TSFX Unit 3 ENd of Year Revision Lecture Part 1 · PDF file• Avoid one word answers for one mark questions ... • An emerging branch of biology which revolves around the structure

Veronica Parsons 2015

VCE Biology TSFX REVISION LECTURE

UNIT 3 Part 1

Biomolecules

CellsBiochemistry

Coordination & Regulation

Pathogens

Immune System

Area of Study 1

Area of Study 2

Unit 3: Signatures of Life

v

Revision‐What Can you Do?

• Lecture today-Listen!• Past VCAA Exams from

Website Going Backwards from 2014 including Sample. Keep Notebook Close by divided into 4 sections for each area of Study-write down theory from questions you are getting wrong

• Read over TSFX notes with highlighter regularly.

• Study Groups-Make Kahoots

• Teach someone!

Exam Horror Stories

Exam Horror Stories

Exam Horror Stories

2014 Exam Horror Stories

Exam Horror Stories

Drawing or Labelling a Plasma Membrane

AB

C

D

Exam Horror Stories

What to Learn from these Horrors???

• Avoid one word answers for one mark questions

• Use the word ‘whereas’ in comparative statements

• Use the word ‘so’ twice in an explain question.

• Draw simple, big, clearly labeled diagrams

• Use data to support your answers• Read questions very carefully-

look for distractors!• One dot point per mark + one for

luck• Ask yourself..”what is the

intention of the question”• Be positive-use the exam as an

opportunity to show them how much you know and how hard you have worked.

Practice Exam QuestionWhich of the following combination of polysaccharides and function is correct:

a. Chitin: Structural component of cell membranes.b. Cellulose: Energy storec. Starch: structural component of plant cell wallsd. Glycogen: Store of energy.

Read each word very carefully!


If a cell could talk??? I exist in this watery world because I have an

insoluble selectively permeable membrane I need to receive inputs, remove wastes & export

products I need to make essential biomacromolecules (by

condensation) You think you have a management problem!

(talking about biology teachers). I need to control & regulate a host of simultaneous reactions that are energy dependent. Provide a constant supply of reactants and export a constant supply of products.

I need to know everything. I need to receive signals and respond.

I need to divide, copy accurately and pass on my information manual to my daughter cells.

Most of the time I get it right, but sometimes things go wrong.

https://www.youtube.com/watch?v=oqGuJhOeMek

The cell is a bag of molecules

Pg 15 Water‐a unique molecule

• Water is the most abundant compound in our

bodies

• Water is the most common solvent (dissolves solid,

liquid, or gaseous solutes, resulting in a solution) in

everyday life.

• Substances that dissolve readily in water are

called hydrophilic or polar.

“Like dissolves Like”“Polar dissolves Polar”“Non Polar dissolves Non Polar”

Pg 18 Biological Hierarchy

Pg 18 Organic vsInorganic

organicmeans that a molecule has a carbon backbone, with some hydrogensthrown in for good measure. Living creatures are made of various kinds of organic compounds. Eg: Carbohydrates, Lipids,Proteins, Nucleic Acids, Coenzymes eg ATP

Inorganicmolecules are composed of other elements. They can contain hydrogen or carbon, but if they have both, they are organic.Eg, H2O, CO2, O2, Cofactors

Pg 19 Organic Molecules


Organic Molecule

Elements Monomer or Subunit

Polymer orlarger unit

Examples

Carbohydrate C H O MonosaccharideGlucose, Ribose

Polysaccharides

Eg Starch, Glycogen, Cellulose, Chitin

ProteiNS C H O N (S) Amino Acid (20)

PolypeptidesProteins

Enzymes, Hormones, AntibodiesNeurotransmitters

Lipid C H O (P) Fatty Acid Phospholipids, Cholesterol. Tryglycerides.Hormones

Nucleic Acid CHONP Nucleotide Nucleic Acids DNA, mtDNA, tRANA, rRNA, mRNA

Diagrammatic Representations of Molecules


VCAA 2006


Pg 20 Synthesis of biomacromoleculesthrough the Condensation Reaction

• Making Polymers is Wet Work!

• Condensation (water releasing)

makes bonds.

