Module 2.1.2 - biological molecules Flashcards
(164 cards)
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
2
Q
What is a molecule?
A
When 2 or more atoms bond
3
Q
All living things are made up from what 4 elements?
A
carbon, hydrogen, nitrogen, oxygen
4
Q
What is the bond rule?
A
Carbon - 4
Nitrogen - 3
Oxygen - 2
Hydrogen - 1
5
Q
What is a covalent bond?
A
When 2 atoms share a pair of electrons
6
Q
What is Ca 2+ needed for?
A
Nerve impulse transmission and muscle contraction
7
Q
What is Na+ needed for?
A
Nerve impulse transmission and kidney function
8
Q
What is K+ needed for?
A
Nerve impulse transmission and stomach opening
9
Q
What is H+ needed for?
A
Catalysis transmission and pH Determination
10
Q
What is NH4+ needed for?
A
Production of nitrate ion by bacteria
11
Q
What are biological molecules made up of?
A
Polymers which are long chain molecules with multiple linked monomers
12
Q
What is OH- needed for?
A
Catalysis of reactions and pH determination
13
Q
What is PO4 3- needed for?
A
Cell membrane formation, nuclei acid, ATD formation and bone formation
14
Q
What is Cl- needed for?
A
Balance of positive charge of sodium and potassium ions
15
Q
What is HCO3- needed for?
A
Maintenance of blood pH
16
Q
What is NO3- needed for?
A
Nitrogen supply to plants for amino acids and protein formation
17
Q
What does polar mean?
A
has areas of positivity and negativity
18
Q
What always has a greater share of electrons compared to hydrogen?
A
Oxygen
19
Q
An atom with a greater share of electrons will be?
A
Slightly more negative
20
Q
An atom with a smaller share of electrons will be?
A
Slightly more positive
21
Q
Why does water have a high boiling point?
A
The hydrogen bonds between the molecules take a lot of energy to break
22
Q
What does water become when it turns into ice?
A
Less dense
23
Q
Why is ice less dense?
A
Hydrogen bonds fix their positions of the polar molecule slightly further apart
24
Q
What does cohesive mean?
A
Moves as one mass because molecules are attracted to each other
25
What does adhesive mean?
Water molecules are attracted to other molecules
26
What does water act as?
- a solvent
- a medium for chemical reactions
- transports dissolved compounds in and out of cells
- a coolant
27
What is the surface tension of water strong enough to hold?
Small insects
28
Why does water provide a constant temperature environment?
It doesn't change temperature or become a gas easily
29
What is the formulae for glucose?
C6H12O6
30
What type of monosaccharide is glucose?
Hexose monosaccharide as has 6 carbons
31
What type of molecule is glucose?
Polar molecule
32
Why is glucose soluble in water?
Hydrogen bonds that form between the hydroxyl groups and water molecules
33
What is the formulae of ribose?
C5H10O5
34
What type of monosaccharide is ribose?
Pentose monosaccharide as has 5 carbons
35
What is the most important pentose present in living organisms?
Ribose
36
What is ribose's functional group?
Aldehydic as it's an aldose sugar
37
What is the formulae for starch?
(C6H10O5)n
38
What is starch?
A polysaccharide made up of 1,4 linkages between glucose molecules
39
What is starch made up of?
Long chains of sugar molecules that are connected together
40
What is the most basic form of starch?
The linear polymer amylose (amylopectin is the branched form)
41
What is the formulae for glycogen?
C24 H4 O21
42
What is the main energy store in animals?
Glycogen
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What is glycogen formed from?
Many molecules of alpha glucose joined together by 1,4 and 1,6 glycosidic bonds
44
What do the side branches of glycogen do?
Means energy can be release quickly as enzymes can act simultaneously on these branches
45
On a molecular diagram, which way do you number the carbons?
Clockwise, starting to the right of oxygen
46
What does Benedicts solution test for?
reducing sugars or non-reducing sugars
47
What are the results of the Benedicts test?
+ brick red colour
- blue colour
48
What happens to non-reducing sugars when combining with Benedicts solution?
They don't react so the solution stays blue
49
What is the most common non-reducing sugar?
Sucrose
50
What does adding HCL to a non-reducing sugar do?
Is hydrolysed by the acid to glucose and fructose, both are reducing sugars
51
What is used to test for starch?
Iodine
52
What are the results of using iodine to test for starch?
+ yellow/brown turns to purple/black
- stays yellow/brown
53
What are reagent strips used for?
