Intro Cell Bio - Exam 1 Poll Everywheres

Name a tenant of cell theory

1. All cells come from a preexisting cell by division 2. All cells have metabolism and trade energy 3. All cells contain heritable info in the form of DNA 4. All living things are made of cells 5. The cell is the basic unit of life 6. All cells are basically the same structure: CHOMBS

A molecule that has both hydrophilic and hydrophobic portions is

Amphipathic

The main source of carbon used in photosynthesis for generation of carbohydrates is:

Atmospheric carbon dioxide

Exocytosis is usually triggered by a release of

Ca++ ions

Which of the following cell processes depend on the movement of membrane components and would probably not be possible if membranes were rigid, nonfluid structures?

Cell movement Cell division Formation of intercellular junctions Endocytosis

What happens to the clathrin coat once the vesicle has budded from the Golgi body?

Clathrin- induces curvature in membrane, allowing formation of vesicle Clathrin isn't necessary once vesicle has budded from Golgi body

How can cells perform a reaction with a positive delta G?

Couple reaction with higher negative delta G

What is the movement of a substance from an area of high concentration to an area of lower concentration

Diffusion

Simple diffusion

Diffusion that doesn't involve a direct input of energy or assistance by carrier proteins

Positive ΔG

Endergonic, anabolic, non-spontaneous

Active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

The process of membrane fusion (between vesicle and plasma membrane) and subsequent content discharge is called

Exocytosis - EXIT

Diffusion during which the substance to be transported binds selectively to a membrane-spanning protein, which helps the process along

Facilitated diffusion

How do phospholipids change sides of the membrane?

Flippase, floppases, and scramblases

What substance joins proteoglycans together into gigantic complexes called proteoglycan aggregates? These complexes can occupy very large volumes.

Hyaluronic acid

Miscelle

Hydrophobic portions (fatty acid tail) facing each other Hydrophilic potion on outside

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer

Integral protein

Placing phospholipids in water will spontaneously form a spherical structure called a:

Liposome (sphere of phospholipid bilayer)

upon what "highway system" do vesicles move through the cell?

Microtubules

A polymer is made of many

Monomers

In the Na+/glucose cotransporter, _____ moving down its gradient drives the transport of _____ against its gradient.

Na+ moving down its gradient drives the transport of glucose against its gradient *example of active transport - uses energy stored in Na+ gradient to get glucose against its gradient

A virus hijacks a cell to make proteins to make new viruses. What is the order in which the new viral proteins travel through the cell?

Once the cell is infected and creates new proteins, the proteins are headed outside the cell to go infect new cells. 1) Rough ER (viral proteins made by ribosome in rough ER) 2) Golgi (proteins become mature in Golgi, then enter another vesicle and head out of cells) 3) Plasma Membrane 4) Viral Envelope (takes some of plasma membrane with it to make viral envelope)

The movement of water through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration is called

Osmosis

A molecule that shares its electrons unequally between its atoms is:

Polar

Prokaryote vs. Eukaryote

Prokaryotes: no nucleus, no membrane bound organelles, circular DNA, no cholesterol in membranes Eukaryotes: nucleus, membrane bound organelles, linear DNA (circular DNA in mitochondria), cholesterol in membranes

Name a function of membranes

Protection Compartmentalization Selective permeability Barrier Place for reception

Lipid anchored protein

Protein that is attached to the membrane via a lipid molecule. Stuck to the membrane - not actually IN the membrane

Peripheral protein

Protein that resides at or near the membrane but is not stuck in the membrane

Name a function of proteins

Receptors (i.e. transmembrane) Motor Structural (i.e. cytoskeleton) Kinases (modify other molecules by adding a P) Enzymes (allow reactions to take place faster by lowering activation energy)

Why is ATP hydrolysis often used in coupled reactions?

Releases free energy

Where does protein synthesis occur?

Ribosomes occurs in the rough ER (by bound ribosomes) or in the cytoplasm (by free ribosomes)

Which microscope is best suited to study the detailed surface of cells?

Scanning Electron Microscope

What affect does the binding of the SRP to the growing peptide chain have on the ribosome?

Synthesis stops until the ribosome associates with the ER SRP - signal recognition particle - like the stick in the spokes of bicycle wheel Recognizes signal on growing protein and stops ribosome from working until ribosome binds to ER and SRP falls off.

The three-legged assembly of protein chains that makes up a clathrin molecule and that can assemble into a network of polygons resembling a honeycomb is called a

Triskelion

What would happen if you disrupted SNARE proteins (vesicle fusion) in a cell?

Vesicle fusion would not take place. Vesicles could not fuse with target compartment. In exocytosis, vesicles will just hang out near the membrane. Would just be a lot of unfused vesicles. Organism would die. *Tetanus and botulism are caused by cleaving of SNARE proteins

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called:

active antiport *active - uses energy *antiport - solutes moving in opposite direction against each other

How are proteins modified in the Golgi?

glycosylation

Which type of cytoskeletal element is described as tough, ropelike fibers composed of a variety of related proteins like keratin?

intermediate filaments

Where are hydrophobic interactions most likely to occur?

the core of a water-soluble protein I.e. on the inside (core) so away from the water, because hydrophobic means it doesn't like water Example: adipocytes (fat cells) have reservoir of fatty acids. Hydrophobic interactions would take place in that reservoir. Cornfield cells: fatty acids/waxes thicken the plasma membrane.