• Loss of OH from one monomer

and H from another results in

overall loss of one water

molecule in forming the bond

• Anabolic‐building up reactions eg

protein synthesis


FAQ’s


• Students are expected to recognise diagrammatic representations of glucose, identify glucose as a monomer of polysaccharides and other carbohydrates, and understand the mechanism of the condensation reaction (that is, a water molecule is lost when a monomer is added to another monomer or a polysaccharide structure).

Pg 21 Glucose

Glucose is created in the process of photosynthesis and is used in the process of cellular respiration.

Polysaccharides


Pg 26 FAQ’s


• For lipids, students are expected to recognisediagrammatic representations of fats (triglycerides) and phospholipids, and identify the role of phospholipids in the cell membrane. Students should understand that the formation of triglycerides involves condensation reactions. Although the role of cholesterol in the plasma membrane should be understood, the specific chemical structure of cholesterol is not required.

LipidsTriglycerides Phospholipids


• Fats & Oils-saturated fats & unsaturated fats

• Triglycerides have three fatty acid molecules attached to a single glycerol molecule.

• Formation involves Condensation Reactions.

• Functions include o insulation layers which resist heat loss or gaino Energy storageo Buoyancy for aquatic animals.

Structural backbone of membranes.Phospholipids have two fatty acids attached to a glycerol.

Pg 26‐Functions of Lipids‐SHIP


Function of Lipids• Lipids can serve many

functions within the cell, including:

• Storage of energy for long-term use (e.g. triglycerides)

• Hormonal roles (e.g. steroids such as estrogen and testosterone)

• Insulation (retention of thermal energy)

• Protection of internal organs (e.g. triglycerides and waxes)

• Structural components (e.g. phospholipids, cholesterol)

•

Pg 31 Phospholipids


• Consists of a phosphate group (hydrophillic) and 2 fatty acid tails (hydrophobic).

• Within a membrane, the phosphate faces aqueous areas both inside cell (cytosol) and outside cell (extracellular fluid).

• The fatty acid tails are buried in the middle.

• The hydrophobic nature of the tails ensure that only lipid soluble (lipophillic, hydrophobic) or non polar substances (eg steroid hormones, alcohol, chloroform etc) can directly diffuse through cell membranes.

Role of lipids in the plasma membrane

• Lipids move laterally and can change place in the one layer =dynamic nature

• Can fuse with vesicles for endocytosis and exocytosis.

• Kinks in Fatty Acid tails enhance fluidity

• Cholesterol reduces fluidity by reducing phospholipid movement.


Pg 35 FAQ’s


• Students are expected to understand that polypeptides and proteins are polymers of amino acids, formed

through condensation reactions. They are also expected to understand that the primary structure of a

polypeptide or protein is the sequence of amino acids that form the polypeptide or protein, and that the way

that polypeptides and proteins are folded, coiled or pleated can be described by secondary (within the chain)

and tertiary (overall chain shape) structures, and that those proteins made up of two or more polypeptide chains

may be described by a quaternary structure. Students are expected to identify α-helices and β-pleated sheets as

being the most common secondary structures. They are expected to understand that the shape of a protein

determines its properties and that protein denaturation through changes in temperature, changes in pH or

reaction with various chemicals may lead to a loss of biological function. Classifications of, and differences

between, different types of proteins such as globular and fibrous proteins are not required.

Pg 35 Amino AcidsAn amino acid is a relatively small molecule with characteristic groups of atoms that determine its chemical behaviour.

The structural formula of an amino acid is shown at the end of the animation below. The R group is the only part that differs between the 20 amino acids.

O

RO

HH

HH N C CH3C

CH3

C HCH

H H

GlycineAlanineValineCysteinePhenylalanine

HH

CS

H HCH H

Amino Acid


Pg 38‐40 Levels of Protein Structure

• 4 different levels of organization:

• Primary Structure: The order of amino acids

in the molecule.

• Secondary Structure (within the chain)Local

3D folding structure formed by hydrogen

bonds.

• Tertiary Structure: T(overall chain shape) he

total folding of the protein, held together

by hydrogen or ionic bonds.

• Quaternary Structure: Is a structure

consisting of two or more polypeptide

chains.


