VCE 3/4 biology exam revision

Research question

a testable achievable and specific question that an investigation sets out to answer

Testable

you must be able to measure the factors you are interested in

Aim

the objective of an investigation

Dependant variable

the factor/s measured in the experiment that are charged when the IV is manipulated

Independent variable

the factor/s that are manipulated in an experiment

Controlled/constant variables

factors that are kept constant throughout an experiment.

Extraneous/uncontrolled variables

factors that are not kept constant or account for throughout the experiment

Hypothesis

a testable statement that describes how you think your independent variable will affect your dependant variable, including direction of change

if [change in IV] then [change in DV]/(When compared to [control group]) because [why]

Method

the steps followed in a scientific investigation

Methodology

the strategy or overarching framework followed in a scientific investigation

Case study

An investigation of an event or problem that involves a real or hypothetical situation. Includes; historical analysis, role-play of an imagined situation, or designing a solution to a real-world problem

Classification and identification

classification is the arrangement of individuals or objects into logical. manageable sets. Identification is used to recognise where new individuals or objects belong in these sets

Controlled experiment

An investigation into the impact of an IV on a DV, controlling for all other variables

Correlational study

observing and recording events that have not been manipulated or controlled to understand associations that exist between variables. Typically still measures the effect of an IV on a DV, but the IV is not manipulated by the experiment and some conditions may be less controlled than a laboratory experiment

Fieldwork

A correlational study or controlled experiment set up outside a controlled environment usually in a selected ecosystem.Typically still measure the effect of an IV on a DV, but the IV but some conditions may be less controlled than a laboratory experiment

Literature review

The collation and analysis of other people's scientific findings or viewpoints concerning a particular topic. consideration of the reliability of sources and methods is important in literature reviews. THey are used to provide background information on a topic of interest and/or identify potential areas of research.

Modeling

the construction of a model or representation that approximates an object or event. this could be a drawing, an equation, ect. and can be used to describe systems or make predictions.

Product, process or system development

design of an object, process, or system to meet a human need

Simulation

the process of using a model to observe and predict what many happen in a real or theoretical system

Sample groups should be

Representative and unbiased

Experimental group/treatment group

a group of individuals/samples in which the independent variable is manipulated

Control group/ experimental group/control treatment/the control

a group of individuals/samples that are not exposed to the independent variable

Random sampling

ensures that each member is equally likely to be included

Systematic sampling

involves taking samples at regular intervals along and environment gradien

Stratified sampling

when a population has clearly defined zones or characteristics, and you wish to sample proportionately from each zone, you may wish to use stratified sampling

Judgement/selective sampling

the researcher/an expert-chooses which individuals to sample according to their needs. Judgment sampling can be biased and leads to unrepresentative data, and should only be used when necessary

Convenience sampling

taking a group of individuals based on who is easy to reach, which leads to biased and unrepresentative samples that make results unreliable.

Personal error

mistakes or miscalculation due to human fault. Can be eliminated by performing the experiment again, and for measurements relying on human accuracy get multiple people to make the same measurement

systematic error

error which causes results to differ by a consistent amount each time,typically due to faulty equipment, which affect accuracy and cannot be minimised by repeating the experiment. To avoid them re-calibrane instruments, or use more reliable equipment

random error

errors which are caused by unpredictable variations in the measurement process and result in a spread of readings. To avoid them replicate the experiment, increase the sample size, or use more precise measuring equipment.

Uncertainty

a quantification of the error associated with a measurement, often represented by the symbol ±

Valid

a measurement or experiment that actually tests what it claims to be testing

Accuracy

how closely a measurement is to the true value

True value

the value that would be obtained by a perfect measurement without the influence of error

precise

two or more measurements that closely align with each other

Repeatable

an experiment/measurement which scientists, using the method they designed can obtain the same result multiple times

Reproducibility

an experiment/measurement in which a group of scientists, using methods designed by others, can obtain the same results as another group's experiment

Replicaion

the process of running your test/experiment multiple times

-Increasing replication allows scientists to determine if their results are precise.

-Replication allows scientists to take the average of their results which reduces the impact of outliers and random error, which could improve the accuracy of the experiment

Numerical variables

a factor that is measured as a number

Continuous data

variables that can take any value between a set of real numbers.

Typically graphed using line graphs or scatter plots

Discrete numerical data

variables that can be counted and takes a particular value.

