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Biology > Module 2.1.2 - biological molecules > Flashcards

Module 2.1.2 - biological molecules Flashcards

1
Q

What is an ion?

A

An atom or molecule in which the total number of electrons is not equal to the number of protons

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2
Q

What is a molecule?

A

When 2 or more atoms bond

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3
Q

All living things are made up from what 4 elements?

A

carbon, hydrogen, nitrogen, oxygen

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4
Q

What is the bond rule?

A

Carbon - 4
Nitrogen - 3
Oxygen - 2
Hydrogen - 1

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5
Q

What is a covalent bond?

A

When 2 atoms share a pair of electrons

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6
Q

What is Ca 2+ needed for?

A

Nerve impulse transmission and muscle contraction

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7
Q

What is Na+ needed for?

A

Nerve impulse transmission and kidney function

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8
Q

What is K+ needed for?

A

Nerve impulse transmission and stomach opening

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9
Q

What is H+ needed for?

A

Catalysis transmission and pH Determination

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10
Q

What is NH4+ needed for?

A

Production of nitrate ion by bacteria

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11
Q

What are biological molecules made up of?

A

Polymers which are long chain molecules with multiple linked monomers

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12
Q

What is OH- needed for?

A

Catalysis of reactions and pH determination

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13
Q

What is PO4 3- needed for?

A

Cell membrane formation, nuclei acid, ATD formation and bone formation

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14
Q

What is Cl- needed for?

A

Balance of positive charge of sodium and potassium ions

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15
Q

What is HCO3- needed for?

A

Maintenance of blood pH

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16
Q

What is NO3- needed for?

A

Nitrogen supply to plants for amino acids and protein formation

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17
Q

What does polar mean?

A

has areas of positivity and negativity

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18
Q

What always has a greater share of electrons compared to hydrogen?

A

Oxygen

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19
Q

An atom with a greater share of electrons will be?

A

Slightly more negative

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20
Q

An atom with a smaller share of electrons will be?

A

Slightly more positive

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21
Q

Why does water have a high boiling point?

A

The hydrogen bonds between the molecules take a lot of energy to break

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22
Q

What does water become when it turns into ice?

A

Less dense

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23
Q

Why is ice less dense?

A

Hydrogen bonds fix their positions of the polar molecule slightly further apart

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24
Q

What does cohesive mean?

A

Moves as one mass because molecules are attracted to each other

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25
Q

What does adhesive mean?

A

Water molecules are attracted to other molecules

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26
Q

What does water act as?

A
  • a solvent
  • a medium for chemical reactions
  • transports dissolved compounds in and out of cells
  • a coolant
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27
Q

What is the surface tension of water strong enough to hold?

A

Small insects

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28
Q

Why does water provide a constant temperature environment?

A

It doesn’t change temperature or become a gas easily

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29
Q

What is the formulae for glucose?

A

C6H12O6

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30
Q

What type of monosaccharide is glucose?

A

Hexose monosaccharide as has 6 carbons

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31
Q

What type of molecule is glucose?

A

Polar molecule

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32
Q

Why is glucose soluble in water?

A

Hydrogen bonds that form between the hydroxyl groups and water molecules

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33
Q

What is the formulae of ribose?

A

C5H10O5

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34
Q

What type of monosaccharide is ribose?

A

Pentose monosaccharide as has 5 carbons

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35
Q

What is the most important pentose present in living organisms?

A

Ribose

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36
Q

What is ribose’s functional group?

A

Aldehydic as it’s an aldose sugar

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37
Q

What is the formulae for starch?

A

(C6H10O5)n

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38
Q

What is starch?

A

A polysaccharide made up of 1,4 linkages between glucose molecules

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39
Q

What is starch made up of?

A

Long chains of sugar molecules that are connected together

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40
Q

What is the most basic form of starch?

A

The linear polymer amylose (amylopectin is the branched form)

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41
Q

What is the formulae for glycogen?

