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bio 215 > test 2 > Flashcards

test 2 Flashcards

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Biology 101 flashcards
1
Q

shared cell structures

A
  1. cell membrane (lipid bilayer, membrane proteins, short carbs)
  2. genetic material as chromosomes
  3. ribosomes
  4. cytoskeletal elements (rod like proteins)
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2
Q

organelles

A

membrane bound (organelle membranes just like cell membrane)

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3
Q

cell wall

A

fiber like carbs + other molecules
stiff wall (rigid shape + protection)

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4
Q

flagella

A

cell movement
thin long projections
spin to propel through water

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5
Q

archae

A

make them resilient
- different hydrocarbon chains/carbs make up membrane/cell wall
- NOT multicellular

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6
Q

bacteria

A

small
most have singular chromosome

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7
Q

eukaryote

A

kernel=nucleus (2membrane -> nuclear envelope has pores)
mitochondria (2membrane ->inner membrane series of tubes + sacs)

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8
Q

plants

A
  • cellulose (fiber wall)
  • vacuole 90% plant cell (store molecules, turgor pressure)
  • chloroplast (2membrane)
    - interior stacks of membrane bound sacs = vesicles
    - photosynthesis
  • avg plants have more genes
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9
Q

endoplasmic reticulum

A
  • network of tubules + sacs
  • originates at nuclear envelope
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10
Q

golgi

A
  • at outermost part of ER
  • sequence of sacs close but not connected
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11
Q

types of cytoskeletal elements

A
  1. actin filaments
  2. intermediate filaments
  3. microtubules
    - dynamic (grow and shrink from either end)
    - only for eukaryotes
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12
Q

actin filaments

A
  • 2 coiled strands made of protein strings -> actin
  • found beneath plasma membrane of animal cells
  • critical in most types of cell movement (muscle contraction)
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13
Q

intermediate filaments

A
  • intermediate between the diameter of actin filaments and microtubules
  • structural support
  • can made wide array of different proteins that intertwine to form fibers
    - inside nuclear envelope
    - stiffen structure of nuclear envelope + provide attachment sites for chromosomes
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14
Q

microtubules

A
  • long hollow cylinders
  • made of combos of alpha tubulin and beta tubulin
  • form roadways where cargo moves to specific destinations
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15
Q

surface area and volume in organelles

A
  • high surface area-to-volume ratio
  • high surface area: molecular machines integrated into lipid bilayer that form the sacs/tubes
  • integrated, efficient unit -> assembly line
  • low volume: ingredients (proteins + other compounds) for key reactions are closer together and run into each other more often
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16
Q

virus variability

A
  • enveloped: exterior surface has lipid bilayer (HIV-1) also have capsid around genomes
  • non enveloped: -> envelope/jacket of protein molecules called capsid
  • both enveloped + non have surfaces studded with proteins
  • DNA/RNA genes single/double stranded
    - RNA: can be complementary/identical to mRNA
    - may or may not need to be reverse transcribed into DNA to turn into proteins
  • DO NOT follow central dogma
17
Q

virus life cycle

A
  1. binding event between a surface protein on the virus and a membrane protein (receptor) on a host cell (very specific)
  2. genetic material enters cell
    enveloped: lipid bilayers fuse and contents diffuse/entire virus surrounded by cell membrane
    no enveloped (bacteria): part of the protein coat changes shape after binding to the receptor and actually injects the viral genes into the cell
  3. Viral proteins and nucleic acids are produced by host cell enzymes, amino acids, nucleotides, and ATP.
  4. structural proteins processed in ER + copies of virus’ genes , copies of genome are made from native RNA polymerase,
  5. proteins and RNA genome copies are assemnled into the start of new virons in the golgi and carried out of the cell/pieces are shipped to exterior of cell and assemble there
  6. exit
    enveloped: viruses steal part of membrane when they enter, lipid bilayers become envelopes of offspring virions that bud off cell
    non enveloped: lysis- blast a hole into the cell membrane/wall to exit
18
Q

protease

A

protein cleaving machine encoded in viral genome

19
Q

how are copies of virus’ RNA genome made?

A

non structural virus protein: an rna polymerase not found in host cell

20
Q

endomembrane system

A
  • group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins
  • proteins bind to mRNA and carry it out through a nuclear pore into the cytoplasm
  • ribosome manufactures the primary sequence of the protein and it enters the endomembrane system
  • start of protein sequence contains signal sequence that binds to an RNA protein particle which binds to a receptor in the membrane of the ER, which guides protein through channel into interior of ER
  • proteins in there do two things 1. remove signal sequence 2. assist folding/add carbohydrates
  • travel to golgi in tubes that grow along microtubules (extensions of ER and form and retract over time)
    smooth ER manufactures membrane lipids and transports to golgi as well
  • once inside golgi: 1. final mods 2. sorted into compartments that correspond to destinations in cell (molecular bar codes bind to receptor proteins in membrane of a vesicle in golgi stack)
  • leave golgi in vesicles and get to destination
    1. exterior is studded with proteins (molecular zip codes) that bind to receptors at destination
    2. vesicles get carried by motor proteins (change shape) that walk along microtubules tracks (kinesin protein)

ribosome -> ER tube/sac -> tube from ER to Golgi -> moved through golgi in sequence and enter a vesicle -> motor proteins/cytoskeletal elements walk vesicles to cell membrane -> vesicle fuses with cell membrane

21
Q

why does kinesin change shape?

