03 Chemistry and Biochemistry 1 Flashcards
1
Q
What are the 3 things atoms are made of?
A
Electrons, protons and neutrons.
2
Q
How many different elements are present in the human body and which ones account for 96% of them (percentages)?
A
26. Oxygen (O2) 65%, Carbon (C) 18%, Hydrogen (H) 10%, Nitrogen (N) 3%.
3
Q
What makes up the nucleus of an atom, and which are poz and neg charged? What are their masses?
A
Protons and neutrons.
Protons - positive.
Neutrons - no charge.
Both have a mass of 1 each.
4
Q
What do electrons do, what is their charge and what is their mass?
A
Negatively charged and buzz around the outside of the nucleus, creating electron cloud/shell.
Virtually no mass at all.
5
Q
What is a stable element?
A
It has same number of protons and electrons giving overall neutral charge.
6
Q
What does the atomic number mean that is assigned to each element of the periodic table top left?
A
Means the total number of protons in each element.
7
Q
What does the mass number mean that is in each element of the periodic table at the bottom?
A
Means the total number of protons and neutrons in each element.
8
Q
How do we work out the number of neutrons in an element?
A
Mass number minus atomic number (protons).
9
Q
What is an Isotope?
A
Atoms of the same element, which have different numbers of neutrons in the nucleus, which changes the mass.
10
Q
What are the basic number of electrons around an atom that are the minimum stable requirement?
A
2, 8, 8, 8.
11
Q
How many protons, neutrons and electrons in a hydrogen atom and why is it highly reactionary?
A
1x proton and 1x electron. No neutrons.
It looks for other atoms that need only one electron to fill it’s shell.
12
Q
Why are some elements inert?
A
Because they have their outer shell filled with the perfect number of electrons, so don’t react.
13
Q
How does an atom become an ion, what is this process called and are they positive or negatively charged?
A
By giving up or gaining electrons.
Ionisation.
Can be either + or -
14
Q
What is the name for the removal of electrons from an atom or molecule, and how does this effect the potential energy of a compound?
What does it mean when something is reduced and results in what change in energy?
If something has been reduced, what atom is it usually indicative of it gaining?
A
Oxidisation. Decreases potential energy.
Reduction means that it GAINS electrons and results in an increase of energy of that molecule.
Reduction usually indicative of gaining Hydrogen.
15
Q
What is the usual element that is removed from a molecule in oxidation and what is the name of this?
A
Usually hydrogen.
Called dehydrogenation.
16
Q
What does Ca2+ mean?
A
Calcium element that has a positive charge because 2 electrons have been removed from it (electrons are negatively charged, so when they are removed, the element becomes more positively charged).
17
Q
What is the difference between a neutral and non-neutral element?
A
Neutral has same amount of protons (+) to electrons (-).
If an element has more or less electrons added or minused, it then affects the charge of the element making it more positive or negative.
18
Q
What does Cl- mean?
A
Chlorine element that has had 1 electron added making it more negatively charged.
19
Q
What is a redox reaction?
A
When oxidation and reduction happens together.
20
Q
What are free radicals and what do they do and what is this called?
What then happens to the attacked molecule?
A
Molecules or compounds that have an unpaired electron in their outer shell.
They steal electrons from other stable molecules (oxidation).
Chain reaction of oxidative damage occurs in the attacked molecule.
21
Q
Where are free radicals created in the following environments:
The body?
The outside environment?
What is a healthy body able to do with free-radicals?
A
Aerobic respiration, metabolism, inflammation, exercise.
Pollution, sunlight, x-rays, smoking, alcohol.
Healthy body has mechanisms to mop up excess free radicals.
22
Q
What are 4 types of antioxidants and what do they do?
What makes a good antioxidant?
A
Vitamins, minerals, phytochemicals and enzymes.
Neutralise free radicals by donating an electron to the free radical making them harmless.
Good antioxidants remain stable after giving away an electron.
23
Q
What is a molecule and a compound?
A
A molecule is a group of atoms bonded together in a specific arrangement.
A compound is and electrically neutral substance containing two or more elements in a defined ratio.
24
Q
What is ion bonding and what are the two types?
A
When ions that are trying to become stable, bond with other ions so that they have the right amount of electrons on their outer shell.
Electrovalence (ionic) bonding.
Covalent bonding.
25
What is the difference between electrovalence (ionic) bonding and covalent bonding?
