Lecture 6-10 Flashcards

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1
Q

Name the 4 lipids.

A

1) fatty acids
2) triacylglycerols
3) phospholipids
4) steroids

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2
Q

How can fatty acids vary?

A
  • chain length
  • presence, number, position of double bonds
  • isomers
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3
Q

Compare saturated and unsaturated fatty acids.

A
  • saturated: single bonds causing the molecule to be fairly straight and packed together
  • unsaturated: cis double bonds present that put a bend in the molecule (polyunsaturated fatty acids have multiple double bonds)
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4
Q

What is the structure of fatty acids?

A

has a carboxyl and methyl end

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5
Q

What is the structure of triacylglycerols and its bonding?

A
  • three fatty acids attached to a glycerol backbone

- ester linkages are formed between glycerol and fatty acid from dehydration reaction

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6
Q

Identify the differences between plant and animal lipids. Name the exceptions.

A

plants:
-rich in unsaturated fatty acids and are liquid at room temperature
-coconut oil
animals:
-rich in saturated fatty acids and solid at room temperature
-duck fat

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7
Q

What are the characteristics of trans fats?

A
  • produced by hydrogenation of vegetable oils
  • unsaturated fats with trans double bonds
  • solid at room temperature
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8
Q

What is the structure of phospholipids?

A
  • two fatty acids
  • a phosphate group with a charged molecule attached
  • glycerol backbone
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9
Q

How are phospholipids oriented in a two layered bilayer?

A
  • hydrophilic head interact with themselves and water, facing the outside
  • hydrophobic tails interact with themselves and face the inside of the bilayer
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10
Q

What is the structure of steroids?

A

-carbon skeleton with 4 rings

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11
Q

What is cholesterol and what is its role?

A
  • steroid
  • maintains structure and fluidity
  • component of cell membranes
  • precursor of sex hormones
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12
Q

All cells must be able to…

A

1) keep internal environment different from external
2) expel wastes
3) make proteins with ribosomes
4) divide and replicate (reproduction)

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13
Q

Explain the fluid mosaic model.

A
  • phospholipid bilayer where hydrophobic tails are on the inside and hydrophilic heads are facing the outside
  • proteins embedded in bilayer and are unequally distributed (proven by freeze fracturing)
  • glycoproteins are on the outside of the bilayer
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14
Q

Where are the integral, peripheral, and transmembrane proteins located?

A

integral: within the bilayer
peripheral: attached to the surface
transmembrane: span the whole bilayer

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15
Q

Identify the 6 functions of membrane proteins.

A

1) transport of solutes and molecules
2) enzymatic activity in metabolic reactions
3) signal transduction
4) cell to cell recognition
5) intercellular joining
6) attachment to cytoskeleton and extracellular matrix

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16
Q

How do you explain the movement of phospholipids in the fluid mosaic model?

A
  • mostly move laterally in bilayer

- flip flop rarely

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17
Q

What is the role of cholesterol in membrane fluidity?

A
  • stabilizes membrane fluidity

- reduces movement and prevents packing

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18
Q

Explain the permeability of the plasma membrane.

A
  • permeable to small non polar molecules

- not permeable to large charged molecules

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19
Q

Explain the importance of cell size.

A
  • volume must be large enough to contain all material necessary for functions of life
  • volume must be small enough so the surface area can maximize its capabilities to control inputs and outputs
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20
Q

Which are the first eukaryotes to evolve?

A

Protists- unicellular eukaryotes

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21
Q

What are the differences between prokaryotes and eukaryotes?

A
  • eukaryotes are larger
  • prokaryotes have no membrane bound organelles
  • genetic information is free in a nucleoid in prokaryotes; in a nucleus in eukaryotes
  • prokaryotes don’t have mitochondria or chloroplasts
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22
Q

What are the similarities between prokaryotes and eukaryotes?

A

have extracellular structures (outside of plasma membrane)

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23
Q

List the order in which organisms evolved.

A

1) prokaryotes
2) atmospheric oxygen
3) single-celled eukaryotes
4) multicellular eukaryotes
5) animals
6) colonization of land
7) phanerozoic eon

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24
Q

What happened before the oxygen revolution in the Earth’s history?

A

earliest prokaryotes generated ATP without oxygen, used other molecules instead, due to low levels of oxygen in the atmosphere

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25
Q

How did oxygen accumulate during the oxygen revolution?