Test for the presence of reducing sugars (glucose)
54
How can the concentration of the sugar be determined when using a reagent strip?
Colour-coded chart
55
What are carbohydrates made of?
Carbon, hydrogen and oxygen
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What are monosaccharides?
Monomers that make up carbohydrates
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What are the monomers that make up carbohydrates called?
Monosaccharides
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What are monosaccharides joined together by?
Glycosidic bonds
59
What is a disaccharide?
When 2 monosaccharides join together
60
What is a polysaccharide?
When more than 2 monosaccharides join together
61
What is the main energy store in plants?
Starch
62
How do plant cells get energy?
From glucose and excess glucose is stored as starch
63
Why is starch good for storage?
It is insoluble so doesn't cause water to enter via osmosis
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What is starch a mixture of?
A mixture of 2 polysaccharides of alpha glucose : amylose and amylopectin
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What is amylose?
A long unbranched chain of alpha glucose
66
Why is amylose good for storage?
Angles of the glycosidic bonds give it a coiled structure which makes it
good for storage
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What is amylopectin?
A long branched chain of alpha glucose
68
Why can glucose be released quickly from the branched on amylopectin?
The side branches allow the enzymes that break down the molecule to get at the glycosidic bonds easily - glucose is released quickly
69
What is the main energy store in animals?
Glycogen
70
Where do animals get energy from?
Glucose but excess glucose is stored as glycogen
71
What is good about the many branches on glycogen?
Glucose can be released quickly which is important in animals
72
How is glycogen good for storage?
It is compact
73
What is the main component of cell walls in plants?
Cellulose
74
What type of branches does cellulose have?
Long unbranched chains of beta-glucose
75
What does cellulose form?
Long straight chains that are linked together by hydrogen bonds to form strong fibres called microfibrils
76
What does cellulose provide for plant cells?
Structural support
77
What are lipids commonly known as?
Fats or oils
78
What are the 3 types of lipids?
- triglycerides
- cholesterol
- phospholipids
78
What is the structure of cholesterol?
- has a hydrocarbon ring structure attached to a hydrocarbon tail
- the ring structure has a polar hydroxyl group attached to iy
79
What is the structure of triglycerides?
- 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
What are saturated fats?
Have a single bond between carbon atoms so are saturated with hydrogen
81
What is the structure of phospholipids?
- 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
What are unsaturated fats?
Have at least 1 double bond between carbon atoms which causes the chain to have a kink
83
What are the functions of triglycerides?
- 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
What are the functions of cholesterol?
- 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
What are the functions of phospholipids?
- 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
What is chromatography used for?
To separate mixtures
e.g. biological molecules
87
What are the 2 types of chromatography?
- paper chromatography
- thin layer chromatography (TLC)
88
What is the mobile phase in chromatography?
Where the molecules can move (the liquid)
89
What is the stationary phase in chromatography?
Where molecules cannot move
- the paper in paper chromatography
- a thin layer of solid in TLC
90
What is the equation to find the retention factor?
Distance moved by the solute/distance moved by the solvent
91
What would be used for the mobile phase in paper chromatography?
Ethanol or water
92
What does the time spent in the different phases of chromatography do?
Separates the components of the mixture
93
What is DNA and RNA?
Molecules that are essential to the function of living organisms and both made up of nucleotides
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What is contained in a nucleotide?
Carbon, hydrogen, oxygen, nitrogen and phosphate
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What are nucleotides made up from?
A pentose sugar, nitrogen containing base and a phosphate group
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What is DNA used for?
Storing genetic information
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What is RNA used for?
To make proteins from the instructions in DNA
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What bases pair together?
A with T that has 2 hydrogen bonds
C and G with 3 hydrogen bonds
98
What do the bases stand for?
Adenine
Thymine
Cytosine
Guanine
Uracil
99
What is RNA?
Single polynucleotide chain, ribose sugar, U replaces T
100
What are adenine and guanine?
Both purines
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What are cytosine, thymine and uracil?
Both pyrimidines
102
How many carbon-nitrogen rings does purine contain?
2 carbon-nitrogen rings joined
103
How many carbon-nitrogen rings does pyrimidine contain?
Only 1 carbon-nitrogen ring
104
What does phosphorylated mean?
Added phosphate
105
What does ADP contain?
Base adenine, sugar ribose and 2 phosphate groups
106
What does ATP contain?