Elec (ionic) - one element donates an electron to another.
| Covalent - two elements sharing electrons so they both have the number of electrons that they need.
26
What is electronegativity and what are 4 of the most electronegativital elements?
Where some elements have a lot of electron pulling power.
| Fluorine, Chlorine, Oxygen, Nitrogen.
27
What types of bonds to hydrophilic and hydrophobic substances have?
Hydrophilic - polar-bonds.
| Hydrophobic - non-polar covalent bonds.
28
What is an electrolyte, what can these solutions conduct an why are they essential for the body?
When an ionic compound is dissolved in a solution e.g. salt.
Conduct electricity.
Body needs to conduct electricity for nerve and muscle function.
Exert osmotic pressure for water balance.
Acts as buffers for some acids to maintain the acid/base balance.
29
What is contained in an acid and what is a base (alkali)?
Acid releases lot's of H+ ions when dissolved in water.
| A base substance binds hydrogen ions in a solution which creates lot's of OH-.
30
What does potential and kinetic energy mean?
Where can energy be stored and what is this known as?
What can energy change into?
Stored and expended energy causing movement.
Can be stored between different atoms - known as chemical energy.
Can change into heat.
31
What are the 4 states of matter and how can matter move from one state to another?
Solid, liquid, gas, plasmas.
| Can move state using using physical force such as pressure or temperature.
32
Every reaction results in the transfer of energy in what three ways?
What are endothermic and exothermic reactions?
To potential energy, to kinetic energy or to heat.
Endothermic takes in heat to use as energy.
Exothermic releases heat into the environment.
33
What are chemical reactions reliant on and how can this be achieved?
COLLISION of molecules.
Enough molecules in order to collide.
The correct temperature.
Higher energy molecules move faster and more chance in colliding.
Increase in pressure also forces molecules closer together.
34
What do catalysts do?
Speeds up reactions by lowering the activation energy required, which makes the reaction faster or happen at a lower temperature.
35
What are inhibitors?
Act antagonistically to catalysts by making them less effective.
36
What are 4 types of chemical reactions? Explain.
Anabolic = synthesis (building reactions).
Generally endothermic = take in heat.
Catabolism = breaking down reactions.
Generally exothermic = releases energy.
37
What is a hydrolysis reaction?
| What reaction is it when water is formed as the waste product of a reaction?
When water is used to break down the molecule.
| Dehydration synthesis reaction.
38
What symbol is used to show reversible reactions?
Two arrows pointing both ways.
39
What is biochemistry?
What are the molecules of living things made from and what is the name of other molecules attached to the carbon molecule?
The chemistry of living things.
Carbon.
Functional group.
40
Name 7 functional molecular groups and what are their main characteristics?
Hydroxyl group - alcohols, -OH, polar h'philic.
Sulfhydryl group - thiols, -SH, polar h'philic.
Carbonyl group - keytones, aldenhydes-a, polar h'philic.
Carboxyl group - in amino acids, h'philic, weak acid or neg particle.
Esters - in lipids and triglycerides.
Phosphates - h'philic, can form double neg charge.
Amines - -NH2 act as weak base. All amino acids contain an amine group at one end.
41
What are 3 types of carbohydrate, what are they made of?
| What do they have many of and what does this allow it to do?
Starches, sugars and cellulose.
Carbon, Hydrogen, Oxygen - C(H2O)
Many OH groups, allows it to form hydrogen bonds and water.
42
What are the 3 main types of carbohydrate?
Monosaccharide, disaccharide, polysaccharide.
43
What are the 5 monosaccharides and how many atoms do they have?
```
3-7 atoms.
Glucose.
Fructose.
Galactose.
Deoxyribose.
Ribose.
```
44
What are the 3 disaccharides, what is each made from and how many atoms?
2 mon-sac atoms joined by dehydration reaction.
Sucrose = glucose + fructose
Lactose = glucose + galactose
Maltose = 2x glucose
45
What are the 3 polysaccharides, what re they made from and how many atoms?
Glycogen, starch, cellulose.
All made from glucose chains.
10-100's of mono-sac atoms joined by dehydration reaction.
46
What are monosaccharides, how are they grouped into families and what are their names?
Single sugars that can exist as single molecules.
Grouped into families named after how many carbon atoms they have.
Triose (3), pentose (5), heptose (7).
47
What are isomers and epimers?
