cell biology- lecture #7 Flashcards

1
Q

what are the 2 major types of cells

A

prokaryotes and eukaryotes

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2
Q

what does a prokaryotic cell consist of?

A

no nucleus
basically no compartments
no membrane bound organelles
ribosomes are scattered throughout its cytoplasm
cell is either archaea or bacteria

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3
Q

where is the prokaryotic cells DNA located?

A

in a region of the cytoplasm called the nucleoid region (region is not enclosed by a membrane)

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4
Q

what does a eukaryotic cell consist of?

A

has a nucleus
DNA is located inside the nucleus (bound by a double membrane)
have membrane bound organelles
multiple linear chromosomes
includes protists, fungi, plants and animals

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5
Q

what are common features in all cells

A

plasma membrane
chromosomes
cytoplasm
ribosomes

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6
Q

what is the difference between cytosol and cytoplasm?

A

internal components are suspended within the fluid
together cytosol and suspended components are the cytoplasm

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7
Q

what is an excellent target for antibiotics?

A

ribosomes

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8
Q

why do antibiotics target ribosomes?

A

selective toxicity
the drug can inhibit ribosome function without damaging the host

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9
Q

what is bigger, eukaryotes or prokaryotes?

A

eukaryotes are larger then prokaryotes (10x bigger)

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10
Q

what are the advantages and disadvantages to being small?

A

advantage: can reproduce fast, less likely to be seen and killed)
disadvantage: cells can only be so small before they lose ability to form key tasks

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11
Q

what are 2 important cell features?

A

plasma membrane forms the boundary of every cell
SA to volume ratio

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12
Q

what would happen if there was no plasma membrane?

A

there would be no cell because all the contents of the cell would spill out

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13
Q

what does the plasma allow to pass through from high to low concentration through passive diffusion?

A

vital nutrients, O2 and CO2

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14
Q

what would an increase in cell size mean for SA to volume ratio?

A

SA to volume ratio would decrease as the cell gets bigger
the smaller the cell the greater the SA to volume ratio
-high SA to volume ratio is ideal

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15
Q

where is DNA mainly found?

A

bulk of all DNA is in the nucleus

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16
Q

what is the nucleus enclosed by

A

nuclear envelope
(double membrane consisting of outer membrane, perinuclear space, inner membrane)

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17
Q

what do the pores do on the nuclear envelope?

A

regulate entry and exit of protein and mRNA

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18
Q

how is the shape of the nucleus supported?

A

lamina (microfilaments)

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19
Q

what are chromosomes? what is chromatin?

A

long segments of DNA complexed together with protein
DNA and proteins together is chromatin

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20
Q

what do the proteins do on the chromosomes?

A

organizes DNA creating a more compact structure

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21
Q

what is the number of chromosomes dependent on? how many do we have in comparison to dogs?

A

dependent on species and class of the cell
humans have 46 chromosomes (diploid cells)
humans have 23 chromosomes (haploid cells)
dogs have 78 chromosomes (somatic cells)
dogs have 39 chromosomes (sex cells)

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22
Q

when a cell isn’t dividing what are chromosomes doing? when a cell is dividing what are chromosomes doing?

A

uncoiled and active when a cell isn’t dividing
condensed and easily visible during cell division

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23
Q

when is the nucleolus prominent?

A

when the cell isn’t dividing

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24
Q

what happens to the nucleolus when the cell is dividing?

A

the nucleolus disappears

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25
Q

what is the nucleolus made up of? what kind of membrane does it have?

A

made of proteins and RNA
does not have a membrane

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26
Q

how much of the nucleus is the nucleolus?

A

about 25% but there can be more then one nucleolus

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27
Q

process of RNA to protein synthesis

A

RNA is made in the nucleus (from DNA)
exported through nuclear pores
to the cytoplasm
in the cytoplasm it will be used by the ribosome to synthesize protein

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28
Q

what is the nucleolus main function?

A

to reassemble RNA and combine it with proteins, results in an incomplete ribosome

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29
Q

what is the ribosome made up of?

A

rRNA and protein

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30
Q

what are ribosomes always responsible for?

