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BIO 111 > Exam #2 - chapter 3-6 > Flashcards

Exam #2 - chapter 3-6 Flashcards

Exam #2 Material

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Biology 101 flashcards
1
Q

define denaturation

A

protein loses structure and function

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2
Q

things that cause denaturation

A
  • pH
  • temp
  • ionic concentration of solution (salt concentration)
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3
Q

lipids

A
  • insoluble in water
  • high proportion of nonpolar C-H bonds cause the molecule to be hydrophobic
  • fats, oils, waxes, some vitamins
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4
Q

Fats

A

triglycerides
* composed of 1 glycerol and 3 fatty acids

trans fat: produced industrially

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5
Q

unsaturated fat

A

1 or more double bonds
* low melting point
* plant origin
* liquid at room temp

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6
Q

saturated fat

A

no double bonds between carbon atoms
* higher melting point
* animal origin
* solid at room temp

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7
Q

phospholipids

A

composed of:
- glycerol
- 2 fatty acids (nonpolar tails)
- a phosphate group (polar head)

forms all biological membranes, life wouldn’t exist without this

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8
Q

micelles

A

lipid molecules orient with polar (hydrophilic) head toward water and nonpolar (hydrophobic) tails away from water

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9
Q

phospholipid bilayer

A

more complicated structure where 2 layers form:
- hydrophilic heads point out
- hydrophobic tails point inward toward each other

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10
Q

cell size and what affects rate of diffusion

A
  • small due to a reliance on diffusion of substances in and out of cells
    rate of diffusion is affected by:
  • surface area available
  • temp
  • concentraion gradient
  • distance
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11
Q

microscope resolution

A

minimum distance two points can be apart and still be distinguished as two separate points

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12
Q

2 types of microscopes

A
  1. Light
    - use magnifying lenses with light
    - compound and dissection scopes
  2. Electron
    - use beam of electrons
    - SEM: scanning e- microscope
    - TEM: transmission e- microscope
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13
Q

structural similarities of cells

A
  1. Nucleoid or nucleus where DNA is located
  2. Cytoplasm
    - semifluid matrix of organelles and cytosol
  3. Ribosomes
    - synthesize proteins
  4. Plasma membrane
    - phospholipid bilayer
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14
Q

prokaryotic cells

A
  • don’t have nucleus; DNA is in nucleoid
  • simplest organisms
  • cell wall is outside of plasma membrane
  • contain ribosomes (not membrane bound organelles)
  • 2 domains: archaea and bacteria
  • cell wall is what gives it the structure
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15
Q

bacterial cell walls

A
  • composed of peptidoglycan
  • protects the cell, maintains its shape, and prevent excessive uptake or loss of water
  • susceptibility of bacteria to antibiotics often depends on the structure of the cell walls
  • archaea lack peptidoglycan
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16
Q

flagella

A
  • present in some prokaryotic cells
  • used for locomotion
  • rotary motion propels the cell
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17
Q

eukaryotic cells

A
  • possess a membrane-bound nucleus
  • more complex than prokaryotic cells
  • possess a cytoskeleton for support and to maintain cellular structure
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18
Q

animal vs plant cell

A

plant cells have the following:
* central vacuole
* cell wall
* chloroplast

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19
Q

nucleus

A
  • most eukaryotic cells possess a single nucleus
  • nucleolus: region where ribosomal RNA synthesis take place
  • nuclear envelope:
    – 2 phospholipid bilayers
    – nuclear pores: control pasage in and out
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20
Q

ribosomes

A
  • cell’s protein synthesis machinery
  • found in all 3 domains
  • ribosomal RNA (rRNA): protein complex
  • protein synthesis requires messengar RNA (mRNA) and transfer RNA (tRNA)
  • ribosomes may be free in cytoplasm or associated with interal membranes
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21
Q

endomembrane system

A
  • series of membranes throughout the cytoplasm
  • divides cell into compartments where different cellular functions occur
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22
Q

rough endoplasmic reticulum

A
  • attachment to ribosomes to the membrane is what gives it a rough appearance
  • synthesis of proteins to be secreted, sent to lysosomes or plasma membrane
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23
Q

smooth endoplasmic reticulum

A
  • relativley few bound ribosomes
  • variety of functions: synthesis, store Ca2+
  • ratio of RER TO SER depends on the cell’s function
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24
Q

golgi appartus

A
  • flattened stacks of interconnected membranes (golgi bodies)
  • functions in packaging and distribution of molecules synthesized at one location and used at another within the cell or even outside of it
  • Cis and Trans faces
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25
Q

vesicles

A

transport molecules to destination

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26
Q

lysosomes

A
  • membrane-bounded digestive vesicles
  • arise from golgi apparatus
  • enzymes catalyze breakdown of macromolecules
  • destory cells or foregin matter that the cell has engulfed by phagocytosis
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27
Q

microbodies

A

variety of enzyme-bearing, membrane-enclosed vesicles
Peroxisomes
- contain enzymes involved in the oxidation of fatty acids
- H2O2 produced as by-product – rendered harmless by catalase