A

early prokaryotes had specialized cell membranes for photosynthesis where oxygen was a byproduct

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26
Q

Where are free and bound ribosomes located in prokaryotes and eukaryotes?

A

prokaryotes: in the cytosol
eukaryotes: free ribosomes in the cytosol
bound ribosomes are attached to the endoplasmic reticulum

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27
Q

What is the function of the free and bound ribosomes?

A

carry out protein synthesis

free: make cytosolic proteins
bound: make proteins that are inserted into membranes

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28
Q

What is the structure of ribosomes?

A

composed of protein and rRNA (ribosomal RNA) that are made in the nucleus

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29
Q

How are membranes within the cell continuous or connected?

A

vesicles

30
Q

Name the 5 components of the eukaryotic endomembrane system.

A

1) nuclear envelope
2) endoplasmic reticulum
3) golgi apparatus
4) vesicles and vacuoles
5) lysosomes

31
Q

What is the key difference between the smooth and rough ER of the endoplasmic reticulum?

A

smooth ER: lacks ribosomes

rough ER: with ribosomes

32
Q

Identify the functions of the smooth endoplasmic reticulum.

A

1) synthesizes lipids
2) metabolizes carbohydrates
3) detoxifies poison
4) stores calcium

33
Q

Identify the functions of the rough endoplasmic reticulum.

A

1) modifies proteins
2) distributes transport vesicles
3) produces membranes

34
Q

How does the golgi apparatus have directionality?

A

cis face: receiving side of the golgi apparatus

trans face: shipping side of the golgi apparatus

35
Q

Identify the functions of the golgi apparatus.

A

1) modifies products of the ER
2) manufactures macromolecules
3) encloses materials in transport vesicles (some go to the plasma membrane and some rejoin the golgi for further modification

36
Q

Identify the functions of vacuoles.

A
  • storage
  • transport
  • digestion
37
Q

Compare contractile vacuoles, central vacuoles, and food vacuoles.

A

contractile vacuoles: pump excess water out of cells in freshwater protists
central vacuoles: hold organic compounds and water in plant cells
food vacuoles: formed by phagocytosis

38
Q

What are the functions of lysosomes?

A
  • joins vacuoles to digest macromolecules

- involved in phagocytosis and autophagy

39
Q

Compare phagocytosis and autophagy.

A

phagocytosis: cell engulfs and digests material outside the cell
autophagy: cell digests and recycles own organelles and macromolecules within the cell

40
Q

What are the functions of peroxisomes?

A
  • break down fatty acids
  • detoxification
  • takes H ions from substrates plus oxygen to produce hydrogen peroxide and water
41
Q

What is the structure of the mitochondria?

A

2 membranes folded into cristae:

  • smooth outer membrane
  • inner membrane (associated with circular DNA)
    1) intermembrane
    2) mitochondrial matrix
42
Q

What is the role of the ribosomes in the mitochondrial matix?

A

make proteins for the mitochondrion

43
Q

What is the role of cristae in mitochondrion?

A

increase surface area for the enzymes

44
Q

How do mitochondria vary?

A
  • cell/tissue type

- response to factors

45
Q

What is the structure of the chloroplasts?

A
  • inner and outer membranes
  • thylakoid membranes
  • intermembrane space (between inner and outer)
46
Q

Explain the endosymbiosis theory.

A
  • mitochondria and chloroplasts arose from endosymbiosis
  • prokaryotes respiring with oxygen were taken up by another cell and became mitochondria
  • prokaryotes that photosynthesized were taken up by another cell and became chloroplasts
47
Q

Show the evidence that helps prove the endosymbiosis theory.

A
  • membrane of chloroplasts and mitochondria are similar to some prokaryotes
  • circular DNA is similar to prokaryotes
  • ribosomes more similar in mitochondria and chloroplasts to those of prokaryotes than to cytosolic ribosomes in eukaryotes
48
Q

Identify the functions of the cytoskeleton.

A
  • supports cell
  • maintains shape
  • regulates biochemical activities
  • anchors organelles in eukaryotes
49
Q

Identify the function of the motor proteins, such as dynein.

A
  • produce motility that helps move organelles and vesicles along the cytoskeleton
  • bends cilium using ATP
50
Q

Rank the cytoskeleton fibers from thinnest to thickest.