Isomers have same chemical formula but different structures.
| Epimers have a difference on one carbon atom.
48
What is a glycosidic bond?
The bond formed during the dehydration synthesis of a disaccharide.
49
Are polysaccharides water soluble and are they sweet?
| What is the most common type of polysaccharide in the body?
No and no.
| Body's most common type is glycogen.
50
What is starch the main source of and what is it made up of?
Main source of dietary carbohydrate.
| Made up of 20-25% Amylose and 75-80% Amylopectin.
51
What is amylose and how is each glucosidic bond formed?
Single chain of glucose molecules.
| Each bond is formed between the first carbon of one glucose molecule and the fourth carbon of another.
52
What is amylopectin made from and what is it's structure shape?
How many glucose units can a molecule of amylopectin contain?
How are these glucose units linked?
Also made from glucose chains, but has a branch-like structure.
About 1 million glucose units.
Linked like amylose (1+4), but branching takes place with 1+6 bonds, occurring every 24-30 glucose units.
53
What is glycogen, what is it's primary function and what organs make it?
Polysaccharide of glucose.
Primary short term energy storage.
Made by the liver and muscles.
54
How many glucose molecules make up a glucose chain and how linked?
Approx 60,000 glucose molecules.
| Linked 1+4, ut about every 12, another chain/branch is linked by 1+6 by glucosidic bond.
55
What is cellulose and why can't our bodies break is down?
The structural material of plants.
| We are lacking cellulase in order to break the bonds of glucose in cellulose.
56
What are the 3 functions of carbohydrates?
Energy.
Limited form energy storage as glycogen in muscles.
Fibre - needed for proper bowel function.
57
How is glucose broken down in the body?
Where does digestion of carbohydrates stop, why, and where does it start again using what?
What enzymes from where, complete digestion?
a-amylase in the saliva splits the 1+4 glycosidic bonds.
Stops in the stomach due to pH.
Starts again in small intestine with pancreatic amylase.
Sucrase, maltase and lactase from the mucosal cells in the jejunum brush border complete digestion.
58
What 4 body processes is glucose used for?
ATP production.
Glycogen synthesis.
Triglyceride synthesis.
Amino acid synthesis.
59
What do carbohydrates and lipids have in common, but why different?
What makes lipids hydrophobic and what helps them move around the body? What do they then form?
Contain same elements of carbon, hydrogen and oxygen, but in different ratios.
Lipids have fewer OH groups which make them hydrophobic.
Attach to a protein to make more soluble - called lipoproteins.
60
What are triglycerides, what are they a concentrated form of, and are they solid or liquid?
How are they made up?
The main form of dietary fat and a concentrated for of chemical energy.
Can be solid or liquid depending on temperature.
1x single glycerol molecule with 3x fatty acid molecules attached to it.
61
What reaction takes place to attach fatty acids to glycerol to make a triglyceride and what is the name of the resulting bond?
How are they broken down?
Dehydration synthesis reaction (H2O removed) from each link leaving just O.
Resulting bond is called an ester linkage.
Broken down by hydrolysis reaction.
62
What are some functions of triglycerides?
Source of energy.
Storage of excess calorie intake.
Insulation.
Protection of body parts.
63
What type of bonds do saturated fats between their carbon atoms and what is each atom saturated with?
Are there any double bonds in a saturated fat chain?
Are saturated fats generally solid or liquid at room temperature, and why?
Single covalent bonds.
No double bonds in a saturated fat chain.
Saturated with a hydrogen atom.
Generally solid due to the way the molecules can pack closely together.
64
Why do monounsaturated fats have a bent shape?
| Are monounsaturated fats generally solid or liquid at room temperature, and why?
Contains one double covalent bond between two carbon atoms in the chain.
Generally liquid due to the way the molecules not being able to pack closely together because of it's shape.
65
How are fatty acids named and what would 20:4 mean?
Using the Greek alphabet, what letter is given the first carbon atom after the carboxyl join and what letter is given to the last carbon in the chain?
Named by the amount of carbon atoms and double bonds in the chain.
20:4 = 20 carbon atoms and 4 double bonds.
Alpha - first carbon.
Omega - last carbon.
66
How many double bonds are in a polyunsaturated fat chain resulting in what?
Solid or liquid at room temp?
Contains more than one double bond, making it's entire shape kinked.
Liquid due to it's shape and not being bale to pack together.
