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Nutrition Y1 - Semester 1 > Chemistry & Biochemistry 1 > Flashcards

Chemistry & Biochemistry 1 Flashcards

1
Q

What is an element

A

Cannot split into a simpler form

Substance made up of 1 type of atom and cannot be split into simpler substances

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2
Q

How many elements in the human body

A
  1. 4 major ones are
    Carbon
    Hydrogen
    Oxygen
    Nitrogen
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3
Q

What makes an atom

A

Protons (+) and neutrons form nucleus = 1 atomic mass each

Electrons (-) outside of nucleus = virtually no mass at all

Atom will have an equal number of protons and electrons giving overall neutral charge to the atom

All chemical properties of an atom are down to its number of protons and electrons

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4
Q

Electrons

A

Move in groups along the nucleus known as electron shells

Electrons pair up within their shells

First pair in the ring is 2, then second ring is up to 8
Except hydrogen which is so small it only has 1 electron.

Atom becomes reactive if outer shell isn’t full or loses an electron.

More it loses, more reactive = free radical

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5
Q

Oxidation

A

Positive charged = volatile and creates tissue damage
Any atom with unfulfilled orbits of electrons are unhappy

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6
Q

Periodic table

A

Arranged in columns and rows to show which elements share reactivity and physical properties

The number assigned shows how many protons and therefore electrons each atom had

Large number is the mass (in atomic units).

To find out how many neutrons=
Mass number - atomic number

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7
Q

Halogens

A

In Row 17

Share very similar chemical properties

Thyroid issues: If chlorine and fluoride are present in body, they can enter the thyroid preventing formation of T3&T4 which insides hypothyroidism

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8
Q

Isotopes

A

Atoms of the same element which have different numbers of neutrons in the nucleus

Doesn’t affect chemical activity, only the mass

Isotopes and radiation
Some have imbalance of protons and neutrons in the nucleus which causes them to be unstable and therefore causes radioactivity. Unstable atom needs to get rid of energy to become stable
PET scan imaging technique, radioactive isotopes are introduced and often injected into the body

Radiotherapy uses gamma rays from radioactive isotopes to target rapidly dividing cells.

Breathe test for H.pylori uses urea labelled with either radioactive carbon or non-radioactive carbon

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9
Q

Electron shells

A

All of the reactions that happens in chemistry are driven by atoms trying to end up with a stable and full outer shell either by stealing or giving away or sharing a electrons

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10
Q

Inert elements

A

Atoms with outer shell filled with perfect number so rarely involved in chemical reactions

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11
Q

Bonding

A

Atoms trying to become stable by bonding with other atoms so they can get just the right number of electrons in their outer shell.

2 types; ionic and covalent

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12
Q

Ionic bonding

A

When one atom donates some of its electrons to another

Usually occurs when there are 1. 2 or occasionally 3 electrons to donate
Moving any more isn’t energetically favourable

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13
Q

Ions

A

If atom gives up or gains electrons to fill its outer shell, it becomes an ion

Ionisation: process of giving or gaining electrons

Gives an electron = positive charge
Takes an electron = negatively charged

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14
Q

Covalent bond

A

When 2 elements share electrons so that they both have the magic number they are looking for.

Tends to happen when 2 atoms are similar or when lots of space to be billed to reach a full outer shell

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15
Q

Polar bonds

A

Forms when electrons are shared unequally.
Happens as some atoms have a lot of electron pulling power

Electronegative: Some have lots of protons compared to number of electron shells (ie strong + centre) so they tend to pull shared electrons toward themselves
These electronegative atoms are able to pull electrons in a bond towards them, leading to uneven distribution of charge

Fluoride, chloride, oxygen and nitrogen are lost electronegative elements

Hydrogen and O2 making water most important example. 02 pulls electrons towards itself, resulting in - charge area over 02 and + over H
H are then attracted to the - charge
Loving interactions called H bonds and gives water its special properties:
Surface tension and ability to dissolve many things.

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16
Q

Hydrogen bonding

A

Hydrogen and O2 making water most important example. 02 pulls electrons towards itself, resulting in - charge area over 02 and + over H
H are then attracted to the - charge

Loving interactions called H bonds and gives water its special properties:
Surface tension and ability to dissolve many things

Water serves as medium for most chemical reactions
As water contains polar bonds, ideal docent for dissolving chemicals into their separate ions.

