Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
93 Cards in this Set
- Front
- Back
Membrane phospholipids associate to form bilayers T/F |
True |
|
Membrane phospholipids have hydrophobic tails and hydrophilic heads T/F |
True |
|
Membrane phospholipids give the membrane fluidity T/F |
True |
|
Membrane phospholipids readily flip-flop from one side of the membrane to the other T/F |
False |
|
The main difference between a cell that responds to a signal and the one that does not is the presence of a |
receptor |
|
The signals that bind to receptors of the same cell that made them are known as |
autocrine signals |
|
The general name for an enzyme that transfers phosphate groups from ATP to a protein is |
protein kinase |
|
Which of the following is NOT a membrane receptor |
cortisol receptor |
|
Which of the following is NOT a second messenger |
ATP |
|
A researcher treats cells with a chemical that prevents DNA synthesis from starting. This treatment would trap the cells in which part of the cell cycle? |
G1 |
|
The restriction point is |
G1-to-S transition |
|
Plasmodesmata are most similar in function to which of the following structures in animal cells? |
gap junctions |
|
Biological membranes are composed of |
lipids, proteins and carbohydrates |
|
Which ofthe following includes all the others? |
passive transport |
|
Anartificial cell consisting of an aqueous solution enclosed in a selectively permeable membrane is immersed in a beaker containing a different solution. Initially, the solution outside the cell is____ to the cell |
hypotonic |
|
Knowledge of the cell cycle has led to improved means of treating cancer. The drug 5-fluorouracil blocks the synthesis of thymine. This drugs inhibits the cell cycle at the end of |
G1 |
|
A deer smells a predator as it passes by and quickly bounds to safety. Which of the following represents the correct order of steps in the olfactory signal transduction pathway that is involved?a. Receptor binds signal, conformational change occurs in signal, signal travels to target cell, signal is transduced within the cell, effects from the signal transduction occur |
Signaltravels to target cell, receptor binds signal, conformational change occurs inreceptor, signal is transduced within the cell, effects from the signaltransduction occur |
|
__________ is an enzyme that converts ATP to cAMP? |
Adenylyl cyclase |
|
You view an animal cell through a microscope and observe dense, duplicated chromosomes scattered throughout the cell. Which state of mitosis are you looking at? |
prophase |
|
______is the region on a duplicated chromosome that holds the sister chromatids together? |
centromere |
|
Nucleosomes |
consist of DNA wound around a histone core |
|
Which of the following phases of the cell cycle is NOT part of interphase? |
M |
|
The general structure of biological membranes is known as the ________? |
fluid mosaic model |
|
animal cell membranes may be up to ________ cholesterol |
25% |
|
What membrane proteins lack exposed hydrophobic groups and don't penetrate the bilayer? |
Peripheral membrane proteins |
|
What membrane proteins have hydrophobic and hydrophilic regions and domains? |
Integral membrane proteins |
|
What is the technique that reveals proteins embedded in the phospholipid bilayers of cellular membranes? |
Freeze-fracturing |
|
________________ extend all the way through the phospholipid bilayer |
transmembrane proteins |
|
Glycolipids have what ? |
carbohydrate + lipid |
|
Glycoproteins have what? |
carbohydrate + protein |
|
What is the same molecule sticks out from both cells and forms a bond? |
homotypic |
|
The cells have different proteins is what? |
heterotypic |
|
___________ help ensure directional movement of materials. |
tight junctions |
|
Desmosomes are like what? |
spot welds |
|
___________ allow communication |
gap junction |
|
What protein binds to the matrix outside epithelial cells and non covalent? |
integrin |
|
Some substances can pass through but not others is what? |
selective permeability |
|
No outside energy required (diffusion) |
passive transport |
|
Energy required is what? |
active transport |
|
the difference in concentration between one side of the membrane andthe other. |
concentration gradient |
|
The process of random movement toward equilibrium |
diffusion |
|
Diffusion rate depends on what ? |
diameter of molecules, temperature, and concentration gradient |
|
Small molecules pass through the lipid bilayer |
