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Flashcards in Midterm 1 Deck (133):
1

What is modern cell theory

al living things are made up of one or more cells, all cells arise from pre existing cells by division

2

What features do all cells share?

-contain DNA
-plasma membranes
-enzymes
-ATP

3

small molecules only have _ - forms of amino acids and _- forms of sugars

L + D

4

WHt are some characteristics of prokaryotes

-no internal membrane components
-no organelles like mitochondria and vaccuoles
-transcription and translation coupled

5

What are some characteristics of eukaryotes

-internal membrane components
-eukaryote is a monophyletic group
-membrane bound organelles

6

What separates transcription and translation

the nuclear membrane

7

What is the nuclear envelope

small molecules and ions can passively diffuse though, however large proteins and RNA require active transport

8

What is endocytosis

regions of the plasma membrane containing transmembrane protein receptors are invaginated by cytoplasmic coating which pinches off a coated vesicle.

9

What is phagocytosis

Large insoluble extracellular material taken into a phagosome and delivered to lysosome from destruction

10

what is autophagy

intracellular material and damaged organelles are engulfed by ER membrane

11

what is the difference between mono and polycistronic mRNA

monocistronic mRNA is used by eukaryotes and only can translate a single protein at a time
polycistronic mRNA is used by prokaryotes and can translate more than one protein at a time

12

T or F- Nuclear export can occur in both eukaryotes and prokaryotes

F- only in eukaryotes

13

T or F- Prokaryotes and Eukaryotes have different ribosome structures

T, 30S+50S prokaryotes + 40S+60S eukaryotes

14

Are proteins held together by covalent or ionic bonds

covalent

15

are lipids held together by covalent or ionic bonds

ionic

16

What are the 4 protein hierarchies + brief descriptions

Primary structure
Secondary structure- a helix and B pleated sheets
Tertiary structure- Folded into 3D conformation
Quaternary structure- multimeric conformation

17

What are the roles of quaternary proteins

regulation, signalling, transport, catalysis and movement

18

what is the difference between nucleotides and nucleosides

nucleosides lack a phosphate

19

phospholipids contain a ________ head and _________ tails

hydrophillic head + hydrophobic tails

20

what is the endosymbiotic theory

mitochondria and chloroplasts were once primitive bacterial cells

21

T or F- mitochondria and chloroplasts replicate separately from nuclear DNA

T

22

what kind of DNA reveals ancient human migration patterns

mtDNA

23

how is malaria trated

choloroquine and quinine interfere with merozoites ability to degrade hemoglobin, needed for parasite protein synthesis and energy

24

what are antibiotics

small molecules that ill or inhibit growth or microorganisms

25

what are useful features for a model organsims

small, easy feeding, non dangerous, short generation time, readily available

26

what is a common model organsim

yeast, many benefits of both bacteria and eukaryotic cells

27

what are temperature sensitive mutations

organism only able to grow at permissive tempature, unfolds at nonpermissive temperature

28

what are the four types of animal tissues

connective, epithelial, muscle and nervous

29

what is a plants delivery system

the xylem and phloem

30

how are plant cells held together

plasmodesmata

31

how are animal cells held together

CAMs (cell adhesion molecules), made of collagen

32

the cells of epithelium are _______.

polarized

33

blood vessels are lined with _______ to prevent leakage

endothelium

34

only about __ % of human DNA encodes proteins

10%

35

how do we study gene regulation?

observing the pattern of expression through delevopmental time

36

how are C. elegans a model organsim

-smal, short generation time (3 days) , hermaphroditic, transparent, easy to culture and maintain

37

T or F- worms can model human disease

T, disease model for alzheimers, parkinsons, etc

38

T or F: the order in humans and in mice is conserved

T, we share around 99% of genes with mice

39

what is synteny

occurence of genes in the same order on a chromosome in 2 or more difference species

40

why do humans appear so different from apes?

