Biochemistry 1 Flashcards
What is ‘matter’?
Everything around us that has mass and occupies space.
What is chemistry?
The science and study of matter (gases, liquids and solids)
List 3 forms of ‘matter’.
Gases
Liquids
Solids
What is ‘biochemistry’?
The science and study of the chemical and physiochemical processes and substances within LIVING organisms.
What is the difference between chemistry and biochemistry?
Chemistry is the science concerned with substances and various forms of elementary matter, whilst biochemistry is the science concerned with the same in LIVING organisms.
What 3 things are atoms made up of?
Electrons, Protons and Neurons
What are atoms?
Small particles that make up ‘matter’. They’re like lego bricks that make up everything in our universe
‘bio’ = ______
Life
An ‘element’ is a substance made up of just one type of _____.
Atom
Why can’t elements be split up into simpler substances?
Because elements are substances made up of just one type of atom (lots of identical lego bricks together)
All the elements we know of are in the ______ ______
Periodic Table
What is the chemical symbol for carbon?
C
What is the chemical symbol for hydrogen?
H
What is the chemical symbol for calcium?
Ca
What is the chemical symbol for magnesium?
Mg
Name 4 elements from the periodic table
Carbon
Hydrogen
Calcium
Magnesium
What is the name given to a group of individual atoms joined together by bonds?
A molecule
How many different elements are normally present in the human body?
26
There are 4 major elements which account for 96% of the human body. Name them.
Carbon
Hydrogen
Oxygen
Nitrogen
What is Fe?
Iron
Name 3 ‘transition metals’
Iron
Zinc
Copper
Why do transition metals and some other groups of elements on the periodic table interfere with each others absorption?
Because they are a similar size and similar chemical reactivity, so compete for the same transporters.
Name 3 halogen elements
Fluorine
Chlorine
Iodine
What are subatomic particles?
The components of an atom.
How many subatomic particles are there? List them.
3 - Protons, neutrons, electrons
Which subatomic particles together form the nucleus of an atom?
Protons and neutrons
Which of the subatomic particles carries a positive charge?
Protons
Which of the subatomic particles carries no charge?
Neutrons
Which of the subatomic particles carries a negative charge?
Electrons
Which of the 3 subatomic particles is the smallest?
Electrons
State the individual masses of the 3 subatomic particles.
Protons = 1 atomic unit Neutrons = 1 atomic unit Electrons = virtually no mass at all / nothing
An element will have an equal number of protons and electrons. True or false?
True
What are electron shells?
Layers of electrons moving in groups around the nucleus of an atom.
What happens to an atom if it has an electron that isn’t paired? What name is given to that atom in this situation?
It becomes very stable.
Free radical
When does an atom become reactive?
If its outer electron shell isn’t full, or if it loses an electron.
What are free radicals?
Atoms or molecules that have an unpaired electron.
What is the difference between atoms and molecules?
Atoms are single neutral particles.
Molecules are neutral particles made of 2 or more atoms bonded together.
Are atoms and molecules positive, negative or neutral?
Neutral.
Do protons have a positive or negative charge?
Proton = Positive
Do electrons have a positive or negative charge?
Electrons = Negative
How many electrons can be found in the first electron shell (nearest the nucleus of the atom)?
2
How many electrons can be found in the second electron shell?
Up to 8
How many electrons can be found in the third electron shell?
Up to 8
What is the periodic table?
A list of all the currently known elements
Why is the periodic table arranged in particular columns and rows?
To show which elements share similar reactivity and physical properties.
In the periodic table, what does the number assigned to each element tell us?
The atomic number tells us the number of protons in the nucleus
Potassium (K) has an atomic number of 19. What does this tell us?
That there are 19 protons in the nucleus of a single atom of potassium.
A single atom of potassium (K) has 19 protons in it’s nucleus (atomic number 19). How many electrons does it have?
- The number of protons always matches the number of electrons.
What does the second (bigger) number attached to an element on the periodic table tell us?
The mass / atomic weight of one atom of that particular element.
Potassium carries the atomic number 19, and has an atomic mass of 39. How many neutrons does it have in its nucleus?
20
39 - 19
All of the elements in column 1 (Group 1) of the Periodic Table react with ______
Water
All of the elements in column 1 (Group 1) of the Periodic Table have how many electrons in their outer shell?
1
This means they’re very reactive.
What name is given to the elements in column 7 of the Periodic Table?
The halogens
List 3 elements in the halogen group?
Fluorine, Chlorine, Iodine. Bromine, Astatine
Why is iodine important when it comes to thyroid health?
