-polymerization mean
removing many pieces
cilia and flagella are ___ groups of ____ around a central group of ____ microtubules
9, 2, 2
how many membranes does the nuclear envelope have
2, the inner and outer membranes
what is the outer membrane of the nuclear envelope continuous with
the rough er
what is the purpose of the nuclear envelopes pores
allows things to go in and out of the nucleus (signals/proteins/RNA/ribosomes)
what does the nucleolus do
make ribosomes
what is the nucleolus made up of
DNA, RNA, and protein
what is chromatin
colored material that forms the genetic library of the cell
what is chromatin made of
DNA and a histone protein
what are the 2 forms of chromatin
heterochromatin and euchromatin
describe heterochromatin
dark colored, tightly wound DNA, unused genetic material of the cell
describe euchromatin
lightly stained, unwound DNA, used genetic material by the cell
what is the G1 phase
the gap/growth phase of the cell
what is S phase
synthesis of DNA
what is the G2 phase
preparation for division
what is G0 used to describe
cells that don’t divide