different regulation of genes

41

what are many genetic diseases casued by

mutations

42

what are the three steps for isolating organelles

1. lyse the cells
2. seaparate organelles
3. use for further study

43

what are three techniques that can be used to disrupt the cell membrane

High speed blending
Sonication
Tissue homoginizer

44

what is simple diffusion

can move freely across a concentration gradient

45

what is facillitated diffusion

channels against a concentration gradiet

46

after lysis, the mix of suspended cellular components is called the _______

homogenate

47

What is sequential differential centrifugation

yeilds fractions of organelles that differ in mass and density

48

what is equilibrium density-gradient centrifugation

separates cellular components by density, more specific

49

how can cell components be identified after centrifugation

using organelle specific antibodies
or proteomic analysis to identify the protein components

50

How do organelle specific antibodies work

binding of the antibody provides and handle that helps identify and pruify the organelle

51

what are the three steps in proteomic analysis of organelles

1. isolation of organelle at high purity
2. digest with protease, determine pass and sequence using spectrometry
3.genome sequence for reference comparison

52

what does a hermatocrit do

it is the volume of blood cells that are packed by centrifugation, can detect anemia

53

what is the fluorescence activated cell sorter (FACS)

analyzes and selects cells from thousands of others and sorts them into a separate culture dish

54

what are monoclonal antibodies

antibodies that are made by identical immune cells that are all clones of a unique parent cell. They all bind to the same epitope

55

what is the definition of a drug

non-food compounds that cause physiological changes, by binding to targets

56

what dictates the outcome of a drug

the interaction between the drug and its target

57

WHat are the two types of strategies when it comes to drug development

Phenoytpe based approach
Target based approach

58

What is a phenotype based approach

start with asssays, add potential drugs and look for desirable change, then identifiy hits and targets

59

what is a target based approach

start with a target selected from a biochemical pathway that is linked to a specific disease state, produce enough to convert hits to leads

60

in light microscopy, resolution is limited by ____ _________

light wavelength

61

What is the coefficient for resolution and what does it mean?

D, the minimum distance between two distinguishable objects, smaller D value, the better the resolution

62

What is phase contrast microscopy

degree of darkness depends on the refractive index

63

what is differential interference contrast microscopy

thin optical section of the objects, detail in thicker objects

64

what are the three steps in preparing tissues for light microscopy

1. Fixing- chemical cross linking of proteins
2. Sectioning- cutting tissue into thin slices
3. Staining

65

What is an H+E stain

a stain in which hematoxylin binds to basic molecules wile eosin binds to acidic molecules

66

what is fluroescence microscopy

absorbs light at one wavelength and requires a dichroic mirror, uses stains

67

what is immunoflourescence microscopy

commonly used to detect the location of specific proteins, indirect because the flurorochrome is on the secondary antiobdy

68

what are some advantages to immunoflurescence microscopy

images for different wavelenghts, electronically merged images, secondary antibodes are cheaper

69

how else can antibodies be targeted to a protein of interest

make a recombiant protein that contains an epitope tag

70

what are two drawbacks to fluorescence microscopy

cant visualize thick specimens, blurring the image outside the plane of focus

71

what is confocal microscopy

collect many images and build up the final figure electronically, collect light from small areas at a time

72

what are the two different types of advance fluorescence microscopy technieques

FRAP (fluoresence recovery after photobleaching) and FRET (forster resonance energy transfer)

73

What is FRAP

uses high intensity light to pleach transmembrane protein until it no longer fluresces

74

what is FRET

measures the distance between fluorochromes, reveals protein interactions

75

What is electron microscopy and the 2 main types

short wavelength yields high resolution images, TEM and SEM

76

What is Transmission electron microscopy

image is derived from electrons that have passed through the specimen

77

what is scanning electron microscopy (SEM)

metal-shadowed material reveals the surface features

78

phospholipids are ampipathic-- what does this mean?

have both hydrophillic and hydrophobic properties

79

T or F: heat can affect the fluidity of a membrane

T!

