life sciences Overview Grade 12 Notes and Study Guides. Life science studies living organisms and processes. It spans a vast swath of scientific research, from aiding our understanding of microorganisms such as viruses or bacteria, to deciphering the physiological processes of the largest land and marine animals on the planet
LIFE SCIENCES OVERVIEW GRADE 12 NOTES – LIFE SCIENCES STUDY GUIDES
OVERVIEW
LIFE SCIENCES
STUDY GUIDES AND NOTES GRADE 12
Dear Grade 12 learner
This Mind the Gap study guide helps you to prepare for the end-of-year CAPS Life Sciences Grade 12 exam.
The study guide does NOT cover the entire CAPS curriculum, but it does focus on core content of each knowledge area and points out where you can earn easy marks.
You must work your way through this study guide to improve your understanding, identify your areas of weakness and correct your own mistakes.
To ensure a good pass, you should also cover the remaining sections of the curriculum using other textbooks and your class notes.
OVERVIEW OF THE EXAM FOR CAPS LIFE SCIENCES GRADE 12
The following topics make up each of the TWO Life Sciences exam papers that you write at the end of the year:
PAPER 1 | WEIGHTING | |
Topic | % | MARKS |
Term 1 | ||
Meiosis | 7 | 11 |
Reproduction in Vertebrates | 4 | 6 |
Human Reproduction | 21 | 31 |
Term 2 | ||
Responding to the Environment (Humans) | 27 | 40 |
Term 3 | ||
Human Endocrine System | 10 | 15 |
Homeostasis in Humans | 7 | 11 |
Responding to the Environment (Plants) | 7 | 11 |
Term 4 | ||
Human Impact (Grade 11) | 17 | 25 |
100 | 150 |
PAPER 2 | WEIGHTING | |
Topic | % | MARKS |
Term 1 | ||
DNA: Code of Life | 19 | 27 |
Meiosis | 7 | 12 |
Term 2 | ||
Genetics and Inheritance | 30 | 45 |
Terms 3/4 | ||
Evolution | 44 | 66 |
100 | 150 |
Both Paper 1 and Paper 2 will include the following types of questions:
Section | Type of question | Marks |
A | Short answer, objective questions such as multiple-choice questions, terminology, columns/statement and items | 50 |
B | A variety of question types. There will be two questions of 40 marks each. Both of these questions will be divided into two to four subsections. | 2 × 40 |
C | Essay | 20 |
How to use this study guide
This study guide covers selected parts of the different topics of the CAPS Grade 12 Life Sciences curriculum in the order they are usually taught during the year. The selected parts of each topic are presented in the following way:
- An explanation of terms and concepts;
- Worked examples to explain and demonstrate;
- Activities with questions for you to answer; and
- Answers for you to use to check your own work.
- A checklist from the exam guidelines for Life Sciences has been provided on page xvii for you to keep track of your progress. Once you have mastered the core concepts and have confidence in your answers to the questions provided, tick the last column of the checklist.
- The activities are based on exam-type questions. Cover the answers provided and do each activity on your own. Then check your answers.
Reward yourself for the things you get right. If you get any incorrect answers, make sure you understand where you went wrong before moving on to the next section. - In Chapter 12, you will find a section on graphing skills which you must master when preparing for both Paper 1 and Paper 2. This chapter also provides guidelines on how to answer essay-type questions in the exam.
- You will be asked to draw a labelled diagram in the exam. On page 115 to 132 are a set of blank diagrams that you can use to practise your drawing and labelling skills. Filling in these blank diagrams is a good way to test yourself and work out what you know well and what you still need more practice in.
- Use this study guide as a workbook. Make notes, draw pictures and highlight important concepts.
- Exemplar Exam papers are included in the study guide for you to do. Check your answers by looking back at your notes and the exam memoranda. Past exam papers go a long way in preparing you for what to expect and help reduce exam anxiety.
Top 10 study tips
- Have all your materials ready before you begin studying – pencils, pens, highlighters, paper, etc.
- Be positive. Make sure your brain holds on to the information you are learning by reminding yourself how important it is to remember the work and get the marks.
- Take a walk outside. A change of scenery will stimulate your learning. You’ll be surprised at how much more you take in after being outside in the fresh air.
- Break up your learning sections into manageable parts. Trying to learn too much at one time will only result in a tired, unfocused and anxious brain.
- Keep your study sessions short but effective and reward yourself with short, constructive breaks.
- Teach your concepts to anyone who will listen. It might feel strange at first, but it is definitely worth reading your revision notes aloud.
- Your brain learns well with colours and pictures. Try to use them whenever you can.
- Be confident with the learning areas you know well and focus your brain energy on the sections that you find more difficult to take in.
- Repetition is the key to retaining information you have to learn.
