Observation

This question was the least popular question among the candidates.  Most of the candidates that attempted it did not do it well.
Candidates attempted other aspects fairly.

            The expected answers are:
(a)        Sexual reproduction in Rhizopus

By conjugation;

It is usually between two strains of hyphae;

Known as + and -/plus and minus/opposite mating types;

The hyphae come in contact;                                                                                           

And produce small projections on their walls;                                                     

Which develop into progametangia with several nuclei;

The two progametangia enlarge;

Each progametangium develops a cross wall to divide into two parts; the gametangium and suspensor;

Subsequently the wall dissolves/breaks; and their contents/nuclei fuse to form a zygote;

The zygote develops a thick wall to form a resistant zygospore;

The zygospore germinates during favourable /damp/wet condition;

Into hyphae which bear sporangia.                                                             

(b) (i) Name of hormone
Adrenalin/Adrenaline                                                                                                
NOTE: Spelling must be correct to score

      (ii) Part where hormone is produced
Adrenal gland/Medulla                                                                                              
NOTE: Spelling must be correct to score

      (iii) Changes that must have taken place as a result of the hormone

Increase in heart beat;

Increase in rate of respiration;

Arterioles of skin and alimentary canal constrict;

Dilation of blood vessels that cause more blood to flow to the muscles/heart/lungs;

Increase in muscular tone/voluntary muscles become tensed;

Glycogen is converted to glucose/increase in blood sugar level;

To produce more energy;

Dilation of pupils of the eye;

Momentary freight/fear/anxiety/heavy breathing;

Spleen releases more Red Blood Cells from its reserve;

Increase in blood pressure.                                                                       

 

(c) (i) Differences between excretion in flowering plants and excretion in humans

Flowering plants	Humans
- No definite excretory organs - Waste products include tannins/resins/alkaloids/ gums e.t.c.	Definite excretory organs/presence of kidney/liver/skin; Waste products include urine/urea/sweat/salts e.t.c.
- Excretory products produced in small quantities	Excretory products produced in large quantities;
- Excretory products released at a slower rate	Excretory products released at a faster rate;
- Most excretory products/tannins/resins/alkaloids/ gums are stored	Most excretory products are completely removed;
- Some excretory products/carbondioxide/oxygen/ water vapour can be reused	Some excretory products/urea/uric acid cannot be reused;
- Excretory products are derived from simple organic molecules	Excretory products are derived from complex organic molecules.

                                                                                                                                                           
NOTE: No Tabulation minus (-) 1 mark.

(ii) Organelles in plant cells responsible for excretion of metabolic wastes
Mitochondrion/ mitochondria; chloroplast/chloroplasts                                            
NOTE: Spelling must be correct to score