80

with a small polar head, what shape does the layer form?

favour inverted micelles

81

with a similar polar head and hydrophoic regions what does the layer form?

pefers bilayers

82

with a bulky polar head and only one acyl chain, what does the layer form?

pefers micelles

83

What are the three types of phospholipids

phosphoglycerides, sphingolipids, and sterols

84

What are sphingolipids

class of compounds that are fatty acid derivatives of sphingosine

85

what are sterols

single polar hydroxyl with conjugated 4 ring hydrocarbon tail

86

where are phospholipids synthesized

cytosolic face of ER

87

where is sphingomylein synthesized

exoplasmic face of Golgi complex

88

what helps maintain fluidity in the lipid bilayer

cholesterol

89

are lysolipids more on the inner or outer leaflet

outer leaflet

90

where are excess lipids soterd

ER membrane

91

What are the 3 types of biological membranes

intergral, lipid anchored and periphrial proteins

92

What are some characteristics of intergral proteins

maily hydrophobic, 20-25 amino acids, positively charged with Arg _ Lys anchor

93

what are annular phospholipids

fatty acyl chains pack tightly against irregular hydrophobic outer face to form shell around the protein

94

what are transmembrane helices

guide assembly and stabilization of the bilayer core

95

what are lipid anchored proteins

protein bound covalently to one or more lipid molecules, lipid protein inserted to one leaflet of the membane

96

T or F: membrane proteins can flip flop across the membane

F

97

what are preiphrial membrane proteins

do not directly contact the hydrophobic core, invocled with associating cytoskeleton with plasma membrane

98

what do lipid binding motifs do

target periphrial proteins to the membane

99

What do detergents do

can be sued to solubilize lipids and membrane proteins

100

T or F: detergents are ampipathic

T

101

what is the difference between ionic and nonionic detergents

ionic deterents contain a charged group while nonionic detergents lack one

102

what do ionic detergents do

tend to denature proteins

103

what do nonionic detergents do

can extract transmembrane proteins in folded (Active) form

104

T or F: Detergents cannot form micelles

F, at high concentrations

105

What is the soluble portion of the chloroplast

the stroma

106

where does light energy capture occur in chloroplasts

thykaloid membrane

107

photosynthesis consists of both ____ and ____ reactions

light and dark

108

where do dark reactions occur

in the stroma

109

what happens in the dark reaction

uses NADPH and ATP to drive the endergonic process of sugar formation (hexose)

110

what are the 4 stages of photosynthesis

1. light absorption and O2 formation from H2O
2. Electron transport binding to reduce NADP + to NADPH and PMF generation
3. Synthesis of ATP
4. Carbon fixation, conversion of CO2 to carbohydrates

111

what does DCPIP do

it can replace the final electron acceptor in photosynthesis

112

how do cells synthesize new membranes

by the expansion of existing membranes

113

what is fatty acid biosynthesis needed for

phospholipids and sphingolipids

114

Saturated fatty acids have __ double bonds

no

115

what does fatty acid synthease do

generates saturated fatty acids from ocndensation of malonyl coA and acetyl CoA

116

what do cytosolic proteins do

transport fatty acids in the cytosol

117

What are the four types of lipoproteins in the bloodstream

Chylomicrons- transport triglycerides
VLDL (Very low density lipoproteins) synthesize and release by lliver, cells remove triglycerides becoming LDL
LDL- less healthy, deliver cholesterol to tissues
HDL- healthy, return excess cholesterol from tissues and bring back to liver

118

What are lipid bilayers impermeable to

ions, amino acids, water, sugars

119

T or F- without lipid bilayer, life would not be possible

T

120

simple diffusion rate is proportion to its _____ _______

concentration gradient

121

how do we measure simple diffusion

partition coefficeint, K. the higher the K the faster to cross a bilayer

122

What are the 3 types of transport proteins

Channels, transporters and ATP powered pumps

123

What do channels do

Form protein lined pathway though the membrane, allows hydrophillic molecules to avoid interacting with the interior

124

What do transporters do

selective, unipoerters, symporters and anitporters transport molecules up or down a concentration gradient

125

what do ATP-powered pumps do

use energy of ATP hydrolysis to transport up a chemical concentration gradient, primary active transport

126

Is the Na/K pup primary or secondary active transport

primary

127

Na/lysine symporter primary or secondary

secondary

128

K+ channel releases K+ ___ (up or down) gradient

down

129

Glucose is used as a substrate for ___

ATP

130

what is Vmax

the maximum transport rate

131

what does GLUT1 do

a uniporter of glucose

132

what happens to glucose inside the cell

enters glycolysis. phosphorylation rapid and constant

133

aquaporins increase water _____ of cellular membranes

permebillity