5.4 Heart muscle has a high demand for oxygen. Describe how the heart muscle is supplied with oxygen. (3)

 1.1        (1)

EXTRA ESSAY ANSWER SPACE Only use this space if necessary. 

1.27 Below are tissues found in the walls of blood vessels. Which tissues are present in the walls of all blood vessels?   1.    Collagen 2.    Elastic 3.    Endothelial 4.    Smooth muscle (1)       A) 1, 2, 3 and 4   B) 3 only   C) 2 and 3 only   D) 1, 3 and 4 only  

1.23 Which of the following occurs during DNA replication, transcription, and translation?     1.    Condensation reactions occur to form a polymer 2.    ATP provides energy 3.    Hydrogen bonds form between purine and pyrimidine bases (1)       A) 1 and 2 only   B) 1, 2 and 3   C) 2 only   D) 3 only  

1.28 Which one of the following is a product produced by the action of carbonic anhydrase? (1)       A) Haemoglobinic acid   B) Carbaminohaemoglobin   C) Hydrogencarbonate ions   D) Oxyhaemoglobin    

1.33 Which of the following reactions take place in a capillary of an active tissue?   1.    Carbonic acid is formed from carbon dioxide and water 2.    Haemoglobin and hydrogen ions are formed from haemoglobinic acid 3.    Carbaminohaemoglobin is formed from carbon dioxide and haemoglobin 4.    Carbon dioxide and water are formed from hydrogencarbonate ions and hydrogen ions (1)       A) 1 and 3 only   B) 1, 2, 3 and 4   C) 1 and 2 only   D) 2 and 4 only    

1.29 Which one of the following instruments can be used to hear the movement of heart valves? (1)       A) Cardioverter   B) Endoscope   C) Stethoscope   D) Sphygmomanometer  

1.24 Ricin is a toxic protein which inactivates ribosomes. Which effect will this have on protein synthesis? (1)       A) Anticodons on mRNA molecules will not base pair to codons on tRNA molecules   B) Peptide bonds will not form between adjacent amino acids in the growing polypeptide   C) Amino acids will be unable to bind to the binding sites on specific tRNA molecules   D) RNA nucleotides will be unable to join by condensation reactions for form rRNA  

6. Fig. 6.1 is a photomicrograph of some xylem vessels.     Right-click on the blue button to open Fig. 6.1