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THE CHEMISTRY OF LIFE Flashcards

(75 cards)

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1
Q

The basic unit of all elements

A

Atoms

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2
Q

Ionic bonds

A

Bonds formed when atoms give or receive electrons; they result in charged particles called ions

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3
Q

Covalent bond

A

Bonds formed when atoms share electrons; covalent molecules maybe polar if electrons are not shared equally

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4
Q

The separation of charge in a molecule when the electrons in the covalent bond are not evenly shared

A

Dipole

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5
Q

Polar molecule

A

A polar molecule is a molecule containing a dipole; a dipole is the separation of charge in a molecule when the electrons in a covalent bond are not evenly shared

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6
Q

When is a polarity particular common

A

If the bond contains one or more hydrogen atoms

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7
Q

Dissociation

A

Splitting of a molecule into smaller molecules, atoms, or ions especially by reversible process

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8
Q

Importance of NO3

A

Nitrate ions are needed in plants to make DNA and also amino acids and therefore protein from the products of photosynthesis

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9
Q

PO4

A

Phosphate ions are needed in all living organisms to make ATP and ADP as well as DNA and RNA

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10
Q

Cl

A

Chloride ions are needed in nerve impulses, sweating and many secretory systems in animals

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11
Q

HCO3

A

Hydrogencarbonate ions are needed to buffer blood pH to prevent it becoming to acidic

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12
Q

Na+

A

These are needed in nerve impulses, sweating and many secretory systems in animals

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13
Q

Ca 2+

A

Calcium ions are needed for the formation of calcium pectate for middle lamella between two cell walls in plants and for bone formation and muscle contraction in animals

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14
Q

H+

A

Hydrogen ions are needed in cellular respiration and photosynthesis and in numerous pumps and systems as well as pH balance

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15
Q

Mg 2+

A

These are needed for production of chlorophyll in plants

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16
Q

Why is water a polar molecule

A

Because the electrons are held closer to the oxygen atom than to the hydrogen atom

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17
Q

Hydrogen bonds

A

Hydrogen bonds are weak electrostatic intermolecular bonds formed between polar molecules containing at least one hydrogen atom

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18
Q

Why does water have a relatively high melting and boiling point

A

Because it takes a lot of energy to break down all the hydrogen bonds that hold the molecules together

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19
Q

Importance of water. Name 10

A

1.Water is a polar solvent because of this most of the chemical reactions within cells occurs in water

2.Water an excellent transport medium because the dipole nature of water enables many different substances to dissolve in it

  1. For insulation, as ice is less dense than Water.
  2. To maintain relatively constant temperature- water has a high specific heat capacity (4200J/Kg/°C) as it needs to break hydrogen bonds.

5.Water is a liquid that cannot be compressed. This is important in Hydraulic mechanisms in living organisms

  1. Water molecules are cohesive the forces between the molecules mean that they stick together. This is very important in the movement of water from the roots to the leaves of plants.
  2. Water molecules are adhesive. They are attracted to different molecules. Important in plant transport systems and surface tension.
  3. Water has a high surface tension because the attraction between the water molecules is greater than the attraction between water molecules and the air. It is important in plant transport systems and affects life at the surface of ponds and other water masses.
  4. As a coolant
  5. As a reagent and reactant; important in metabolic reactions particularly in hydrolysis and photosynthesis
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20
Q

General formula of monosaccharides

A

(CH2O)n

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21
Q

Simplest and most common groups of monosaccharides

A

Triose sugars- important in mitochondria, where the respiration process breaks down glucose into triose sugars

Hexoses

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22
Q

Pentose sugars ( what for )

A

Ribose and deoxyribose important in RNA and DNA

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23
Q

Features of hexose sugars

A

Exist as straight chains or commonly as rings

Ring forms have to types 1. a structure
2. B structure

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24
Q

Describe how a disaccaride is formed

A

Two single sugar units can join together and form a disaccaride in a condensation reaction, this results in a glycositic bond between the two monosaccharides