Base adenine, sugar ribose and 3 phosphate groups
107
What is energy from glucose used to make?
ATP and then molecules of ATP provide energy for chemical reaction
107
What doe plant and animal cells release?
Energy from glucose
108
How is a phosphate bond formed?
ATP is synthesised from ADP and inorganic phosphate. The ADP is phosphorylated to form ATP and phosphate bond is formed
109
What is stored in phosphate bonds?
Energy
110
What is release from the phosphate bond and used by the cell?
Energy
111
What happens when energy is needed by a cell?
ATP is broken down back into ADP and inorganic phosphate
112
What is DNA made up of?
2 nucleotide chains joined together
113
What do nucleotides joined together to form?
Polynucleotides
114
What do nucleotides join up between?
The phosphate group of one nucleotide and the sugar of another (by a condensation reaction)
This forms a phospholipid-ester bond
115
What is a phospholipid-ester bond?
Phosphate group and 2 ester bonds
116
What is the sugar phosphate backbone?
Chain of sugars and phosphates
117
What is a chain of sugars and phosphates known as?
Sugar phosphate backbone
118
How can polynucleotides be broken back down?
Hydrolysis
119
What is DNA composed of?
2 polynucleotides strands joined together to form a double helix shape
120
How do polynucleotides join together in DNA?
Hydrogen bonding between the bases
121
How many bonds does adenine and thymine have?
2 hydrogen bonds
122
How many bonds does cytosine and guanine have?
3 hydrogen bonds
123
What does DNA replicate for?
To copy itself before cell division so that each new cell has the full amount of DNA
123
Why is DNA replication important?
For making new cells and for passing genetic info from generation to generation
124
What is the process of DNA replication?
1. DNA helicase (breakdown)
2. template/copy
3. DNA polymerase (joined together)
125
What is DNA helicase?
Breaks down hydrogen bonds between 2 polynucleotide DNA strands. Helix unzips to form 2 single strands
126
What is the template stage in DNA replication?
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
What is the DNA polymerase stage in DNA replication?
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
What is semi-conservative replicating?
1 original and 1 new strand that form to make a double helix DNA molecule
129
How accurate is DNA replication?
99.99%/ very accurate
130
Why does DNA replication have to be very accurate?
Makes sure genetic info is conserved each time cell is replicated but random spontaneous mutations can still occur
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What is a mutation?
Change in sequence of DNA bases
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What is a gene?
Sequence of DNA nucleotides that code for a polypeptide
133
What determines the order of the amino acids?
Different proteins have a different number and order of amino acids. The order of the nucleotide bases in a gene determines this.
134
What is each amino acid coded by?
3 bases (triplet) in a gene, different sequences of bases code for different amino acids
135
What do the sequence of bases in a section of DNA used as?
A template used to make proteins during protein synthesis
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Where is DNA found?
In the nucleus
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Why cant DNA move out of the nucleus?
It is too large so a section is copied into mRNA
This is called transcription
138
What doe mRNA do as it leaves the nucleus?
Joins with a ribosome in the cytoplasm where it can be used to synthesis a protein
This is called translation
139
What is RNA?
Single polynucleotide strand
140
What does RNA contain?
Uracil instead of Thymine
140
What are the 3 types of RNA?
- mRNA
- tRNA
- rRNA
141
What is mRNA?
Messenger RNA
single polynucleotide strand, made in nucleus during transcription
142
What does mRNA do?
Carries genetic code from DNA in nucleus to cytoplasm where its used to make proteins during translation
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What is tRNA?
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
What does tRNA do?
Carries the amino acids that are used to make proteins to the ribosomes, as have an amino acid binding site at 1 end
144
What is rRNA?
Ribosomal RNA
forms 2 subunits in a ribosome along with the proteins, ribosome moves along mRNA strand during protein synthesis
145
What does rRNA do?
rRNA in ribosomes helps catalyze the formation of peptide bonds between the amino acids
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What is the genetic code?
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
What is the first stage of protein synthesis?
Transcription
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What are the 4 stages of transcription?
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
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What happens in the first stage of transcription?
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
What happens in the second stage of transcription?
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
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What happens in the third stage of transcription?
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
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What happens in the fourth stage of transcription?
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
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Where does transcription take place?
Nucleus
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Where does translation take place?
Cytoplasm
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What is the first stage of translation?
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
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What is the second stage of translation?
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
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What is the third stage of translation?
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
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What is the fourth stage of translation?
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
