Embedded Files
2.3.U.1 Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
2.3.U.1 Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Be able to:
Define monosaccharide, disaccharide and polysaccharide.
List three examples of monosaccharides.
List three examples of disaccharides.
List three examples of polysaccharides.
Use molecular diagrams to draw the formation of maltose from two glucose monomers.
Explain a condensation reaction connecting two monosaccharides in the formation of a disaccharide.
Carbohydrates (also called saccharides) are molecular compounds made from just three elements: carbon, hydrogen and oxygen. Monosaccharides (e.g. glucose) and disaccharides (e.g. sucrose) are relatively small molecules. They are often called sugars. Other carbohydrate molecules are very large (polysaccharides such as starch and cellulose).
Carbohydrates are:
a source of energy for the body e.g. glucose and a store of energy, e.g. starch in plants
building blocks for polysaccharides (giant carbohydrates), e.g. cellulose in plants and glycogen in the human body
components of other molecules eg DNA, RNA, glycolipids, glycoproteins, ATP
monosaccharides:
monosaccharides:
glucose
fructose
galactose
disaccharides
disaccharides
sucrose
maltose
lactose
polysaccharides
polysaccharides
cellulose
glycogen
starch
Condensation reactions make bonds.
condensation synthesis reactions link two monosaccharide monomers forming one disaccharide molecule and one H2O molecule. Repeated additions of monosaccharides produces a polysaccharide.
Hydrolysis bonds break these bonds.
a polysaccharides can be broken down into monosaccharides. H2O molecules used as a sources of -H and a -OH groups are catalyzed by enzymes
2.3.U.2 Fatty acids can be saturated, monounsaturated or polyunsaturated.
2.3.U.2 Fatty acids can be saturated, monounsaturated or polyunsaturated.
Be able to:
Describe the differences between saturated and unsaturated (mono- or poly-) fatty acids.
Fats are a group of chemical compounds that contain fatty acids. Energy is stored in the body mostly in the form of fat. Fat is also needed in the diet to supply essential fatty acids that are substances essential for growth but not produced by the body itself
There are three main types of fatty acids: saturated, monounsaturated and polyunsaturated. All fatty acids are chains of carbon atoms with hydrogen atoms attached to the carbon atoms.
Saturated fatty acid
Saturated fatty acid
Hydrogen atoms attached to every carbon atom.
All of the carbons are attached to each other with single bonds.
Monounsaturated fatty acid
Monounsaturated fatty acid
A pair of hydrogen atoms in the middle of a chain is missing, creating a single gap that leaves two carbon atoms connected by a double bond rather than a single bond.
Polyunsaturated fatty acid.
Polyunsaturated fatty acid.
A pair of hydrogen atoms in the middle of a chain is missing, having more than one gap that leaves two carbon atoms connected by a double bond rather than a single bond."
2.3.U.3 Unsaturated fatty acids can be cis or trans isomers.
2.3.U.3 Unsaturated fatty acids can be cis or trans isomers.
Be able to:
Describe the differences between cis- and trans- fatty acids.
While a saturated fatty acid is a straight molecule on the average, the double bond in an unsaturated fatty acid produces a kink in the molecule. This is because a double bond cannot rotate. The bend in the carbon chain is much more pronounced in the cis isomer compared to the trans isomer. For this reason, cis fatty acids (and triacylglycerols made from them) do not solidify as readily as trans fatty acids. Due to the larger bend, the cis isomers cannot line up next to one another in as ordered a fashion as the trans isomers.
The configuration of the double bond in an unsaturated fatty acid can take two forms (or, to chemists, isomers): the naturally predominant cis form, in which both of the hydrogen atoms are on the same side of the chain; and the uncommon-in-nature trans isomer, in which the hydrogen atoms are on opposite sides. The trans form is (in most cases) best thought of as 'damaged'.
2.3.U.4 Triglycerides are formed by condensation from three fatty acids and one glycerol.
2.3.U.4 Triglycerides are formed by condensation from three fatty acids and one glycerol.
Ba able to:
Outline the difference between fats and oils.
Explain a condensation reaction connecting fatty acids and glycerol to form a triglyceride.
State two functions of triglycerides.
Triglycerides are lipids consisting of one glycerol molecule bonded with three fatty acid molecules. The bonds between the molecules are covalent and are called Ester bonds. They are formed during a condensation reaction. Triglycerides are hydrophobic and so insoluble in water. The charges are evenly distributed around the molecule so hydrogen bonds do not form with water molecules.
2.3.A.1 Structure and function of cellulose and starch in plants and glycogen in humans.
2.3.A.1 Structure and function of cellulose and starch in plants and glycogen in humans.
Be able to:
State the structural difference between alpha and beta glucose.
Contrast the structure and functions of cellulose, amylose, amylopectin and glycogen.
2.3.A.2 Scientific evidence for health risks of trans fats and saturated fatty acids.
2.3.A.2 Scientific evidence for health risks of trans fats and saturated fatty acids.
Be able to:
Discuss the relationship between saturated fatty acids and/or trans fat intake and rates of coronary heart disease.
