CSEC Human and Social Biology Paper 2 May/June 2013 - Free CXC Past Paper with Answers

State TWO ways in which the structure of a plant cell differs from that of an animal cell.

Figure 1 shows a diagram of a specialized cell.

Figure 1. Diagram of a specialized cell

Identify the type of cell shown in Figure 1.

Explain how the structure of the cell shown in Figure 1 makes it suitable for its function.

List THREE characteristics of living organisms, other than respiration and feeding.

Whodat tells his teacher that a car is more alive than a plant because it takes in oxygen and gives out carbon dioxide, and because it moves.

Explain why respiration and feeding are characteristics that CANNOT be applied to a car.

Respiration

Feeding

Enzymes are biological compounds which speed up the rate of chemical reactions.

Give the names of TWO enzymes associated with digestion in humans, and state ONE function of EACH enzyme named.

Enzyme Function

Enzyme Function

The breakdown of food takes place in the mouth, stomach and small intestine. Name the type of digestion for which the teeth in the mouth are responsible.

Humans have four types of teeth. State which type of tooth is MAINLY responsible for the digestion named in (a)(ii) above.

Both temperature and pH affect the manner in which enzymes function. Figures 2 and 3 are graphs showing the rate of reaction of amylase over a range of temperatures and pH.

Figure 2. Rate of reaction of amylase over a range of temperatures

Figure 3. Rate of reaction of amylase at different pH levels

At approximately which temperature and pH does amylase function the BEST?

Temperature pH

Suggest what effect temperatures GREATER than $55^\circ C$ would have on enzymes.

Consumption of excessive amounts of carbohydrates and fats may contribute to the development of diabetes mellitus. Explain the role of the pancreas in the development of this disease.

Suggest TWO methods, other than the use of medication, which could be used to manage diabetes mellitus.

Mitosis and meiosis are two types of cell division which take place in humans.

Which type of cell division results in identical offspring?

State the number of chromosomes that will be found in the daughter cells of the cell division named in (a)(i) above.

In which type of cell does mitosis take place?

During meiosis, an event occurs in which there is the exchange of small parts of DNA between homologous chromosomes.

State the name of this event.

State the source of the homologous chromosomes and the importance of the event named in (b)(i) above.

Source

Importance

Figure 4 shows the menstrual cycle of a human female, highlighting changes which occur in hormonal levels, the uterus and the ovary.

Figure 4. The menstrual cycle of a human female

Describe the changes occurring in the menstrual cycle from

Day 0 – Day 5

Day 6 – Day 14.

Describe the changes that take place with progesterone levels AFTER ovulation, if pregnancy occurs, and if pregnancy does NOT occur.

After ovulation

If pregnancy occurs

If pregnancy does not occur

Outline how follicle-stimulating hormone (FSH) controls the production of oestrogen.

Name the vector for leptospirosis and the vector for gastroenteritis.

You are asked to educate your community about BOTH leptospirosis and gastroenteritis. Write the information that must be provided for EACH disease, using the following headings:

• Name of disease
• Signs and symptoms
• Ways to prevent pathogens from entering the body
• Prevention and control of the vectors

Write your answer to Question 5 here.

Define the term 'pollutant', and give an example of a pollutant that CANNOT be seen or touched.

Outline ONE way in which water can be purified on a small scale.

Explain how water can become polluted after a hurricane.

After drinking water at school, some students become ill.

Describe a test for determining if your school's water supply is contaminated with bacteria, and explain how the results of the test are to be interpreted.

Write your answer to Question 6 here.