Pg 42 Functions of Proteins (HITSME)


• Proteins are very diverse and serve a number of different roles within the cell, including:

• Structure: Support for body tissue (e.g. collagen, elastin, keratin)

• Hormones: Regulation of blood glucose (e.g. insulin, glucagon)

• Immunity: Bind antigens (e.g. antibodies / immunoglobulins)

• Transport: Oxygen transport (e.g. haemoglobin, myoglobin)

• Movement: Muscle contraction (e.g. actin / myosin, troponin / tropomyosin)

• Enzymes: Speeding up metabolic reactions (e.g. catalase, lipase, pepsin)

• Amino acids can be joined together in a condensation reaction to form a dipeptide and water

• This results in the formation of a peptide bond, and for this reason long chains of covalently bonded amino acids are called polypeptides

Protein Structure FunctionEnzymes Specifically shaped

active site that is complementary to a specific substrate

Catalyse chemical reactions

Channel Proteins Specific shape that allows a particular chemical (often hydrophilic) to move through

Transport

Receptors Specific shape that allows a specific signalling molecule to bind which will lead to a cellular response

Initiate signal transduction

Antibodies Y shaped molecule with 2 complementary antigen binding

Deactivate a pathogen

Hormones Specific shape that is complementary to a

Initiate cellular responseVeronica Parsons 2015

Pg 42How does Structure relates to Protein Function

Pg 43 Nucleic Acids(Polynucleotides)

There are two kinds of nucleic acid:

• deoxyribonucleic acid (DNA) is

located in chromosomes in the

nucleus of eukaryotic cells and in

cytosol of prokaryotic cells.

• It it also found in the

mitochondria and chloroplasts

• ribonucleic acid (RNA) –there

are 3 types-ribosomal, messenger

and transfer.

• Nucleic Acids are mostly

information storage molecules.Veronica Parsons 2015

FAQ’s


• Students are expected to recognise the monomers of DNA and RNA and identify complementary base pairs.

Monomer of a Nucleotide


• Nucleotides are the building blocks of DNA &RNA and contain a phosphate component (not phosphorus), a 5-carbon sugar component (not sugar) and a nitrogenous base component (not base).

DNA Template Strand


• The DNA Strand has the sequence

5’ A-G-C-T 3’What is the complementary mRNA strand

Pg 48 DNA vs RNA SummaryDNA RNA

No. of Nucleotide Strands

2 1

Sugar Deoxyribose RiboseBases Adenine

CytosineGuanineThymine

AdenineCytosineGuaninUracil

Functional Location Nucleus (Eukaryotes)Cytoplasm (Prokaryotes)

Nucleus & Ribosome (Eukaryote)Cytoplasm & Ribosome (prokaryote)

Do task pg 49 +pg 50Stop Codons: UGA UAA UAG

Pg 57 Proteomics


• An emerging branch of biology which revolves around the structure and function of proteins. This involves a thorough study of the proteome ( all proteins expressed within a cell for the duration of the life of the cell) and is very closely related to the study of the genome ( the entire DNA content of the cell).

• The genome carries genes (sections of DNA) that provide the blueprint for protein synthesis. Certain sections of the DNA are transcribed into RNA and then translated into a protein within the cell so that the specific function of the cell can occur.

Why did the phospholipid scream?

• …because it saw the cytoskeleton

The Cell Theory pg 61• All living things are

composed of cells and/or

their products

• All cells come from pre-

existing cells.

• The cell is the basic unit

of life.


Pg 82 STRUCTURE =FUNCTION


Cell Ultrastructures‐Structures Function


• the role played by organelles in the export of proteins

• Ribosomes- Free (intracellular protein synthesis)

• Rough endoplasmic reticulum- Transport of extracellular proteins

• Golgi apparatus –packaging of extracellular proteins into vesicles

• Mitochondria-ATP for endocytosis, Active transport or exocytosis

•

Absorptive Cell Kidney

Endocrine Pancreatic Cell

End of Part 1Enjoy a 10 minute break!