A

C24 H4 O21

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42
Q

What is the main energy store in animals?

A

Glycogen

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43
Q

What is glycogen formed from?

A

Many molecules of alpha glucose joined together by 1,4 and 1,6 glycosidic bonds

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44
Q

What do the side branches of glycogen do?

A

Means energy can be release quickly as enzymes can act simultaneously on these branches

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45
Q

On a molecular diagram, which way do you number the carbons?

A

Clockwise, starting to the right of oxygen

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46
Q

What does Benedicts solution test for?

A

reducing sugars or non-reducing sugars

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47
Q

What are the results of the Benedicts test?

A

+ brick red colour
- blue colour

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48
Q

What happens to non-reducing sugars when combining with Benedicts solution?

A

They don’t react so the solution stays blue

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49
Q

What is the most common non-reducing sugar?

A

Sucrose

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50
Q

What does adding HCL to a non-reducing sugar do?

A

Is hydrolysed by the acid to glucose and fructose, both are reducing sugars

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51
Q

What is used to test for starch?

A

Iodine

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52
Q

What are the results of using iodine to test for starch?

A

+ yellow/brown turns to purple/black
- stays yellow/brown

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53
Q

What are reagent strips used for?

A

Test for the presence of reducing sugars (glucose)

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54
Q

How can the concentration of the sugar be determined when using a reagent strip?

A

Colour-coded chart

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55
Q

What are carbohydrates made of?

A

Carbon, hydrogen and oxygen

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56
Q

What are monosaccharides?

A

Monomers that make up carbohydrates

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57
Q

What are the monomers that make up carbohydrates called?

A

Monosaccharides

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58
Q

What are monosaccharides joined together by?

A

Glycosidic bonds

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59
Q

What is a disaccharide?

A

When 2 monosaccharides join together

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60
Q

What is a polysaccharide?

A

When more than 2 monosaccharides join together

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61
Q

What is the main energy store in plants?

A

Starch

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62
Q

How do plant cells get energy?

A

From glucose and excess glucose is stored as starch

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63
Q

Why is starch good for storage?

A

It is insoluble so doesn’t cause water to enter via osmosis

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64
Q

What is starch a mixture of?

A

A mixture of 2 polysaccharides of alpha glucose : amylose and amylopectin

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65
Q

What is amylose?

A

A long unbranched chain of alpha glucose

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66
Q

Why is amylose good for storage?

A

Angles of the glycosidic bonds give it a coiled structure which makes it
good for storage

67
Q

What is amylopectin?

A

A long branched chain of alpha glucose

68
Q

Why can glucose be released quickly from the branched on amylopectin?

A

The side branches allow the enzymes that break down the molecule to get at the glycosidic bonds easily - glucose is released quickly

69
Q

What is the main energy store in animals?

A

Glycogen

70
Q

Where do animals get energy from?

A

Glucose but excess glucose is stored as glycogen

71
Q

What is good about the many branches on glycogen?

A

Glucose can be released quickly which is important in animals

72
Q

How is glycogen good for storage?

A

It is compact

73
Q

What is the main component of cell walls in plants?

A

Cellulose

74
Q

What type of branches does cellulose have?

A

Long unbranched chains of beta-glucose

75
Q

What does cellulose form?

A

Long straight chains that are linked together by hydrogen bonds to form strong fibres called microfibrils

76
Q

What does cellulose provide for plant cells?

A

Structural support

77
Q

What are lipids commonly known as?

A

Fats or oils

78
Q

What are the 3 types of lipids?

A
  • triglycerides
  • cholesterol
  • phospholipids
78
Q

What is the structure of cholesterol?

A
  • has a hydrocarbon ring structure attached to a hydrocarbon tail
  • the ring structure has a polar hydroxyl group attached to iy
79
Q

What is the structure of triglycerides?