A

protein synthesis

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31
Q

if a cell synthesizes large quantities of protein what will it contain? and what will also be more important?

A

more bound ribosomes (many ribosomes)
nucleolus will also be more important

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32
Q

where are the 2 locations ribosomes exist?

A

free in the cytoplasm
attached to the rough ER

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33
Q

what do ribosomes create when they’re free in the cytoplasm?

A

create proteins to be used within the cell

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34
Q

ribosomes attached to the ER also make proteins but where are these proteins destined to go? ___,___,___

A

inserted into membranes
packaged into organelles
secreted from the cell (exocytosis)

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35
Q

what has larger ribosomes, prokaryotes or eukaryotes?

A

eukaryotic cells (80s ribosome)
prokaryotic cells have smaller 70s ribosomes

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36
Q

what is needed for ribosome synthesis?

A

RNA

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37
Q

what does the endomembrane system consist of? (6)

A

nuclear membrane (envelope)
lysosomes
vacuoles
endoplasmic reticulum
golgi apparatus
plasma membrane

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38
Q

what is the endoplasmic reticulum connected to?

A

nuclear membrane

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39
Q

what does the smooth ER do? ___,___,___

A

makes lipids
detoxifies drugs
stores calcium ions

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40
Q

how does the smooth ER increase drug tolerance?

A

the more drugs that are consumed the more ER will be produced, increasing tolerance to ALL drugs (not specific)

41
Q

why is it called the rough ER?

A

“rough” because ribosomes are on the surface giving it a rough appearance

42
Q

what is the rough ER responsible for?

A

Produce more membrane phospholipids which are then inserted into the membrane

43
Q

what is the process of packaging a secretory protein from the rough ER (6 steps)

A

polypeptide is synthesized by a bound ribosome
then inserted into the rough ER via a protein pore
polypeptide folds into its final shape
sugar chain is added creating a glycoprotein
packaged into transport vesicle, transport vesicle buds off
travels to golgi apparatus

44
Q

when the transport protein gets to the golgi apparatus, what happens?

A

enters through the cis face
as it travels through the golgi it gets modified

45
Q

what would be some destinations of this transport protein?

A

exocytosis (leave through plasma membrane)
lysosomes (endocytosis)
cytoplasm (endocytosis)

46
Q

what kind of modifications happen to the transport protein?

A

adds phosphate, sulfate, carbohydrates

47
Q

what happens when phosphate is added to the protein?

A

phosphate has a (-) charge
it serves as an identification tag and can change the behavior

48
Q

what is the main function of the golgi apparatus?

A

sorts and modifies proteins that have arrived from the rough ER

49
Q

what are the lysosomes known as?

A

garbage collector

50
Q

what do lysosomes contain?

A

digestive enzymes

51
Q

what do digestive enzymes break down?
what can they do after being broken down?

A

lipids, carbohydrates and proteins
can be used by the rest of the cell

52
Q

what makes lysosomal enzymes?

A

made by the rough ER then modified by the golgi apparatus

53
Q

what is tae-sachs disease?

A

no lipid digesting enzyme, therefore, can’t breakdown fat
fat accumulates in the brain and causes impaired function

54
Q

what kind of impaired function can tae-sachs lead to?

A

decreased destruction of bacterial cells

55
Q

what can lysosomes fuse with?

A

vacuoles containing food
vacuoles containing bacteria
damaged organelles

56
Q

what are vacuoles?

A

membrane bound sacs acquired from the ER and golgi apparatus

57
Q

what are the 3 main function of vacuoles?

A

store food, transport solutes and remove excess water from the cell

58
Q

what is a central vacuole and what cell are they located in?

A

central vacuole is like a pantry to store anything (sap, necessary nutrients, waste products, excess ions…)
found in plant cells

59
Q

what is the mitochondria dependent on?

A

the quantity of metabolism occuring

60
Q

what is mitochondrias function?

A

cellular respiration in all eukaryotic cells

61
Q

cells that need more energy will have more what?

A

mitochondria
because the mitochondria produces energy

62
Q

what is some thing that is unique to the mitochondria?

