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cells to systems > cell structure, organelles,ionic homeostasis and membrane transport > Flashcards

cell structure, organelles,ionic homeostasis and membrane transport Flashcards

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1
Q

what are prokaryotic cells?

A

simple cells that have no nucleus and are mostly unicellular bacteria

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2
Q

what are eukaryotic cells?

A

complex cells that have a nucleus and sub cellular structures
-all fungi, plants and animals are eukaryotes

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3
Q

what is the plasma membrane?

A

-a semi permeable regulator that covers and protects the cell and regulates what comes in and out and links to other cells and helps identify cells to other cells

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4
Q

what do lipids in the plasma membrane do?

A

acts as a barrier to certain polar substances
-it has a fluid mosaic structure

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5
Q

what do ion channels do?

A

-allow specific ions to move through water-filled pores and to move down their electrochemical gradients

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6
Q

what do carrier proteins do?

A

-carries specific substances across the membrane by changing shape e.g amino acids needed to synthesise new proteins enter body cells via carriers

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7
Q

what do receptors do?

A

-recognises specific ligands and alters cells functions

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8
Q

what do enzymes do?

A

-catalyses reactions in or outside cells

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9
Q

what do linkers do?

A

-anchors filaments inside and outside the plasma membrane providing stability for the cell

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10
Q

what do glycoproteins do?

A

distinguishes cells from other cells

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11
Q

what is the selective permeability of the plasma membrane?

A

-Small,neutrally charged,lipid soluble substances can freely pass,however water is highly polar but still is permeable,due to its size so can easily pass through the bilayer

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12
Q

what does facilitated diffusion require?

A

-does not require energy but requires a specific channel or carrier molecule ,particles spread from high conc to low conc

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13
Q

what does diffusion depend on?

A

-Amount of substance
-Conc gradient
-Temp
-Surface area
-Diffusion distance

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14
Q

state the ion gradients for different ions

A

-Mg2+-inside 35mM ,outside 2mM
-Ca2+inside 0.2mM ,outside 5mM
-Na+ inside 10mM,outside 140mM
-Cl- inside 4mM,outside 100mM

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15
Q

what ways to do the Na2+ and K+ ions move?

A

-Na2+ always wants to move in and K+ always wants to move out

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16
Q

what are the factors that affect the mechanisms of gating(opening and closing)?

A

-Voltage
-Ligands
-Temp
-ph
-Mechanical stress

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17
Q

what do transporters do?

A

-allows passive movement of solutes across the membrane down their concentration e.g GLUT1 (a glucose transporter)

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18
Q

describe the process transporters work by…

A

-Binds to carrier at the membrane side where the conc is highest
-The protein changes shape
-The solute is released to the other side
this process is conc-gradient dependent

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19
Q

what is osmosis?

A

the passive net movement of water through a partially permeable membrane from area of high conc to low conc and is opposed by hydrostatic pressure

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20
Q

when does osmosis occur?

A

when a membrane is permeable to water but not solutes

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21
Q

what are the 2 ways water can pass through a plasma membrane?

A

-by simple diffusion through the lipid bilayer
-through aquaporins

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22
Q

what is tonicity?

A

-a measure of a solutions ability to change the volume of cells by altering their water content
-this happens due to semi-permeable membranes having separate fluid compartments so osmosis can occur between any fluid space

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23
Q

give examples of primary active transport mechanisms

A

-sodium potassium pumps

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24
Q

what do primary active transport mechanisms (pumps) do?

Study These Flashcards
A

-these pumps are required for solutes that need to move against their conc gradient
-it gets the energy it requires through the hydrolysis of ATP
-these pumps are essential for maintaining cell volume and ionic gradients, responsible for setting resting membrane potential and generating action potentials.