A
  • made up of 1 molecule of glycerol with 3 fatty acids attached to it
  • are synthesised by the formation of an ester bond between each fatty acid and glycerol molecule
  • each ester bond is formed by a condensation reaction
  • they break down when the ester bond is broken (in a hydrolysis reaction)
  • the hydrophobic tails make the lipid insoluble in water
  • saturated fats have a single bond between carbon atoms
  • unsaturated fats have at least 1 double bond between carbon atoms
80
Q

What are saturated fats?

A

Have a single bond between carbon atoms so are saturated with hydrogen

81
Q

What is the structure of phospholipids?

A
  • are similar to triglycerides but 1 of the fatty acid molecules is replaced by a phosphate group
  • the phosphate group is hydrophilic and the fatty acid tails are hydrophobic
82
Q

What are unsaturated fats?

A

Have at least 1 double bond between carbon atoms which causes the chain to have a kink

83
Q

What are the functions of triglycerides?

A
  • insoluble so don’t cause water to enter the cells by osmosis
  • bundle together as insoluble droplets in cells because the fatty acid tails are hydrophobic
  • used as an energy storage molecules in animals and plants
  • some bacteria use them to store energy and carbon
  • good for storage as the long hydrocarbon tails of the fatty acids contain lots of chemical energy
84
Q

What are the functions of cholesterol?

A
  • help regulate the fluidity of the cell membrane by interacting with the phospholipid bilayer in eukaryotic cells
  • small and flattened shape so can fit between phospholipid molecules in the membrane
  • at higher temps, the bind to the hydrophobic tails of the phospholipids, causing them to pack more closely together
  • makes the membrane less fluid and more rigid
  • at lower temps, prevents phospholipids packing too close together so increases membrane fluidity
85
Q

What are the functions of phospholipids?

A
  • found in cell membranes of all eukaryotes and prokaryotes
  • make up the phospholipid bilayer
  • center of the bilayer is hydrophobic so water soluble substances can’t pass through it easily
86
Q

What is chromatography used for?

A

To separate mixtures
e.g. biological molecules

87
Q

What are the 2 types of chromatography?

A
  • paper chromatography
  • thin layer chromatography (TLC)
88
Q

What is the mobile phase in chromatography?

A

Where the molecules can move (the liquid)

89
Q

What is the stationary phase in chromatography?

A

Where molecules cannot move
- the paper in paper chromatography
- a thin layer of solid in TLC

90
Q

What is the equation to find the retention factor?

A

Distance moved by the solute/distance moved by the solvent

91
Q

What would be used for the mobile phase in paper chromatography?

A

Ethanol or water

92
Q

What does the time spent in the different phases of chromatography do?

A

Separates the components of the mixture

93
Q

What is DNA and RNA?

A

Molecules that are essential to the function of living organisms and both made up of nucleotides

94
Q

What is contained in a nucleotide?

A

Carbon, hydrogen, oxygen, nitrogen and phosphate

94
Q

What are nucleotides made up from?

A

A pentose sugar, nitrogen containing base and a phosphate group

95
Q

What is DNA used for?

A

Storing genetic information

96
Q

What is RNA used for?

A

To make proteins from the instructions in DNA

97
Q

What bases pair together?

A

A with T that has 2 hydrogen bonds
C and G with 3 hydrogen bonds

98
Q

What do the bases stand for?

A

Adenine
Thymine
Cytosine
Guanine
Uracil

99
Q

What is RNA?

A

Single polynucleotide chain, ribose sugar, U replaces T

100
Q

What are adenine and guanine?

A

Both purines

101
Q

What are cytosine, thymine and uracil?

A

Both pyrimidines

102
Q

How many carbon-nitrogen rings does purine contain?

A

2 carbon-nitrogen rings joined

103
Q

How many carbon-nitrogen rings does pyrimidine contain?

A

Only 1 carbon-nitrogen ring

104
Q

What does phosphorylated mean?

A

Added phosphate

105
Q

What does ADP contain?