Because it is required to make the thyroid hormones T3 and T4
What’s different about Column 7 (the halogens) of the Periodic Table, versus the other columns?
The reactivity tends to be higher at the top of the column, rather than at the bottom.
i.e, fluorine is more vigorous in its reactivity than iodine is.
Explain why fluorine and chlorine present a risk to thyroid health.
Fluorine and Chlorine are more reactive than iodine, but the thyroid will uptake all of them.
The more reactive halogens will elbow the iodine out of the way, creating problems with the body absorbing and using the iodine properly.
This can cause hypothyroidism.
Which of these assigned to an element is always bigger; the atomic mass or the atomic number?
The atomic mass
Atomic number = number of _______
Protons
Mass number = number of ______ + number of ____
Protons + neutrons
The total mass of an atom is always in its nucleus
Number of neutrons = _______ number minus ______ number
Mass number - atomic number
What are isotopes?
Atoms of the same element which have a different number of neutrons in their nucleus.
Essentially, isotopes are different versions of the same atom.
The chemical reactivity stays the same, but the atomic weight varies. i.e, isotopes are lighter and heavier versions of the same atom.
For every element on the periodic table, there is often more than one version (various isotopes). Give an example of an element to which this applies and describe its isotopes.
Carbon.
Most of the carbon in the universe is carbon 12 (6 protons and 6 neutrons)
But small amounts of Carbon 14 (8 neutrons) exist.
What causes an isotope to become radioactive?
An imbalance of protons and neutrons in its nucleus.
The imbalance causes the atom to become unstable, so it’s tries to rebalance itself by releasing particles of energy. This is radiation.
Name 1 way in which radioactive isotopes are used in medicine.
PET scans (via injected short-lived radioactive isotopes)
What is the difference between short-lived and long-lived radioactive isotopes?
Short-lived isotopes release their excess energy quickly (over hours / days), so don’t remain radioactive for long.
Long-lived radioactive isotopes release their energy slowly (over days / weeks / months / years), so remain radioactive for much longer.
Name 2 diagnostic tests / medical treatments that use radioactive tracers
- Radiation
2. H-Pylori breath test
What are radioactive tracers?
Radioactive isotopes that emit gamma rays from within the body
What is gamma radiation?
Very high energy wavelengths that damage rapidly dividing cells.
The wavelengths in this type of radiation are so small that they can actually get into the nucleus of the cell, damaging the DNA and making it unviable.
What is the downside to medical treatments that utilise gamma radiation?
Gamma radiation is not just specific to unhealthy / cancer cells. It also damages healthy cells.
What is the food source for H-Pylori in the stomach?
Urea
Electrons always want to be in ______
Pairs
What makes one atom want to bond with another?
The drive to pair electrons and end up with a stable/full outer shell.
All of the reactions that happen in chemistry are driven by…..
Atoms trying to get a stable/full outer shell of electrons
either by donating one, stealing one (or more), or sharing
There are 3 ways in which atoms can obtain a stable/full outer shell of electrons. What are they?
- Donate
- Steal
- Share
Name the ‘simplest atom’ and explain why it has that name.
Hydrogen is the ‘simplest atom’
Because it has 1 proton, 1 electron and no neurons
Why is hydrogen very reactive?
Because it only has 1 electron.
In nature, hydrogen atoms don’t exist on their own. Why not?
Because they’re so reactive (with only 1 electron) that hydrogen always pairs with itself via sharing of electrons, or bonds to something else.
What is an ‘inert’ element?
An element with a full outer shell of electrons.
Why are inert elements rarely involved in chemical reactions?
Because they have a full outer shell of electrons, so are not highly reactive.
Name the 2 main types of bonding.
- Ionic bonding
2. Covalent bonding
Describe what happens in ionic bonding.
Electrons are transferred from one atom to another
What is the difference between ionic and covalent bonding?
In ionic bonding, electrons are transferred from one atom to another, in order to form electron pairs.
In covalent bonding, electrons are shared between atoms, in order to form electron pairs.
When does Na- become Na+ ?
When it gives away its spare electron.
The charge changes, as it then has more protons (+ve charged) than electrons (-ve charged).
What is ‘ionisation’?
The process of giving or gaining electrons
What does + or - written next to an ion (i.e, Cl-) indicate?
Their positive or negative charge after bonding.
A +ion has more protons than electrons
A -ion has more electrons than protons
Remember: a raw atom has an equal number of protons and electrons (parents and children!)
An ion is also known as a _______ particle.
Charged particle.
Sometimes atoms give away more than one electron. How might you see this written?
Calcium
Ca2+ is a calcium atom that has given away 2 electrons.
Name the 4 most electronegative elements.