A

Phosphorylation is the addition of a phosphate group (PO43-), typically from ATP.

but phosphate carries three full negative charges. In kinesin’s case, an entire ATP molecule, containing four full negative charges, is added to change its shape. Adding an ATP or a single phosphate group to a protein delivers a thunderous bolt of charge that repels nearby negatively charged R-groups and attracts positively charged R-groups, causing at least part of the protein to move.

22
Q

endomembrane system (codon learning)

A
  1. mRNA is exported from the nucleus, through a nuclear pore.
  2. Protein synthesis (linking amino acids via peptide bonds) begins in a ribosome.
  3. A signal sequence on the new protein binds to an RNA-protein particle, which interacts with a receptor on the ER membrane.
  4. The protein enters the inside of the ER, through a channel.
  5. Processed proteins and other products move to the Golgi from ER through “connection tunnels.”
  6. Products move through each sac in the Golgi, being processed, sorted by destination, and loaded into a vesicle.
  7. Kinesin walks along microtubules to carry vesicles that bud off the Golgi to their destination.
23
Q

plasmodesmata

A

channels that pass between adjacent plant cell walls connect their cytoplasm

24
Q

gap junctions

A
  • develop when a set of six proteins (connexins) in plasma membrane arrange themselves in an oval donut shape -> connexon
  • when pores align, channel forms
  • cardiac muscle
25
Q

cell anchoring junctions

A
  • resist external forces that pull cells apart
  • symmetrical linkage to cell + cytoskeleton
  • each type is found at characteristic positions in epithelial tissue
  1. tight junctions
  2. adherens
  3. desmosomes
  4. hemidesmosomes
26
Q

tight junctions

A
  • watertight seal between two adjacent animal cells
  • near apical region
  • claudius and occludin proteins hold cells against each other/o
27
Q

adherens junctions

A
  • at apical end of cell, just below tight junctions
  • built around transmembrane proteins that belong to cadherin family,
    cadherin molecules in plasma membrane of cells bind to e/o across cells and tethered to actin cytoskeleton through linker proteins
  • form continuous adhesion belt around interacting epithelial cells that can influence shape and folding
28
Q

desmosomes

A
  • located on lateral surfaces of epithelial cells act like spot welds
  • formed when special type of cadherin protein in plasma membrane connects to intermediate filaments inside cells
  • maintain cells in a sheet like formation that stretch
  • provide tensile strength to epithelial tissues for preserving tissue integrity
29
Q

hemidesmosomes

A
  • link basal surface of cells to extracellular matrix of basal laminated
  • include adhesion protein receptor integrin instead of cadherins
    integrins linked indirectly to intermediate filaments inside cell
  • crucial for anchoring the epithelial sheet tot he basal lamina
30
Q

extracellular matrix

A

material that cells secrete around themselves
- primarily made of proteins
- most abundant protein-> collagen
- collagen fibers interwoven with proteoglycans (carbohydrate containing protein molecules)

hold cells together to form tissues
allows cells within tissue to communicate with each other via integrin transmembrane protein receptors (intracellular domain interacts with actin microfilaments)

31
Q

microfilaments

A
  • provide rigidity and shape to a cell
  • can depolymerize and form quickly
  • it is the formation and breakage of these attachments on either end of an integrin molecule that allows the cell to crawl through the extracellular matrix of a tissue
  • in epithelial tissues, hemidesmosomes link cells to the extracellular matrix of the basal lamina through integrin receptors. However, the intracellular domain of these integrins interacts with intermediate filaments instead of actin.
32
Q

Electric potential gradient

A

A difference in charge carried by ions in one area versus another, almost always across a cell membrane or organelle membrane. Substances move down their electric potential gradients passively and spontaneously, toward unlike charges and away from like charges.

33
Q

Electric current

A

In cells, a flow of charge in the form of ions.

34
Q

Concentration gradient

A

A difference in the concentration of an ion or molecule in one area versus another, often across a cell membrane or organelle membrane. Substances move down their concentration gradients passively and spontaneously, via diffusion.

35
Q

Membrane voltage

A

In cells, an electrical potential created by a separation of charge across a membrane. Also called a transmembrane potential or a membrane potential.

36
Q

In cells, an electrical potential created by a separation of charge across a membrane. Also called a transmembrane potential or a membrane potential.

A

The overall gradient across a cell membrane or organelle membrane, produced by differences in concentration of substances and differences in the distribution of charge.

37
Q

transport proteins

A
  • transmembrane/integral membrane proteins

Channels have an opening or pore that allows, under certain conditions, a specific ion or molecule to travel down its concentration or electrical gradient from one side of the membrane to another.

Carriers have a binding site that is specific to a particular molecule. When that molecule hits the binding site and sticks to it, the carrier changes shape in a way that allows the molecule to diffuse down its concentration or electrical gradient, into the solution on the opposite side of the membrane.

Pumps are involved in active transport. These proteins use energy in the form of ATP to move ions and molecules against their concentration or electrical potential gradient, from one side of a membrane to the other. In fact, in many cases, pumps function to create concentration or electrical potential gradients that later drive passive transport through channels or carriers.

38
Q

membrane potential

A

By convention, the outside of a cell membrane serves as the reference point and is considered to have a potential of 0. The charge difference between the two sides of the membrane is then measured and recorded as the membrane potential.

can be measured directly with microelectrodes

bio 215 (3 decks)

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