Everything Life Sciences Grade 10

Investigation: PART B

Aim:

To demonstrate the effect of temperature on catalase activity

Method:

• Add 3 ml of hydrogen peroxide to two separate 10 ml graduated measuring cylinders.
  Mark one cylinder ”frozen chicken liver” and the other ”boiled chicken liver”.


• Cut a 0.1 g square from each of the frozen and boiled chicken livers. Add the liver
  pieces to the correspondingly labelled measuring cylinder with hydrogen peroxide in
  it.


• Leave both pieces of liver for four minutes and measure the height of bubbles pro-
  duced.

Questions:

1. Give reasons for the differences observed across the three measuring cylinders.


2. Name the dependent and independent variables in this experiment.


3. How could you make this experiment more accurate?


4. What would you conclude from your observations?

Nucleic acids DUMMY

Nucleic acids are large organic molecules that are key to all living organisms. Nucleic acids
arepolymersmade up ofnucleotides. Nucleotides are made up of a sugar, a phosphate and
a nitrogenous base. Nucleotides are joined together byphosphodiesterbonds, joining the
phosphate of one nucleotide to the sugar of the next. DNA is synthesised using intermediate
products of carbohydrate and amino acid metabolism.

Nucleic acids include:

• Deoxyribonucleic acid (DNA): which contains the ’instructions’ for the synthesis of
  proteins in the form of genes. DNA is found in the nucleus of every cell.


• Ribonucleic acid (RNA): is important in transferring genetic information from DNA to
  proteins. It is found on ribosomes, in the cytoplasm and in the nucleus.

Chapter 2. The chemistry of life 47