Typically graphed using a bar graph

Categorical variables

a factor that is qualitative, typically describing characteristics

Categorical oriental data

variables that can be logically ordered eg size

-typically graphed using a bar chart or pie chart

Categorical nominal variable

variables that cannot be ordered in a logical sequence eg gender

-typically graphed using a bar chart or pie chart

Title

-can be written as a question or statement that describes the main phenomenon you are trying to describe.

-it should be one sentence and in present tense

Introduction

-justifies why you needed to perform your experiment

includes;

1.background information

-why the system or model is important to study

-the broader implications of answering your particular question

-any prior research that has been undertaken

-Any gaps in knowledge, and how your experiment could fill in those gaps

2.The aim of the experiment

3.The variable being tested

4.The hypothesis

5.The final sentence usually suggests the big-picture influence of the experiment

-should be 1-4 paragraphs long in mostly present and future tense

Methodology

outlines all the materials and steps you took during an experiment

Structure;

Sample-who/what is being investigated and how many

Group-Division of sample into experimental group and any control group

Control variables-All variables that are being kept the same

IV

DV

Equipment-Any equipment used and draw and label complex experimental setups

Time-What period of time will the investigation run prior to collecting the results

Outliers, averages

Repeat/reproduce

should be no longer than half a page and written in past tense

Discussion

-determines if the data obtained supports the hypothesis and to explore the implications of the findings.

Structure of a paragraph

1.Restate key data

2.State if the results supported or refutes your hypothesis

3.Discuss if your findings support or differ from prior research

-Be sure to reference source

4.weight up strengths and weaknesses of the data to determine if the results can be trusted

-Identify reasons why these results may be invalid or unreliable referring to errors

-Precision accuracy and uncertainty of data

-Problems with experiment design

-Other studies that contradict your data

5.Identify reasons why the results may be limited- what is the date not telling us that would be useful

6.Suggest how the method could be charged to overcome any problems

7.Identify any strengths that support the validity, reliability, and scope of the results

-Should be at least 1 paragraphs, but is 3-4 paragraphs, and is mostly present tense

Conclusion

Conclusion-summarises the study

Structure

1.Was the hypothesis supported or rejected and justification of why

2.Summary of limitations and improvements

3.The broader implications of the results

-Future research

-Impact of scientific knowledge

-The impact on society/environment

-One paragraph in a mix of tenses but most present tense.

Bioethical approach

a decision making framework that helps guide ethical behaviour

Consequence based approach

an approach to bioethics that aims to maximise positive outcomes while minimising negative outcomes

*Duty/rule-based*-an approach to bioethics that promotes the responsibility of the agent above all else, and places importance in the duty of each individual

*Duty/rule-based*

an approach to bioethics that promotes the responsibility of the agent above all else, and places importance in the duty of each individual

Virtue-based approach

an approach that places importance on the duty of each individual goodness of the agent, and promotes acting in accordance with the values of a 'moral' person, such as honesty and compassion

Ethical Concepts/principles

Integrity, Justice, Beneficence, Non-maleficence, Respect

Integrity

an ethical concept that encourages a full commitment to knowledge and understanding as well as the honest reporting of all sources of information and results

Justice

an ethical concept that encourages fair consideration of competing claims, and ensures that there is no unfair burden on a particular position or course of action

Beneficence

an ethical concept that seeks to maximise benefits when taking a particular position or course of action

Non-maleficence

An ethical concept that discourages causing harm, or when harm is unavoidable, ensuring that the harm is not disproportionate to the benefits from any position or course of action

Respect

an ethical concept that encourages the acknowledgment of the intrinsic value of living things, and considers the welfare, beliefs, customs, and cultural heritage of both the individual and the collective

Social

the influence of the technology on society rather than just one or two individuals

Ethical

a sense of right and wrong in producing or obtaining the technology due to morals and beliefs

Economic

The availability of funds to obtain or produce technology

Biology

The effect of technology on other living organisms in an particular environment

Tertiary structure

The overall three-dimensional shape formed by R-group interactions between amino acids

Condensation reaction

when monomers link to form polymers producing water as a byproduct

peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Quaternary structure

Two or more folded polypeptide chains joined together

function of a protein's shape

A protein's shape determines its ability to bind molecules and perform its function

Denaturation

Any change to a protein's 3D structure that prevents proper function

Disease caused by errors in protein formation

Misfolded proteins can cause disease by failing to perform vital functions or by accumulating and disrupting cellular function

