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general biology I > lectures 5/6 cell & osmosis > Flashcards

lectures 5/6 cell & osmosis Flashcards

cell membrane, manufacturing & energy; osmosis; intra/extra cellular features and transcription

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1
Q

which domains are prokaryotic?

A

bacteria and archaea

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2
Q

what defines prokaryotes (3)?

A

they are small, bacteria contains a single chromosome composed of double stranded DNA (survival genes), have a cell wall

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3
Q

what are some characteristics of prokaryotic genetics (3)?

A

no nucleus - has a nucleoid region (DNA is “thrown in a corner”)
some bacteria possess plasmids
DNA is transferred between bacterial cells by pili

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4
Q

what are plasmids?

A

non essential genes that exist/reproduce independently of chromosome

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5
Q

what are some characteristics of eukaryotic cells (4)?

A

domain eukarya, big, round/squarish, nucleus, some do not have cell walls

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6
Q

why is cell size limited (3)?

A

can’t be too small (hold DNA and organelles), can’t be too big (boundaries function as selective barriers for oxygen, waste, etc.), there is only so much surface area for traffic - at a certain point will become to small for cells increased volume

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7
Q

phospholipids (4)

A
  • form micelles when dumbed in water
  • amphipathic
  • can form a bilayer
  • phospholipids can move slightly
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8
Q

describe the structure of a phospholipid?

A

hydrophillic head (choline, phosphate, glycerol) and hydrophobic tail (fatty acids)

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9
Q

who proposed the fluid mosaic model?

A

Singer & Nicholson

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10
Q

what is the fluid mosaic model (5)?

A
  • membrane is fluid structure
  • proteins embedded in membrane/on it
  • phospholipids make up membranes
  • membrane is built by endoplasmic reticulum (ER)
  • proteins in membrane have hydrophobic regions
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11
Q

what are integral proteins?

A
  • amphipathic & must be properly oriented
  • pass into non-polar region of phospholipid layer
  • placement maintained by polar vs non polar section and cytoskeleton
  • proteins can allow specific polar molecules to pass through
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12
Q

where do you find integral proteins?

A

proteins that go through cell membrane

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13
Q

what are peripheral proteins?

A
  • never cross membrane
  • attached to integral proteins or polar surface of membrane
  • decrease in temperature will solidify membrane more and proteins won’t function
  • surface proteins inside differ from outside
  • have directional orientation
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14
Q

where do you find peripheral proteins?

A

only on one side of the membrane

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15
Q

how do proteins work in the membrane?

A

they are a channel for different substances to pass through - they will change shape to allow for these substances which pushes on phospholipids

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16
Q

can you speed up/down the chemical going through the gate?

A

no you can’t - if you want more of a chemical, you need to add proteins to the cell membrane. if you want less of a chemical, you need to remove proteins from the cell membrane

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17
Q

how does the cell membrane stay together?

A

the phospholipids are bonded by hydrophobic reactions

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18
Q

what do we mean by fluidity in the cell membrane?

A

want to hold it together but you want it to move

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19
Q

cholesterol

A
  • helps membrane resist changes in fluidity
  • keeps phospholipids in place
  • prevents close packing of phospholipids
  • adding more cholesterol will make membrane more fluid
  • need a normal cholesterol level to function
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20
Q

how does cholesterol affect fluidity

A
  • more cholesterol, phospholipids can’t pack close together - unsaturated hydrocarbon tails = fluid
  • less cholesterol, phospholipids are more tightly packed together - saturated hydrocarbon tails = viscous
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21
Q

rules for transport

A

1- cell membranes don’t all look the same
2- can’t affect speed (speed up add protein, slow down remove protein)
3- inside doesn’t match outside

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22
Q

functions of transport proteins in cell membrane

A

polar molecules move through membrane proteins, very selective, some are like channels across the membrane, others change shape and hydrolyze ATP as energy

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23
Q

functions of enzyme proteins

A

so rxns can take place, form teams of enzymes for pathways, built into the membrane and are sometimes many enzymes together organized as a team

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24
Q

function of receptor proteins

A

outer surface of protein is used to bind a chemical messenger, can cause shape changes in protein, shape is very specific, different cells have different receptors

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25
Q

function of cell to cell recognition proteins

A

ID tags that are specifically recognized by other cells - all glycoproteins that identify type of cell (skin vs liver), species (human vs dog) or individual (me vs you). ex: blood types

sort cells into tissues and organs in embryo
vary among species/individuals

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26
Q

function of cell to cell anchor proteins

A

hold cells together with each other, can be mechanical or for communications, joined together so nothing is getting through

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27
Q

function of cytoskeleton anchor proteins

A

bonds to proteins, anchors keep cell shape and controls where proteins are put

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28
Q

list of cell membrane proteins

A

transport, enzymes, receptor binding sites, cell to cell recognition (ID tags), cell to cell anchors, cytoskeleton anchors

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29
Q

what two substances don’t require transport across membrane?

