Gr11 LS 15 Exam Preparation Paper 2

Grade 11 Life Sciences: Exam Preparation Paper 2 Topics: 1) Biodiversity and classification of microorganisms 2) Biodiversity of Plants 3) Biodiversity of Animals Revision of Key Concepts: Biodiversity of Animals Key Concepts: 1. Invertebrates are animals without a backbone 2. According to backbone and some other features animals are classified accordingly 3. There are five features to track the increasing complexity among different animals. These are as follows: Body of symmetry Type of gut Type of body cavity Segmentation Cephalisation 4. Each phylum has its own body plan. A body plan refers to the way the body is structured.

Question 1: Match each description in Column A with the correct term from Column B. Write the answer (letter only) from column B in the space provided. (7) Column A Answer Column B 1.1. Long strands of a fungus that can A fungi extend over a substrate. 1.2 An opportunistic infection of an B saprotrophs HIV-positive person 1.3 Together with bacteria, fungi of this C archae type break down dead organic matter 1.4 An organism that causes malaria D hyphae 1.5 The kingdom of microbes which E pneumonia produce antibiotics 1.6 Cells that have a membrane bound F phytoplankton nucleus and cell organelles 1.7 Animal-like protista G AIDS H vector I Eukaryote J Plasmodia K Protozoa Question 1.2: Differentiate between the following terms: 1.2.1 Diploblastic and triploblastic. (2) 1.2.2 Blind gut and through-gut. (2) 1.2.3 Explain the advantages of cephalisation and why is essential in bilateral animals (4) Question 1.3: 1.3 Indicate whether each of the statements in COLUMN Ι, applies to A ONLY, B ONLY, BOTH A and B, or NONE of the items in COLUMN ΙΙ. Write A ONLY, B ONLY, BOTH A and B, or NONE next to the question number in the ANSWER BOOK.

Question 1.4: 1.4 Study the graph below and answer the questions that follow. 1.4.1 In which year was the highest number of TB cases reported? (1) 1.4.2 Calculate the total number of TB cases in 2003 and 2004. (1) 1.4.3 What trend is shown by the data on the graph? (2) 1.4.4 Suggest ONE reason why this trend is taking place. (1)

Question 3: Learners wanted to investigate the effect of different antibiotics on the growth of a certain bacterial species. They set up nutrient agar plates and placed sterile discs containing three different antibiotics on each of the plates. Study the diagram and answer the following questions. 3.1 What is an antibiotic? (2) 3.2 What is the function of the agar plates? (1) 3.3 Mention ONE precaution that the learners would have taken toensure that their results were valid. (1) 3.4 Which factors would the learners have kept constant during theinvestigation? (2) 3.5 Use the information in the diagram to describe the results of the investigation. (3)

Lesson 15: Exam Preparation paper 2 Question 1: Question 1.1. 1.2 1.3 1.4 1.5 1.6 1.7 Answer D E B J A I K Question 1.2: 1.2.1 Diploblastic: animals that have two layers in their embryo are calleddiploblastic animals Triploblastic: If there are three layers in the embryo like humans or other animals, then they are referred to as being triploblastic. 1.2.2 A gut with a separate mouth and anus is called a through-gut. A gut with a single opening through which food enters and waste leaves is called a blind gut 1.2.3 It is the concentration of organs, especially sensory organs, feeding appendages and nervous tissue near the anterior end of the animal. It is common among animals that are bilaterally symmetrical. This allows for the concentration of nerves at the anterior end; thus allowing bilaterally symmetrical organism a developed nervous system. Question 1.3 Question 1.4: 1.4.1. Answer: 2003 1.4.2 88 559 1.4.3 The number of TB cases increased from 1997 to 2003 and decrease slightly in 2004. 1.4.4 Probably due to an increase in the population. /More people living in poor conditions Question 3: 3.1 It is a chemical substance that reduces the growth of bacteria by killing them/preventing them from reproducing 3.2 They provide the bacteria with nutrients for growth. 3.3 To make sure that the agar plates are set up in sterile conditions. To make sure that the agar plates are not contaminated with other bacteria and fungi.

3.4 Kept all plates at the same temperature. Ensured that the plates had the same amount of nutrients in the same concentration 3.5 Antibiotic 3 was the most effective in destroying the bacteria. Antibiotic 2 was ineffective against the bacteria. Antibiotic 1 was fairly effective