Keep going – don’t give up! - Sleeping at least 8 hours every night, eating properly and drinking plenty of water are all important things you need to do for your brain. Studying for exams is like strenuous exercise, so you must be physically prepared.
Study skills to boost your learning
This guide includes 3 study techniques you can use to help you learn the material:
- Mobile notes
- Mnemonics
- Mind maps
Mobile notes
Mobile notes are excellent techniques will tools for learning all the key help you to study concepts in the study guide. smarter!
Mobile notes are easy to make and you can take them with you wherever you go:
- Fold a blank piece of paper in half. Fold it in half again. Fold it again.
- Open the paper. It will now be divided into 8 parts.
- Cut or tear neatly along the folded lines.
- On one side of each of these 8 bits of paper, write the basic concept.
- On the other side, write the meaning or the explanation of the basic concept.
- Use different colours and add pictures to help you remember.
- Take these mobile notes with you wherever you go and look at them whenever you can.
- As you learn, place the cards in 3 different piles:
- I know this information well.
- I’m getting there.
- I need more practice.
- The more you learn them, the better you will remember them.
Mnemonics
A mnemonic code is a useful technique for learning information that is difficult to remember.
Below are two examples of mnemonics.
Here is a made-up word to help you remember the structure of a sperm cell – each letter of the word stands for a part of the cell:
M – Mitochondria
A – Acrosome
N – Nucleus
T – Tail
Here is a sentence to help you remember the 4 nitrogenous bases in DNA – each word in the sentence begins with the same letter as one of the nitrogenous bases:
All Teachers Get Chocolate
Adenine Thymine Guanine Cytosine
Mnemonics code information and make it easier to remember.
The more creative you are and the more you link your ‘codes’ to familiar things, the more helpful your mnemonics will be.
This guide provides ideas for using mnemonics. Be sure to make up your own.
Mind maps
There are several mind maps included in this guide, summarising some of the sections.
Have a look at the following pictures of a brain cell (neuron) and, below it, a mind map:
Mind maps work because they show information that we have to learn in the same way that our brains ‘see’ information.
As you study the mind maps in the guide, add pictures to each of the branches to help you remember the content.
You can make your own mind maps as you finish each section.
How to make your own mind maps:
- Turn your paper sideways so your brain has space to spread out in all directions.
- Decide on a name for your mind map that summarises the information you are going to put on it.
- Write the name in the middle and draw a circle, bubble or picture around it.
- Write only key words on your branches, not whole sentences. Keep it short and simple.
- Each branch should show a different idea. Use a different colour for each idea. Connect the information that belongs together. This will help build your understanding of the learning areas.
- Have fun adding pictures wherever you can. It does not matter if you can’t draw well.
On the day of the exam …
- Make sure you have all the necessary stationery for your exam, i.e. pens, pencils, eraser, protractor, compass, calculator (with new batteries). Make sure you bring your ID document and examination admission letter.
- Arrive on time, at least one hour before the start of the exam.
- Go to the toilet before entering the exam room. You don’t want to waste valuable time going to the toilet during the exam.
- Use the 10 minutes reading time to read the instructions carefully. This helps to ‘open’ the information in your brain. Start with the question you think is the easiest to get the flow going.
- Break the questions down to make sure you understand what is being asked. If you don’t answer the question properly you won’t get any marks for it. Look for the key words in the question to know how to answer it. A list of these words is on page xiv of this study guide.
- Try all the questions. Each question has some easy marks in it so make sure that you do all the questions in the exam.
- Never panic, even if the question seems difficult at first. It will be linked with something you have covered. Find the connection.
- Manage your time properly. Don’t waste time on questions you are unsure of. Move on and come back if time allows. You have 150 minutes (2½ hours) to answer each of the 150-mark Life Sciences question papers. Spend the following amounts of time on each question:
- Question 1: 50 marks = 45 minutes
- Question 2: 40 marks = 35 minutes
- Question 3: 40 marks = 35 minutes
- Question 4: 20 marks = 15 minutes
The remaining 20 minutes can be used to check your answers and attempt to answer any question that you might have left out.
- Check weighting – how many marks have been allocated for your answer? Take note of the ticks in this study guide as examples of marks allocated. Do not give more or less information than is required.
- Write big and bold and clearly. You will get more marks if the marker can read your answer clearly.
Question words to help you answer questions
It is important to look for the question words (the words that tell you what to do) to correctly understand what the examiner is asking. Use the words in the table below as a guide when answering questions.
