Unit 2 - Biochemistry

What are the 7 components of a balanced diet?

Carbohydrates, proteins, lipids, vitamins, fibre, water & minerals

Why is water important in organisms?

If not consumed within a few days, death would be likely as it serves many uses throughout the body. It is consumed directly through drinking or indirectly through food.

What are the 4 uses of water in the human body?

Solvent, transporter of substances in solution, heat regulator & reagent

How is water used in the body as a solvent?

All metabolic reactions occur in solution & in the excretion of waste substances in solution (urine)

How is water used as a transporter of substances in solution?

Food, hormones etc. have to be transported in solution in either blood or sap

How is water used as a heat regulator in the body?

It absorbs heat without drastic temperature changes, keeping bodies cool (sweating) & removes heat when evaporated also keeping bodies cool (evaporation of sweat)

How is water a reagent in the body?

"It's a substance added to a system to form a chemical reaction & thus considered to be a reagent"

What are the elements that make up carbohydrates & lipids?

Hydrogen, carbon & oxygen

What are the elements which make up proteins?

Hydrogen, carbon, nitrogen & oxygen (sometimes sulphur)

What are the 3 carbohydrate groups?

Monosaccharides, Disaccharides & Polysaccharides

What are monosaccharides?

"They're the simplest form of carbohydrate with one ring of atoms joined together"

What are 3 monosaccharides?

Glucose & fructose (found in fruit) and galactose (found in milk)

Which is the simplest & most common carbohydrate?

Glucose - C6H12O6

Mention 1 feature of glucose

Glucose is soluble thus easily transported in the blood & dissolves in the cytoplasm of cells

What are disaccharides?

"They're 2 monosaccharides joined together forming a pair. Their name depends on the 2 sugar rings making it [disaccharide] up."

What is the bond between disaccharides called?

Glycosidic bond

What are 2 examples of a disaccharide?

Maltose & Lactose

What are polysaccharides?

"They're carbohydrates made up of many monosaccharide molecules joined together. They differ in length & structure of their chains"

What are 4 polysaccharides?

Glycogen, starch, cellulose & chitin

What is glycogen?

"It's a storage carbohydrate in animals"

What is starch?

It is a storage carbohydrate in plants

What is cellulose?

It is a structural component of plant cell walls

What is chitin?

"It forms the exoskeleton around insect's bodies to protect their internal organs"

How would one determine the solubility of a carbohydrate?

Their solubility decreases as the size of the molecules increases

What are the functions of carbohydrates?

"They're the main energy source for living cells through respiration which breaks them down to form energy for all the cell activities, they're used to store energy when required, in the making of plant cell walls, in the manufacturing of paper etc."

What are 4 carbohydrate-rich foods?

Potatoes, rice, bread & pasta

What are lipids?

"They're fats & oils"

"What's the difference between fats and oils?"

Fats are solid at RTP whilst oils are liquid

What is a feature most lipids share?

"They're greasy to the touch and are hydrophobic (insoluble in water)"

What is a triglyceride (typical fat molecule) made up of?

A glycerol molecule chemically bonded to 3 fatty acids

How are fats different?

Different fats have different fatty acids

How is fat formed?

"It's formed through a condensation reaction through the formation of a water molecule as a result of fat formation"

What are the 2 types of lipids?

Saturated & unsaturated

What is the difference between saturated & unsaturated fats?

Saturated fats are found in animal foods whilst unsaturated fats are found in plant foods

What are saturated fats?

"They're saturated with hydrogen atoms & have no double bonds in their chemical structure meaning that they're solid at RTP"

What are unsaturated fats?

"They're typically contain one or more double bonds making them liquid at RTP"

What are 5 foods which contain saturated fats?

Animal meat (beef, poultry & pork), some plant oils (palm, kernel or coconut oil), dairy products (cheese, butter & milk), processed meats (sausages, hot dogs & bacon) and pre-packaged snacks (crackers, crisps, biscuits & pastries)

Which 5 foods contain unsaturated fats?

Nuts, plant oils (canola, vegetable or plant), fish (salmon, tuna & anchovy containing omega 3), olives and avocados

What are 7 lipid uses?

They can be a source of energy (provide twice as much energy than carbohydrates), an energy store (insoluble in water, can be used in respiration for energy), used as insulation (mammals have fat under their skin to keep them warm), used for water-proofing the skin (oils on the surface of the skin), used in the protection of delicate organs from abrasion (kidneys), used in the formation of cell membranes (phospholipids) and when providing vitamins to the body (vitamins A, D & E are soluble in lipids.

Mention lipid-rich foods

Fats & oils found in butter, cheese & meat as well as nuts & seeds

What are proteins made up of?

Amino acids

How many amino acids are there? And what are essential amino acids?

In nature, there are about 20 amino acids & some of which must be supplied in the diet making them essential amino acids

What is a peptide chain?

"It's 5 amino acids linked together by peptide links"

What is a polypeptide chain?

"It's more than 5 amino acids linked together with peptide links"

What is the function of a peptide/polypeptide chain?

It joins other chains & forms functional proteins

How do proteins differ from each other?

It depends on they type of amino acids present in their chains, the sequence of different amino acids in the chain and the way the chains are folded & arranged

What are the 2 types of proteins?

Globular & fibrous proteins

What is globular protein?

It is a soluble protein which occurs in solution in cells, blood etc. (e.g. albumen, enzymes etc.)