A

has 2 membranes in order to keep organized
this creates a outer membrane, intermembrane space and inner membrane

63
Q

why are mitochondria able to synthesize more energy (ATP)?

A

cristae has many folds which increases SA
this allows for a greater ability to synthesize energy

64
Q

what is mitochondrias temperature and why?

A

around 50 degrees (10 degrees more then our body temp)
this is because metabolism produces heat

65
Q

between the mitochondria and chloroplasts, which one consumes oxygen and which releases oxygen?
which one stores energy and which releases energy?

A

mitochondria consumes oxygen and releases energy
chloroplasts release oxygen and store energy

66
Q

what is chloroplasts main function?

A

photosynthesis in eukaryotes

67
Q

what kind of membrane do chloroplasts have?

A

double membrane

68
Q

what is the stroma? what does it contain?

A

fluid in the chloroplast
contains enzymes, DNA and ribosomes

69
Q

what are stacked inside the chloroplast interior?

A

thylakoids are stacked sacks
these stacks are called granum

70
Q

what do chloroplasts do in high light conditions?

A

they move to the outskirts of the cell to not receive too much light

71
Q

where are pigments found in chloroplasts?

A

thylakoid membranes

72
Q

where are chloroplasts concentrated in green plants?

A

in the leaves and accumulate in the mesophyll (middle tissue of the leaf)

73
Q

how does CO2 enter and O2 exit the chloroplast?

A

through the pores called the stomata

74
Q

what does endosymbiont mean?
what were endosymbiont?

A

small cell living within a larger cell
mitochondria and chloroplasts were originally prokaryotes that began living inside of larger cells according the the endosymbiont theory

75
Q

mitochondria share many structures with what?

A

bacteria

76
Q

what do enzymes inside peroxisomes do?

A

form hydrogen peroxide
another enzyme inside converts H2O2 into water and oxygen

77
Q

where are peroxisomes found?

A

cytoplasm of animal and plant cells

78
Q

what kind of membrane do peroxisomes have?

A

single membrane

79
Q

what happens if peroxisome packets let loose?

A

the toxic insides will cause damage to other parts of the cell

80
Q

when are peroxisomes used?

A

fatty acid breakdown and detoxification

81
Q

what are the 2 main function of the cytoskeleton?

A

provides structural support and assist movement of organelles

82
Q

what are the 3 proteins the cytoskeleton consists of?

A

microfilaments, intermediate filaments, microtubules

83
Q

what is the structure of microfilaments?

A

2 intertwined strands of actin, made to withstand force

84
Q

where are microfilaments located and what is their main function?

A

located right beneath the plasma membrane
provides support of the cell shape

85
Q

what is the structure of the intermediate filaments?

A

fibrous proteins coiled into cables

86
Q

what is the function of intermediate filaments?

A

anchor organelles in place

87
Q

what is the structure of microtubules?

A

hollow tubes consisting of tubulin

88
Q

what are the main functions of microtubules?

A

shape and support the cell
moves organelles

89
Q

what does the plant cell wall protect agaisnt?

A

osmotic rupture

90
Q

what is thicker, plasma membrane or the plant cell wall?

A

plant cell wall

91
Q

how are adjacent cells connected to one another?

A

plasmodesmata (membrane bound channels filled with cytoplasm)

92
Q

what is the middle lamella?

A

thin sticky layer that glues adjacent cells together
(where the intersection of the plant cells are)

93
Q

some plant cells have a secondary cell wall, why?

A

for protection and support

94
Q

what is the extracellular matrix mainly composed of?

A

glycoproteins mainly collagen in animals

95
Q

what is the extracellular matrix?

A

the part outside the cell, blood for example

96
Q

what is the extracellular matrix composed of?

A

glycoprotein
elastin fibres
proteoglycan
interstitial fluid
collagen fibres

97
Q

do we want gaps between cells? why or why not?

A

don’t want gaps
-an element of control

98
Q

how are plant cells connected to one another? how are animal cells connected to one another?

A

plant cells: plasmodesmata and middle lamella
animal cells: desosomes

99
Q

how much of your body is collagen?

A

1/3 of your body is collagen