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17
Q

Hydrophilic molecules

A

Polar bonds.
Dissolve easily (eg alcohol)

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18
Q

Hydrophobic molecules

A

Non polar covalent bonds
Don’t dissolve easily

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19
Q

Electrolyte

A

Formed when ionic compound (eg salt) dissolves in water

Can conduct electricity

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20
Q

Key electrolytes in body

A

Potassium
Magnesium
Sodium
Chloride
Phosphate
Bicarbonate
Calcium

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21
Q

Electrolyte important body constitutions because

A

Conduction of electricity I’d essential for nerve/muscle function

Exert osmotic pressure important for water balance

Some play important role in acid base balance

pH balance

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22
Q

What is an acid

A

Substance that released a high amount of H+ ions when dissolved in water

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23
Q

What is a base

A

Substance which binds to H ions in solution.
Creates a lot of OH-

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24
Q

Water

A

Neutral solution
Because every H+ ion released and OH- is also created.
pH scale was developed using water as standard

pH is 7
(Blood is 7.35 - 7.45)

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25
Q

pH and digestive system facts

A

Fruit and veg contain organic acids. Low pH measured before consumption
- organic acids metabolised by body and intestinal bacteria make it alkaline
- foods high in alkaline minerals (potassium, magnesium, calcium) also contribute to net alkaline effect

Dairy not very acidic before consumption, high in calcium.
Yet more acidic due to high protein and sulphur content
The sulphur aa increases sulphuric acid formation, then disrupts blood ph drawing more calcium from bones and calcium loss in urine

Meat high in acid
Refined sugar and processed foods
Stress and sedentary acidic environment

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26
Q

Chemical reactions

A

Occurs when new bonds are formed or old bonds are broken between different molecules

Every reaction involves the transfer of energy to either potential (stored) energy, kinetic energy or heat

Starting molecules = reactants
End molecules = products

Reactions must always balance in electrons from one side to another

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27
Q

Collision theory (for chemical reaction to occur)

A

Needs to be an opportunity for 2 molecules to collide
- higher the energy of the molecule, the faster they move and the greater chance they have of reacting
- min energy that is required for a reaction is known as the energy of activation
- chemical reactions are reliant on the correct temp and enough reactants
- changes in pressure can also change the speed of reward on, with increased pressure forcing molecules closer together

28
Q

Catalyst

A

Speeds up reactions by lowering the activation energy required

Means reaction is faster or can occur at lower temps

Body catalysts are enzymes

29
Q

Inhibitors

A

Act antagonistically to catalysts

Stop catalysts from being so effective by making the activation energy higher and hence slow down the reaction time

Many drugs inhibitors - eg statins are HMG-CoA reductase inhibitors

30
Q

Anabolic chemical reaction

A

Synthesis (building) reactions

Occurs when body is making new substances and building new bonds

Eg taking aa and building a protein. Requires energy

A+B = A - B

31
Q

Catabolism chemical reaction

A

Reactions where breaking down occurs

Eg when breaking down food, releasing energy from them.
Trap energy as ATP

A - B = A+B

32
Q

Hydrolysis reaction

A

When water is medium and breaks molecule into smaller pieces

33
Q

Dehydration synthesis

A

When water formed as the waste product of a reaction

Normally when larger molecules are being made - eg making carbs

34
Q

Reversible reactions

A

Products of the reaction can react together to produce the original reactions

A + B = AB / AB = A + B

These reactions establish equilibrium where are always some starting materials and some product present

Controlling direction of reversible reactions is very important in the body. Done using enzymes and having mechanisms in place that allow us to remove starting materials and products

35
Q

Buffer system

A

Substances that maintain H+ concentration in the body within normal limits. They can bind to H+ ions and OH- to ensure the blood pH remains between 7.35 and 7.45

Most important is bicarbonate buffer system which mops up excess acidity. (HCO3)

36
Q

Bicarbonate buffer system

A

Catalysed by carbonic anhydrase

CO2 from cellular respiration reacts with water in the blood to for. A carbonic acid which rapidly dissociates to form a bicarbonate and hydrogen ion

Reactions are reversible and any given time there is a balance of CO2, H2O carbonic acid, H+ and HC03 in the blood

Carbonic anhydrase
CO2 + H20 <-> H2CO3 <-> HCO3- + H+

When extra H ions accumulate in the blood, eg lactic acd, the reaction is able to adjust to mop up the excess H+ ions, making more CO2 and H20

Then accounted for by increased breathing rate and exhalation of C02 through lungs

Kidneys also play role in buffer system as they can produce HC03- buffer. Also can excrete H+ ions

Kidneys fairly slow in this system and their production of HC03- is fairly strenuous upon the organ, therefore important to avoid an acidic diet so as to reduce the stress on the system

37
Q

Oxidation

A

Removal of electrons from an atom or molecule is oxidation

Reduces potential energy in a compound

Generally most oxidation occurs by removing electrons with the help of hydrogen.

