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Flashcards in W1 Deck (100)
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1
Q

what is a molecule made up of

A

elements

2
Q

what are elements

A

cannot be broken down or converted into other substances by chemical means

3
Q

what is a chemical element

A

consists of one type of atom

4
Q

what is an atom

A

the smallest particle of an element that still retains the elements distinctive chemical properties

5
Q

what charge is a proton

A

positive

6
Q

what charge is an electron

A

negative

7
Q

what does the atomic number equal

A

number of protons

8
Q

what does the number of protons equal

A

atomic number and the number of electrons

9
Q

what does the number of electron equal

A

the number of protons

10
Q

what charge is neutrons

A

neutral

11
Q

electrons fill the shells from the ________ to the _____ shell

A

innermost, outer

12
Q

most atoms have ___________ outer most electron shells making it reactive

A

unfilled

13
Q

what is a covalent bond

A

sharing of electrons

14
Q

what rotation is there about a single covalent bond

A

full

15
Q

what rotation is there about a double covalent bond

A

restricted

16
Q

what are the non covalent interactions

A

hydrogen bonds, ionic interactions, van der waals attractions and hydrophobic forces

17
Q

what is the biological relevance of non covalent interactions

A

mediates molecular interactions and stabilises macromolecule structures

18
Q

what are polar covalent bonds

A

unequal sharing of electrons belonging to a bond between two atoms

19
Q

how is a polar covalent bond formed

A

causes if one atom has a higher electronegativity to electrons than other atoms such as hydrogen and oxygen in water

20
Q

what are hydrogen bonds

A

polar covalent bonds create attraction (dipole) which can tract other polarised molecules.

21
Q

how do hydrogen bonds form

A

is the polarised molecular contains a hydrogen atom and this hydrogen atom is between two electron attracting atoms

22
Q

what is the strength of a hydrogen compared to a covalent bond

A

1/20th the strength of a covalent bond

23
Q

when is a hydrogen bond the strongest

A

when 3 atoms are in a straight line

24
Q

what are ionic interactions

A

electrons lost or gained by atoms –> electrically charged ions. opposite attractions hold each other together.

25
Q

how are ionic interactions in water

A

weak because the charges are shielded by water

26
Q

how are ionic interactions without water

A

strong

27
Q

what are van der waals attractions

A

weak interactions due to fluctuating electrical charges between atoms, effective when atoms move close together

28
Q

what are hydrophobic forces

A

hydrophobic molecules forced together due to repulsion by water molecules such as oil and water

29
Q

what are macromolecules

A

most abundant compound inside cells after water

30
Q

in biology, what are some macromolecules

A

nucleic acids (DNA and RNA), proteins, polysaccharides, lipids-phospholipids. most are polymers

31
Q

what is the building block of macromolecules

A

carbon and the stable rings and chains it can form

32
Q

what can carbon chains and rings be building blocks for

A

macromolecules, energy source or both

33
Q

what are carbohydrates

A

hydrates of carbon (CH2O)n where n is typically 3,4,5,6

34
Q

what is the basic form of carbohydrates

A

monosaccharides

35
Q

what is glucose

A

C6H121O6, monosaccharide with 6 carbon ring and structure includes 5 carbons and one oxygen

36
Q

what are polysaccharides

A

composed of sugar subunit or monosaccharides

37
Q

what is an example of a disaccharide

A

sucrose which is glucose and fructose

38
Q

what is an oligosaccharide

A

3-50 monosacchrides

39
Q

what is a polysaccharide

A

100s to 1000s subunits

40
Q

how can we form di and polysaccharides

A

condensation reactions

41
Q

what are condensation reactions

A

leads to generation of water molecule as covalent bond forms between subunits

42
Q

what is a hydrolysis reaction

A

addition of a water molecule cleaves bond linking two subunits

43
Q

what are hydrolysis and condensation reactions catalysed by

A

enzymes and commonly found in the formation or cleavage of macromolecules

44
Q

what are the two forms of glucose molecules (and other monosaccharides)

A

alpha and beta

45
Q

what does alpha and beta formations of a monosaccharide mean

A

the hydroxyl group on the carbon atom that carries the aldehyde or ketone can rapidly change from one position to the other. the two positions are alpha and beta

46
Q

what is alpha hydroxyl

A

the alcohol group is down

47
Q

what is beta hydroxyl

A

the alcohol group is up

48
Q

what happens when you link two monosaccharides

A

it freezes the alpha or beta form

49
Q

where is cellulose found

A

walls of plant cells

50
Q

what is the most organic molecule on earth

A

cellulose

51
Q

what is cellulose made up of

A

repeating glucose units

52
Q

where is chitin found

A

exoskeletons of arthropods and insects and cell wall of fungi

53
Q

what is chitin

A

linear molecule of repeating units of the sugar derivative N-actylglucosamine in beta-1-4 linkage