A

Base adenine, sugar ribose and 2 phosphate groups

106
Q

What does ATP contain?

A

Base adenine, sugar ribose and 3 phosphate groups

107
Q

What is energy from glucose used to make?

A

ATP and then molecules of ATP provide energy for chemical reaction

107
Q

What doe plant and animal cells release?

A

Energy from glucose

108
Q

How is a phosphate bond formed?

A

ATP is synthesised from ADP and inorganic phosphate. The ADP is phosphorylated to form ATP and phosphate bond is formed

109
Q

What is stored in phosphate bonds?

A

Energy

110
Q

What is release from the phosphate bond and used by the cell?

A

Energy

111
Q

What happens when energy is needed by a cell?

A

ATP is broken down back into ADP and inorganic phosphate

112
Q

What is DNA made up of?

A

2 nucleotide chains joined together

113
Q

What do nucleotides joined together to form?

A

Polynucleotides

114
Q

What do nucleotides join up between?

A

The phosphate group of one nucleotide and the sugar of another (by a condensation reaction)
This forms a phospholipid-ester bond

115
Q

What is a phospholipid-ester bond?

A

Phosphate group and 2 ester bonds

116
Q

What is the sugar phosphate backbone?

A

Chain of sugars and phosphates

117
Q

What is a chain of sugars and phosphates known as?

A

Sugar phosphate backbone

118
Q

How can polynucleotides be broken back down?

A

Hydrolysis

119
Q

What is DNA composed of?

A

2 polynucleotides strands joined together to form a double helix shape

120
Q

How do polynucleotides join together in DNA?

A

Hydrogen bonding between the bases

121
Q

How many bonds does adenine and thymine have?

A

2 hydrogen bonds

122
Q

How many bonds does cytosine and guanine have?

A

3 hydrogen bonds

123
Q

What does DNA replicate for?

A

To copy itself before cell division so that each new cell has the full amount of DNA

123
Q

Why is DNA replication important?

A

For making new cells and for passing genetic info from generation to generation

124
Q

What is the process of DNA replication?

A
  1. DNA helicase (breakdown)
  2. template/copy
  3. DNA polymerase (joined together)
125
Q

What is DNA helicase?

A

Breaks down hydrogen bonds between 2 polynucleotide DNA strands. Helix unzips to form 2 single strands

126
Q

What is the template stage in DNA replication?

A

Each original strand acts as a template for a new strand. Free floating nucleotides join to exposed bases on each original template strand by complimentary base pairing

127
Q

What is the DNA polymerase stage in DNA replication?

A

Nucleotides on new strand are joined together by the enzyme DNA polymerase. This forms the sugar-phosphate backbone. Hydrogen bonds form between the bases on original and new strand. The strands twist to form a double helix. Each new DNA molecule contains 1strand from new and 1 original strand DNA molecules

128
Q

What is semi-conservative replicating?

A

1 original and 1 new strand that form to make a double helix DNA molecule

129
Q

How accurate is DNA replication?

A

99.99%/ very accurate

130
Q

Why does DNA replication have to be very accurate?

A

Makes sure genetic info is conserved each time cell is replicated but random spontaneous mutations can still occur

131
Q

What is a mutation?

A

Change in sequence of DNA bases

132
Q

What is a gene?

A

Sequence of DNA nucleotides that code for a polypeptide

133
Q

What determines the order of the amino acids?

A

Different proteins have a different number and order of amino acids. The order of the nucleotide bases in a gene determines this.

134
Q

What is each amino acid coded by?

A

3 bases (triplet) in a gene, different sequences of bases code for different amino acids

135
Q

What do the sequence of bases in a section of DNA used as?

A

A template used to make proteins during protein synthesis

136
Q

Where is DNA found?

A

In the nucleus

137
Q

Why cant DNA move out of the nucleus?

A

It is too large so a section is copied into mRNA
This is called transcription

138
Q

What doe mRNA do as it leaves the nucleus?