As hydrogen is lost, often called dehydration reaction

When something is reduced, gains an electron resulting in the increased energy in that molecule

38
Q

Free radical

A

Molecules or compounds that have impaired electron in outer shell

Wants to stabilise so tries to steal electrons from other stable molecules

Becomes destructive and causing oxidation

Leaves attacked molecule with impaired electron, so chain reaction of oxidative damage

Free radicals even take electrons from DNA which can ultimately result in cancerous changes

39
Q

Oxidative damage

A

Free radicals can cause oxidative damage to tissues in the body

Linked to cancer, atherosclerosis, fibromyalgia, and neurodegenerative diseases

Need to reduce exposure to free radicals. Whilst optimising antioxidant status to help protect

40
Q

Antioxidant

A

Work by donating electron to free radicals to covert them to harmless molecules, without being damaged themselves.

Consists of group of vitamins, photochemical and enzymes

Key to good antioxidant is must be stable once it has given away its electron

41
Q

Types of antioxidant

A

Beta - carotene
Vitamin e
VIT c
Quercetin
Glutathione perioxodase
Alphahpoid acid (meat, eggs)

42
Q

Biochemical molecules

A

Living things that are characterised by molecules made from carbon

Functional groups: any other groups of atoms attached to the carbon skeleton. Contributes to the structure and function of that molecule

Biochemical date important when considering the living nature of biochemistry

43
Q

Functional groups

A

Hydroxyl group: alcohols. Polar and hydrophobic

Sulfhydryl group: common in some protein chains. Found in sulphur containing cysteine
Polar and hydrophilic

Carboxyl group: found in aa.
Hydrophilic and can interact as a weak acid or as negative particle

Amine group: found in as
-NH2 group can act as a weak base if necessary

Esters: predominant bond in triglycerides
Long term energy source

Phosphates: found in ATP
Very hydrophilic as they can form double negative charge
Can attract a lot of energy

44
Q

Carbohydrates

A

Includes starches, cellulose (plants) and sugars
Carbon atoms normally arranged in a ring with 02 and H+ atoms attached
Have many OH- groups so they break for H bonds. Meaning smaller carbs such as simple sugars can dissolve easily in water

45
Q

Monosaccharides

A

3-7 carbon atoms
Simple sugars, most have sweet taste
Grouped into families named after the number of carbon atoms

All end in -ose

Glucose
Fructose
Galactose
Deoxyribose
Ribose (in DNA)

46
Q

Disaccharides

A

2 monosaccharides joined together as dehydration reaction to form a disaccharide

Removing water to form a glycosidic bond

If we’re to ingest a disaccharide we can break it down by putting water back into the bond

Sucrose (glucose and fructose)
Lactose (glucose and galactose)
Maltose (glucose and glucose)

47
Q

Polysaccharides

A

10s to 100s of monos in glycosidic bonds - joined together by dehydration reaction

Normally insoluble in water (given up many OH molecules)
Do not taste sweet
Digestion begins in oral cavity

Glycogen (most common type)
Starch
Cellulose
(All glucose chains)

48
Q

Starch: amylose and amylopectin

A

Starch is major dietary source of carbs
Digestion begins in oral cavity
Found in breads; rice, pasta, etc

Made up of 2 different polysaccharides:

25-25% amylose
76-80% amylopectin

Amylose: single chain of glucose units (limits surface area exposed for digestion)
Foods high in this referred to as resistant starch and digested more slowly
Ends up in large intestine and acts as good source for bacteria there

Amylopectin: branch like structure, also made by glucose (more surface area available for digestion: broken down quicker = blood sugar spike and higher rise in insulin)

49
Q

Glycogen

A

Polysaccharides of glucose which functions as primary short term energy storage

Each molecule made up of 60,000 glucose molecules and even more branches than amylopectin

Made and stored primarily in liver and muscles

Glycogen in liver can be used to maintain blood sugar levels, whereas in muscle can only be used by that particular muscle

50
Q

Cellulose

A

Structural material of plant cell walls

Glucose polymer but linked in a way to make flat ribbon like strand with overall rigid structure

Humans lack correct enzyme to break unique bond between glucose molecules so we cannot digest it

Cellulose acts as fibre assisting with bowel movement through intestines

Most abundant organic compound on earth

51
Q

Carbohydrate functions

A
  • Energy
  • Fibre (proper bowel functions, prevents against cardiovascular disease, against diabetes, increase satiety, aids weight loss, protects against colorectal cancer)
  • number of processes: ATP production, glucogen synthesis, aa synthesis
52
Q

Carbohydrate digestion

A

Salivary amylase starts working on the end of the long glucose chains in starches (chew for long time tastes sweet)

Salivary analyse works well in fairly neutral pH but neutralised by stomach acid

In small intestine, pancreatic analyses continues carb digestion, goes into disaccharide units.

