Category Archives: Unit 3 Biology

Step Up to 2017!

sparkling trails of light drawing out the numbers 2017 in glowing light to welcome in the new year

Welcome to the step up week for Year 12 Biology in 2017. This post is to let you know about some of the resources that are available for your studies. It is a new course for Unit 3 and 4 next year and we will be using the Heinemann textbook (3rd edition). You will also need a copy of the Heinemann Student Workbook for practical activities and revision questions.

The Hawkesdale Biology Quizlet page is where you can access learning activities for each Chapter to assist you with key terms and definitions. Please sign up to Quizlet and join the class.

Andrew Douch is a very experienced VCE Biology teacher who produces free weekly podcasts (Douchy’s Biology Podcasts) that are worth listening to. He also has a popular Facebook page where you can ask questions.

Mr Barlow has produced four apps, one for each Biology unit, which are available on iTunes. You may find these useful for revision.

Unit 3 – Area of Study 1 – How do cellular processes work? 

Outcome 1: On completion of this unit the student should be able to explain the dynamic nature of the cell in terms of key cellular processes including regulation, photosynthesis and cellular respiration, and analyse factors that affect the rate of biochemical reactions.

Unit 3 – Area of Study 2 – How do cells communicate?

Outcome 2: On completion of this unit the student should be able to apply a stimulus-response model to explain how cells communicate with each other, outline human responses to invading pathogens, distinguish between the different ways that immunity may be acquired, and explain how malfunctions of the immune system cause disease.

Unit 4 – Area of Study 1 – How are species related?

Outcome 1: On completion of this unit the student should be able to analyse evidence for evolutionary change, explain how relatedness between species is determined, and elaborate on the consequences of biological change in human evolution.

Unit 4 – Area of Study 2 – How do humans impact on biological processes?

Outcome 2: On completion of this unit the student should be able to describe how tools and techniques can be used to manipulate DNA, explain how biological knowledge is applied to biotechnical applications, and analyse the interrelationship between scientific knowledge and its applications in society.

Unit 4 – Area of Study 3 – Practical Investigation

Outcome 3: On the completion of this unit the student should be able to design and undertake an investigation related to cellular processes and/or biological change and continuity over time, and present methodologies, findings and conclusions in a scientific poster.

Term 4 Exam Revision

My class have identified three areas in each of Unit 3 and Unit 4 that they would like to do more work on before the exams:

Unit 3: Signatures of Life

Unit 4: Continuity and Change

Homeostasis – Regulation of Blood Glucose Levels

isle of langerhans

The pancreas is an important exocrine and endocrine gland located between the stomach and small intestine. It has two important roles (1) as an exocrine gland it releases digestive enzymes into the duodenum that aid in the break down of food (2) as an endocrine gland it releases insulin and glucagon into the bloodstream.

Insulin is produced in the beta cells of the islets of Langerhans in response to the stimulus of rising blood glucose levels. Insulin travels in the bloodstream and binds with receptor sites on the cell membranes, resulting in a cascade of events dependent on the cell type. In liver cells, for example, glucose in converted to glycogen, fat and carbon dioxide.

Glucagon is produced by alpha cells in the islets of Langerhans in response to the stimulus of falling blood glucose levels. Glucagon travels in the bloodstream and binds to receptor sites on liver cell membranes, resulting in the breakdown of stored glycogen into glucose. This results in an increase in blood glucose levels.

These two hormones act to regulate the body’s blood glucose levels, maintaining an average concentration of 5.0 mmol/Litre (between 3.5 mmol/Litre after several hours without food and 7.0 mmol/Litre soon after a meal). This is a negative feedback loop, as the response results in a change in the stimulus in the opposite direction. A person with diabetes is unable to regulate their own blood glucose levels without external intervention – it may be that their body does not produce enough insulin, as in Type 1 Diabetes mellitus.

Week 4: Molecular Biology in Medical Diagnosis

DNA_RNA_protein

Image source

This week we will study how molecular biology can be used for a range of applications in medicine, including diagnosis of deficiency conditions before and after birth, rational drug design and the production of hormones and plant vaccines. We will also consider some of the ethical concerns that may be associated with the application of molecular biology. First, we will review the process of DNA transcription and translation, as the first stage in the genetic process that results inherited diseases being expressed in an individual.