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25
Isomers
Molecules that have the same chemical formula, but different molecular structures
26
What are reducing sugars and non reducing sugars and how can they be tested
Sugars that react with benedicts solution. ( which contains copper (11) ions - and reduce them into copper ( 1 ) ) Sugars that don't react woth Benedicts solution are known as non reducing sugars. (sucrose) add a few drops of HCl and neutralizer it with sodium hydrogen carbonate to hydrolyse the glycosidic bond
27
Hydrolysis of disaccharides
When the glycosidic link between 2 sugar units in a disaccharide can be split by hydrolysis.
28
What type of carbohydrate group has little effect on water potential
Polysaccharides ( because soluble molecules like glucose would lower the water potential of cell cytoplasm, starch would not)
29
Explain the process of how triglyceride is formed
One glycerol and 3 fatty acids combine through a condensation reaction between the carboxyl group of a glycerol and the hydroxyl group of a FA resulting in three ester bond forming a triglyceride
30
How are lipids divided and give a brief explanation
Saturated fatty acids- if the fatty acid chain in a lipid contains the maximum number of hydrogen atoms they are said to be saturated. Long and straight No C=C bonds Pack together closely, results in fats in room temperature. Nonstaturated fatty acids- containing C=C double bonds Mono- 1 CC double bond Poly- many Kinked healthy Oils
31
Where is cholesterol made in Functions
The liver. Vital component in the cell membrane. The steroid sex hormone progesterone and testosterone and some other hormones and bile are produced from cholesterol
32
Phospholipids
Similar to triglycerides but one FA is replaced by a negatively charged phosphate group
33
Waxes
Hydrophobic, completely insoluble in water. they are good water repellent. formed when a long chain fatty acid esterified with a long chain alcohol
34
Functions of lipids
As a storage food energy storage animals living in dry conditions conserve water protect vital organs to absorb some vitamins and minerals easily insulate the body component of the cell membrane Rapid impulse transmission some of the hormones steriods waxes act as a water proof layer
35
Functions of lipids
As a storage food energy storage animals living in dry conditions conserve water protect vital organs to absorb some vitamins and minerals easily insulate the body component of the cell membrane Rapid impulse transmission some of the hormones steriods waxes act as a water proof layer
36
What are triglycerides soluble in
Organic solvent including Ether chloroform and ethanol
37
Formation of proteins
Formed by the polymerisation of amino acids linked by peptide bonds
38
Features of proteins
Consists of carbon hydrogen oxygen nitrogen and some sulphur 3D shape resulting from coiling and folding of polypeptide chains. Insoluble in water except for many enzymes difficult to crystallize can be denatured by temperature strong acids and strong bases heavy metals and mechanical fossil
39
Amino acids
20 common amino acids crystalline soluble in water The amino acid group of AA has basic properties and carboxyl group as acidic properties. ( amphoteric ) - positively charged at one end and negatively charged at the other end is known as a zither ion
40
Describe amylose
Straight chain, a-glucose 1,4 glycosidic bond. Spiral shaped with H bonds More compact
41
Describe amylose
Straight chain, a-glucose 1,4 glycosidic bond. Spiral shaped with H bonds More compact Soluble
42
Describe amylopectin
a glucose- 1,4 and 1,6 glycosidic bond Branched Less compact, cannot form a helix Not soluble
43
Glycogen
Main storage polysaccharide and animals bacteria and fungi. In animals this is mailly stored in liver and muscles. Access cookers converted to glycogen and stored in the liver, It can increase osmotic potential of the cell. The large polymer is stored in the cells as in a semi-soluble granular form. side branches rapidly hydrolyse giving easy access to store energy More compact than amlopectin
44
Advantages of glycogen as an energy storage molecule
A large molecule can allow storage of large amounts of energy compact insoluble- no osmotic effects Inert Large molecule Many side branches- can rapidly hydrolize to release large amount of energy
45
What is a peptide bond? Dipeptide
The bond formed by condensation reaction between amino acids, Two AA joined through a peptide bond
46
What are the factors that affect the structure of protein
1.Sequence of AA 2.Presence of hydrophobic and hydrophilic side chains in R group 3.Interactions between different groups of AA ( H bonds, disulphide bonds)