• the structure and function of the plasma membrane and the movement of substances across it:– the fluid‐mosaic model of a plasma membrane– the packaging, transport, import and export of biomacromolecules (specifically proteins)– the role played by organelles including ribosomes, endoplasmic reticulum, Golgi apparatus and associated vesicles in the export of proteins

Pg 89 Fluid Mosaic Model of Plasma Membrane


VCAA 2006 EXAM

VCAA 2012


VCAA 2012


VCAA 2011 (2 Marks)


Answer


FAQ’s


• Diffusion, osmosis, active transport, facilitated diffusion, endocytosis and exocytosis are required in Unit 3. Although simple diffusion, active transport and facilitated diffusion are introduced in Unit 1, they are also relevant in Unit 3, in particular with respect to protein transport, movement of neurotransmitters across a synapse and the movement of other substances important in cellular processes such as photosynthesis and cellular respiration. Exocytosis and endocytosis are also important in both Units 3 and 4 as they are relevant to events including the release of signalling molecules, secretion of antibodies from plasma cells and the phagocyticity of macrophages and neutrophils.

Movement Across Plasma Membrane

• Diffusion • Osmosis• Facilitated

Diffusion• Active

Transport• Vesicular

TransportVeronica Parsons 2014

Osmosis Osmosis

• Osmosis is the passive movement of water molecules from a regions of lower solute concentration to a region of higher solute concentration across a partially permeable membrane until equilibrium is reached.

• Passive (does not require energy).

Pg 92 Movement Across the Plasma Membrane


Pg 94 Osmosis in Animal and Plant Cells


Porins


Plasma Membrane

Active Transport Active Transport

• DOES require energy

• Movement of substances is AGAINST THE CONCENTRATION GRADIENT:

from low high concentration

• This type of transport will only occur in the presence of ATP

• eg. Na+/K+ Pump

Movement Across the Plasma Membrane


Vesicular Transport Vesicular Transport

• Vesicular transport is transport of substances that

requires the use of a vesicle

• It requires ENERGY

• Vesicles are used to transport substances both within

the cell (intracellular) and out of the cell

(extracellular)

• Possible because:

1) Membrane has some fluidity

2) Small amounts can be added or removed without

tearing the membrane (endo‐ & exo‐ cytosis)

3) Membranes of all organisms are the same

Movement Across the Plasma Membrane


Exam Question• How does a monosaccharide enter an epithelial

cell?

Acceptable Answers

Facilitated DiffusionActive TransportProtein Channels

Protein Carrier Molecules



• the nature of biochemical processes within cells:– catabolic and anabolic reactions in terms of reactions that release or require energy

– the role of enzymes as protein catalysts, their mode of action and the inhibition of

the action of enzymes both naturally and by rational drug design

– the role of ATP and ADP in energy transformation

– requirements for photosynthesis – excluding differences between CAM, C3 and C4

plants

– including: the structure and function of the chloroplast; the main inputs and outputs

of the light dependent and light independent stages

– requirements for aerobic and anaerobic cellular respiration: the location, and main

inputs and outputs, of glycolysis; the structure of the mitochondrion and its function

in aerobic cellular respiration including main inputs and outputs of the Krebs Cycle

and the electron transport chain

Book 2 Pg 3 CATS EX SPIRE


• Catabolic Processes are Exergonic (breakdown)

• Example Cellular Respiration

• Hydrolysis reactions are also catabolic.

Role of ATP & ADP in Energy Transformations


Enzymes


• Enzymes are large protein molecules responsible for the thousands of metabolic processes that sustain life. They are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of DNA

• Like all catalysts, enzymes work by lowering the activation energy for a reaction, thus dramatically increasing the rate of the reaction.

• As a result, products are formed faster and reactions reach their equilibrium state more rapidly.

• Enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts in that they are highly specific for their substrates.

Pg 5‐ Enzymes Lower Activation Energy

Activation Energy

Q9 p 16

MOVIE

Pg 8 Competitive Inhibition


• Similar shape to substrate so compete for the active site & prevent the formation of Enzyme-Substrate Complex

• They fit into the Active Site, but remain unreacted since they have a different structure to the substrate but less substrate molecules can bind to the enzymes so the reaction rate is decreased.

• Competitive Inhibition is usually temporary, and the Inhibitor eventually leavesthe enzyme.

Non Competitive Inhibition


• Prevent formation of Enzyme-Product

Complexes. So they prevent the substrate

from reacting to form product.

• Usually, Non-competitive Inhibitors bind to a

site other than the Active Site, called an

Allosteric Site.

• Doing so distorts the 3D Tertiary structure of

the enzyme, such that it can no longer

catalyse a reaction.

