Assignment Biochemistry I (2)

Wan Muhamad Qusyairi Bin Wan Mazlan	AS1142B1
Diploma in Microbiology	BIOCHEMISTRY I

QUESTION CHAPTER 1, 2 AND 3

1.      Why linear/ Fischer should change to Haworth Projections?

      Because they are convenient and easy to draw.

2.      List reducing and non-reducing sugar.

        

Reducing Sugar	Non-Reducing Sugar
Glucose	Sucrose
Fructose
Maltose
	Trehalose
Lactose
Galactose

3.   
   How to know it reducing or non-reducing sugar?

       

Reducing Sugar	Non-Reducing Sugar
Such sugar bear a free aldehyde (-CHO) or ketone (- CO) group	These sugar do not have such groups
Reducing sugar has the capacity to reduce cupric ions of Benedict’s or Fehling solution to cupric ions.	Non-reducing sugar fails to reduce the cupric ion of Benedict’s solution to cupric ions.
Maltose, lactose, melibiose, gentiobiose, cellobiose, mannotriose, rhamnotriose	Sucrose, trehalose,raffinose, gentiarose, melezitose

4.      Butterfly wings made of what?

      The main structure of the wing is made of thin layers of chitin, a protein that also makes up the outer "shell" of the body.

5.      What type of algae those use in the food industry? Why?

      Seaweeds are edible algae that have been used for centuries as food in many coastal regions all over the world.  They may belong to one of three groups of multicellular algae.  Algae are of excellent nutritional value since they contain complete protein (in contrast to plant food Harvested on land), fibre, and sometimes high levels of omega-3 fatty acids. In fact, the omega-3 acids in fish come from the microalgae consumed at the bottom of the food pyramide and gradually passed up to the fish at the top.  Algae are also rich in many vitamins, such as A, C, B1, B2, B3 and B6, as well as minerals, such as iodine, calcium, potassium, magnesium and iron. They are consumed cooked, dried and raw.

6.      What is conjugated protein?

      A compound, such as haemoglobin, made up of a protein molecule and a non-protein prosthetic group.  A biochemical compound consisting of a sequence of amino acids making up a simple protein to which another non-protein group (a prosthetic group), such as a carbohydrate or lipid group, is attached.

7.      What is a precursor?

      A precursor is a compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway.

8.      Why vitamin B and C does not soluble in lipid?

      Because Vitamin B and C are water soluble not fat soluble.

9.      Why α amino group just 19 and why 20 is not?

      Because Proline (amino group 20) is nonessential amino acid and it is secondary amino acid.   Besides, it has a secondary amino group and contains a pyrrole ring, such as found in haemoglobin and the cytochromes. This structure causes proline in a protein to impart a rigid protein structure.

10.  Why L-form of an amino acid is commonly found in protein?

      Because during translation in the ribosome.

11.  Name the bond that exists in these structures.

      Double bond, single bond, covalent bond, R group chain

12.  What are examples of reversible denaturation/renaturation?

        An example of denaturing in proteins comes from egg whites.  Another example of denaturation is the coagulation that occurs when milk is heated with an acid leading to the formation of cheese. 

13.  Why only L-form amino acids are commonly found in protein?

      The L-form amino acids are more commonly found in protein because only L-form amino acid is manufactured in cells and incorporated into proteins.  The eukaryotes cells do not have the enzymes to synthesize the D-form amino acids.  The D-form amino acids are more commonly found in lower organisms in the cell walls of bacteria, but not in bacterial proteins.

14.  Why amino acid is important for babies?

      Because we normally ingest more protein (and thus amino acids) then we need, only a small % is used to make new protein.  For example, less than 5% of the amino acid phenylalanine is used even in a growing child and even less in a grown adult.  All the rest is burned as energy or converted to another amino acid called tyrosine and other amino acids important to the way the brain functions.  When an infant cannot burn an amino acid normally, several things happen:

• 1.  Excess is converted in the body to other compounds, many of which are toxic

• 2.  There can be a deficiency of some compounds which are made from that amino acid—often things important for brain function.

15.  What is the function of H₂O₂ in hair dyes?

      Basically, hydrogen peroxide is involved in a reaction to (apparently) eliminate melanin from hair, but how exactly does it do that? Well, it doesn’t really eliminate melanin, but in the presence of hydrogen peroxide, this pigment is oxidized and converted to a colourless compound.  Looking at it in more detail, hydrogen peroxide converts melanin’s double bonds into single bonds, blocking its ability to absorb light, thus effectively making it “disappear”. This reaction also releases sulphur, accounting for the characteristic odour of hair colour treatments. In this case, the natural yellowish colour of keratin comes through instead, effectively producing blonde hair. As eumelanin is attacked faster than phaeomelanin, some shades of red can still be visible after a short treatment with hydrogen peroxide. In contrast, if the treatment is too long, the result is a pure white hair, after both forms of melanin are completely oxidized.

Typically, hair lightening products are mixed in an alkaline solution, to make it easier for hydrogen peroxide to cut through the cuticle and reach the medulla, where melanin is stored. While any base could soften the cuticle, old hair product recipes relied on ammonia for this effect, as this compound could also break down small melanin particles, allowing easier access for the hydrogen peroxide. However, concerns about its harshness led to the development of alternative components and most modern products boast an ammonia-free content. Other ingredients may include persulphate salts to accelerate the reaction and multiple stabilizing chemicals to prevent a breakdown of hydrogen peroxide.

16.  What is the function of H₂O₂ inside our body antibacterial protecting?

      Hydrogen peroxide is generated in vivo by the dismutation of superoxide radical both non-enzymatically and catalyzed by superoxide dismutase enzymes. Hydrogen peroxide is also directly produced by a range of oxidase enzymes including glycollate and monoamine oxidases as well as by the peroxisome pathway for beta-oxidation of fatty acids. With the apparent exception of cardiac muscle, mitochondria in most tissues appear to have limited capacity to remove H₂O₂, in that they readily generate substantial amounts of H₂O₂ in vitro and probably in vivo. Although mitochondria contain glutathione peroxidase and thioredoxin-linked peroxidase activities, the efficiency of these enzymes in removing H₂O₂ is uncertain given the ease with which mitochondria release H₂O₂. It thus seems likely that most or all human cells are exposed to some level of H₂O₂, with the mitochondria being an important source. However, certain tissues may be exposed to higher H₂O₂ concentrations.

17.  What is the function of Fe³⁺ react with H₂O₂?

      A Fe3+ ion acts as a catalyst in the reaction.  In this reaction, it acts as a homogeneous catalyst in which the catalyst is in the same phase as the reaction mixture.  The Fe³⁺ ions will speed up the rate of reaction of hydrogen peroxide and lower the activation energy of the reaction.  The reaction will be like this :

Fe³⁺ + H₂O₂ + OH.           Fe³⁺ + HOO. + H₂O             Fe²⁺ + H⁺ + O₂ + H₂O

18.  What are the properties of enzymes?

      Enzymes are proteins that are biological catalysts

      They reduce the activation energy required for a reaction to occur and thus speed up a reaction

      Temperature, above a certain point (optimum temperature), causes them to break down and they are gradually destroyed (denaturing)

      They work best at a particular pH (optimum pH) and are once again destroyed by low or high pH's

      They have a specific shape, with one particular part, known as the active site, which is specific to the substrate they speed the reaction of. These means they are specific to one type of reaction.

      They aren't used in the reaction so they're re-usable.

19.  What are the characteristic of enzymes and how they bind and the example of enzymes?