A

oxygen, carbon dioxide

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30
Q

what protein does water require to cross membrane?

A

aquaporin

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31
Q

what are the 2 basic types of transport across membrane?

A

passive and active

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32
Q

passive transport

A

free - no cost, two types: simple diffusion = no protein (oxygen, co2) or facilitated diffusion = needs a protein

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33
Q

active transport

A

costs energy (ATP) and needs a protein, moves AGAINST concentration gradient - goes UPHILL (LOW-HIGH)

essentially: paying for special protein with ATP to do something weird
ex: Na+/K+ pump

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34
Q

simple diffusion

A

always high to low concentration, driven by kinetic energy of molecules, no need for protein, more concentrated = faster diffusion (ex: oxygen, co2)

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35
Q

facilitated diffusion

A

through special membrane proteins - can show saturation: max speed = number of proteins available

needs a protein, can be a channel open all the time or that can open/close, substances move in one direction, obeys high-low concentration gradient

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36
Q

diffusion of water is called what?

A

osmosis

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37
Q

osmosis

A

doesn’t need energy, water is diffused across a semi-permeable membrane so that concentration INSIDE = OUTSIDE, solute cannot cross but solvent can, concentration of solutions refers to concentration of solute in water (high solute conc, = low water conc.)

WATER ALWAYS MOVES HIGH TO LOW

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38
Q

what is equal concentration called?

A

isotonic

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39
Q

what happens to cells in hypertonic solution? (concentrated)

A

cells shrivel up and die

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40
Q

what happens to cells in hypotonic solution?

A

cells lyse (explode) and die

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41
Q

hypertonic

A

more concentrated

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42
Q

hypotonic

A

less concentrated

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43
Q

isotonic

A

equal concentration

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44
Q

plasmodyzed

A

cells become shrunken

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45
Q

lysed

A

cells explode or break open

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46
Q

why can’t plant cells explode?

A

they have cell walls

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47
Q

explain animal cells in different types of solution

A

hypotonic solution - lysed
isotonic solution - normal
hypertonic solution - shriveled

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48
Q

explain plant cells in different solutions

A

hypotonic solution - turgid (normal)
isotonic solution - flaccid
hypertonic solution - plasmolyzed (plant dead - not coming back)

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49
Q

endomembrane system

A
  • seperates functions in cell

- not all membranes involved are the same

50
Q

what does the endomembrane consist of?

A
  • organelles: nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vesicles, vacuole, plasma membrane
51
Q

what folds the proteins?

A

organelles

52
Q

if ribosomes and mitochondria aren’t a part of what?

A

endomembrane system

53
Q

where does everything start?

A

starts at nucleus and radiates outwards - no quality control (can’t go back to fix mistakes)

54
Q

“manufacturing” steps

A

1- nuclear envelope connected to rough ER which is continuous with smooth ER
2- membranes/proteins produced by ER flow as transport vesicles to golgi
3- golgi pinches off transport vesicles that give rise to lysosomes and other special vesicles
4- lysosomes are available to fuse with vesicles for digestion
5- transport vesicle carries proteins to plasma membrane
6- plasma membrane expands from fusion of vesicles & proteins are secreted from cell

55
Q

nucleus

A
  • largest organelle
  • dark when stained (under microscope)
  • holds DNA (chromatin btwn division, chromosomes during division)
  • cell division (makes identical daughter cells)
  • stores info/blue prints for making & running cell
  • required for long term survival of cells
56
Q

explain how DNA is contained in the nucleus

A

the DNA is coiled up in the form of chromatin (later on chromosomes) and holds all the blueprints for the cell, where everything is set up

57
Q

what is the name of the little dots on nucleus?

A

ribosomes - involved in making proteins

58
Q

nuclear membrane

A
  • double membrane called nuclear envelope
  • has pores for communication, to pass molecules/RNA/proteins/ribosomal subunits
  • only present during interphase (cell not dividing)
59
Q

nuclear lamina

A

protein filaments that maintain shape

60
Q

nucleolus

A
  • dark area in nucleus
  • size and # varies
  • builds ribosomal subunits (recipe for ribosomes)
  • uses RNA
  • easy to access because we make so many ribosomes
61
Q

ribosomes

A
  • not a part of endomembrane system
  • make proteins
  • large and small subunit
  • no membrane (they are solid)
  • free (cytoplasm) bound (ER)
62
Q

endoplasmic reticulum

A

folded membrane - creates cavity separated from cytoplasm

two types: rough (has ribosomes, folds proteins) smooth (no protein, deals with lipids)