- Fluorine
- Chlorine
- Oxygen
- Nitrogen
Some elements have lots of protons compared to their number of electron shells (i.e, a strong positive centre). These elements are referred to as _________
Electronegative
What is the name given to an element that has a strong positive centre and tends to pull shared electrons towards itself?
Electronegative
What is the name given to covalent bonds where the electrons are shared, but unequally?
Polar bonds
Why do polar bonds occur?
Become some atoms have more electron ‘pulling power’ than others. They pull shared electron clouds towards themselves.
Why are polar bonds important in Chemistry?
Because they create little magnets in our molecules, which allow molecules to stick to each other.
Give an example of one of the most important polar bonds in biochemistry.
Oxygen and hydrogen (water)
________ bonding is an example of polar bonding, and gives water its surface tension and ability to dissolve so many things.
Hydrogen bonding
________ bonding is an example of polar bonding, and gives water its magnetic surface tension (i.e, sticking a glass to a coaster) and ability to dissolve so many things.
Hydrogen bonding
What serves as the medium for most chemical reactions in the body?
Water
What is the ‘Universal Solvent’?
Water
Hydrophilic molecules are molecules that have _____ covalent bonds.
Polar
Hydrophobic molecules are molecules that have ____-____ covalent bonds.
Non-polar
What type of bonds are magnetic-creating bonds?
Polar bonds
What is an ion?
A charged particle. It is an atom that has either gained an electron, or given one away.
Explain what is meant by an isotope.
Isotopes are chemical elements that are the same elements but with a different number of neutrons. So they have different atomic masses.
i.e, carbon 14, versus carbon 12
Describe the association between iodine and fluorine.
They’re both halogens (Group 7 on the periodic table). However fluorine is more reactive/powerful than iodine, so an excess of fluorine in the body can push iodine out of the way and compromise thyroid function.
How many electrons are required to fill the second electron shell?
8
Describe what happens in ionic bonding.
One element (atom) gives an electron to another element, resulting in 2 positive and negatively charged atoms that are attracted to each other.
Give an example of a polar molecule.
Water.
Explain what is meant by ‘The Universal Solvent’.
Water’s unique ability to dissolve anything with polar bonds, or ionic compounds (things with positive and negative ions).
Electrolytes can conduct ________
Electricity
Solutions of ionic compounds are called ________
Electrolytes
Name 4 of the key electrolytes in the body.
- Sodium
- Potassium
- Chloride
- Calcium
- Magnesium
- Phosphate
- Bicarbonate
When / how is an electrolyte formed?
When an ionic compound (i.e, salt) dissolves in water
List 3 functions of electrolytes within the body.
- Conducting electricity (essential for nerve and muscle function)
- Exerting osmotic pressure (essential for water balance)
- Some play an important role in acid-base balance.
Our bodies essentially run on electrical chemistry. True or false?
True
Our acid-base balance within the body is often referred to as our _H
pH
What does pH stand for?
Potential of Hydrogen
What is an acid?
A substance that releases a high amount of hydrogen (H+) ions when dissolved in water.
What is a base?
A substance that binds to hydrogen ions in solution.
What is the difference between an acid and a base?
An acid releases a high amount of hydrogen ions when dissolved in water, whilst a base binds to hydrogen ions in a solution.
What is the pH of water?
7
More more hydrogen a substance releases in water, the ____ its pH, and the more acidic it is.
Lower
What is OH-?
Hydroxide
Water is a neutral solution because for every H+ released, an ____ is created.
OH-
Anything below pH 7 is an _____
Acid
Anything above pH 7 is an ______
Base (alkali)
What pH is neutral?
pH 7
The pH of blood is carefully maintained and balanced within what range?
7.35 - 7.45 pH
What is the optimum pH of the stomach?
2-3 pH
Why do we need the body to maintain particular pH levels?
Because it provides the perfect conditions for essential enzymes to work correctly.
Why might a lot of fruits and vegetables have a low pH if measured before consumption?
Because they contain organic acids.
These are metabolised by the body and intestinal bacteria to become alkaline.
List 3 alkaline minerals.
- Magnesium
- Potassium
- Calcium
Before consumption, dairy is not very acidic and is also high in calcium, an alkaline mineral. So why does it have an acidic effect of the body once consumed?
Because it has a high content of protein and sulphur amino acids. These cause the formation of sulphuric acid in the body, which disrupts blood pH.
Why does dairy consumption cause loss of calcium leaching, even though it is high in calcium itself?
Because dairy contains a high level of sulphur amino acids. These cause formation of sulphuric acid in the body, which disrupts blood pH; drawing more alkaline calcium from the bones to neutralise the acid, and increasing calcium loss in urine.