• Many Non-competitive Inhibitors are

irreversible and permanent, and denature the

Rational Drug Design


• A focussed approach using information about structure of a drug receptor or it’s ligand to identify or create candidate drugs.

• *Ligand-substances that are able to bind to a biomolecule such as substrates, inhibitors, neurotransmitters

Relenza


End of Part 2Enjoy a 20 minute break

2011 Question

2011 Answer

The ChloroplastThe chloroplast is enclosed by an envelope consisting of two membranes separated by a very narrow intermembrane space.

Membranes also divide the interior of the chloroplast into compartments:

flattened sacs called thylakoids, which in places are stacked into structures called grana.

the stroma (fluid) outside the thylakoids.

They contain DNA and also ribosomes, which are used to synthesize some of the proteins within the chloroplast.

Stroma, the liquid interior of the chloroplast

Thylakoid sac (disc)

Thylakoid membranes

Grana, are stacks of thylakoid membranes containing chlorophyll

Outer membrane

Inner membrane


Light Dependant Phase


• INPUTS: Light, ADP +Pi

12H2O (Water), NADP+,

• OUTPUTS: NADPH, 6O2, ATP

• Inputs=LAWN• Outputs= NOA• *NADP= nicotinamide

adenine dinucleotide phosphate

Light Independent Phase


• INPUTS: CO2• ATP• NADPH

• OUTPUTS: 6H2O Water• ADP +Pi• NADP+• Gucose

• CAN WANG


Biochemical Processes

Photosynthesis

Stage Site Inputs Outputs ProcessLight Dependent Eukaryote: Grana of

ChloroplastProkaryote: Free Floating Chlorophyll

Light12 H2ONADP+

ADP + Pi

*6O2

NADPHATP

Light energy absorbed by chlorophyll

Water molecules split to form H+

ions + O2 gas O2 gas released via stomata Excited electrons flow through an

electron transport chain to provide energy for ATP synthesis

Unloaded electron acceptor molecules NADP+ accept H+ ions to form NADPH

Light Independent Eukaryote: Stroma of ChloroplastProkaryote: Cytosol

6CO2

NADPHATP

C6H12O6

6 H2ONADP+

ADP +Pi

In the Calvin Cycle, 6CO2 + H+ ions (from NADPH) used to synthesise sugars. This is called carbon fixation.

This is catalysed by tshe enzyme RuBisCO

Energy provided by the ATP produced in LD reaction.

GLYCOLYSIS (NAG NAP)


• INPUTS: NAD+• ADP +Pi• Glucose

• OUTPUTS: 2NADH • 2ATP • 2Pyruvate

Anaerobic Respiration



Anaerobic Respiration

Glycolysis Cytosol C6H12O6

2NAD+

4ADP + Pi

2 Pyruvate2NADH +H ions2ATP

Glucose molecule is broken down to 2 pyruvate molecules

Hydrogen ions are removed from glucose and used to form loaded acceptor molecules NADH.

2 molecules of ATP are also produced

Anaerobic (Fermentation)(Plants&Yeast)

Cytosol Pyruvate is further broken down into ethanol & CO2

Anaerobic(Fermentation) (Animals)

Cytosol Pyruvate is further broken down into Lactic acid & Water


Aerobic RespirationStage Site Inputs Outputs Process

Glycolysis Cytosol C6H12O6

2NAD+

4ADP + Pi

2 Pyruvate2NADH +H ions2ATP

Glucose molecule is broken down to 2 pyruvate molecules

Hydrogen ions are removed from glucose and used to form loaded acceptor molecules NADH.

2 molecules of ATP are also producedKreb’s Cycle (Citric Acid Cycle)

Eukaryote: Matrix of MitochondriaProkaryote: Cytosol

2 Pyruvate6NAD+

2FAD2ADP + Pi

4CO2

6NADH +H ions2FADH2

2ATP

Pyruvate is converted to acetyl CoA and 1 Co2molecule is released

Acetyl CoA enters Krebs Cycle and another 2 Co2 are released for each pyruvate.

The hydrogen ions are released from cycle and used to form NADH & FADH2

2 molecules ATP produced.