63
Q

rough ER

A
  • makes, puts together & exports proteins, glycoproteins and membrane proteins
  • surface facing cytosol is studded with ribosomes
  • stores glycoproteins and proteins in RER cavity until exported
  • transitional - between RER & SER produces vesicles
  • essentially, protein folding
64
Q

smooth ER

A
  • looks like RER but without ribosomes
  • makes/stores/exports lipids
  • detoxifies poisons/drugs
  • stores carbs and glycogen (liver)
  • exact specialization varies with each cell
  • enzymes that make lipids are rich in ER (ex: sex hormones, liver cells)
  • always more RER than SER
  • amount of SER with vary between individuals
65
Q

golgi complex

A
  • modification, storage, shipping of products
  • manufactures polysaccharides in plant walls
  • step after ER
  • sacs called cisterna for transport
  • polarity because it had shipping and receiving sides
  • receiving = cis = next to ER
  • shipping = trans = next to cell membrane
  • molecules carried from one cisterna to the next
  • add signals to vesicle products to direct where to go
66
Q

explain golgi body

A

essentially, its the “case” of the phone - everything is put together and works, receives proteins from ER and ships them to next step

67
Q

which organelles are responsible for manufacturing?

A

nucleus, nuclear membrane, nuclear lamina, nucleolus, ribosomes, RER, SER, golgi complex

68
Q

vesicles

A

temporary, for movement within cell

  • endocytosis: enter
  • exocytosis: exit
69
Q

vacuole

A
  • membrane sac (larger than vesicle)

- for storage

70
Q

animal vacuoles

A
  • food vacuole: intake by phagocytosis

- contractile vacuole: pump out water

71
Q

plant vacuole

A

central vacuole: stores molecules (toxins, proteins, inorganic ions, pigments), develops osmotic pressure

72
Q

lysosomes

A
  • responsible for breakdown
  • digestive compartments
  • sac with hydrolytic enzymes used to digest
  • enzymes work best at pH 5 (pumps H+ in to lower pH)
  • if lysosome breaks, enzymes are weak since cell pH = 7
  • made by ER and golgi body
73
Q

phagocytosis

A

lysosome digesting food (addition of H)

74
Q

lysosomes - protists vs animals

A

protists - used to eat food

animals- clean up (janitor), immune system, development

75
Q

autophagy

A

lysosome engulfs broken organelle (clean up)

76
Q

macrophages

A
  • animals have special type of lysosome that destroys invaders
  • part of immune system
77
Q

programmed destruction

A

lysosomes are used for making developmental changes (ex: tadpole to frog, human embryo - hands and feet)

78
Q

organelles for transport/breakdown/storage

A

vesicles, vacuoles, lysosomes,

79
Q

energy use

A

two types: autotrophs and heterotrophs

80
Q

autotrophs

A

make their own energy from inorganic sources

81
Q

heterotrophs

A

digest other organisms for energy

82
Q

animals are chemoheterotrophs - what does that mean?

A

digest other organisms to get their biomolecules

83
Q

subtypes of autotrophs

A

photoautotrophs, chemoautotrophs

84
Q

photoautotrophs

A

energy source: light
carbon source: co2
ex: plants

85
Q

chemoautotrophs

A

energy source: inorganic chemicals
carbon source: co2
ex: certain prokaryotes

86
Q

heterotrophs subtypes

A

photoheterotrophs, chemoheterotrophs

87
Q

photoheterotrophs

A

energy source: light
carbon source: organic compounds
ex: certain prokaryotes

88
Q

chemoheterotrophs

A

energy source: organic compounds
carbon source: organic compounds
ex: animals, fungi, some plants, many prokaryotes and protists

89
Q

plant/animal mitochondria

A
  • amount depends on need (ex: muscle has many, fat has few), you always have more than one
  • site of cellular respiration (why we have lungs)
  • needs o2
  • enclosed by two membranes (smooth outer, folded inner)
  • mitochondria have their own DNA (circular)
  • mitochondria are technically bacteria we absorbed into our system
90
Q

what is our #1 energy source?

A

adenosine triphosphate ATP

91
Q

where do we get ATP?

A

glucose

92
Q

how do we use ATP

A

body uses ATP as an immediate source of energy, must be made before being used - energy gained by adding & removing phosphate

ex: ATP sits in our bodies - breaking a phosphate bond gives a burst of energy. then we stick it back on for more energy and so on. never remove more than one P. we use mitochondria to put it back together

93
Q

ATP cycle

A

“spend energy to make energy”
1 - ATP hydrolosis to ADP+P yields energy
2- use energy for work (sports, anything really)
3- digest glucose
4- mitochondria uses that energy and ATP synthesizes from ADP+P

94
Q

chemical equation for cellular respiration

A

C6H12O6 +6 O2 –> 6 CO2 + 6 H20
glucose + oxygen –> carbon dioxide + water

30 ADP + 30P = 30 ATP

95
Q

where are glucose levels regulated?

