AP Biology: Cells
describe endocrine, paracrine, and autocrine
endocrine - made here, transported, acts somewhere else paracrine - made here, works on nearby cells autocrine - made here, works here
Water potential of the solution at equilibrium will be ________ to the water potential of the potato cells
equal
what are the two most important parts of the endomembrane system
er and golgi
what is the function of glycoproteins and glycolipids in the cell membrane?
"name tags" - make it recognizable to the immune system (cell recognition)
T/F: All cell processes of diffusion require an input of energy
false
T/F: Glucose is too big to fit through the dialysis bag pores
false, SUCROSE is too big
Higher the molarity, _______ the osmotic rate
faster
Molecules can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through ______.
gap junctions
Epinephrine will cause the breakdown of _________.
glycogen
this organelle produces lysosomes
golgi
name three endocrine signals
growth, thyroid, and sex hormones
what kind of molecules CANNOT cross the cell membrane?
hydrophilic large polar molecules or ions- require channels and transport proteins
A sucrose solution in a beaker would be _______ to the dH2O in the bag.
hypertonic
water will always travel to a ____________ environment
hypertonic
As molarity increases, solute potential ....
increases
describe exocytosis
internal vesicles fuse with the plasma membrane to secrete large macromolecules out of the cell
how can testosterone pass through the cell membrane?
its nonpolar
What is the name of the enzyme that *adds* a phosphate to a molecule?
kinase
Since they are too _____, Extracellular signal molecules can't pass through the membrane
large and hydrophilic
the official name for a molecule that attaches to a cell receptor:
ligand
describe receptor-mediated endocytosis
ligands bind to specific receptors on the cell's surface which causes a vesicle to form around the substance and push it into the cytoplasm
cells must be _____ in order for materials to diffuse
moist
why is high SA in lungs useful?
more area for diffusion to occur
give an example of exocytosis
neurotransmitters being sent to a neuron via vesicles
Growth factors released by a cell cause nearby cells to grow. This is an example of:
paracrine signaling
When a secreting cell acts on nearby cells this is known as __________ signaling.
paracrine signaling
what three things is the plasma membrane made of?
phospholipids proteins carbs
If plant cells are placed in hypertonic solution, they become _______.
plasmolyzed - cell membrane separates from cell wall
Cell signaling pathways were ______ before multicellular organisms appeared on Earth.
present
function of golgi
proteins are modified stored and shipped
what is the function of cholesterol in the phospholipid bilayer?
provide membrane fluidity
_____________ is the regulation of gene expression in response to fluctuations in cell-population density.
quorum sensing
______ is the target cell's detection of a signal molecule coming from outside the cell
reception
Which molecule performs the primary signal transduction step in a signaling cascade
receptor protein
Protein phosphatases will ______ a phosphate.
remove
__________ is the specific cellular response to the signal molecule
response
what is the only organelle that all plant cells, animal cells, and prokaryotes have?
ribosomes
examples of high SA:V ratios
root hairs cells of alveoli cells of villi microvilli
cAMP can be described as a...
second messenger
_______ can initiate a phosphorylation cascade resulting in a cellular response
second messengers
what kind of molecules freely pass across the membrane?
small, non polar molecules
_______ cells have a more favorable SA:V ratio
smaller
The ovaries produce estrogen. Which organelle is most likely to be in abundance in ovarian cells?
smooth er - estrogen is a lipid and smooth er makes lipids
Which two molecules did NOT cross the dialysis bag?
sucrose and starch
function of rough er
synthesize proteins
You have a bag of dH2O in a .2 M sucrose solution. Which has the higher water potential?
the bag: water wants to leave it more
where are gap junctions found in the human body?
the heart
What kind of cell is most efficient in exchanging nutrients with the environment by diffusion?
those with the highest SA:V ratio
name the three transduction methods:
- protein phosphorylation - calcium ions - cAMP
three functions of smooth er?
- synthesis of lipids - metabolism of carbs - detox of drugs and poisons
A cellular response could include regulating cytoplasmic activity or _____________.
transcription
The activation of kinases displays this 2nd step of a signaling pathway
transduction
________ is the conversion of the signal to a form that can bring about a specific cellular response
transduction
T/F: In prokaryotes and fungi, the cell wall is outside the cell membrane
true
T/F: The binding between a ligand and a receptor is highly specific
true
the ability of a single ligand to activate multiple cellular responses is a key feature for the receptor ______.
tyrosine kinase
The physical property that predicts the direction in which water will flow is called...
water potential
Which neurotransmitter passes from a neuron to a muscle cell?
Acetylcholine (ACh)
Lipid-soluble signaling molecules, such as testosterone, cross the membrane of all cells but affect only target cells because... A) only target cells retain the appropriate DNA segments B) intracellular receptors are présent only in target cells C) most cells lack the Y chromosome required D) only target cells possess the cytosilic enzymes that transduce testosterone
B
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because... A) they are species specific B) they always lead to the same cellular response C) they amplify the original signal manyfold D) they counter the harmful effects of phosphatases
C
Which cell would be best for studying lysosomes? A) muscle cell B) nerve cell C) phagocytic white blood cell D) leaf cell of a plant
C
In what way do the membranes of a eukaryotic cell vary?