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28
Q

vacuoles

A

membrane bounded structures in plants and animals
3 different types of vacuoles:
1. Central vacuole in plant cells
2. Contractile vacuole of some protists
3. Storage vacuoles

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29
Q

mitochondria

A
  • found in all types of eukaryotic cells
  • bound by membranes
    – Outer membrane
    – Intermembrane space
    – Inner membrane has cristae
    – Matrix
    have their own DNA adn their own ribosomes
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30
Q

chloroplasts

A
  • Organelles present in cells of plants and some other eukaryotes
  • Contain chlorophyll for photosynthesis
  • Surrounded by 2 membranes
  • Thylakoids are membranous sacs within the inner membrane
    Grana: are stacks of thylakoids
  • Have their own DNA
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31
Q

endosymbiosis

A

One cell, a prokaryote, was engulfed by and became part of another cell, which was the precursor of modern eukaryotes
- Mitochondria and chloroplasts

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32
Q

cytoskeleton

A

Network of protein fibers found in all eukaryotic cells
- Supports the shape of the cell
- Keeps organelles in fixed locations
Dynamic system – constantly forming and disassembling

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33
Q

3 types of fibers

A

**Microfilaments (actin filaments)
**
- 2 protein chains loosley twined together waith each part being largest of the cytoskeletal
Microtubules
- Largest of the cytoskeletal elements
- Hollow tubes
**Intermediate filaments
**
- Between the size of actin filaments and microtubules

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34
Q

centrosomes

A

Region surrounding centrioles in almost all animal cells
Microtubule-organizing center
- Can nucleate the assembly of microtubules
Animal cells and most protists have centrioles – pair of organelles
Plants and fungi lack centrioles

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35
Q

movement within cells

A
  • Actin and microtubules are important for movement within cells.
  • Movement often requires the use of ATP
  • Some cells crawl using actin microfilaments to “push” the cell membrane forward
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36
Q

flagella

A

9 + 2 arrangement of microtubules
Not like prokaryotic flagella
Microtubules move past each other and this leads to undulation of the flagella
Surrounded by the plasma member with cytoplasm inside
Cilia are shorter and more numerous

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37
Q

extracellular matrix (ECM)

A
  • secrete an elaborate mixture of glycoproteins into the space around them
  • form a protective layer over the cell surface
  • integrins link ECM to cell’s cytoskeleton
  • animal cells lack cell walls*
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38
Q

glycolipids

A

most tissue-specific cell surface markers

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39
Q

MHC proteins

A

recognition of “self” and “nonself” cells by the immune system

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40
Q

3 types of cell connections

A
  1. Tight Junction
  2. Adhesive Junction
  3. Communicating Junction
41
Q

plasmodesmata

A

allows direct communication of molecules between adjacent plant cells

42
Q

membrane structure

A
  • phospholipids arranged in a bilayer
  • globular proteins inserted in the lipid bilayer
  • Fluid Mosiac Model: mosaic of proteins floats in or on the fluid lipid bilayer like boats on a pond
43
Q

4 structures of cellular membrances

A
  1. phospholipid bilayer
  2. transmembrane proteins
  3. interior protein network
  4. cell surface markers
44
Q

membranes and microscopes

A

both TEM and SEM are used to study membranes

45
Q

phospholipids

A

structure: - glycerol
- 2 fatty acids
- phosphate group
spontaneously forms a bilayer
(fatty acids on the inside, phosphate on both surfaces)

46
Q

environmental influences on the membrane

A
  • saturated fatty acids make the membrane less fluid than unsaturated fatty acids
  • warm temps make the membrane more fluid than cold temps
  • lipid conpositiion of the ER membrane, golgi stack, & plasma membrane are distinct
47
Q