Many factors affect heart disease, however, diets low in saturated fat and cholesterol may reduce the risk of this disease. Cholesterol carried throughout the body as low density lipoproteins (LDL) and high density lipoproteins (HDL).. Cholesterol in LDSs get deposited in the walls of blook vessels whild HDLs revome cholesterol from blood vessels. Research show that high LDL, low HDL levels in blood increase risk of heart disease and low LDL, high HDL levels reduce risk of heart disease. Therefore, important for diet to reduce LDL levels and increase HDL levels.
2.3.A.3 Lipids are more suitable for long-term energy storage in humans than carbohydrates
2.3.A.3 Lipids are more suitable for long-term energy storage in humans than carbohydrates
Be able to:
Explain the energy storage of lipids compared to that of carbohydrates.
Carbohydrates are soluble in water unlike lipids. This makes carbohydrates easy to transport around the body (from and to the store). Also, carbohydrates are a lot easier and more rapidly digested so their energy is useful if the body requires energy fast. As for lipids, they are insoluble which makes them more difficult to transport however because they are insoluble, lipids do not have an effect on osmosis which prevents problems within the cells in the body. They also contain more energy per gram than carbohydrates which makes lipids a lighter store compared to a store of carbohydrates equivalent in energy
2.3.A.4 Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids
2.3.A.4 Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids
Be able to:
Define evaluation in respect to evidence from and methods of research.
Outline the manner in which the implications of research can be assessed.
Outline the manner in which the limitations of research can be assessed.
Evaluate a given health claim made about lipids.
Most research looking at the health claims of diets or nutritional components in a diet are based on observational studies. Outlined below are the differences between observational studies and experimental tests and considerations that need to be taken when making any conclusions regarding observational studies
Observational Studies:
Observational Studies:
these studies only give you correlations and do not allow for establishing the causal relationship between the phenomena studied,
the research observes what happens to people under exposure conditions that have been self-selected or have been determined by influences outside the control of the researcher
these studies, regardless of their size or number, only provide hypothesis generating data.regardless of their size or number, only provide hypothesis given have to be rigorously generating data
Experimental Tests
Experimental Tests
uses hypothesis then have to be rigorously tested using the scientific process
the research can choose what conditions to study by controlling all key factors except those being test
the researcher observes what happens to people under exposure conditions that have been self-selected or have been determined by influences outside the control of the research
2.3.S.1 Use of molecular visualization software to compare cellulose, starch and glycogen.
2.3.S.1 Use of molecular visualization software to compare cellulose, starch and glycogen.
Be able to:
Demonstrate use of JMol to view molecular structures, including changing image size, rotating the image and changing the style of the molecular model.
Identify carbon, hydrogen and oxygen atoms by color.
2.3.S.2 Determination body mass index by calculation or use of a nomogram
2.3.S.2 Determination body mass index by calculation or use of a nomogram
Be able to:
Calculate BMI using the formula.
Determine BMI using a nomogram.
Outline effects of a BMI that is too high or too low.
Body mass index, or BMI, is used to determine whether you are in a healthy weight range for your height.
It is useful consider BMI alongside waist circumference, as increases or decreases in weight outside the healthy range may increase your health risks.
Body Mass Index Nomogram
BMI compares your weight to your height, and is calculated by dividing your weight in kilograms by your height in metres squared.
It gives you an idea of whether you’re underweight, a healthy weight, overweight, or obese for your height. BMI is one type of tool to help health professionals to assess risk for chronic disease. Another important tool is waist circumference. It is also important to understand your other risk factors.
Body Mass Index Nomogram
The Body Mass Index (BMI) Nomogram is a graph that shows a person's Body Mass Index as the point on the chart nearest the dashed line (representing the Body Mass Index) where height (in inches or centimetres) and weight (in pounds or kilograms) intersect.
Height is shown on the x-axis in centimetres or inches, and weight is shown on the y-axis in kilograms or pounds.
Dashed lines, representing the Body Mass Index, are displayed on the graph as calculated by the formula of weight (in kilograms) divided by height squared (in metres).
In the News
In the News
- Rural areas drive increases in global obesity (2019-05-08)
- Dietary fat is good? Dietary fat is bad? Coming to consensus (2018-11-15)
- How To Be A Savvy Consumer Of Science News (2018-07-17)
- Industrial trans fats must be removed from food supply, WHO says (2018-05-14)
- Pasture feeding may improve nutritional benefits of red meat (2015-01-21)
- A novel shuttle for fatty acids (2015-02-03)
- Salty, sweet, sour. Is it time to make fat the sixth taste? (2015-02-18)
- More light shed on on biomass breakdown (2015-01-23)
- A taxi ride to starch granules (2015-02-26)
- How stick insects handle indigestive food (2016-03-10)
- Dietary Guidelines for Americans—Eat Less Fat (2016-05-03)
- A call for a low-carb diet that embraces fat (2014-09-01)
- Trans fat bans lessen health risks, research suggests (2017-04-14)
- Don't use body mass index to determine whether people are healthy (2016-02-04)
- Higher BMI not associated with increased risk of heart attack or early death, twin study shows (2016-08-01)
- F.D.A. sets 2018 deadline to rid foods of trans fats (2016-06-16)
- The Food Industry's Influence In Nutrition Research (2016-09-17)
Report abuse