Electron Transport Eukaryote: Cristae of MitochondriaProkaryote: Cytosol

OxygenNADH +H ionsFADH2

32(34) ADP + Pi

6 H2ONAD+

FAD32(34)ATP

NADH & FADH2 come to cristae to transfer electrons from one cytochrome to another releasing ATP in the process. Oxygen is the final electron acceptor forming water

Krebs Cycle


• INPUTS: NAD+• 2 ADP+Pi• Pyruvate• FAD• NAPS are FADS ?

• OUTPUTS: 6CO2• 2ATP• NADH• FADH2

Aerobic Respiration; Electron Transport


• INPUTS: O2• FADH2• 32-34 ADP+Pi• NADH

• OUTPUTS: FAD• 32-34 ATP• Water• NAD

2010 Metabolism

Answer

VCAA 2006 EXAM

Summary Experimental Design

Year Topic Marks Command Terms2006 Designer Drugs 3 Design

2007 Enzymes 3 Outline ExperimentExplain Results

2008 Disease 5 State hypothesisOutline ExperimentDescribe Results

2009 Signalling Molecules (Pheromones)

4 Outline ExperimentDescribe Results

2010 Metabolism (Energy) 3 State hypothesisOutline ExperimentDescribe Results

2006 Experimental Design• Design an experiment, using

mice, to test the

effectiveness of the (anti‐

viral) drug you have

designed.

(3 Marks)

Examiner Report‐Common Errors

• Selecting only two mice without referring to repetition of the experiment;

• Not mentioning the similarity of the mice and/or environment;

• Injecting mice with the virus and then waiting days or weeks before the

drug was used;

• Administering the drug first and then exposing the mice to the virus days

or weeks later;

• General statements about comparing the results, without any reference to

what result would indicate effectiveness of the drug.

Some Guys Prefer IndiViduals That Really Rock pg 10‐14

• Sample‐eg Two large groups of identical members of the sample kept in

the same environmental conditions . State a specific number (of reasonable

magnitude) in each group, instead of simply describing a ‘large’ group or

replication of the experiment.

Group_ Divide the sample into two groups of equal size‐One is the

experimental Group and One is the Control Group.I

• Pretest‐ infection of both groups with the virus against which the drug has been designed.

• Independent Variable‐One of the groups then needed to receive no further treatment (the control group), the other group (the trial group)

receives the drug under investigation

• Time after a few days, each of the groups needs to Examined ‐the number of mice that have developed the viral disease in each group

counted.

• Results‐ If the number of mice in the trial group is significantly less than

the number in the control group, the drug has been effective.

• Repeat‐experiment a number of times

S Sample

G Allocate to 2 Groups (Experimental group and Control Group)

P Pretreatment

IV State the Independe4nt Variable

T Time

R Results

R Repeat


2007 Experimental DesignA student predicted that if a temperature graph was

prepared for carrot catalase activity, the optimal

temperature would be expected to be much lower

than that shown by catalase from humans.

WHY????Describe (or outline) an experiment you would

carry out with pieces of carrot to test the accuracy

of the prediction. Hydrogen peroxide is available as

a 3% in water solution.

Explain fully what results would support or negate

the student.s prediction.

(3 marks)


Examiner’s Report• The use of at least two groups of identical pieces of carrot, placed at various temperatures (for

example, 16°C and 37°C) in the same concentration of hydrogen peroxide. A specific number of

carrot pieces could have been given (for example, 10). Students who mentioned the variable and

other factors which were controlled adequately demonstrated their understanding of the

experimental design and were awarded the first mark.

• For the second mark, students needed to discuss how catalase activity would have been measured.

For example, collecting the gas to measure the production of oxygen gas, or observing the bubbles

being produced.

• The third mark was awarded for a discussion of the expected results and a conclusion based on the

student’s prediction. For example, more oxygen gas produced at 16°C compared to 37°C would

support the prediction


2008 Experimental DesignThe human hormone vitamin D is found in high levels in some

immunological tissues. A scientist predicted

that a defi ciency of vitamin D may play a role in the

development of rheumatoid arthritis and hence treatment

with vitamin D tablets may reduce development of the

disease. The scientist decided to test this idea by using a

strain of laboratory mice that normally developed

rheumatoid arthritis.

Design an experiment to test the scientist’s prediction.

In your answer you should

state the hypothesis that you are testing

outline the experimental procedure that you follow

describe results that would support your hypothesis.