54
Q

what is common in chitin and cellulose

A

they both are made up of long chains of glucose subunits

55
Q

what are some examples of lipids

A

fatty acids and derivatives, fats, oils, and phopholipids and steroids

56
Q

describe the structure of fatty acid

A

have a hydrophobic tail and hydrophilic head. `

57
Q

what does amphipathic mean

A

a molecule having hydrophilic and hydrophobic parts

58
Q

describe the hydrophilic head of a fatty acid

A

carboxylic head, chemically reactive-nearly all covalently linked to other molecules

59
Q

describe the hydrophobic head of a fatty acid

A

hydrocarbon tail- differ in length and position of double and single bond

60
Q

what is an unsaturated fatty acid

A

double bond(s) linking carbon atoms in hydrophobic tail, can’t stack very well because of the double bond and the bend. therefore liquid at room temperature such as plant oils.

61
Q

what is a saturated fatty acid

A

no double bonds, tight packing, solid at room temperature such as animal oils

62
Q

describe energy reserve in cells as a role of fatty acids

A

provide 6 times as much usable energy as glucose (on a weight basis). It is stored as triacylglycerid molecules

63
Q

what are phospholipids

A

two fatty acids linked to glycerol, 3rd site on glycerol linked to phosphate group and small hydrophilic group attached covalently to phosphate group making is strongly amphipathic

64
Q

unsaturated tails _____ membrane fluidity

A

increase

65
Q

saturated tails ____ fluidity

A

decrease

66
Q

what are glycolipids

A

similar to phospholipids but sugar groups replace phosphate. Amphipathic nature retained

67
Q

what is the role of glycolipids

A

cell-to-cell recognition

68
Q

what are the two main types of steroids

A

membrane and non-membrane steroids

69
Q

what are non-membrane steroids

A

signalling molecules, hormones like testosterone and estradiol, can pass through membrane

70
Q

what is RNA

A

transcient carrier of information

71
Q

what is DNA

A

long term storage of hereditary material

72
Q

what is DNA and RNA composed of

A

nucleotides

73
Q

what are nucleotides

A

nitrogenous base, five carbon sugars (pentose), phosphate group (one or more)

74
Q

what are nitrogenous bases

A

contains nitrogen, made up of pyridines and purines

75
Q

what are pyrimidines

A

single ring structure , cytosine, thymine and uracil

76
Q

what are purines

A

double ring structure, adenine and guanine

77
Q

what bases do DNA have

A

ACGT

78
Q

what bases do RNA have

A

ACGU

79
Q

what is a nucleoside

A

nitrogenous base and pentose

80
Q

what is an example of a nucleoside

A

adenoside

81
Q

what is more stable out of ribose and deoxyribose

A

deoxyribose because it doesn’t form an intermediate

82
Q

what bonds connect phosphate groups

A

phosphoanhydride

83
Q

what is conserved in a phosphoanhydride bond

A

high amounts of energy- cells use this as a source of energy

84
Q

what charge does a phosphate group give to a nucleotide

A

negative charge

85
Q

what charge are DNA and RNA

A

negatively charged

86
Q

what are the different bases in DNA and RNA

A

DNA has guanine and Rna has guanine

87
Q

what sugar does DNA have

A

2-deoxyribose

88
Q

what sugar does RNA have

A

ribose

89
Q

how are nucleotides joined together

A

through condensation reactions

90
Q

what bonds link adjacent nucleotides in nucleic acids

A

phosphodiester

91
Q

true or false- the hydroxyl group on 3’ carbon of pentose is covalently linked to phosphate group attached to 5’ carbon of adjacent pentose

A

true - forming the sugar-phosphate backbone

92
Q

what way by convention is the sequence of bases read in a nucleic acid strand

A

5’ to 3’ using single letter code

93
Q

how are strands of DNA held together

A

by hydrogen bonds

94
Q

what is the ratio to purines and pyrimidines

A

1:1

95
Q

what are three other functions of nucleotides

A

carriers of chemical energy, combined with other groups as coenzymes and signalling molecules

96
Q

how can nucleotides be used as chemical energy

A

phosphoanhydride bonds can be hydrolysed

97
Q

how can nucleotides be used as signalling molecules

A

activate enzymes and turn on genes such as cyclic AMP which is the starving signaller for a cell

98
Q

at what pH are the side chains of amino acids ionised

A

7

99
Q

what are the different groups on an amino acid

A

amino group, carboxyl group and a side chain with the carbon in the middle known as the alpha-carbon.

100
Q

Define antiparallel

A

Describes the relative orientation of the two strands in a DNA double helix or two paired regions of a polypeptide chain, the polarity of one strand is oriented in the opposite direction to that of the other