A

Joins with a ribosome in the cytoplasm where it can be used to synthesis a protein
This is called translation

139
Q

What is RNA?

A

Single polynucleotide strand

140
Q

What does RNA contain?

A

Uracil instead of Thymine

140
Q

What are the 3 types of RNA?

A
  • mRNA
  • tRNA
  • rRNA
141
Q

What is mRNA?

A

Messenger RNA
single polynucleotide strand, made in nucleus during transcription

142
Q

What does mRNA do?

A

Carries genetic code from DNA in nucleus to cytoplasm where its used to make proteins during translation

143
Q

What is tRNA?

A

Transfer RNA
single polynucleotide strand that folded into a clover shape, hydrogen bonds hold molecules together in this shape, every molecule has a sequence of 3 bases called an anticodon at 1 end, found in cytoplasm

143
Q

What does tRNA do?

A

Carries the amino acids that are used to make proteins to the ribosomes, as have an amino acid binding site at 1 end

144
Q

What is rRNA?

A

Ribosomal RNA
forms 2 subunits in a ribosome along with the proteins, ribosome moves along mRNA strand during protein synthesis

145
Q

What does rRNA do?

A

rRNA in ribosomes helps catalyze the formation of peptide bonds between the amino acids

146
Q

What is the genetic code?

A

Sequence of base triplets in DNA or mRNA which codes for a specific amino acid, each triplet is read in sequence, more codons than amino acids, some triplets tell cell to stop production of a protein by a stop signal

147
Q

What is the first stage of protein synthesis?

A

Transcription

147
Q

What are the 4 stages of transcription?

A
  1. RNA polymerase attaches to the DNA
  2. Complementary mRNA is formed
  3. RNA polymerase moves down the DNA strand
  4. mRNA leaves the nucleus
148
Q

What happens in the first stage of transcription?

A

RNA polymerase attaches to double helix at beginning of a gene. Hydrogen bonds between 2 DNA strands in the gene break, separating the strands and the DNA molecule uncoils. 1 strand is then used as a template to make an mRNA copy

149
Q

What happens in the second stage of transcription?

A

RNA polymerase lines up free RNA nucleotides along the template strand. Complementary base pairing means that the mRNA strand ends up being a complementary copy of the DNA template strand. Once RNA nucleotides have paired up, they’re joined together by RNA polymerase forming mRNA strand

150
Q

What happens in the third stage of transcription?

A

RNA polymerase moves along the DNA and assembles the mRNA. Hydrogen bonds between the uncoiled strands of DNA re-form once the RNA polymerase has passed by and the strands go back into a double helix

151
Q

What happens in the fourth stage of transcription?

A

When RNA polymerase reaches a stop codon, it stops making the mRNA and detaches from the DNA. mRNA moves out of the nucleus through a nuclear pore and attaches to a ribosome

152
Q

Where does transcription take place?

A

Nucleus

153
Q

Where does translation take place?

A

Cytoplasm

154
Q

What is the first stage of translation?

A

Amino acids joined together by a ribosome to make a polypeptide chain(protein). Follows a sequence of codons carried by mRNA. mRNA attaches itself to a ribosome and the tRNA molecules carry the amino acid to the ribosome

155
Q

What is the second stage of translation?

A

tRNA molecule with an anticodon that is complementary to the start codon attaches to mRNA by complementary bas pairing. Second tRNA molecule attaches itself to the next codon on the mRNA in the same way

156
Q

What is the third stage of translation?

A

Ribosomal RNA in the ribosome catalyzes the formation of a peptide bond between the 2 amino acids attached to tRNA molecules. This joins amino acids together. First tRNA molecule moves away leaving its amino acid behind

157
Q

What is the fourth stage of translation?

A

Third tRNA molecule binds to the next codon on the mRNA. Amino acid binds to the first 2 and second tRNA moves away. This process continues until there’s a stop codon on the mRNA molecule

Biology (10 decks)

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