Certain proteins are unique to each membrane.
Which structure-function pair is mismatched? A) nucleolus; production of ribosomal units B) lysosomes; intracellular digestion C) ribosome; protein synthesis D) microtubule; muscle contraction
D
describe endosymbiont theory and three reasons why it may be valid
Mitochondria and chloroplasts are believed to have developed from symbiotic bacteria - has DNA - 2 membranes - same size/shape
Puffer fish tetrodotoxin interferes with...
Na+ channels
give an example of three gases that can diffuse across the cell membrane
O2, N2, CO2
Plant cells have ______ to pass materials between cells.
Plasmodesmata
what is tetrodotoxin?
a neurotoxin that clogs up sodium channels in the nervous system, causing paralysis
what is a g-protein
a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein
The Na+/K+ pump is an example of...
active transport (PUMP MEANS ACTIVE TRANSPORT)
A protein kinase activating many other protein kinases is an example of _____.
amplification
water moves across membranes and through channel proteins called _______.
aquaporins
Liver cells manufacture glycoproteins, while adipose cells store fat. Which of the following subcellular structures is likely to be more prominent in liver cells than in adipose tissue? a) Nucleus b) Golgi apparatus c) Cytoskeleton d) Plasma membrane
b
A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continue to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures? a) Nucleus b) Mitochondrion c) Smooth ER d) Golgi complex
d
Cells interact through chemical signals which either bind to receptors on the membrane or: a) pass through the plasma membrane b) trigger responses from inside the cell c) bind to intracellular receptors d) all of the above
d
Which of the following is associated with secondary messengers in a cell? a) cAMP b) IP3 / Ca c) initiated by G protein receptors d) all of the above
d
Which of the following is associated with the release of cytokines by Helper T Cells? a) creation of memory cells b) production of antibodies c) recruitment of macrophages d) all of the above
d
if signal transduction is blocked, what can happen?
diabetes, heart disease, etc
how does the immune system fight invaders?
- macrophages capture pathogens and display them on APCs - seen by helper t-cells and activates cytotoxic t cell or b cell
name the three possible cell responses:
- activity regulation - transcription - amplification
name the four reception methods:
- g-proteins - tyrosine kinase - ion channels - intracellular
what are the two primary functions of passive transport?
- import of resources - export of wastes
what two factors affect water potential?
1. addition of solute lowers water potential 2. increase in pressure raises water potential
Which of the following factors would tend to increase membrane fluidity? A) a greater proportion of unsaturated phospholipids B) a greater proportion of saturated phospholipids C) a lower temperature D) a relatively high protein content in the membrane
A
T/F: energy is not required for active transport
FALSE, ATP is required to move molecules from low to high
T/F: embedded proteins are always hydrophobic
FALSE, they can be either hydrophilic or hydrophobic
This molecule travels along the inside of a cell membrane to make a signal transduction.
G protein
T/F: As cells increase in volume, the relative SA decreases and demand for material resources increases.
True
Which of the following statements is true regarding the movement of substances across cell membranes? a) Ions are able to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are hydrophobic. b) Ions are unable to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are hydrophobic. c) Water is able to move through the phospholipid bilayer because the nonpolar tail regions of the phospholipids are charged. d) Water is unable to move through the phospholipid bilayer because the polar head regions of the phospholipids are charged.
b
Which statement reflects the action of testosterone on a cell? a) Extracellular reception b) Intracellular reception c) No DNA involvement d) Use of G-Protein
b
example of a cascade reaction
blood clotting
Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is given to a patient? a) The cells that are exposed to hypotonic solutions will shrink as a result of salt moving into the blood. b) The liver will secrete additional insulin into the blood to raise the tonicity of the administered fluid. c) The cells that are exposed to the hypotonic solutions will expand as water moves osmotically into the cells from the blood. d) The patient's respiration rate will slow to compensate for the higher levels of circulating blood.
c
Which of the following best describes a feature that is unique to archaea and bacteria? a) The organism is surrounded by a cell wall. b) The organism contains ribosomes. c) The organism does not have a nuclear membrane surrounding genetic material. d) The organism is not capable of making or providing itself with ATP.
c
Which of these these could NOT diffuse through a membrane and bind to an intracellular receptor: a) estrogen b) steroid hormone c) glucose d) testosterone
c
what is pinocytosis
cell drinking
describe endocytosis
cell takes in macromolecules by forming new vesicles from the plasma membrane
In a ligand-gated ion channel, the channel is normally __________ without the ligand.
closed
difference between cytoplasmic ribosomes and those attached to er:
cytoplasmic - produce proteins that will be used in the cell bound - make proteins that leave cell