simple diffusion |
|
The diffusion of water |
osmosis |
|
Higher solute concentration |
hypertonic |
|
Equal solute concentration |
isotonic |
|
lower solute concentration |
hypotonic |
|
Plant cells with rigid cell wallsbuild up internal pressure that keeps more water from entering |
turgor pressure |
|
No cellular energy is required but cellular protein(s) and a concentration gradient are necessary |
Passive |
|
Integral membrane proteins that form a channel. |
Channel proteins |
|
Membrane proteins that bind some substances and speed their diffusion through the bilayer |
Carrier proteins |
|
Specific channel proteins with hydrophilic pores |
ion channels |
|
How does an ion channel allow one ion to pass through but not another? |
Its not a matter of size or charge of ion |
|
Water can cross a membrane by ‘hitchhiking’ with ions, or moving through special water channels called |
aquaporins |
|
What transports polar molecules such as glucose across membranes in both directions. |
carrier proteins |
|
The facilitated diffusion system is said to be |
saturated |
|
What protein moves one substance in one direction? |
uniporter |
|
What protein moves two substances in one direction? |
Symporter |
|
What protein moves two substances in opposite directions? |
Antiporter |
|
Symporters and anti porters are also called what and why? |
Coupled transporters because they move two substances at once |
|
What requires direct hydrolysis of ATP? |
primary active transport |
|
What is it when energy comes from an ion concentration gradient that is established by primary active transport? |
secondary active transport |
|
What is a primary active transport? |
The sodium–potassium (Na+–K+) pump (an antiporter) |
|
Where is the Na+- K+ pump found? |
animal cells |
|
Macromolecules can be taken in or secreted by means of what? |
Membrane vesicles |
|
What processes that brings molecules and cells into a eukaryotic cell? |
Endocytosis |
|
What process is when molecules or entire cells areengulfed? |
phagocytosis |
|
What process is when a vesicle forms to bring small dissolved substances or fluids into a cell and constant in endothelial cells? |
Pinocytosis |
|
What process is when material in vesicles is expelled from a cell? |
Exocytosis |
|
What is the sequence of events that lead to a cell's response to a signal? |
Signal transduction pathway |
|
What signals affect the cells that made them? |
Autocrine |
|
What signals affect only adjacent cells. |
Juxtacrine |
|
What signals affect nearby cells? |
Paracrine |
|
What does a signal transduction pathway involve? |
signal, receptor and responses |
|
What is signal transduction pathways can be interrelated? |
crosstalk |
|
Receptor proteins have very specific binding sites for what? |
ligands |
|
What else can bind to receptor proteins? |
inhibitors or antagonists |
|
Where can receptors be located |
cytoplasm or cell membrane |
|
What receptors are small or non polar ligands that can diffuse across the cell membrane? |
intracellular receptors |
|
What receptors are large or polar ligands that bind to cell membrane receptors? |
Membrane receptors |
|
What are channel proteins that allow ions to enter or leave a cell? |
ion channel receptors |
|
What receptor is a gated ion channel? |
acetylcholine receptor |
|
What receptor catalyzes phosphorylation of themselves and/or other proteins? Ex: insulin |
Protein kinase receptor |
|
What receptor has ligand binding change the shape of the cytoplasmic region, which binds to a G protein? |
G protein-linked receptor |
|
What protein binds GDP and GTP, receptor and effector? |
G proteins |
|
Where are intracellular receptors located and what do they do? |
Inside the cell (cytoplasm or nucleus) and they respond to physical signals such as light or chemicals |
|
What small nonprotein molecules can diffuse through the cytoplasm and mediate further steps in pathways? |
second messengers |
|
Protein kinase receptors bind signals called what? |
growth factors |
|
What is a pathway in which one protein kinase activates the next by phosphorylation ? |
protein kinase cascade |
|
What later removes the phosphate allowing the pathways to reset? |
phosphate enzymes |
|
In protein kinase cascade , the signal is what? |
amplified at each step |
|
What are the factors that influence the degree of fluidity of membranes? |
temperature and lipid composition |
|
What happens to animal cells in a hypotonic solution? |
they burst |