Why does meat (organic or not) have an acid-forming effect on the body?
Because of its high sulphur amino acid and purines content, which causes the formation of sulphuric acid and uric acid within the body.
Cancer thrives in an acidic environment. It is thought that a tissue pH of ___ or above would start to kill cancer cells.
8
List 2 ways in which we can measure the pH of the body.
Via saliva & urine testing on litmus paper
When do chemical reactions occur?
When new chemical bonds are formed between molecules, or old bonds are broken.
Every chemical reaction involves the transfer of energy to either _______ (stored) energy, _______ energy or _____.
Potential energy, kinetic energy, or heat
What are ‘reactants’?
The starting materials in a chemical reaction.
What are ‘products’ (in terms of chemical reactions)?
The end / resulting molecules.
Explain ‘Collision Theory’.
For a chemical reaction to occur, there needs to be the opportunity for 2 molecules to collide.
What is the ‘energy of activation’?
The minimum energy required for a chemical reaction
Name to things that can be used in a laboratory situation, to make a reaction go faster.
- Increasing temperature
2. Increasing pressure
A catalyst helps a chemical reaction to take place with less energy required. True or false?
True
What does a catalyst do, and how?
Speeds up chemical reactions by lowering the activation energy required.
This means that the reaction is faster, or can occur at a lower temperature.
What are enzymes?
Catalysts for chemical reactions, that the body produces.
What is the name given to catalysts that the body produces?
Enzymes.
Which enzyme is involved in the production of both cholesterol and Co-enzyme Q10?
HMG-CoA reductase
Inhibitors act antagonistically to catalysts. True or false?
True
What acts antagonistically to a catalyst?
An inhibitor
What do inhibitors do to catalysts?
They stop the catalyst from being so effective, by making the activation energy requirement higher and slowing down the reaction time.
Name a type of drug that is a HMG-CoA reductase inhibitor.
Statins
There are 2 types of chemical reactions. Name them.
Anabolic and catabolic
What can be either anabolic or catabolic?
Chemical reactions
What is the difference between anabolic and catabolic reactions?
Anabolic reactions are building reactions. They occur when the body is making new substances / building new bonds.
Catabolic reactions are “breaking down’ reactions. They occur when substances are breaking down.
Give an example of an anabolic reaction.
Taking amino acids and building a protein.
Give an example of a catabolic reaction.
Breaking down food to release ATP.
What is hydrolysis?
Using water to break a chemical bond
Hydrolysis = ‘water splitting’
What is a hydrolysis reaction?
When water is the medium that breaks down a molecule into pieces.
Give an example of a hydrolysis reaction.
Splitting a carbohydrate molecule into individual sugars
What is ‘dehydration synthesis’?
When water is formed as a waste product of a reaction.
When water is formed as a waste product of a reaction, this is called _________ synthesis.
Dehydration
Give an example of dehydration synthesis.
Joining a chain of sugars together to form a long chain carbohydrate
Explain ‘reversible reactions’.
Chemical reactions whereby the products of the reaction can react together to produce the original reactants (i.e, the chemical reaction can go both ways)
What are buffers?
Substances that maintain the H+ concentration in the body within normal limits
What is the chemical symbol for bicarbonate?
HCO3-
The most important buffer in the bloodstream is the ________ buffer system, which “mops up’ excess acidity and maintains blood pH balance.
Bicarbonate
Carbon dioxide from cellular respiration reacts with water in the blood to form _________ _____
Carbonic acid
What are the two end products of the bicarbonate buffer system?
Carbon Dioxide and water
What role do the lungs play in the bicarbonate buffer system?
They exhale the resulting carbon dioxide
What role do the kidneys play in the bicarbonate buffer system?
They can:
a) produce the bicarbonate buffer (HCO3-)
b) they can excrete excess acidic Hydrogen ions
How does avoiding an acidic diet help preserve the kidneys?
The production of bicarbonate (HCO3-) by the kidneys is slow and requires a lot of effort, so avoiding adding excess acid to the body helps reduce the load on them.
Why do we tend to breathe harder / more rapidly when we have a build up of lactic acid?
To aid in the excretion of CO2, one of the byproducts of the bicarbonate buffer system (which is used to deal with the excess acid in the body)
What is ‘oxidation’?
The removal of electrons from an atom / molecule
What is the name given to the removal of electrons from an atom or molecule?
Oxidation
What does oxidation do?
Reduces the potential energy in a compound
Generally most oxidation occurs by removing electrons with the help of hydrogen. True or false?
True
Name an ion involved in oxidation / reduction reactions.