67
How do omega fatty acids (i.e. 3 and 6 etc.) get their names?
Including the omega carbon atom, it's the total amount of carbon atoms that appear before the first double bond.
68
In the presence of a double bond, what two types of configurations are possible and why?
Cis config' where the hydrogen atom is on the same side of the carbon atom on the other side of the double bond.
Trans config' where the hydrogen atom is on the opposite side of the carbon atom on the other side of the double bond.
69
Between cis and trans fats, which occur naturally in nature and how are cis fats turned into trans fats?
Cis fats occur naturally in nature.
Can be switched to trans by heating to high temperatures and by hydrogenation used to make processed foods and margarine.
70
What are EFA's and name 2 of them?
Essential fatty acids that cannot be made or synthesised by the body, therefore must be obtained through diet.
Omega 3 and 6.
71
Name the families of omega 3 and 6 oils and what can the body convert into each?
Omega 3 = ALA (alpha-linolenic acid), EPA, DHA.
Body can convert ALA into EPA, then EPA into DHA.
Omega 6 = LA (linoleic acid), GLA, AA.
Can convert LA into GLA, then GLA into AA.
72
What are 8 functions of EFA's?
Fluidity and chemical activity of cell membranes.
Synthesis of prostaglandins - hormones like substances that help regulate body processes.
Regulate oxygen use, electron transport and energy production.
Assists in formation of: haemoglobin, digestive enzymes, joint lubricants, bone formation and repair.
Help transport cholesterol in the blood and generate electrical impulses keeping heart rate regular.
Needed by tissue in the brain, retina, adrenal glands and testes.
Help balance immune system prevent allergies.
Helps with nerve transmission.
73
What are polyunsaturated fats prone to becoming and why?
Free radicals.
| Radicals can form at the CH2 groups between double bonds.
74
What 3 elements help free-radical creation, what should never be done with polyunsaturated fats and how should they be stored?
Light, oxygen and heat.
Should never be heated and used for cooking.
Should be stored in dark glass bottles out of light and preferably in the fridge.
75
What are chylomicrons and what do they do?
They carry triglycerides from the intestines to the liver, skeletal muscle and adipose tissue.
76
What are the 3 types of lipoproteins and what do they each do?
VLDL - very low density lipoproteins. Carry new triglycerides from the liver to adipose tissue.
LDL - low density lipoproteins. Carry cholesterol from the liver to body cells. (Bad cholesterol).
HDL - high density lipoproteins. Collects cholesterol from body cells and brings back to the liver. (Good cholesterol).
77
What is the make-up of a phospholipid, what else do they contain?
Are the head and tails polar or non-polar, and what is the name of this?
A glycerol molecule and 2 fatty acid chains.
Also contain a phosphate group linked to a nitrogen atom.
Head is polar (hydrophilic), tail is non-polar (hydrophobic).
Amphiphatic.
78
What are steroids, what is their structure and what are they made from?
Lipids that differ in shape to triglycerides.
| Made from cholesterol - 4 rings of carbon atoms, joined as their base and a hydrocarbon tail.
79
What is a sterol?
Steroid base that contains an –OH group (alcohol).
80
Where in the stomach are bile salts released to break down/emulsify fat?
What is the most important enzyme to break down fat and how does it work, then what further enzyme is used when they reach the small intestine?
The Duodenum.
| Pancreatic lipase breaks down triglycerides into glycerol and fatty acids, then intestinal lipase is used.
81
What are proteins built from and what elements make these?
| How may amino acids are found in human proteins?
Amino acids.
Carbon, hydrogen, oxygen, nitrogen and sometime sulphur.
20 amino acids.
82
What groups do all amino acids contain on their chains (with what exception?) and what is the side chain?
All contain a carboxyl group (–COOH) and an amino group (–NH3) attached to the alpha carbon (with exception of Proline).
Has side chain of R-group that determines characteristics.
83
What are the 9 essential amino acids and why are they essential in the diet?
```
Histidine.
Isoleucine.
Leucine.
Lysine.
Methionine.
Valine.
Phenylalanine.
Threonine.
Tryptophan.
Because they cannot be made by the body, so must be taken in by diet.
```
84
Which 5 amino acids can be made by the body?
```
Alanine.
Aspartic acid.
Glutamic acid.
Serine.
Asparagine.
```
85
What are the 6 conditional essential amino acids and what does conditional mean?