Question word | What is required of you |
Analyse | Separate, examine and interpret |
Calculate | This means a numerical answer is required – in general, you should show your working, especially where two or more steps are involved |
Classify | Group things based on common characteristics |
Compare | Point out or show both similarities and differences between things, concepts or phenomena |
Define | Give a clear meaning |
Describe | State in words (using diagrams where appropriate) the main points of a structure/process/phenomenon/investigation |
Determine | To calculate something, or to discover the answer by examining evidence |
Differentiate | Use differences to qualify categories |
Discuss | Consider all information and reach a conclusion |
Explain | Make clear; interpret and spell out |
Identify | Name the essential characteristics |
Label | Identify on a diagram or drawing |
List | Write a list of items, with no additional detail |
Mention | Refer to relevant points |
Name | Give the name (proper noun) of something |
State | Write down information without discussion |
Suggest | Offer an explanation or a solution |
Tabulate | Draw a table and indicate the answers as direct pairs |
Learner’s checklist
Use this checklist to monitor your progress when preparing for the examination.
The ticks (✔) tell you which aspects of the curriculum are covered in this study guide. The stars (*) tell you to go to textbooks and class notes.
TOPIC | ASPECT | Covered in The Study Guide | I do not understand | I understand |
DNA: The code of life | Discovery of DNA structure | * | ||
Nucleic acids terminology | ✔ | |||
Structure of DNA and RNA | ✔ | |||
Differences between DNA and RNA | ✔ | |||
DNA replication and the importance thereof | ✔ | |||
DNA profiling | ✔ | |||
Protein synthesis | ✔ | |||
Meiosis | The process of meiosis using diagrams | ✔ | ||
Significance of meiosis | ✔ | |||
Abnormal meiosis | ✔ | |||
Differences between meiosis I and meiosis II | ✔ | |||
Reproduction in vertebrates | Diversity in reproductive strategies | ✔ | ||
Human reproduction | Male reproductive system | ✔ | ||
Female reproductive system | ✔ | |||
Puberty | ✔ | |||
Menstrual cycle | ✔ | |||
Development of the foetus | ✔ | |||
Gestation | ✔ | |||
Role of placenta | ✔ | |||
Genetics and inheritance | Genetic terminology | ✔ | ||
Complete dominance | ✔ | |||
Incomplete dominance | ✔ | |||
Co-dominance | ✔ | |||
Inheritance of sex | ✔ | |||
Sex-linked characteristics | ✔ | |||
Dihybrid crossing | ✔ | |||
Mutations | ✔ | |||
Pedigree diagrams | ✔ | |||
Genetic engineering | ✔ | |||
Genetic counselling | ✔ | |||
Paternity testing and DNA fingerprinting | ✔ | |||
Responding to the environment: Humans | The brain | ✔ | ||
Neurons, reflex actions and reflex arcs | ✔ | |||
Peripheral nervous system | * | |||
Autonomic nervous system | * | |||
Brain disorders and injuries | * | |||
Effects of drugs on the central nervous system | * | |||
Structure and functions of parts of the eye | ✔ |
Covered in The Study Guide | I do not understand | I understand | ||
Responding to the environment: Humans | Accommodation | ✔ | ||
Pupillary mechanism | ✔ | |||
Visual defects | ✔ | |||
Structure and functions of parts of the ear | ✔ | |||
Hearing | ✔ | |||
Balance | ✔ | |||
Hearing defects | ✔ | |||
Human endocrine system | Glands and the hormones they secrete | ✔ | ||
Negative feedback – glucose | ✔ | |||
Negative feedback – thyroxin | ✔ | |||
Homeostasis in humans | Negative feedback – glucose | ✔ | ||
Negative feedback – carbon dioxide | ✔ | |||
Negative feedback – water | ✔ | |||
Negative feedback – salts | ✔ | |||
The role of the skin on hot and cold days | ✔ | |||
Responding to the environment: Plants | Functions of auxins, gibberillins and abscisic acid | ✔ | ||
Role of auxins in phototropism and geotropism | ✔ | |||
Plant defence mechanisms is included | ✔ | |||
Evolution | Evidence for evolution | ✔ | ||
Sources of variation | ✔ | |||
Lamarck and Darwin’s theories | ✔ | |||
Natural and artificial selection | ✔ | |||
Punctuated equilibrium | ✔ | |||
Speciation | ✔ | |||
Mechanisms for reproductive isolation | ✔ | |||
Evolution in present times | ✔ | |||
Human evolution: similarities to African apes | ✔ | |||
Human evolution: differences from African apes | ✔ | |||
Major phases in hominid evolution | ✔ | |||
Out of Africa hypothesis | ✔ | |||
Phylogenetic trees | ✔ | |||
Human impact on the environment | Atmosphere and climate change | ✔ | ||
Water availability | ✔ | |||
Water quality | ✔ | |||
Food security | ✔ | |||
Loss of biodiversity | ✔ | |||
Waste disposal | ✔ | |||
Skills | Draw a line graph | ✔ | ||
Draw a bar graph | ✔ | |||
Draw a histogram | ✔ | |||
Draw a pie chart | ✔ | |||
Answering essay questions | ✔ |