Brush border enzymes in small intestine do final stage (lactase, Maltase and sucrase)

53
Q

Lipids

A

Contains elements - carbon, hydrogen and O2,
Like carbs but in different ratios

Few polar OH groups = hydrophobic

To move around body, often gets protein to make them more soluble (lipoproteins)

54
Q

Triglycerides

A

Main form of dietary fats
Contains single glycerol molecule and 3 fatty acid chains (saturated or unsaturated)

Combination will determine if solid or liquid at room temp

Ester: Fatty acids attached to fully Erik by dehydration synthesis - bond known as ester (different from carbs)

Broken down by hydrolysis reaction

55
Q

Triglyceride functions

A

Most efficient energy source, but process of energy released from fat is less efficient than when carbs are used

Provide convenient form to which to store excess calorie intake

Insulation

Protection of body parts and organs

56
Q

Saturated fats

A

Form of triglycerides

Contain single covalent bond between each fatty acid atom
Each carbon atom Saturated with H atoms

Saturated fatty acids are very straight meaning they can line up close to each other and hence more likely to be solid

Eg coconut oil

57
Q

Monounsaturated fats

A

Contains fatty acids with one double covalent bond between 2 carbons

Double bond forces molecule into bent configuration

Monounsaturated fats are generally liquids at room temp (,m can’t pack closely together)

Eg olive oil

58
Q

Polyunsaturated fats

A

Contains more than 1 double bond in carbon chain

Molecules are kinked

Liquid at room temp

Eg sunflower, rapeseed, vegetable oil

59
Q

Fatty acids

A

Omega 3 = double bond is 3 carbons up from end

Omega 6 = double bond is 6 carbons up from the end

Named according to the closest double bond to end of chain

End of chain is always the end without O2

Both essential in our diet

60
Q

Cis and trans configurations

A

Presence of double bond means 2 different molecular configurations are possible

Cis = H atoms on same side of double bond

Trans = H atoms on separate sides of double bond

In nature, nearly all have cis bond.

Cis fats make cell membrane more flexible
Trans stiffens cell membranes and are prone to oxidative damage and making cell membranes leaky
Formed during high heat or hydro generation reactions

61
Q

Omega 3

A

Alpha-linolenic acid (ALA) - essential in diet (flax seeds, walnuts, green leafy veg)

EPA & DHA - oily fish

62
Q

Omega 6

A

Linoleic acid (LA) - essential in diet (veg oils, most nuts and seeds)
GLA - borage oil; evening primrose oil
AA - meat, dairy, eggs

63
Q

Essential fatty acids

A

Polyunsaturated fatty acids that cannot be constructed within the body from other components and therefore must be obtained from diet

Conversion of ALA to EPA and DHA is only about 10% efficient, even lower for LA to GLA & AA

The conversion between them involves adding in double bonds. This involves desaturase enzymes

Same enzymes used; it will ultimately favour EFA

64
Q

Fatty acid oxidisation

A

Polyunsaturated fats such as EFAs are v prone to becoming free radicals

When fats heated, electrons can be lost. Means that a fat is formed that becomes a free radical. (Further reacts with O2 in cooking pan which becomes even more damaging)

CH2 groups between double bond are especially vulnerable because radicals formed at these points in the molecule are very stable

Radical formation accelerated by:
Light, O2 and heat

65
Q

Lipoproteins

A

Fat molecules that have been joined to a protein molecule, enabling lipid to move around the bloodstream

Contains triglycerides and cholesterol internally

Synthesised by the liver

TYPES:
Very low density lip (VLDL): carry newly synthesised triglycerides from the liver to adipose tissue

Low density lip (LDL): carry cholesterol from liver to cells of body. Needed to repair cells; support cell membranes and synthesise sex and adrenal hormones

High density lip (HDL): collect cholesterol from body’s tissues, bringing back to liver

66
Q

Phospholipids

A

Contain glycerol part & 2 fatty acid chains

Phosphate head contains lots of -OH molecules which make it hydrophilic and therefore polar and water soluble

Fatty acid tails non polar and only interact with other lipids - hydrophobic and fat soluble

Fatty acid tails contain saturated and unsaturated fats (cells should contain a balance of these)

Amuphiphatic: soluble on one side, insoluble on other

67
Q

Steroids

A

Lipid forms of cholesterol

Differ in shape than triglycerides where formed of 4 rings of carbon atoms joined together at their base

Sterols are steroid bases that contain -OH group

Used to create hormones, eg oestrogen and cortisol

We do not need to eat/ingest as liver produces it

Nutrition Y1 - Semester 1 (10 decks)

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