47
The 4 levels of protein structures
1. Primary structure 2. Secondary structure 3. Tertiary structure 4. Quaternary structure
48
Primary structure
The linear sequence of amino acids in a peptide
49
Secondary structure
Repeating pattern In the structure of the peptide chains such as an a helix or B peptide sheets
50
Tertiary structure
Three dimensional folding of the secondary structure
51
Quaternary structure
Three dimensional arrangement of more than one tertiary structure
52
Collagen
Strong fibrous protein with a triple helix held together by H bonds
53
Examples for quaternary structure
Insulin, haemoglobin, some enzymes
54
Examples for quaternary structure
Insulin, haemoglobin, some enzymes
55
The structure of hemoglobin
Globular protein Four peptide chains Surrounds an iron containing haem group which each can carry one oxygen atom ( one haemoglobin can carry a maximum of 4 oxygen atoms )
56
What gives the shape of the tertiary and quaternary structures
The bonding between the R groups of amino acids,disulphide bonds,ionic bonds,H bonds
57
Fibrous proteins
Parallel woth no or little tertiary folding. Shapes and lengths of the same protein may vary. Insoluble. Stable. Have a structural function
58
Globular proteins
Have a tertiary structure Specific shape, length Soluble (makes colloidal solution) Not stable Have a chemical function
59
Conjugated protein meaning and examples
Proteins joined to another molecule which is a non protein called prosthetic group Glycoproteins - hold a lot of water making it hard for protease to break it down, gives lubricant reducing friction. Lipoprotein- Involved in transport of cholesterol Myoglobin Heamoglobin
60
What is the information molecule of the cell
Nucleic acids
61
How are polynucleotides formed
Linked by condensation reaction of mononucleotides. The nucleotides join when phosphodiester bonds are formed Gives rise to the sugar phosphate back bone
62
Structure of DNA
Polymer of deoxyribonucleotide N bases- C,T,G,A antiparallel Forms a double helix H bonds form between base pairs Complementary base pairing
63
Structure of RNA
Single polynucleotide chain Ribose C,A,G,U three types- mRNA tRNA rRNA
64
mRNA (it's a single strand)
Used as a template for protein synthesis 3 bases are known as triplet bases or codon Forms the antisense/ template strand by taking the code of the sense strand
65
tRNA
Folded in some areas due to H bonding. ACC which is AA bonding site and other anticodon binding (complementary to mRNA)
66
rRNA
Found in the ribosome.
67
semiconservative replication and write te experimental evidence.
Assumed that DNA unzipped and new nucleotides aligned along each strand Experimenters grew few generations of the gut bacteria e coli in a medium where their only source of nitrogen was from the isotope 15^N. 15^N isotopes are densor than the usual isotope after few generations the entire bacterial DNA was made of 15^N After the bacteria was introduced back to the normal 14^N as te only nitrogenous source If DNA replicates by semiconservative replication then after one replication cycle all of the DNA would have the same density Halfway between that of 15^N and 14^N
68
The mechanism of replication
Synthesis of new DNA stand using old one as a template separating of the double helics of the DNA molecule and coil and unzip along the line of hydrogen bonds from one end of the molecule to the other by the DNA helicase is act as a template N bases form H bonds woth complementary bases of free nucleotides present in the cell DNA polymerase and lipase join nucleotides together to form new DNA
69
Genes
A sequence of bases od DNA coding for a sequence of amino acids in a polypeptide chain
70
Genes
A sequence of bases od DNA coding for a sequence of amino acids in a polypeptide chain
71
Characteristics of genetic code
.Triplet codes .Non overlapping codes .A degenerative code- if the third base is changed this variation could still produce the same amino acids
72
How are all 3 RNA transcribed from DNA
RNA polymerase
73
Transcription
The process by which the DNA sequence is used to make a strand of mRNA In the nucleus. Only one small piece of DNA is copied. RNA polymerase becomes attached to the double helix of the DNA Starting code is methionin. Hydrogen bonds of the region of double helix unwinds One of the stands of the DNA act as a template
74
Translation
The process by which the DNA code is converted into a protein from the mRNA in the nucleus
75
Polysomes
Groups of ribosomes, joined by a thread of mRNA, that can produce large quantities of a particular protein.

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