Biology Enrichment by jennyyingdi

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									                                                                           Biochemistry Notes
                              Biochemistry


Living things are mostly made up of these elements:
                            1. Carbon (C)
                            2. Hydrogen (H)
                            3. Oxygen (O)
                            4. Nitrogen (N)

                          There are two categories of compounds:


                  Inorganic                            Organic

            Carbon OR Hydrogen                    Carbon and Hydrogen

                        There are 4 types of Organic Compounds

                               1. Carbohydrates
                               2. Lipids
                               3. Proteins
                               4. Nucleic Acids

Type of Organic Compound                  Are you familiar with these?
Carbohydrates                             Sugar and Starch(pasta, bread)

Lipids                                    Fats, oils & wax

Proteins                                  Meat, eggs, & nuts

Nucleic Acids                             DNA & RNA
Carbohydrates
     What is the function of carbohydrates?:
      They supply us with energy
      Make up cell wall in plants

     What shape do they have?
      Shaped like a ring

     Are there important facts?
      All have a 1:2:1 ratio C:H:O

     What is the smallest unit? (Building Block)
      Monosaccharide – Simple sugar               Monosaccharide
                                                   (simple sugar)

Monosaccharide
               Are known as simple sugars
               Their chemical formula is C6H12O6
               There are three types of Monosaccharides (simple sugars)




What is the chemical formula for each?
     Glucose ____________           Galactose___________       Fructose __________

What is an isomer?
     Isomers have the same chemical formula but different structure
     (they look different)

Disaccharides:
What happens when TWO monosaccharides are joined together?
   A disaccharide is formed
   Disaccharides have two rings
   Disaccharides are double sugars
Disaccharides (con’t)………

Glucose + Glucose  maltose



                     Glucose + Fructose  Sucrose




Glucose + Galactose  Lactose



What happens when you join a monosaccharide with at disaccharide?
                Polysaccharides are made
Polysaccharides
What are polysaccharides?
                Polysaccharides are STARCHES
                They are called polymers because they are made of many
                 monosaccharides
                Polymers are long chains of monomers (single units)




Where are polysaccharides found?
          Starches are found in plants and animals

What are polysaccharides used for?
     In plants – Starch and Cellulose
         Starch is used for stored energy
         Cellulose is a type of polysaccharide
         Cellulose is what cell wall is made of
         Cellulose gives plants their strong structure
     In animals (humans) `
     – Glycogen and Chitin
                Glycogen is stored in muscle cells & Liver
                Glycogen is used for energy
                Chitin is the exoskeleton in insects
    What is High fructose corn syrup?
    High-fructose corn syrup is a common sweetener and preservative. High-fructose corn syrup is made by changing the sugar
    (glucose) in cornstarch to fructose — another form of sugar. The end product is a combination of fructose and glucose. Because it
    extends the shelf life of processed foods and is cheaper than sugar, high-fructose corn syrup has become a popular ingredient in
    many sodas, fruit-flavored drinks and other processed foods.

    So far, research has yielded conflicting results about the effects of high-fructose corn syrup. For example, various early studies
    showed an association between increased consumption of sweetened beverages (many of which contained high-fructose corn syrup)
    and obesity. But recent research — some of which is supported by the beverage industry — suggests that high-fructose corn syrup
    isn't intrinsically less healthy than other sweeteners, nor is it the root cause of obesity.

    While research continues, moderation remains important. Many beverages and other processed foods made with high-fructose corn
    syrup and other sweeteners are high in calories and low in nutritional value. Regularly including these products in your diet has the
    potential to promote obesity — which, in turn, promotes conditions such as type 2 diabetes, high blood pressure and coronary artery
    disease.

    If you're concerned about the amount of high-fructose corn syrup or other sweeteners in your diet, consider these tips:

            Limit processed foods.
            Avoid foods that contain added sugar.
            Choose fresh fruit rather than fruit juice or fruit-flavored drinks. Even 100 percent fruit juice has a high concentration of
    sugar.
            Choose fruit canned in its own juices instead of heavy syrup.
            Drink less soda.
            Don't allow sweetened beverages to replace milk, especially for children.




                                                         Proteins
    What are the functions of proteins?
      Enzymes - chemical reactions
      hormones
      storage - egg whites, seeds
      transport - hemoglobin
      contractile - muscle
      protective - antibodies
      membrane proteins (receptors, membrane transport, antigens)
      structural – Keratin in hair, collagen
      toxins - botulism, diphtheria
What is the smallest unit of proteins?
     Amino Acids are the monomers of proteins
     Amino acids are the building blocks of proteins
     There are 20 Amino acids, 9 are essential
     The 9 essential cannot be made by the body
     Malnutrition results if 9 ingested




What is the structure of amino acids?
  Amino acids have an amino group and a carboxyl group




   Chains of amino acids make up proteins called polypeptides
                          Fats and Lipids
What are the functions of Fats?
   Fats are used as a reserve energy supply
   They cushion organs
   Animal fat has six times more energy per gram than carbohydrates
   They are the main structure of cell membrane - phospholipids
   Steroids (cholesterol) and some hormones are lipid based

What are the components of Lipids?
  Triglycerides are made of
                  Glycerol
                  Fatty acids




   Triglycerides are either saturated or unsaturated




   Phospholipids make up cell membrane
 Steroids are lipid derived
          Examples are testosterone, estrogen, cholesterol(below)




What happens when we restrict specific nutrients?
What vitamins are essential?
What minerals are necessary in our diets?
Stay away from common food additives
Reading the ingredients on packaged foods before you buy can help in avoiding unhealthy food
additives and reducing exposure to chemicals that adversely affect health.