What is fibrous protein?

It is a tough, insoluble protein which is fibre-like and found in bones, muscle & skin

What are the functions of proteins?

"They're the material from which new tissues are grown & repaired, important components of cell membranes, can be used in respiration as a substitute for cabohydrates & lipids, responsible for making reactions take place quicker making them enzymes and in charge of the organism's activities also making them hormones."

Can proteins be stored in the body?

They cannot be stored in the body but any excess would be turned to glycogen & urea through a deamination reaction

Which foods are rich in protein?

Meat, fish, eggs, beans & peas

What are vitamins?

"They're organic molecules which are necessary in the diet. Each one has a specific function in the body and each vitamin is chemically different. Vitamins aren't digested or broken down for energy & they're not built into the body structures"

Why are vitamins essential?

"They're required for the normal metabolism & chemical activities in the body."

What does a lack of vitamins cause?

This causes vitamin deficiency disease which can be cured in the earlier stages by consuming the vitamin more often.

Why should vitamins be in solution?

For them to do their job, they must be in a solution, either in fats or in water

What are the 2 classes of vitamins?

Fat-soluble vitamins & water soluble

What are fat-soluble vitamins?

"They're mostly found in animal fats or vegetable oils which is a reason why our diet should include some of these fats"

What are water-soluble vitamins?

"They're present in green leaves, fruit & cereal grains"

What is the function of vitamins?

"They assist in enzyme action & they're essential for enzyme action"

What are mineral salts?

"They're required in small amount in the body for the growth & repair of the body or metabolism."

What is Iron?

"It's a mineral required for the synthesis of haemoglobin. The iron in the erythrocytes which break down each day is stored in the liver and used to make more haemoglobin. It is also needed in the muscles for enzyme systems in all the body cells. A total of 15mg are needed per day"

Which foods are rich in Iron?

Red meat (liver & kidney), eggs, ground nuts & spinach

What does a lack of Iron result in?

Anaemia where there is a lack of haemoglobin resulting in a lack of red blood cells meaning that there are reduced oxygen levels meaning that respiration cannot occur properly. This then results in lack of energy & fatigue

What is calcium?

"It's mostly consumed as calcium phosphate and it's important in the formation of bones, teeth & nails. It also helps in calcification (hardening of teeth & bones), blood clotting, muscle contractions and the transmission of nerve impulses. It's mostly found in blood plasma"

Which foods are rich in calcium?

Milk, cheese & fish

What does a lack of calcium result in?

It results in the softening of bones or the abnormal development of bones, teeth & nails in the form of a condition known as rickets in children and osteoporosis in adults

What is fibre?

"It's a carbohydrate found in the plant's cellulose cell wall & cannot be digested by the human body"

"What is fibre's function?"

"It's function is to keep the digestive system healthy & functioning properly. It passes unchanged throughout the digestive system until it arrives at the large intestine where it promotes the growth of certain bacteria that makes the waste material soft & bulky, allowing it pass more easily through the intestines & bowel and out of the body."

What does fibre prevent?

It prevents constipation (small, hard, dry faeces) as it adds bulk and absorbs water helping the waste material move more quickly through the body. It also speeds up the excretion of waste & toxins from the body, preventing the stool from sitting in the intestine or bowel for too long and cause build-up or disease such as bowel cancer

Which foods are rich in fibre?

Bran, wholemeal flour & breads, brown rice, whole grain cereals, vegetables, edible fruit peels, nuts & seeds, lentils, peas, beans, oats, barley, oatmeal, potatoes, dried fruit and soya products

What is malnutrition?

"It's bad nutrition, either undernutrition or over-eating which could lead to an unbalanced diet and severe conditions"

What is obesity?

"It's one of the most common nutritional problems & is caused when there is excessive energy input and less output. Other factors include lack of exercise, consumption of high energy food. Extra fat, carbohydrates, proteins & alcohol can all be converted to adipose tissue (body fat). This all increases the risk of cardiovascular disease & atherosclerosis increasing the risk of high blood pressure due to high levels of blood cholesterol and an increased risk of getting a heart attack"

What is anorexia nervosa?

"It's a loss of appetite through mental illness or self-persuasion, even though the person suffering would be extremely hungry. Once the body would be out of carbohydrates & fats it would turn to protein, deteriorating muscles & other body tissues. It could even result in constipation, low blood pressure, tooth decay, susceptibility to infection and vitamin & mineral deficiencies."

What is bulimia nervosa?

"The process of bingeing & then forcing yourself to vomit, exercise too much or use laxative or diuretics when they're not needed due to the guilt feeling created after over-eating."

What is diabetes type II?

"It is a deficiency disease in insulin production where glucose levels are too high & thus the kidney cannot re-absorb it and its then excreted with urine, i.e. it results from the body's ineffective use of insulin."

What is insulin resistance?

"It's when the body doesn't fully respond to insulin as blood glucose levels are continually rising. This could exhaust the pancreas and result in hyperglycaemia (high blood sugar levels)"

Why do people suffer from type II diabetes?

It is caused as a result of excess body weight, an unbalanced diet & physical inactivity.

How could one prevent diabetes type II?

Eating a healthy diet, limiting ones sugar & saturated fat intake, maintaining a healthy body weight, being physically active and avoiding tobacco use (smoking increases the risk of diabetes & cardiovascular disease)