Chemistry & Biochemistry 1 Flashcards

Question

pH and digestive system facts

Answer 1

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

Answer 2

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

Answer 3

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

Answer 4

Speeds up reactions by lowering the activation energy required Means reaction is faster or can occur at lower temps Body catalysts are enzymes

Answer 5

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

Answer 6

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

Answer 7

Reactions where breaking down occurs Eg when breaking down food, releasing energy from them. Trap energy as ATP A - B = A+B

Answer 8

When water is medium and breaks molecule into smaller pieces

Answer 9

When water formed as the waste product of a reaction Normally when larger molecules are being made - eg making carbs

Answer 10

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

Answer 11

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)

Answer 12

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

Answer 13

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

Answer 14

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

Answer 15

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

Answer 16

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

Answer 17

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

Answer 18

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

Answer 19

**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

Answer 20

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

Answer 21

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)

Answer 22

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)

Answer 23

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)

Answer 24

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)

Answer 25

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

Answer 26

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

Answer 27

- 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

Answer 28

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)

Answer 29

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)

Answer 30

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

Answer 31

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

Answer 32

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

Answer 33

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

Answer 34

Contains more than 1 double bond in carbon chain Molecules are kinked Liquid at room temp Eg sunflower, rapeseed, vegetable oil

Answer 35

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

Answer 36

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

Answer 37

Alpha-linolenic acid (ALA) - essential in diet (flax seeds, walnuts, green leafy veg) EPA & DHA - oily fish

Answer 38

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

Answer 39

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

Answer 40

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

Answer 41

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

Answer 42

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

Answer 43

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

Chemistry & Biochemistry 1 Flashcards

(67 cards)