6 functions of membrane proteins

A
  1. Transporters
  2. Enzymes
  3. Cell-surface receptors
  4. Cell-surface identity markers
  5. Cell-to-cell adhesion proteins
  6. Attachments to the cytoskeleton
48
Q

peripheral proteins

A

anchoring molecules attach membrane protein to surface

49
Q

anchoring molecules modified with lipids

A
  1. Nonpolar regions that insert into the internal portion of the lipid bilayer
  2. Chemical bonding domains that link directly to proteins
50
Q

integral membrane proteins

A
  • span the lipid bilayer (transmembrane proteins)
  • Transmembrane domain
51
Q

membrane proteins

pores

A

Extensive nonpolar regions within a transmembrane protein can create a pore through the membrane

52
Q

passive transport

A

the movement of molecules through the membrane in which:
- No energy is required
- Molecules move in response to a concentration gradient

53
Q

diffusion

A
  • the movement of molecules from high concentration to low concentration
  • will continue until the concentration is the same in all regions
54
Q

major barrier

A

Major barrier to crossing a biological membrane is the hydrophobic interior that repels polar molecules but not nonpolar molecules

55
Q

facilitated diffusion

A
  • Molecules that cannot cross membrane easily may move through proteins
  • Move from higher to lower concentration
    Channel proteins: Hydrophilic channel when open
    Carrier proteins: Bind specifically to molecules they assist
  • Membrane is selectively permeable
56
Q

ion channels

A
  • Allow the passage of ions
  • Gated channels: open or close in response to stimulus (chemical or electrical)

**3 conditions determine direction:
**- Relative concentration on either side of membrane
- Voltage differences across membrane
- Gated channels – channel open or closed

57
Q

osmosis

A

net diffusion of water across a membrane toward a higher solute concentration
* cytoplasm of the cell is an aqueous solution
- water is a solvent
- dissolved substances are solutes

58
Q

osmotic concentration

A
  • Hypotonic solution has a lower solute concentration
  • Hypertonic solution has a higher solute concentration
  • Isotonic solution has the same concentration
    * aquaporins facilitate osmosis
59
Q

maintaining osmotic balance

A
  • some cells use extrusion in which water is ejected thru contractile vacuoles
  • isomotic regulation involves keeping cells isotonic with their environment
  • plant cells use turgor pressure to push cell membrane to cell wall
60
Q

active transport

A
  • Requires energy – ATP is used directly or indirectly to fuel active transport
  • Moves substances from low to high concentration
  • Requires the use of highly selective carrier proteins
61
Q

3 carrier proteins used in active transport

A

uniporters: move 1 molecule at a time
symporters: moves 2 molecules in the same direction
antiporters: move 2 molecules in opposite directions

62
Q

Sodium-Potassium Pump

A
  • direct use of ATP for active transport
  • low internal Na+ and high K+ concentration
  • uses antiporter to move 3 Na+ out of the cell and 2 K+ into the cell
63
Q

coupled transport

A
  • indirect use of ATP
  • uses the energy released to supply energy to active transport of a different molecule
  • symporter is used
  • Glucose-Na+ symporter captures the energy from Na+ diffusion to mvoe glucose against the concentration gradient
64
Q

countertransport

A

move material in opposite directions

65
Q

bulk transport: endocytosis

A
  • movement of substances into the cell
  • phagocytosis: cell takes in particulate matter
  • pinocytosis: cell taken in only fluid
  • requires energy
66
Q

bulk transport: exocytosis

A
  • movement of substances out of the cell
  • used in plants to export cell wall material
  • used in animals to secrete hormones, neurotransmitters, digestive enzymes
  • requires energy
67
Q

define thermodynamics

A
  • branch of chem and physics concerned with energy changes
  • cells are governed by the laws of chem and physics
68
Q

Energy

A

2 states:
1. Kinetic: energy in motion
2. Potential: stored energy
many forms: mechanical, heat, sound, electric current, light, or radioactivity
heat is the most convenient way of measuring energy
1 calorie = 4.2 joule
1 Calorie = 1,000 calories = 1 kcal

69
Q

redox reactions

A

oxidation: atom or molecule loses an electron
reduction: atom or molecule gains an electron, higher level of E than oxidized form

OIL RIG

70
Q

1st law of thermodynamics

A
  • energy cannot be created nor distroyed
  • can only change from one form to another
  • total amt of energy in the universe remians constant
  • during conversion, energy is lost as heat
71
Q

