WAEC GCE Biology 2017 Theory Questions and Answer (Alternative Practical Essay Expo)
This is not the 2017 Waec Gce Biology Alternative To Practical Questions And Answers, but it is the BIOLOGY Obj/Theory Answers you are looking for online. In this page, we will give you some past questions and answers to enable you to write and pass this exam.
2017 Past WAEC GCE Biology Questions & Answers Now Available here
Look below so see all the past questions and answers we have for you today. Please remember that you cannot use them as an expo material but as a tool to study and prepare for the upcoming exam today, tomorrow or next year.
Question 1
(a)(i) Explain briefly sexual reproduction in Rhizopus. [8 marks]
(b) A student suddenly stepped on a big snake, he cried for help and ran away.
(i) Name the hormone produced in the body for the reaction.
(ii) In which part of the human body is the hormone named in 1 (a) (i) produced?
(iii) State five changes that must have taken place as a result of the hormone named in 1 (a) (i). [7 marks]
(c) (i) In a tabular form, state three differences between the excretion in flowering plants and excretion in humans.
(ii) List two organelles found in a plant cell that are responsible for the excretion of metabolic wastes [5 marks]
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
- No definite excretory organs
- Definite excretory organs/presence of kidney/liver/skin;
- Excretory products produced in small quantities
- Excretory products released at a slower rate
- Most excretory products/tannins/resins/alkaloids/gums are stored
- Some excretory products/carbondioxide/oxygen/water vapour can be reused
- Excretory products are derived from simple organic molecules
Humans
- Waste products include tannins/resins/alkaloids/gums e.t.c.
- Waste products include urine/urea/sweat/salts e.t.c.
- Excretory products produced in large quantities;
- Excretory products released at a faster rate;
- Most excretory products are completely removed;
- Some excretory products/urea/uric acid cannot be reused;
- 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
Question 2
(a) Explain how the leaf of a flowering plant is adapted for photosynthesis. [6 marks]
(b) Describe briefly the mode of feeding in tapeworms. [5 marks]
(c) Name one mineral element each needed for the proper functioning of: (i) bones; (ii) red blood cells; (iii) thyroid gland. [3 marks]
(d) (i) State three benefits of including roughage in the diet of humans. [3 marks]
(ii) State three reasons why proteins are important to humans. [3 marks]
Observation
This was one of the most popular questions but majority of the candidates that attempted it could not relate the structures with functions adequately in question 2(a) Many candidates were writing about photosynthesis instead of giving the structures and stating the functions of each structure as required in the question.
Majority of the candidates scored all the marks for question 2 (b). Some candidates wrote iodine as the mineral needed for the proper functioning of bones and red blood cells. Candidates answered 2 (d) (i) and (d) (ii) well, indicating the knowledge of the topic.
The expected answers are:
(a) Adaptation of leaf for photosynthesis
- Broad/flat leaf lamella; exposes large surface area for maximum absorption of light;
- Palisade mesophyll cells contain a lot of chloroplast/chlorophyll; for maximum absorption of light;
- Position of leaf to stem; for optimum reception of light rays/sunlight;
- Thin lamella; allows light penetration into leaf tissue of mesophyll;
- Palisade cells are at right angle/perpendicular to the upper epidermis/chloroplasts are arranged in the periphery of the cells; all for easy activation of the chloroplasts for photosynthesis;
- Large vacuoles of the palisade cells; store photosynthetic products;
- Large intracellular air spaces in the spongy mesophyll; allow oxygen/carbondioxide to diffuse in/out of the chlorophyllus cells/gaseous exchange;
- The epidermal cells have thin cell walls; for easy penetration of sunlight to the mesophyll;
- Guard cells have chloroplast; for the absorption of sunlight;
- The bean-shaped structure of the guard cell; is to allow for gaseous exchange;
- The stomata; open easily when it becomes turgid for diffusion of gases/carbondioxide/oxygen;
- Xylem; conducts water into the leaves for photosynthesis;
- Phloem; transports manufactured food to other parts of the plant.
NOTE: Structure x1 mark
Function x1 mark
Function only does not score; Function must correspond with structure to score.
(b) Mode of feeding of tapeworm
Parasitic mode of feeding; lives in the gut of man/pigs; has hooks/suckers; which enable it attach itself to the lining of the intestine of the host; has a flattened tape-like/ribbon-like body; provide large surface area for easy absorption of digested food; no alimentary/digestive system.
(c) Mineral elements necessary for the proper functioning of;
(i) Bones
Calcium; phosphorus; fluorine
(ii) Red blood cells
Iron; copper
(iii) Thyroid gland Iodine
NOTE: Spelling must be correct to score in (i), (ii) and (iii).
(d) (i) Benefits of including roughages in the diet of humans
- Stimulates bowel movement/peristalsis;
- Reduces blood cholesterol/bowel cancer/gall stones/appendicitis/obesity/diabetes mellitus;
- They do not contribute to weight gain/high blood sugar;
- It releases glucose slowly;
- It prevents constipation.
(ii) Importance of proteins to humans
- For the repair of damaged tissues; replacement of worn-out tissues;
- For body building;
- For growth;
- For the supply of the necessary amino acids;
- For formation of hormones/enzymes/antibodies/forming fibrinogen necessary for blood clotting.
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