Hydrogen
In terms of oxidation and reduction reactions, what does OIL RIG stand for?
Oxidation Is Losing (electrons)
Reduction Is Gaining (electrons)
When something is ‘reduced’ it gains ________
Electrons
Why do reduction reactions result in the increase of energy in that molecule?
Because when something is ‘reduced’ it gains electrons.
Oxidation is always the loss of energy through loss of an electron. True or false?
True
Oxidation is the opposite of ________
Reduction
Reduction is the opposite of ________
Oxidation
What are ‘free radicals’?
Molecules or compounds that have an unpaired electron in their outer shell.
What is the name given to molecules or compounds that have an unpaired electron in their outer shell?
Free radicals.
Why do free radicals cause oxidation and oxidative damage?
Because they go around stealing electrons from other stable molecules (because they have an unpaired electron in their outer shell).
Why can free radicals ultimately cause cancer?
Because free radicals can even take electrons from DNA, which can damage genes and therefore potentially result in cancerous changes.
List 4 pathologies that are closely linked to oxidative damage.
- Cancer
- Atherosclerosis
- Diabetes
- Fibromyalgia
- Various neurodegenerative diseases, i.e, alzheimers
How do antioxidants work to reduce oxidative stress?
They donate an electron to free radicals, to convert them into harmless molecules, without being harmed themselves.
The key to a good antioxidant is that it must be stable once it has given away its electron. True or false?
True
List 5 common antioxidants
- Vitamin C
- Quercetin
- Beta Carotene
- Vitamin E
- Glutathione peroxidase (an natural body antioxidant)
In what foods would you find beta carotene?
In orange fruit and vegetables
List 3 food sources of vitamin E.
- Nuts
- Seeds
- Cold-pressed oils
List 2 food sources of quercetin.
- Apples
2. Red onions
Antioxidant molecules are able to recycle / replenish each other. True or false?
True
Why might taking large doses of a single antioxidant be a bad idea?
Antioxidants don’t exist in isolation in nature, because they don’t work effectively in isolation. They are needed to replenish each other. This is why food sources (natural, not synthetic) of antioxidants are best.
Living things are characterised by molecules made from ________ and ________.
Carbon and hydrogen
What are ‘functional groups’?
Groups of particular atoms that are attached to the carbon skeletons of molecules in living things.
In written biochemistry, what does R represent?
The unreactive, carbon and hydrogen part of a molecule.
The hydroxyl group is made up of _______ and ______ atoms
Hydrogen and oxygen
Alcohols belong to which biochemical functional group?
The hydroxyl group
The sulfhydryl group is made up of _______ and ______ atoms
Hydrogen and sulphur
Which functional group in biochemistry is acidic?
The carboxyl group
Which functional group in biochemistry is nitrogen-based?
The amine group
Which functional group in biochemistry is typically found on the end of amino acids and fatty acids?
The carboxyl group
Which functional group os found at the opposite end to a carboxyl group, in an amino acid?
The amine group
In biochemistry, how many functional groups are there?
6
In biochemistry there are 6 functional groups. List them.
- Hydroxyl group
- Sulfhydryl group
- Carboxyl group
- Amine group
- Esters
- Phosphates
Which functional group is found in triglycerides (fats?)
The Esters
Which functional group consists of phosphorus attached to a whole bunch of different oxygens?
The phosphates group
Which of the biochemical functional groups is found in the energy molecule ATP?
The phosphates
Give 2 functions of electrolytes in the human body.
- Nerve & muscle function
2. Acid-base balance
Explain the role of ‘buffer systems’. Name the main one.
Maintenance of pH. The main one is the bicarbonate buffer system.
What can create acidity in the body?
A high protein diet Too much meat Too much dairy Stress Insufficient exercise
What is meant by a ‘biological catalyst’?
Enzymes, which facilitate chemical reactions at body temperature.
When water is the medium that breaks down a molecule, it is known as what type of reaction?
A hydrolysis reaction.
What do the terms ‘oxidation’ and ‘reduction’ mean?
Oxidation is loss of electrons
Reduction is gaining of electrons
Name 2 functional groups found in all amino acids.
The amino group
The carboxyl group
What biological molecule would you find an ester bond in?
In a triglyceride (fat)
Give a definition of ‘biochemistry’.
The chemistry that goes on inside living organisms.
__________ include starches, cellulose and sugars.
Carbohydrates
All carbohydrates are made of __-__-__
C-H-O (Carbon, hydrogen, oxygen)
Which macronutrient has carbon atoms that are normally arranged in a ring/hexagon, with oxygen and hydrogen atoms attached?