Week 3: Biochemical Processes

living_cells

Image source

The biological cell is not the static, neat drawing you find in text books, but a dynamic, differentiated, three-dimensional, living unit with many specialised processes occurring simultaneously. You should already know the basic structure and function of the cell, including the main organelles. This animated video shows some of the inner life of a cell – can you identify the cell membrane, embedded proteins and ribosomes? Over the next fortnight you will need to better understand the following biochemical cellular processes:

Biology Q&A’s

Screen Shot 2016-02-08 at 10.43.16 AM

Image Source

This site is a great resource for VCE Biology students, allowing you to learn and review key concepts. The Biochemistry section has seven areas of study including:

If you are a Twitter user, you can follow BiologyQuestions for regular questions and links about Biology topics. This site has over 17 thousand followers from across the world, so you will be part of a global community!

Week 2: Proteins

Enzyme_mechanism_1

Image Source

Proteins are polypeptides or chains of peptides (amino acids) joined together by peptide bonds. These large organic molecules have four levels of structure –

  1. Primary – order of amino acids in the chain
  2. Secondary – alpha-helices, beta-pleats and random coils
  3. Tertiary – the folding of the chains due to the presence of disulphide bonds
  4. Quarternary – when two or more polypeptide chains are folded together in a complex molecule

Enzymes are a specific type of protein that play a critically important role in living organisms. The molecules in cells are constantly interacting – being broken down, built up or exchanged. These chemical reactions constitute an organism’s metabolism. An organism is regulated and the rate of it’s chemical activity is maintained by these special proteins, known as biological catalysts. Like all proteins, enzymes are made in the ribosomes by linking together specific amino acids in the cytoplasm, according to the DNA code. Each cell contains and needs a very large number of different enzymes, but not all cells produce all enzymes – it depends on the structure and function of the cell as to which genes are ‘switched on’.

  • Enzymes are proteins and are therefore made up of amino acids (containing carbon, hydrogen, oxygen and nitrogen)
  • Enzymes are ‘biological catalysts’ because they speed up the rate of a chemical reaction
  • Enzymes remain unchanged at the end of the reaction (not used up)
  • Enzymes are only required in small amounts
  • Enzymes are highly specific (one enzyme catalyses one type of reaction)
  • Enzymes work best under optimum conditions of temperature and acidity
  • Enzymes are ‘denatured’ (destroyed) by heat and sensitive to pH
  • Enzymes work like a key fits into a lock – their shape complements the shape of the substrate materials.
  • The ‘active site’ of a particular enzyme has a specific shape into which only one kind of substrate will fit
  • Enzymes may need ‘co-enzymes’ (specific vitamins) or ‘co-factors’  (minerals) to help functioning

Week 1: Biomacromolecules

biological_molecules copy

Image source

During our “step-up” program we studied the four different types of biological macromolecules, known as:

  • Carbohydrates (or saccharides) made up of glucose monomers
  • Lipids made up of fatty acids and glycerol
  • Proteins (or polypeptides) made up of amino acids
  • Nucleic acids (DNA and RNA) made up of nucleic acids

We investigated how these molecules are built up through condensation reactions, in which water is released. Hydrolysis reactions occur when these molecules are broken down with the addition of water.

Exam Revision

Welcome back and thanks for your patience while I have been on study leave. There are only two weeks left before the Unit 3/4 Biology exam on Friday 30th October, so you should have already done the following:

  1. Written out a clear and concise set of study notes, outlining the main concepts in each Area of Study.
  2. Completed practice exams (available at the VCAA website) and identified areas where you need to do further revision.
  3. Joined the Elevate Education #elevatebio Video Series at http://bio.elevateeducation.com/
  4. You may also like to join the Study.com site for a five-day free trial and access their Immunology resources.

Some students have mentioned that they are having most difficulty remembering the cells involved and sequence of events of the cell cycle and immunology. These quick videos and other resources may assist with your revision:

Chapter 8 – Immunology

Immunity