(5 Marks)


Examiner’s ReportHypothesis

That treatment with Vitamin D reduces the chance of mice developing

rheumatoid arthritis

Experimental Design

Use two large groups (for example, 20) of similar mice which normally

develop rheumatoid arthritis.

Treat the experimental group with Vitamin D. The other group, the Control

group, are given a placebo and do not receive Vitamin D.

Keep all other factors constant, such as diet, space, water and

temperature.

Results

For the hypothesis to be supported, fewer mice that are given Vitamin D should

develop rheumatoid arthritis than those in the Control group.


2009 Experimental DesignThe beet caterpillar is an insect pest of the tomato plant.

When a beet caterpillar starts to eat a tomato plant,

the plant responds by producing a chemical known as

jasmonic acid. Jasmonic acid and its derivatives have a

variety of odours.

Some scientists have suggested that these odours attract

wasps to the caterpillar‐affected plants.

i. Outline an experiment you would carry out to test this

hypothesis.

ii. Describe the results that would support the hypothesis.

(4 marks)


Examiner’s Report• Take two groups of tomato plants that are the same age type and state of

health. One group is affected with beet caterpillars, the other is

unaffected.

• Both groups are kept in the same environment (for example, the same

temperature and water availability).

• Wasps are released and their activity is observed.

• Large numbers of plants are used or the experiment is repeated many

times.


2010 Experimental DesignA pet food company has made two different types of food pellets,

one hard and the other soft. Each kind of pellet has the same

energy content. The company intends to test the pellets on a group

of adult mice.

You are provided with

• many adult mice. Each mouse is genetically identical and of the same

weight

• two types of pellets, one hard and one soft.

Outline an experiment that would allow you to determine if the

hardness of the food pellets affects the balance between energy

intake and energy expenditure.

In your answer you should

• state the hypothesis that you are testing

• outline the experimental procedure

• describe the results that would support or negate your hypothesis.

(3 Marks)


Examiner’s Report• Hypothesis: That the mice fed hard pellets will weigh more than mice that are fed soft pellets

• Experimental procedure: Two groups of mice: one group fed hard pellets and the other soft,

and all other variables controlled

• Results: Mice fed hard pellets weighed more than mice fed soft pellets

• Students did not need to state the features of the mice as these were given in the stem of the

question; however, they needed to identify a factor which should have been controlled, for

example, water availability.

• The results needed to relate directly to the hypothesis. Measuring weight was by far the most

feasible method; however, measuring the activity of each group was also considered a suitable

measure in this case.


Look for Patterns and Make Acronyms

• STARR (Sample-Treatment-All Factors Same-Results-Repeat)• RUDD(Rapid Burial-Undisturbed-Decomposer Free-Downward Pressure)• BADFEW(Biochemistry-Anatomy-Distribution-Fossils-Embryology-Witness)• IPMAT (Stages of Mitosis)• UGA UAA UAG (Stop Codons)• COD (Cross with homozygous Recessive-Observe Offspring-Decision)• VSSI (Variation-Struggle-Survival of Fittest-Inheritance)• VSSI with a B (Barrier)• GIFTS (Gene-Insert-From-Transform-Select)• Crocs Are Never Fine- (CO2-ATP-NADH-FADH2)• SHIP- (Storage-Hormones-Insulation-Protection-Structure)• HITSME ( Hormone-Structure-Immunity-Transport-Movement-Enzymes)• CATSEXSPIRE (Catabolic-Exergonic=Respiration)• PRIMATES• COAL (Complement Proteins-Chemotaxis, oponise, Agglutinate, Lysis)

Psychic Predictions• Dihybrid test cross

linked vs unlinked• Describe PCR• Speciation• GMO Mosquitos• Tassie Devils-Founder

Effects• Out of Africa vs

Multiregional.


• Signal Transduction of Lipid Based (Hydrophobic)vs Protein Based (Hydrophillic)

• Explain Active Transport• Cell Mediated-T Cells-

draw one• Explain how T Cells

protect against pathogens or T cells vaccination

• Transcription• Autosomal Dominant

Pedigree

Documents

TSFX Unit 3 ENd of Year Revision Lecture Part 1 · PDF file• Avoid one word answers for one mark questions ... • An emerging branch of biology which revolves around the structure