2nd law of thermodynamics

A
  • entropy (disorder) is continuously increasing
  • E transformations proceed spontaneously to convert matter from a more orded/less stable to less ordered/more stable
72
Q

free energy

A
  • the amout of energy available to break/form bonds
  • G= gibbs free energy = energy available to do work
  • H = enthalpy, energy in molecules chemical bonds
  • T = absolute temp
  • S = entropy, unavilable energy
73
Q

ΔG = ΔH - TS

A

ΔG = change in free energy
+ΔG:
- products have more free energy
- not spontaneous, requires input of energy
- endergonic
- ΔG:
- products have less free energy than reactants
- spontaneous
- exergonic

74
Q

activation energy

A
  • extra energy required to destablilize existing bonds and initiate a chemial rxn
  • exergonic rxn’s rate depends on activation energy
  • rate can be increased by:
    1. Increasing energy of reacting molecules (heating)
    2. Lowering activation energy
75
Q

catalysts

A

substances that influence chemical bonds in a way that lowers activation energy

76
Q

Suns impact

A
  • all life gets energy from the sun
  • every organism is dependent on a very tiny amt of energy we get from the sun
  • stored as potential E in chemical bonds
77
Q

ATP

A
  • adenosine triphosphate
  • Chief “currency” all cells use
    Composed of:
  • Ribose – 5 carbon sugar
  • Adenine
    Chain of 3 phosphates:
  • Key to energy storage
  • Bonds are unstable
  • ADP – 2 phosphates
  • AMP – 1 phosphate – lowest energy form
78
Q

ATP Cycle

A

ATP hydolysis drive endergonic rxns
- couplet reactions results in net -ΔG
- ATP not suitable for long term energy storage
- ATP -> ADP = 7.3 kcal/mole
ATP -> AMP = 10.3 kcal/mole
*between 1-2 billon ATP’s per minute

79
Q

enzymes

A
  • most enzymes are protein
  • some RNA
  • shape of enzyme stabilizes a temporary association between substrates
  • enzyme not changed or consumed in rxn
80
Q

active site

A
  • Pockets or clefts for substrate binding
  • Forms enzyme-substrate complex
  • Precise fit of substrate into active site
  • Applies stress to distort particular bond to lower activation energy
  • Induced fit
81
Q

nonprotein enzymes

A

2 kinds:
1. intramolecular catalysis: catalyze rxn on RNA molecule itself
2. intermolecular catalysis: RNA acts on another molecule
*important in ribosomoes

82
Q

define multienzyme complexes

A

subunits work together to form molecular machine
- Product can be delivered easily to next enzyme
- Unwanted side reactions prevented
- All reactions can be controlled as a unit

83
Q

enzyme function

A
  • rate of enzyme-catalyzed reaction depends on concentractions of substrate and enzyme
  • any chemical or physical condition that affects the enzyme’s shape can change rate of:
  • optimum temp
  • optimum pH
84
Q

define Inhibitor

A

substance that binds to enzyme and decreases its activity

85
Q

2 types of inhibitors

A

competitive inhibitor: competes with substrate for active site
noncompetitive inhibitor: binds to enzyme at a site other than active site
- causes shape change that makes enzyme unable to bind substrate

86
Q

ATP Cycle

A

ATP hydrolysis drivers endergonic reactions
- not suitable for long term energy

87
Q

activation energy

A

amount of energy needed to start a reaction

88
Q

What is ATP composed of

A
  • 5 carbon sugar ribose
    -adenine
  • chain of 3 phosphates
89
Q

Allosteric enzymes

A

enzymes exist in active and inactive forms
- most noncompetitive inhibitors bind to allosteric site (chemical switch on and off)

90
Q

Allosteric inhibitor

A

Bids to allosteric site and reduces enzyme activity

91
Q

allosteric activator

A

binds to allosteric site and increases enzyme activity

92
Q

cofactors

A

-metal ions that are found in the active site participating directly in catalysis

93
Q

coenzyme

A
  • nonprotein organic cofactor molecule
94
Q

anabolic reactions

A
  • expend energy to build up molecules
95
Q

catabolic reactions

A
  • harvest energy by breaking down molecules (cats love to tear apart)
96
Q

biochemical pathways

A

reactions occur in a sequence, product of one reaction is the substrate for the next

97
Q

feedback inhibition

A

shuts down pathway so raw materials and energy are not wasted
- end product of pathway bind to an allosteric site on enzyme that catalyses

98
Q

Organism made of small cells has an advantage over an organism composed of smaller fewer cells? (true/false)

A

True

BIO 111 (12 decks)

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