Life at Cellular Level Flashcards

1
Q

Why are cells small?

A

Small cell keeps a large surface area to volume ratio - needed for easy absorption of substances

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2
Q

Do prokaryotes have mitochondria?

A

No

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3
Q

What is the difference between pluripotent cells and multipotent cells?

A

Multipotent - can differentiate into many cell types

Totipotent - can differentiate into every type of cell in the body

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4
Q

What are the key differences between necrosis and apoptosis?

A

Necrosis - Days, groups of cells, damage to neighbouring cells, inflammation

Apoptosis - Hours, individual cells are induced to die, no damage to neighbouring cells, no inflammation

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5
Q

Describe the shape of mitochondrial DNA

A

Circular

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6
Q

What does the endoplasmic reticulum do?

A

Site of protein and glycolipid synthesis

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7
Q

Which proteins does the golgi apparatus add sugars to?

A

Membrane proteins

Lysosomal proteins

Secretory proteins

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8
Q

What is the word used to describe membrane lipids?

A

Amphipathic

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9
Q

What function do telomeres have?

A

They stabilise the ends of the chromosomes

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10
Q

What function do centromeres have?

A

They ensure distribution of chromosomes to daughter cells when the cell divides

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11
Q

What is splicing?

A

Removing introns during translation

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12
Q

What is the ribosome composed of?

A

Ribosomal RNA

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13
Q

What is responsible for autophagy?

A

The lysosome

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14
Q

What is the function of the cytoskeleton?

A

Holds organelles in place and moves them

Supports and maintains cell shape

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15
Q

What three structures comprise the cytoskeleton?

A
  1. Microfilaments
  2. Intermediate filaments
  3. Microtubules
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16
Q

What is the structure of microfilaments?

A

Made up of actin protein strands - thin and contractile

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17
Q

What are microfilaments responsible for?

A

Provide structure

Cell cell anchoring

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18
Q

What is the structure of intermediate filaments?

A

Consists of fibrous proteins, organised in tough rope-like assemblages

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19
Q

What is the function of intermediate filaments?

A

Stabilise cell structure, prevents collisions within the cell

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20
Q

What is the structure of microtubules?

A

Thick, Long, hollow cylinders made from tubulin (a dimer composed of alpha and beta tubulin)

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21
Q

What is the function of microtubules?

A

Transport materials in cytoplasm

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22
Q

What is the peroxisome responsible for?

A

Oxidation of fatty acids

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23
Q

What type of atoms form the strongest bonds?

A

Light atoms

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24
Q

What are the two isomers of the c-c double bond?

A

Cis (meaning same)

Trans (meaning opposite)

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25
Q

What are the names given to the two forms of carbon?

A

Laevo (left handed)

Dextro (right handed)

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26
Q

What type of amino acids are proteins made from?

A

Left handed (laevo)

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27
Q

What is defined as comformation?

A

The precise arrangement of atoms in a molecule

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28
Q

What is the intermediate product between glucose and pyruvic acid, and what products does its formation produce?

A

Phosphoenolypyruvate

Makes 2 ATP each

Makes 1 NADH each

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29
Q

Is condensation a synthesis or degradation reaction, what does it always produce?

A

It is a synthesis reaction that produces water

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30
Q

What type of reaction occurs between the pentose sugar of one nucleotide and the phosphate of an adjacent nucleotide?

A

Dehydration reduction

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31
Q

What is the difference between a nucleoside and a nucleotide?

A

Nucleoside does not contain a phosphate group

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32
Q

What does the 5’ end of RNA contain?

A

Contains the phosphate

33
Q

What enzyme is used to insert viral DNA into the host genome?

A

Insertase

34
Q

What is the effect of zidovudine?

A

It is a reverse transcriptase inhibitor and prevents the virus producing DNA from RNA

35
Q

What is the structure of triaclyglyceride?

A

A glycerol backbone connected to three fatty acids

36
Q

What is the structure of a lipid?

A

Carboxyl head and a hydrocarbon chain

37
Q

What is the structure of a phospholipid?

A

Same structure as triacylglycerol except one of the fatty acids has been replaced with a phosphate group (forming the hydrophilic head)

38
Q

Are triacylglycerides polar?

A

No

39
Q

What is the definition of amphipathic?