A

microfilaments, intermediate filaments, microtubules

51
Q

Identify the functions and location of the microfilaments.

A
  • resist tension
  • maintain shape
  • involved in movement processes
  • located in cytoplasmic streaming and muscle movement
52
Q

How do the microfilaments in muscles work?

A

myosin and actin filaments move past each other to shorten the muscle cell

53
Q

How do the microfilaments in amoeboid movement work?

A

actin and myosin polymerize to form pseudopodium

54
Q

Identify the functions and location of the intermediate filaments.

A
  • in permanent and semi permanent structures of the cells in animals
  • involved in fixing shape or position
55
Q

Identify the functions and location of microtubules.

A
  • polymers of tubulin
  • involved in movement of cells or organelles
  • components of cilia and flagella that are specialized for beating, that can move liquid or air or past a cell
56
Q

What is the structure of a motile cilium?

A
  • groups of microtubules covered in extension of the plasma membrane
  • anchored by basal body with a ring of 9 groups of 3 microtubules (triplets)
  • ring of 9 groups of 2 microtubules (doublets) *9+2 arrangement
57
Q

Name the extracellular structures.

A

1) cell wall
2) extracellular matrix
3) capsule

58
Q

What is the function of a prokaryote’s capsule?

A

protects against dehydration

59
Q

What are the functions and structures of cell walls in prokaryotes?

A

-protects the cell
-maintains its shape
-prevents excessive uptake of water
-gram positive: thick layer of peptidoglycan
gram negative: thin layer of peptidoglycan plus an outer membrane

60
Q

What are the functions and structures of cell walls in plants?

A
  • cellulose microfibers embedded in a matrix of polysaccharides and protein
    1) primary cell wall
    2) middle lamella: thin layer of polysaccharides between primary walls of adjacent cells
    3) secondary cell wall: between plasma membrane and primary cell wall
    4) plasmodesmata: allows the cytoplasm of one cell to be continuous with another and to communicate between them
61
Q

What is the structure of the animal extracellular matrix?

A
  • fibronectins attached to integrins
  • collagens
  • proteoglycans
62
Q

Compare tight junctions, desmosomes, and gap junctions.

A

tight junctions: form a barrier to prevent leakage by binding cells tightly together
desmosomes: intermediate filaments holding cells together in strong sheets
gap junctions: membrane proteins form pores for cells that need to communicate with others

63
Q

What is the function of transport proteins?

A

speed the passive movement of molecules across the plasma membrane

64
Q

Explain facilitated diffusion.

A

provide corridors for specific molecules or ions into or out of the cell
channel and carrier proteins

65
Q

Compare the channel and carrier proteins.

A

channel proteins: provide hydrophilic corridors

carrier proteins: translocates the solute-binding site across the membrane without changing its shape

66
Q

Compare isotonic, hypertonic and hypotonic solutions.

A

isotonic: equal concentrations of solutes across a membrane where there is no net movement of water
hypertonic: solution with more total solutes
hypotonic: solution with less total solutes

67
Q

What happens to animal cells when it is placed in a hypotonic solution? Hypertonic solution? Isotonic solution?

A

Hypotonic: cell takes in water and bursts
Hypertonic: cell loses water and shrivels up
Isotonic: nothing happens

68
Q

What happens to plant cells when it is placed in a hypotonic solution? Hypertonic solution? Isotonic solution?

A

Hypotonic: turgid, cell wall resists water pressure
Hypertonic: plasmolysis, cell loses water and shrivels up and pulls away from the cell wall
Isotonic: flaccid

69
Q

Name two storage molecules.

A

starch and glycogen

70
Q

What is the role of ATP in active transport?

A
  • ATP hydrolysis releases energy that will be used for active transport
  • phosphate group transferred to a transport protein
  • protein changes shape which allows movement of solute
  • dephosphorylation results in another shape change
  • active transport allows cells to maintain concentrations of solutes different from surroundings
71
Q

What does the sodium potassium pump do for animal cells?

A
  • high concentration of potassium and low concentration of sodium inside the cell
  • has binding sites specific for each ion
  • change of shape during binding and releasing of ions
  • unequal charge exchange, causing a charge difference between the two sides of the membrane
72
Q

What does the membrane potential and electrochemical gradient do inside a cell?

A
  • used to move charged molecules across the membrane
  • more positive inside and more negative outside
  • anions move out and cations move in