Carbohydrates
Carbohydrates have a lot of ______ functional groups on them/
Hydroxyl (-OH)
Carbohydrates are grouped into 3 classes, depending on their size. Name these classes.
Monosaccharides
Disaccharides
Polysaccharides
What is the name given to single sugar (carbohydrate) units?
Monosaccharides
How many carbon atoms are there in a monosaccharide?
3-7
Name 3 types of monosaccharide.
- Glucose
- Galactose
- Fructose
- Deoxyribose
- Ribose
What is the name given to 2 monosaccharides joined together by dehydration reaction?
Disaccharides
Where would you find the monosaccharide deoxyribose?
In DNA
Name 3 disaccharides.
- Sucrose
- Lactose
- Maltose
_________ + _________ = Maltose
Glucose + glucose
_________ + _________ = Sucrose
Glucose + fructose
_________ + _________ = Lactose
Glucose + galactose
What is the name given to 10s - 100s of monosaccharides joined together by dehydration reaction?
Polysaccharides
What is the name of the storage form of carbohydrate, found in the muscles and liver? What type of carbohydrate is it?
Glycogen. A polysaccharide.
Name 3 types of polysaccharide
- Glycogen
- Cellulose
- Starch
Glycogen, Starch and Cellulose are all chains of ______
Glucose
_________ are simple sugars that can exist as single molecules.
Monosaccharides
Which is the sweetest monosaccharide?
Fructose
Monosaccharides are grouped into families named after the number of their _____ atoms.
Carbon
Monosaccharides as a family are named after the amount of carbons in their molecule and arranged into 4 groups. Name these, and note the number of carbon atoms associated with each one.
Triose (3 carbons)
Pentose (5 carbons)
Hexoses (6 carbons)
Heptose (7 carbons)
Name 2 hexose (6 carbon atoms in the molecule) monosaccharides.
Glucose and fructose
The names of all __________ end in -ose.
Monosaccharides
What are ‘isomers’?
Molecules that have the same chemical formula (same atoms) but different structures.
________ is the name given to molecules that have the same chemical formula but different structures.
Isomers
Which disaccharide is formed during the breakdown of starch?
Maltose
Why are polysaccharides normally insoluble in water (i.e, pasta)?
Because they’re such large molecules and have given up many -OH groups.
What is the most common type of polysaccharide in the body?
Glycogen
What is our major dietary source of carbohydrate?
Starch
List 3 food sources of starch.
- Bread
- Pasta
- Rice
Starch is made up of 2 different polysaccharide components. Name them.
- Amylopectin
2. Amylose
What is the difference between amylopectin and amylose (the polysaccharide components found in starch)?
Amylose is a single, curly chain of glucose units
Amylopectin is a multi-branched chain of glucose units, so is quicker to digest
Which produces a higher rise in blood sugar; amylose or amylopectin? Why?
Amylopectin.
Because it’s a multi-branched chain of glucose units that is digested quickly.
Which produces a higher rise in insulin; amylose or amylopectin?
Amylopectin
Which can provide a food source for beneficial bacteria in the intestines; amylose or amylopectin? Why?
Amylose. Because it is digested so slowly.
Starchy foods generally contain around __% amylopectin and around __% amylose.
75% amylopectin
25% amylose
How can we increase the beneficial amylose content in starchy foods?
By cooking them and cooling them down before eating. In this way, some of the amylopectin is converted to amylose.
What is ‘resistant starch’ in terms of food?
Starchy foods that are high in amylose.
Each _____ molecule is made up of about 60,000 glucose molecules.
Glycogen
Glycogen in which organ, can be used to help maintain blood sugar levels?
The liver
Why can’t glycogen stored in the muscles be used to help maintain blood sugar levels?
Because it can only be used by that particular muscle.
What is cellulose?
A polysaccharide. The structural material of plants.
Where is cellulose found?
In plant cell walls.
Why can’t humans digest cellulose, even though it is a polysaccharide made of glucose?
It has different bonds, forming a flatter, more rigid structure to its molecules. Humans lack the correct enzymes to break down these unique bonds.
List 2 dietary benefits of cellulose.
- It feeds friendly gut flora
2. It ‘sweeps’ the intestine
Which type of macronutrient is the primary fuel for energy production?
Carbohydrates
List 2 reasons why carbohydrates are important in the diet.
- They are our primary fuel for energy production.
2. They provide a storage form of energy (glycogen)
List 3 benefits of fibre (cellulose) in the diet.
- Required for proper bowel function
- Protects against CVD and diabetes
- Increases satiety and weight loss
Glucose as an individual sugar is critical for ATP production and glycogen synthesis, but can also be turned into _______ and _____ ______.