```
Arginine.
Cystine.
Glutamine.
Glycine.
Proline.
Tyrosine.
Can be made by the body, but only from the essential amino acids, so if these are lacking, these also become essential too.
```
86
What are stereo-isomers and what are they called, where are their forms and which form does the body use?
Where are D-form amino acids found?
Amino acids that come in mirror images of each other - called enantiomers.
Comes in L-form or D-form.
Body only recognises the L-form.
D-form found in antibiotics and some bacteria walls.
87
What is the difference between atoms, elements and matter?
Atoms are the individual building blocks of matter - like individual lego bricks.
When you have matter that is made out of only one type of atom, this is called an element - as in the periodic table.
88
What are peptides and what are these bonds called?
Amino acids that are joined together in condensation reactions called peptide bonds.
89
What is the name given to 2 and 3 amino acids joined together by a peptide bond?
What is the dipeptide aspartame made up of?
What is the body's own antioxidant glutathione made up of?
Dipeptide and tripeptide.
Aspartame made up of aspartic acid and phenylalanine.
Glutathione made up of L-cystein, L-glutamate and glycine.
90
What types of amino acids can act as buffers?
All free amino acids and charged amino acids in peptide bonds.
91
What is an amino acid's primary and secondary structures and what are the two types of secondary structure?
Primary - main linear sequence of the amino acid chain.
Secondary - amino acid side chain (R-group?) interacts with other amino acids causing a different shape to the molecule.
2 types of secondary - alpha helix and beta pleated sheet.
92
What is a tertiary structure?
| What is the most important interaction in a tertiary protein structure?
A more complex amino acid structure where amino acids join up using the side secondary structure.
Disulphide bond.
93
What do disulphide bonds form between?
Form between sulphur containing amino acids like cysteine.
94
What is a quaternary structure? Give an example.
The association of individual protein molecules within a larger structure.
E.g. A haemoglobin molecule is made up of 4 protein chains.
95
What does denaturing mean and how can this happen and what is the result?
Proteins are broken and become unfolded by breaking any of the bonds between side chains which makes them unable to function.
Heat, solvents, mechanical mixing, strong acids or bases, detergents, ions of heavy metals like lead of mercury.
96
What can cause protein mis-folding with what results? Give an example.
Can be caused by gene mutations which can cause disease processes.
Amyloid protein that is found in Alzheimer's disease.
97
Name 12 functions of proteins.
```
Structure of all body tissues.
Movement of actin and myosin fibres in muscles.
Carrier of molecules e.g. haemoglobin.
Storage of molecules.
Balance fluids in the blood e.g. albumin.
Enzymes.
Hormones.
Immune function e.g. antibodies.
Clotting mechanisms.
An energy source.
Control of gene expression.
Cell membrane receptors.
```
98
Where does protein digestion begin and with what?
| What is then converted into what enzyme to break down protein and what are they broken down into?
In the stomach with HCL with a pH of 2-3.
| Pepsinogen is turned into the active form pepsin enzyme (activated by HCL), then broken down into polypeptides.
99
What hormone and enzyme is released when a meal reaches the small intestine and what do these stimulate?
The hormone cholecystokinin (chol-e-syst-o-kinin - CCK) and secretin released which stimulates pancreatic protenzymes trypsinogen and chymotrypsinogen release.
100
What enzyme are protenzymes trypsinogen and chymotrypsinogen activated by and turned into what?
Once activated, what do the resulting enzymes do?
Activated by enterokinase (entero-kinase) resulting in trypsin and chymotrypsin.
These continue protein metabolism chopping proteins into di- and tri- peptides.
101
What are the building blocks of protein, carbohydrates and triglycerides?
Proteins - Amino Acids.
Carbohydrates - Monosaccharides.
Triglycerides - Glycerol and fatty acids.
102
What types of bonds do protein, carbohydrates and triglycerides have?
Proteins - Peptide bonds.
Carbohydrates - Glycosidic bonds.
Triglycerides - Ester linkage.
103
What reactions form the bonds for proteins, carbohydrates and triglycerides?
Proteins - condensation reaction.
Carbohydrates - condensation reaction
Triglycerides - dehydration reaction
104
How are the bonds of proteins, carbohydrates and triglycerides broken down?
Proteins - ???
Carbohydrates - hydrolysis reaction (???)
Triglycerides - hydrolysis reaction