Biomacromolecules

A large biological polymer

Biomolecule

Substances produced by cells and living organisms

Lipids, proteins, carbohydrates, and nucleic acids are biomolecules

Protein secretory pathway process

1.Proteins are produced at ribosomes

2.Proteins fold in the rough endoplasmic reticulum

3.Proteins move to the Golgi apparatus via transport vesicles

4.Proteins are modified and packaged into secretory/golgi vesicles for export via exocytosis

Exocytosis

Bulk transport that moves large substances out of the cell

process of exocytosis

1.A vesicle containing secretory products is transported to the plasma membrane

2.The vesicle membrane fuses with the plasma membrane

3.Secretory products release into the extracellular environment

Operator

A DNA code section where repressor protein can bind

-if the operator is bound to the repressor, RNA polymerase cannot bind to the prompter, and thus transcription cannot occur

-This occurs when the correct level of mRNA has been produced

polymer

A molecule made up of a large number of smaller repeating units

Monomer

A molecule that forms bonds with other identical molecules to create the repeating units of a polymer

Nucleotide

The monomer of nucleic acids that join together to form DNA or RNA

components of a nucleotide

they consist of a phosphate group sugar and nitrogenous base

DNA structure

DNA is a polymer with a double helix structure

DNA strands are Anti-parallel

The complementary DNA nitrogenous bases

cytosine is complementary to guanine and adenine is complementary to thymine

Number of hydrogen bonds formed between DNA bases

adenine and thymine form two hydrogen bonds

cytosine and guanine form three hydrogen bonds

Purine bases

have two carbon-nitrogen rings.

Adenine and Guanine

Pyrimidine bases

have one carbon-nitrogen ring

Thymine and Cytosine

RNA

The intermediate step in converting DNA's coded information into proteins

Amino acids

Gene expression

The conversion of the code in the DNA of a gene into protein though protein synthesis

Transcription

The process through which a gene, is used to make a molecule of messenger RNA

Process of transciption

1. Initiation: In the nucleus, RNA polymerase binds to the promoter region upstream of the structural gene, unwinding its double helix by breaking hydrogen bonds between the nitrogenous bases

2. Elongation:RNA polymerase moves along the DNA template strand (3 prime to 5 prime), bringing free-floating RNA nucleotides into line via complementarity.

3. Termination: When RNA polymerase reaches the termination sequence, transcription ends and pre-mRNA detaches in the nucleus

RNA polymerase

An enzyme that reads template strands and adds complementary nucleotides to create an mRNA transcript

post-transcription modifications (RNA processing)

1. In the nucleus, Pre-mRNA's introns are spliced out using enzymes called spliceosomes

2. Exons are then joined together, however, may be reshuffled/discarded via alternative splicing to create new mRNA variations

3. Then, a poly-A tail and methyl-guanine cap are added to the 3" and 5" end (respectively) which protects the mRNA against enzyme degradation and maintains a level of stability

Exon

a region of a gene that contains genetic information that codes for the specific protein to be synthesised

Intron

a region of a gene that contains sequences that do not code for the protein to be expressed

Translation

The process of using mRNA information to create a protein

-Occurs at ribosomes in the cytoplasm or on the rough endoplasmic reticulum

-Free ribosomes make proteins for cell use

-Attached ribosomes make proteins for export or secretion

Process of translation

1. In the cytosol, a ribosome attaches to the 5 prime end of the mRNA 5" end, exposing its first codon (start codon). 2. A tRNA molecule with a complementary anticodon binds to the mRNA codon, bringing its associated amino acid into line. This continues for each codon 3. Adjacent amino acids form peptide bonds via condensation polymerisation to produce a polypeptide chain The 'stop' codon denotes the end of translation, causing the polypeptide (primary structure) to detach from the ribosome

The proteome

The complete set of proteins that a cell or organism can express

The human body contains an estimated 80,000 to 400,000 proteins

polypeptide

Polymers made from a series of amino acids

-The amino acid sequence determines protein structure

-Attraction and repulsion between amino acids cause the polypeptide chain to fold into a specific 3D shape

Primary structure

The amino acid sequence in the polypeptide chain

Secondary structure

Hydrogen bonds between amino acid backbones form alpha-helices or beta-pleated sheets, in the lumen of the rough endoplasmic reticulum