Bio 180: EXAM #3: Pretest Questions

myosin

Actin is a critical component of the "thin filament" found in all contractile muscle tissue. What motor proteins binds to actin to cause muscle contraction?

the integrity of the lipid bilayer is broken

After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that...

transmembrane protein

A membrane protein has an alpha helix that crosses the bilayer and on the extracellular surface has several glycoproteins attached. Which is the best descriptor of this protein?

circular

Prokaryotic genomes are composed of what type of DNA?

ribosomes

Mitochondria and chloroplasts both contain their own...?

host plasma membrane

Viral envelopes are stolen from what?

aquaporins

Water passes quickly through cell membranes because of...?

integration

What activity can a temperate phage carry out that a virulent phage cannot? (viral DNA is spliced into host genome)

host ribosomes

What are capsomeres made by?

viral nucleic acids

What are viral nucleic acids copied from?

vaccines

What can prevent the onset of a virus?

lysosome

What cell organelle has a pH of 5?

smooth ER and rough ER

What cell organelles are physically connected?

all

What filaments are made by adding small protein subunits together?

fingernail

What is an example of when you would find an intermediate filament?

cytoplasm is like Atlantic Ocean and the cytosol is like the sea water in it

What is the difference between the cytosol and the cytoplasm?

mutation

What is the most common source of genetic diversity in prokaryotes?

ssRNA

What is the most common viral genome type?

F factor

What is the prerequisite for undergoing conjugation?

centrosomes

What is the term for microtubule organizing centers?

asymmetric

What is the term used to describe when the inner surface of the membrane has a different look, feel, and function than the outside of the membrane?

non-essential

What kind of genes does a plasmid carry?

elf

What movie involving gum off the street best explains transformation?

mitochondria and chloroplasts

What organelles are found in all plants and have their own DNA?

ribosomes and rough ER

What organelles are involved in protein synthesis?

integral proteins

What type of proteins span the phospholipids bilayer, usually a number of times?

it will die out or mutate

What will likely happen to a newly emerged virus that is very rapid and lethal?

keratin

Which of the following cytoskeletal proteins is not associated with a known motor protein? keratin microtubules actin

all

Which of the following will most likely increase the virulence of a bacterium? all A plasmid containing an antibiotic resistance gene a capsule endotoxins

kinesin

Which of the following words is not a term that is associated with Actin? Kinesin muscle microvilli microfilament tension resisting

peroxisomes

Which organelle is NOT a member of the endomembrane system?

host range

This is determined by the proteins on the surface of a virus and that of its host

mitochondria

powerhouse of the cell

lytic cycle

A large number of phages released at the same time is a characteristic of...?

High salt releases peripheral membrane proteins and detergent releases integral membrane proteins.

1. In order to study the different components of a cell scientists will use a blender to lyse (this means break open) a collection of cells and then centrifuge (this means to spin very fast) the cell lysate. Membrane fragments end up in a pellet at the bottom of the centrifuge tube. Membrane proteins were originally classified based upon how easy it was to separate them from this pellet. The mildest treatment involves addition of a concentrated salt solution that competes with ionic and hydrogen bonds. A more aggressive treatment involves the addition of a detergent solution that interrupts Van der Waals bonds. Based on what you know about membrane proteins and the weak bonds that associated them with the membrane which of the following statements do you think is most correct? (P.S. - this is a thinking/application question)

TMV

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. What symptoms would the plants develop?

entry and synthesis

A temperate phage goes dormant between which stages of the lytic cycle?

cell-cell recognition

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

some

Are accessory proteins such as reverse transcriptase present in some, none, or all viruses?

none

Are flagella to help a virus move present in some, none, or all viruses?

none

Are plasmids present in some, none, or all viruses?

none

Are ribosomes for producing viral proteins present in some, none, or all viruses?

false

Determine if the statement in quotations is true or False. If false, identify one of the corrections below that make it a true statement. "The oligosaccharides that sometimes decorate membrane proteins are only found on the cytosolic monolayer of the plasma membrane." Change cytosolic to extracellular

lateral

In a classic membrane experiment, scientists chemically labelled phospholipids with photo labile fluorescent dye. (Photo labile means it is destroyed by light). Labelled cells were observed under a microscope and a small patch of the membrane was exposed to a laser that bleached the fluorescence. Over a 1 hour period the entire cell lost fluorescence. This experiment most likely supports which movement hypotheses?

mobility

Internal membranes do not help with...?

all

Is a capsid made from capsomere proteins present in some, none, or all viruses?

some

Is a viral envelope made from host cell lipid bilayer present in some, none, or all viruses?

all

Is nucleic acid present in some, none, or all viruses?

transduction

The genome of a bacterial cell was sequenced (this means that the order of all the nucleotides was determined) and several stretches of phage DNA were found within the bacterial genome. The most likely explanation is...?

4,1,3,2

The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering. What is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm? 1. membrane composed mostly of lipopolysaccharide 2. plasma membrane 3. peptidoglycan 4. Capsule

different biochemicals in cell wall

Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. What explains the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?

flipping

Transversal Movement of phospholipids in the membrane is most commonly described as...

false

True or False? The inner membrane monolayer of organelle membranes is called the cytosolic leaflet

false

True or False? The two monolayers of a biological membrane have the same phospholipid composition

true

True or False? Transmembrane proteins are always integral membrane proteins

smooth ER

Where does phospholipid synthesis take place?

microtubules

Which cytoskeletal structure is most closely associated with the centrosome?

lateral and transversal

Which movements are common for a protein in a biological membrane?

none of the above are true

Which of the following is true with respect to mitochondrial DNA? None of the above are true Mitochondrial DNA and chloroplast DNA contain the same genes Mitochondrial DNA is likely the remnant of an ancient prokaryote, but does not contain any functional genes Mitochondrial DNA is inherited from both the mother and the father Mitochondrial DNA is single-stranded, circular DNA

outer layer of organellular membrane

Which of the following monolayers is called a cytosolic leaflet?

all

Which of the following structures does not create an integral membrane protein? All of the above create an integral membrane protein Multiple transmembrane alpha helices A lateral alpha helix embedded in a monolayer A lipid anchor A single transmembrane alpha helix