A

A molecule having both hydrophilic and hydrophobic parts.

40
Q

What is the first law of thermodynamics?

A

Energy can neither b converted nor destroyed

41
Q

What is the second law of thermodynamics?

A

All energy transformations ultimately lead to more disorder, an increase in entropy

42
Q

What is enthalpy defined as?

A

The total energy within a system

43
Q

What is entropy defined as?

A

The disorder within a system

44
Q

What is the equation to calculate gibbs free energy?

A
45
Q

What is free energy measured in?

A

Kcal/mol

46
Q

What does a delta G less than 0 indicate?

A

The reaction is spontaneous and energy releasing

47
Q

What does delta G greater than 0 indicate?

A

That the reaction is spontaeous backwards (endergonic)

48
Q

What does a delta G equal to 0 mean?

A

The reaction is at equilibrium

49
Q

What type of delta G do biological reactions require?

A

Positive delta G, since they require more order rahter than less

50
Q

What is meant by energy coupling?

A

An energetically unfavourable reaction is driven by an energetically favourable reaction.

51
Q

What are the features of catabolism reactions?

A

Heat loss

Complex organic molecules are broken down into simpler ones

Releases energy that drives chemical reactions

52
Q

What are the features of anabolic reactions

A

Simpler substances are combined to form more complex molecules

Require energy

53
Q

How do exergonic reactions save free energy?

A

By forming ATP

54
Q

What is the definition of an apoenzyme?

A

Require non-protein co-factors

55
Q

What makes up a holoenzyme?

A

Cofactor + apoenzyme

56
Q

What is the function of water?

A

Bathes our cells

Dissolves and transports compounds

Allows compounds to move between and within cells

Participates in chemical reactions

Dissipates heat

57
Q

Which atom are electrons held closer to in an OH bond?

A

They are held closer to the O atom because the O is more electronegative

58
Q

Describe the H bonds in water?

A

They are continually forming and breaking whilst H2O molecules move

59
Q

Does gaseous H2 contain H bonds?

A

NO

60
Q

Where does a hydrogen bond take place?

A

Between any any electronegative atom and an H atom that is electropositive

61
Q

When are H bonds strongest?

A

When the three atoms involved lie in a straight line

62
Q

What is the change in H bonding when a hydrophilic molecule like alcohol, aldehyde or ketone is dissolved in water?

A

H bonds within water and the solute are replaced with more energetically favourable solute-water H bonding

63
Q

Why is O2 and CO2 poorly soluble in water?

A

No polarity

64
Q

Describe the structure of dissolved sodium chloride

A

Water forms screens around each ion

65
Q

What effect does does the interaction between a substrate and an enzyme have on the order of water?

A

Enzyme substrate reaction displaces dsordered water

66
Q

What is meant by the hydrophobic effect?

A

They arrange themselves in water to minimise the disruption of hydrogen bonding in the surrounding water molecules

This is energetically favourable

67
Q

Describe the structural arrangement of water around alyl chains?

A

H2O molecules form cages around hydrophobic alkyl chains

68
Q

How do phospholipids minimise disruption of H bonding in solution?

A

They form bilayers or mixed micells

69
Q

What kind of structure will proteins adopt when they are in aqeous solution?

A

They fold up so that the hydrophilic parts of the chain are on the outside and the hydrophobic parts are on the inside, allowing them to be water soluble.

70
Q

What calculation is used to calculate the dissociation of water?

A
71
Q

What does Kw (ionic product of water) always equal in the dossociation of water

A

1x10-14

72
Q

How do you calculate pH from the concentration of H+?

A

pH = -Log [H+]

73
Q

How do you describe the movement of protons in both acids and bases?

A

Acids are proton donors and bases are protein acceptors

74
Q

What equation is given to the equilibrium constant of an acid?

A
75
Q

What does the eqilibrium constant measure?

A

It measures the tendancy for any acid to lose a proton and form its conjugate base

76
Q

What is pKA?

A

It is the -log of the acid dissociation constant

77
Q

What is significant about the midpoint of the titration of a weak acid and a base?

A

Exactly half of tha base is added and half the weak acid is remainingpH = pKa

78
Q

What is the henderson hasslebalch equation?

A
79
Q

What are natural buffers in the body?

A

Phosphate in the cellsBicarbonate in the blood