More and more evidence is revealing that it is not just the type of food people eat that is important to
health, but also what is in the food. Twelve common food additives, such as hydrogenated oils, high-fructose
corn syrup and artificial sweeteners, once thought safe, are being found to be more toxic and detrimental to
people’s well-being.

Food Additives – A Cause for Concern

The World Health Organization says, “The contamination of food by chemical hazards is a worldwide public
health concern and is a leading cause of trade problems internationally. Contamination may occur through
environmental pollution… or through the intentional use of various chemicals, such as pesticides, animal
drugs and other agrochemicals. Food additives and contaminants resulting from food manufacturing and
processing can also adversely affect health.”

According to the U.S. Department of Agriculture Food Safety and Inspection Service, “about 2,800
substances are used as food additives” in this country, making synthetic additives a significant part of what
people eat.

List of additives to avoid:
• hydrogenated or partially hydrogenated oils
• high-fructose corn syrup
• artificial colorings
• artificial sweeteners such as aspartame, sucralose and saccharin
• BHA or BHT
• monosodium glutamate
• hydrolyzed vegetable protein or autolyzed yeast extract
• potassium bromate
• propyl gallate
• sulfites
• sodium nitrate
• sodium benzoate or benzoic acid



Reasons to Avoid Food Additives

The food chemicals listed have been linked to heart disease, obesity, cancer, hyperactivity and other allergic
reactions. The Center for Science in the Public Interest (CSPI), explains why each should be avoided.

Hydrogenated or partially hydrogenated oils - Trans fats created by these oils have been linked to
heart disease. Since 2006 the FDA has required food manufacturers to list the amount of trans fats on
nutrition labels. But read the ingredients list carefully, as foods are allowed to be labeled as having “0 trans
fats” if they have 0.5 grams per serving. Look for labels that say “no trans fats,” which means none at all.
High-fructose corn syrup – Some studies have suggested that high-fructose corn syrup may be linked to
obesity. According to Catherine Guthrie in the article “Good Earth” in the October 2008 issue of Experience
Life, another reason to avoid this additive is that much of it is made from genetically modified corn that is
sprayed with chemical pesticides and fertilizers.

Artificial colorings – Some reports suggest that artificial colorings may cause various types of cancer.
According to CSPI, colorings have been shown to “cause hyperactivity in some sensitive children.”

Artificial sweeteners – Studies from the 1970s through 2007 indicate that sweeteners such as aspartame
and saccharin probably increase the risk of cancer.

BHA or BHT – Linked to cancer, BHA has been shown to cause cancer in lab animals. In its Report on
Carcinogens, the U.S. Department of Health & Human Services includes BHA on its list of chemicals
“reasonably anticipated to be a human carcinogen.”

Monosodium glutamate (MSG) – Studies have shown that some people are sensitive to large amounts of
this additive. According to CSPI, “reactions include headache, nausea, weakness, and burning sensation in
the back of neck and forearms….wheezing, changes in heart rate, and difficulty breathing.”

Hydrolyzed vegetable protein or autolyzed yeast extract – Used to enhance the natural flavor of
food, these additives contain MSG and may cause reactions in sensitive people.

Potassium bromate – Bromate is banned in most countries except Japan and the United States because it
causes cancer in animals. Look for it in the ingredients list of bread products.

Propyl gallate – This preservative is often used with BHA and BHT. Studies suggest that this additive might
cause cancer.

Sulfites – Used to prevent discoloration and bacteria growth, sulfites also destroy vitamin B-1 in foods.
Sulfites are known to cause reactions in people, especially those with asthma.

Sodium nitrate – Found in deli and other cured meats such as bacon and hot dogs, nitrates have been
linked to several types of cancer.

Sodium benzoate or benzoic acid – In sensitive individuals, sodium benzoate can cause allergic reactions
such as hives or asthma. When combined with ascorbic acid in beverages, the chemical benzene is formed
which causes leukemia and other cancers.

How to Avoid Food Additives -While it may seem hard to avoid products that contain these chemicals, it
is possible to find additive-free foods at your local supermarket. Next time you shop, spend time reading the
labels on foods before you put them in your shopping cart. Don’t be fooled by “0 trans fats” or other claims.
By paying attention to the ingredients list, you can avoid consumption of potentially harmful additives that
may affect your health.

								
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