25
what are secondary active transport mechanisms?
-mechanisms that use the energy stored in Na+ or H+ conc gradients to drive the transport of solutes against their conc gradients -these gradients have been made already by primary active transport
26
what energy does p-transport mechanisms use?
-they indirectly use the energy from ATP hydrolysis
27
what do anti porters and symporters do?
-antiporters carry two substances across the membrane in the opposite direction -symporters carry two substances across the membrane in the same direction
28
what are the different parts of a nucleus?
-nuclear envelope -nuclear pores -nucleolus
29
what is the nuclear envelope?
-a double membrane that separates the nucleus from the cytoplasm
30
what are nuclear pores?
-numerous openings in the nuclear envelope, it controls the movement of substances between the nucleus and the cytoplasm
31
what does the nucleolus do?
produces ribosomes
32
what is the mitochondria?
-organelle that generates ATP by aerobic respiration, it is found in active cells such as th muscles,liver and kidneys, the cells replicate during times of increased cellular demand or before cell division -it is important for apoptosis (cell death)
33
what is the cristae and the matrix ?
cristae-a structure of the mitochondria which is a series of folds in the inner membrane -matrix-the large central fluid filled cavity
34
what do proteasomes do?
-continually destroy needed,damaged proteins, they are found in the cytosol and the nucleus and contain many protease enzymes
35
what do peroxisomes do?
-detoxify several toxic substances such as alcohol using oxidase enzymes and there is an abundance in the liver
36
what are lysosomes?
-vesicles that form the golgi complex and contain powerful digestive enzymes, they have a low internal pH due to H+ -ATPase
37
what is the golgi complex?
-3-20 flattened, membrane sacs called cisternae -it modifies, sorts and packages proteins for transport to different destinations -proteins are transported by different vesicles (secretory, membrane and transport)
38
what is the endoplasmic reticulum?
-a network of membrane bound flattened sacs
39
what is the rough endoplasmic reticulum (RER)?
-it is connected to the nuclear envelope and is a series of flattened sacs, he surface is studded with ribosomes and produces proteins
40
what is the smooth endoplasmic reticulum (SER) ?
-a network of membrane tubules, it ha son ribosomes, it synthesises fatty acids and steroids and detoxifies certain drugs (alcohol, pesticides & carcinogens)
41
what is the ribosomes?
-site of protein synthesis that contains large amounts of rRNA, attached to the outer surface of the nuclear membrane and endoplasmic reticulum
42
what is the cilia?
-short,hair-like projections from the cell surface, they move fluids along a cell surface
43
what is the flagella?
-longer than cilia,they move an entire cell
44
what is the cytoskeleton?
-a network of protein filaments throughout the cytosol that provide structural support for the cell, there are three types: microfilaments,intermediate filaments, microtubules
45
what are microfilaments?
-includes actin/myosin and generates movement and mechanical support
46
what are intermediate filaments?
filaments that stabilise organelle position and attach cells together
47
what are microtubules?
-hollow tubes that consists of tubular which forms microtubules together, it determines cell shape and movement of organelles and vesicles
48
what is the cytoplasm?
-an organelle that consists of cytosol -it is the site of many reactions and energy is released by these reactions and the reactions provide what is needed for cell maintenance,structure,function and growth
49
what is cytosol?
an intracellular fluid surrounding the organelles
50
what is exocytosis?
a process that releases materials from cells, it is important for neurotransmitter signalling
51
what is bulk phase endocytosis?
-a process that does not involve receptor proteins -there is a transport of extracellular fluid -the plasma membrane folds inwards
52
what is phagocytosis?
-a form of endocytosis where cells engulf large particles such as viruses,bacteria or dead cells -two main types of phagocytes are macrophages and neutrophils
53
what happens in receptor-mediated endocytosis?
-receptor protein recognizes and binds to a specific particle e.g cholesterol containing low density proteins (LDLs),vitamins,antibodies,hormones -clathrin molecules form a basket like structure on the cytosolic side of a membrane forming a vesicle -the vesicle fuses with the endosome and receptors are recycled -vesicles bud off the endosome to transport particles that are required into the cell - the LDLs are broken down in lysosomes-cholesterol,amino acids and fatty acids -the cholesterol is used to rebuild membranes or make steroid hormones
54
what is a vesicle?
-a small spherical sac formed by budding off from a membrane
55
what is endocytosis?
a process that moves materials into a cell in a vesicle
56
describe the process of endocytosis...
-receptor-mediated endocytosis -phagocytosis -bulk-phase endocytosis (pinocytosis)
57
what is transcytosis?
a combination of endocytosis and exocytosis
58
what does vesicular transport require?
-ATP

cells to systems (14 decks)

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