Cells and membranes Flashcards

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1
Q

What is the difference between cell death through necrosis and apoptosis?

A

Apoptosis is physiological, individual cells die over hours and cause no damage/inflammation to adjacent cells;
Necrosis is pathological, groups of cells die over days, their membranes burst and cell contents cause damage and inflammation to adjacent cells

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2
Q

What is the difference between pluripotent and multipotent stem cells?

A

Pluripotent can turn into all cell types in the body, multipotent can turn into all cell types in certain tissues

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3
Q

What characteristics separate prokaryote cells from eukaryote cells?

A

Prokaryotes have no nuclear membrane, no mitochondria and do not have organelles surrounded by membranes

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4
Q

Name five different classes of cell-cell junctions

A
Gap junctions
tight junctions
desmosomes (intermediate keratin filaments)
adherens junctions (actin filaments)
hemidesmosomes
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5
Q

What different types of structures make up the cytoskeleton?

A

Microfilaments (actin)
intermediate filaments (fibrous keratin)
microtubules

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6
Q

What are the main characteristics of mitochondria?

A

their own DNA, ribosomes and proteins
self replicate
an inner membrane arranged in cristae
produce energy from breakdown of molecules

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7
Q

What are the main characteristics of the nucleus?

A

Contain DNA (heterochromatin or euchromatin), membrane bound with pores

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8
Q

What are the structural and functional differences of the smooth and rough endoplasmic reticulum?

A

RER - has ribosomes on its surface, it’s mainly involved in protein synthesis (RNA translation into amino acid sequences)
ER - mostly involved in breakdown of molecules (eg drugs) and synthesis of some molecules (eg lipids)

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9
Q

What is the role of lysosomes?

A

They contain digestive enzymes for breakdown of cell’s or foreign molecules

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10
Q

What are the 10 main elements of life?

A

H - hydrogen, O - oxygen, N - nitrogen, C - carbon, Na - sodium, S - sulphur, P - phosphorus, Cl - chloride, K - potassium, Ca - calcium

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11
Q

List the five chemical reaction of life

A
Reduction/oxidation
Making/breaking C-C bonds
Group transfers
Internal rearrangements
Condensation/hydrolysis
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12
Q

What do oxidation and reduction mean respectively?

A

Oxidation Is Loss of electron (OIL)

Reduction Is Gain of electron (RIG)

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13
Q

define configuration and conformation of a molecule

A

configuration - fixed arrangement of molecules, can only be altered by breaking and reforming bonds
conformation - specific arrangement of molecules, which can change depending on their interaction without making/breaking bonds

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14
Q

what ties together nucleic acid monomers?

A

covalent phosphodiester bonds

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15
Q

what are the purines in nucleic acid and their characteristics?

A

Guanine
Alanine
double ring bases

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16
Q

what are the pirimidines in nucleic acid and their characteristics?

A

thymine
uracil
cytosine
single ring bases

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17
Q

what is the chiral centre of a molecule?

A

the center of an asymmetric molecule

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18
Q

what are features of glucose that causes it to have reducing and non-reducing ends?

A

when polymers are made glucose sits in ring shape (non reducing)
the end group of the molecule is linear (ALDEHYDE) and reducing

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19
Q

what is the concept of energy coupling in cells?

A

coupling an anabolic with a catabolic reaction, to use energy from spontaneous reaction to fuel an energetically unfavourable reaction

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20
Q

what do endergonic and exergonic reactions mean?

A

exergonic - catabolic reaction

endergonic - anabolic reaction

21
Q

what is the dissociation constant for water and for OH and H respectively?

A

water: 1x10^-14
OH: 1x10^-7
H: 1x10^-7

22
Q

what is the definition of weak and strong acids/bases?

A

strong - fully dissociate

weak - partially dissociate

23
Q

what is the pH of water normally?

A

pH = pOH = 7

24
Q

is water a polar or non-polar compound, and why?

A

polar compound, because O is negative and H is positive

25
Q

are oxygen and carbon dioxide polar or non-polar, and how does this affect their solubility?

A

both non-polar

poor water solubility, have to be carried by hemoglobin and bicarbonate

26
Q

which molecules can form hydrogen bonds?

A

any electronegative ions can form hydrogen bonds with positive H+

27
Q

what is the strongest hydrogen bond configuration?

A

all atoms in a straight line

28
Q

how are charged molecules desolved in water?

A

they attract water molecules which arrange themselves around molecule and form a coating

29
Q

how do hydrophobic molecules arrange themselves in water?

A

don’t desolve

hydrophobic effect - cluster together to exclude water (eg oil in water)

30
Q

how do phospholipids arrange themselves in water?

A

form bilayer structures to exclude water (eg micelles, cell membranes)

31
Q

what does the p stand for in the dissociation equation of water?

A

-log10

32
Q

what are the properties of acid and basic solutions?

A

acids: high H and low OH
basic: high OH and low H

33
Q

what are conjugate acid-base pairs?

A

molecules in which the acid has given up one of its protons to a base

34
Q

what is the acid dissociation constant called?

A

pKa

35
Q

what is the purpose of the Henderson-Hasselbalch equation?

A

it allows calculation of how a pH will change depending on the buffer systems it comes into contact with

36
Q

what are the main buffer systems in the body?

A

in cells - phosphate buffer

in blood - bicarbonate buffer

37
Q

what is the purpose of buffer systems in the body?

A

maintaining pH at optimal level by binding or unbinding H+ ions depending on whether solution has become too acidotic or too alkaline

38
Q

what ions and molecules have higher concentrations in cells compared to outside cells?

A

K
proteins
phosphates

39
Q

what ions and molecules have higher concentrations outside cell compared to inside cells?

A

Na
Cl
bicarbonate

40
Q

what are the four main classes of membrane proteins?

A

receptors
transporters
enzymes
peripheral proteins

41
Q

what is an example of a peripheral protein, where are they found in the membrane and what is a major function?

A

glycoproteins: cell-cell recognition

always on outside of membrane

42
Q

what are the two different types of transporter membrane proteins?

A
channel proteins (gated or open)
carrier proteins
43
Q

what is the protein content of cell membranes?

A

depends on the function of that cell

44
Q

what is the main characteristic of a molecule to allow it to cross a membrane?

A

has to be UNCHARGED

45
Q

what are the three characteristics of a molecule to allow it to cross a membrane?

A

small size
lipophilic
uncharged

46
Q

what uses up 40% of the body’s resting energy, and to do what?

A

Na/K ATPase pump
pumps out 3Na
pumps in 2K

47
Q

what is the normal human plasma osmolarity?

A

285 mOsmol (300)

48
Q

what is the main difference between osmolarity and tonicity?

A

osmolarity: measure total number of particles in solution (penetrating + non penetrating)
tonicity: only measures number of non-penetrating particles in solution