A

pancreas and liver

96
Q

how do we burn energy?

A

1 - carbs (sugars) –> glycolysis (default path)
2- fats (glycerol, fatty acids) –> glycolysis
will not burn fat unless there are no carbs left
3- proteins (amino acids) –> glycolysis and NH3
can be burned but creates toxic biproduct - only happens when there is so little food intake you burn muscle (severe anorexia, wartime starvation) not sustainable for long.

97
Q

how to plants get energy?

A

photosynthesis - amount of mitochondria and chloroplasts will vary, choloplasts (chlorophyll) is what makes plants green

98
Q

photosynthesis

A

requires chloroplasts, light, water and co2
it is the process by which plants make sugars
THEY NEED THE MITOCHONDRIA TO USE THOSE SUGARS

99
Q

photosynthesis equation

A

6 CO2 + 6H20 –> C6H12O6 + 6O2

100
Q

how do plants get their green colour?

A

chloroplast absorbs every spectrum of light except green

101
Q

extra mitochondria details

A

made independently - have their own DNA (like bacteria), RNA, ribosomes and proteins
only increase in number by self-division (like bacteria)
mitochondria are maternally inherited

102
Q

how did mitochondria and chloroplasts evolve?

A

they evolved independently through endosymbiosis

103
Q

why do we, humans, not have chloroplasts

A

animals were invaded once - mitochondria
plants were invaded twice - mitochondria and chloroplasts

both are bacteria absorbed into cells - every cell has it

104
Q

who has only mitochondria?

A

animals, fungi - therefore, we have to eat things to survive

105
Q

who has both mitochondria and chloroplasts?

A

protists and plants

106
Q

extracellular matrix (ECM) - outer surface of cell

A
  • support, adhesion (sticking cells together), movement, recognition, regulation
  • has glycoproteins on outer surface of cell
  • viruses (ex: covid-19) use ECMs to recognize host cells
  • found in most tissues (abundant in connective tissues)
  • composed of glycoproteins and fibrous carbohydrate molecules
107
Q

what are examples of glycoproteins and what do they do?

A

glycoproteins provide support
elastin - elastic, resists change
collagen - plastic surgery

108
Q

collagen

A

most abundant protein of ECM
present in the dermis of skin
provides strong, durable support for overlying epidermis

109
Q

how are cells attached to the ECM?

A

by special ECM glycoproteins, ex: fibronectin
fibronectin is bound to cell-surface receptor proteins called integrins, which are built into membrane
within cytoplasm, integrins are bound to microfilaments

110
Q

ECM of animals

A
  • integrins are positioned to transmit signals between ECM and cytoskeleton (they integrate change outside and inside cell)
  • through integrins, ECM regulates a cell’s function
  • microfilaments are how integrins transmit signal to nucleus
111
Q

cytoskeleton

A

network of fibers in cytoplasm used for support and movement; motor proteins

112
Q

microtubules (movement)

A
  • made of alpha and beta tubulin and covered by plasma membrane
  • centriole/centrosome/spindle fibers: used for cell division
  • cilia structure and flagella (sperm): core of microtubules, used for locomotion & moving liquid
  • used as railroad for vesicles to move along (ATP is involved so it costs something)
113
Q

ex of microtubules

A

sperm moving along, mucus moving down

all tubes are filled with mucus, which it moved down by little hairs (cilia)

114
Q

microfilaments

A
  • made of actin and myosin filaments
  • deform & shape change (angle & push microfilaments to ooze around)
    ex: muscles (pair of cylindrical structure - slide into each other when contracting), amoeba (sperm cells), plants (cytoplasmic streaming - circulates in cell)
115
Q

intermediate filaments

A
  • structural support
  • tension bearing
  • made of keratin, each type slightly different
  • fix position of organelles
  • reinforce cell shape
  • protection (hair, nails, feathers)
  • not a baggy: jelly filled sphere where everything is where it needs to be
116
Q

cell-to-cell attachment

A

cells are attached together by 2 proteins: cadherins or integrins

117
Q

cell junctions

A

tight junctions, desmosomes, gap junction

118
Q

tight junctions - NO SPACE BETWEEN CELLS

A

as if cells are sewn tightly together, any transport must be through special molecule, prevents extra cellular fluid from circulating between cells

119
Q

desmosomes - STRENGTH

A

button like rivets, attach two plasma membranes with intermediate filaments, very strong - think muscles

120
Q

gap junction - COMMUNICATION

A

permits materials to transfer directly from one cell to another (in plants, plasmodesmata)

general biology I (20 decks)

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