Triglycerides and amino acids
Glucose is critical for the body, but we don’t need to consume lots of glucose in the diet. Why is this?
Because we can create glucose from the breakdown of starches.
When it comes to carbohydrate digestion, everything starts in the _____.
Mouth (salivary amylase)
Salivary amylase, pancreatic amylase, lactase, maltase and sucrase are all enzymes involved in the digestion of ___________.
Carbohydrates
The last stage of carbohydrate digestion involves ______ ______ enzymes in the small intestine. These are lactase, maltase and sucrase.
Brush border enzymes
Where would you find the enzymes that can digest maltose, lactose and sucrose?
In the brush border of the small intestines.
Why can digestive pathologies such as coeliac disease lead to poor carbohydrate digestion?
Because the brush border of the small intestine is often damaged in these pathologies, which means that brush border enzymes are compromised.
Lipids contain 3 elements, the same as carbohydrates, but in a different ratio. Name them.
Carbon, hydrogen and oxygen
If lipids are hydrophobic, how do they move around our water-dense bodies?
They bond to proteins to become ‘lipoproteins’.
____________ are the main form of dietary fat.
Triglycerides
Triglycerides are formed from a single _______ backbone, joined to 3 _____ _____ tails.
Glycerol backbone with 3 fatty acid chains/tails
List 3 reasons why we need fats / triglycerides in our diet.
- Insulation
- Protection of body parts (i.e, the kidneys)
- Source of energy-dense energy
Why are saturated fats called saturated fats?
Because every carbon in their backbone has a maximum number of bonds to a hydrogen.
Each carbon atom is saturated with hydrogen atoms.
________ fats are generally solid at room temperature.
Saturated
________ fats are very straight molecules
Saturated
________ fats are kinked / v-shaped molecules
Monounsaturated
________ fats are generally liquid at room temperature.
Monounsaturated
Monounsaturated fats contain fatty acids with __ double covalent bond between 2 carbons.
1
In terms of molecular structure, what is the difference between monounsaturated and polyunsaturated fats?
Monounsaturated fats have 1 double covalent bond between 2 carbons. So they have a kink in their chain.
Polyunsaturated fats have more than one double bond in their carbon chain, so have multiple kinks.
Give a food example of a polyunsaturated fat.
Sunflower oil
Rapeseed oil
Vegetable oil
Nuts & seeds in whole food form
Give a food example of a monounsaturated fat.
Olive oil
Give a food example of a saturated fat.
Coconut oil, butter, lard, meat fat.
The end of a fatty acid chain is always the end without the ______
Oxygens.
i.e, the end furthest away from the carboxyl functional group
Fatty acids are named according to the closest double bond to the end of the chain. So…
In Omega 3 fatty acids, the double bond is ___ carbon molecules from the end of the chain.
In Omega 6 fatty acids, the double bond is ___ carbon molecules from the end of the chain.
Omega 3 = double bond is 3 carbon molecules from the end of the chain.
Omega 6 = double bond is 6 carbon molecules from the end of the chain.
Wherever we have a double carbon bond in a fatty acid, there are 2 possibility of where the hydrogens can go. True or false?
True
The hydrogen atoms are found on the same side as the double carbon bond in the configuration of ____ fatty acids.
Cis
The hydrogen atoms are found on opposite sides of the double carbon bond in the configuration of ____ fatty acids.
Trans
In nature, do nearly all fats have a cis or trans structure?
Cis
Do our bodies recognise and easily use cis or trans fats?
Cis fats
Explain the difference between cis and trans fats.
Cis fats have hydrogen atoms on the same side as their double carbon bond, whereas trans fats have hydrogen atoms on opposite sites of their double carbon bond.
Nearly all fats found in nature are cis fats. These are more easily recognised and utilised by the body.
Trans fats are found in industrially synthesised fats. True or false?
True
____ fats have a nice kink in their molecule structure, whilst ___ fats are straighter and more rigid.
Cis fats = kinked
Trans fats = straight and rigid
____ fats make cell membranes more flexible.
Cis
____ fats make cell membranes more stiff, making them more leaky and prone to oxidative damage.
Trans
Which industry process helps to make vegetable oils more solid?
Hydrogenation
Explain how cis fats are turned into trans fats.
By heating to high temperatures, or heating oil repeatedly.
(The hydrogen on the double carbon bond spins around).
What are essential fatty acids (EFA’s)?
EFA’s are polyunsaturated fatty acids that can’t be constructed within the body, and therefore must be obtained from the diet.
Can the human body make essential fatty acids (EFA’s)?
No
Are essential fatty acids (EFA’s) saturated, monounsaturated or polyunsaturated fats?
Polyunsaturated
Name the 2 families of EFA’s.
Omega 3’s and Omega 6’s
As well as Omega 3 and Omega 6, there are other omega fatty acids but they’re not essential to human health. True or false?
True
Name 3 food sources of EFA’s.
- Nuts
- Seeds
- Oily fish
Which Omega fatty acid family does alpha-linolenic acid belong to?
Omega 3
Which Omega fatty acid family does linoleic acid belong to?
Omega 6
Which fatty acid family includes ALA, EPA and DHA
Omega 3’s
Which fatty acid family includes LA, GLA and AA
Omega 6’s
The Omega 3 fatty acid ALA, can be converted into the other omega 3 fatty acids EPA and DHA in the body. True or false?
True
The Omega 6 fatty acid LA, can be converted into the other omega 6 fatty acids GLA and AA in the body. True or false?
True
Name 3 food sources of the Omega 6 fatty acid Arachadonic Acid.
- Meat
- Dairy products
- Eggs
Name 3 food sources of Alpha-linolenic acid (ALA, Omega 3)
- Walnuts
- Green leafy vegetables
- Flaxseeds
Name 1 food source of EPA & DHA (Omega 3)
Oily fish
Name 2 food sources of linoleic acid (LA, Omega 6)
- Most nuts and seeds
2. Vegetable oils
Is evening primrose oil an omega 3 or omega 6 fatty acid?
Omega 6 (GLA)
Why is it important to eat a variety of well-sourced omega 3 and 6 fatty acids?
To help give cell membranes both flexibility (omega 3) and structure (omega 6).
The conversion of ALA to EPA and DHA, and the conversion of LA to GLA and AA, requires ________ enzymes.
Desaturase enzymes
List 5 functions of Essential Fatty Acids (EFA’s).
- Fluidity and structure of cell membranes
- Synthesis of prostaglandins
- Formation of haemoglobin
- Support the production of digestive enzymes
- Help transport cholesterol in the blood.
List 3 things that can accelerate oxidation and the formation of free radicals, when it comes to polyunsaturated fats.
- Light
- Oxygen
- Heat
To cook with, you should use ________ fats. This is because they are stable at high temperatures.
Saturated fats (no double carbon bonds, so more stable)
How should unsaturated fats be stored?
In dark glass bottles, in a dark place, in the fridge once opened.
What is a lipoprotein and what is its purpose?
A fat molecule that has been joined to a protein molecule.
Lipoproteins enable lipids to move around easily in the bloodstream.
(Remember that fats on their own are hydrophobic).
What would you find inside a lipoprotein?
Triglycerides and cholesterol
Lipoproteins are synthesised by which organ?
The liver
Name the 4 types of lipoproteins.
- Chylomicrons
- Very Low Density Lipoproteins (VLDLs)
- Low Density Lipoproteins (LDLs)
- High Density Lipoproteins (HDLs)
Very Low Density Lipoproteins (VLDLs) are used to carry newly-synthesised triglycerides from the ______ to the ______ tissue.
From the liver to adipose tissue
Which form of lipoprotein if high, indicates over-eating?
VLDLs
Low Density Lipoproteins (LDLs) are used to carry ______ from the ______ to the cells of the body.
Cholesterol from the liver to the cells
Which type of lipoprotein collects cholesterol from the body’s tissues and brings it back to the liver?
HDLs
_______ is needed to repair cells, support cell membranes and synthesise sex and adrenal hormones.
Cholesterol
Phospholipids contain a ________, 2 _____ _____ tails and a phosphate head.
A glycerol molecule, 2 fatty acid tails…
What is the name given to lipids that are formed from cholesterol?
Steroids
What are steroids?
Lipids that are formed from cholesterol
Why don’t we need to eat cholesterol?
Because our liver can produce it.
Name 3 hormones created from steroids (‘steroid hormones’).
- Oestrogen
- Testosterone
- Cortisol
Which type of lipid is formed from 4 rings of carbon atoms, joined at their base?
Steroids
Name 2 monosaccharides.
- Glucose
- Fructose
- Galactose
Explain what is meant by an isomer.
Something that is made of the same atoms (chemical formula) but which has a different chemical structure. i.e, glucose and fructose
What is the name of the type of bond between two monosaccharides?
Glycosidic bond (formed by dehydration synthesis).
Which digests faster - amylose or amylopectin? Why?
Amylopectin. Because it has a branching structure
Where is glycogen stored?
In the liver and muscles
Why are lipids hydrophobic?
Because they have very few polar bonds (unlike water).
Which types of fat are prone to oxidation?
Polyunsaturated fats
