VCE Biology- Unit 1

AREA OF STUDY 1Cells in action

allaf.layal.l@edumail.vic.gov.au

Studying biology – the practice of science The importance of observation

What do we observe? They way organisms function Their interactions with each other and the environment.

How do we observe? Using our senses A variety of instruments

What are some observations that we can make about plants or animals?

Flying Blind – Lazzaro Spallanzani and Bats

The Scientific Method

Hypothesis – Possible explanation (can either be supported or rejected by experiments) If one hypothesis is supported by all the material then

the hypothesis is then given the status THEORY or PRINCIPLE

Science can prove that something is wrong but it can not prove that a theory is correct in every single circumstance!

Experimental hypothesis must be testable, otherwise what’s the point?

You must ask the right question to get the right answer.

Once you have a testable and relevant hypothesis then you must test it.

Methods and Results

Methods must be reliable – that means if someone else repeats it they get the same result.

There must be enough detail in your method so that someone else can repeat your experiment.

When running an experiment one must be objective rather than subjective.

Results for an experiment must be shown clearly and separate from a discussion (so without any interpretation).

In Science experiments must be repeated at least 3 times to make sure you didn’t get your result due to chance alone. Results are checked using a p-test this tells us if there is less

than 5% chance that your results were by chance

Experimental Controls Experimental variables are things that can

affect the result.

To eliminate experimental variables we use experimental controls.

Conclusions After you have found your results from your

experiment you can make conclusions. Conclusions must be based on your results

and other knowledge.

In the conclusion you only say things that you have shown in your experiment.

Speculation is going beyond the results and having your own explanations, this is fine but not in the conclusion.

Limitations What are some limitations of the Scientific

Method?

It can only be applied to hypothesis that can be tested.

It can only be used on questions that can be answered.

It can’t be used to test morality or ethics .

Organisms are living things How do we know that something is living or

non-living? Animals: - respond, move, eat, reproduce

Plants: - grow, reproduce, obtain materials and energy

Mould: -

Living and dead can also be used to refer to part of animals and plants.

Living or deadItem Living or dead Explanation

Fruit in a bowl

Leaves attached to a tree

Bark on a tree

Paper

Egg

Water

Fish in the ocean

Potato

Characteristics of organisms

MovementRespiration Sensitivity Growth Reproduction Excretion Nutrition

Evolution explain diversity

Evolution is a fundamental principle of biology. The diversity of living things, their

similarities and differences, the richness of the fossil record, the geographic distribution of organisms, the discovery of DNA and the genetic code and the ability to sequence and compare DNA all contribute to the understanding that all living things change and evolve over time. How is the interesting part.

Phylogeny is the study of evolutionary relationships.

Scientific classification is used to categorise animals based on their phylogeny.

Organisms are adapted to their environment Different organisms have special features that

help them live in their habitat. Antarctic ice-fish have anti-freeze in their blood so that

their blood doesn’t freeze. Banksia seedlings are protected by a tough cone that

only breaks during fires.

ADAPTATION – over time species become structurally, physiologically and behaviourally adapted to that particular environment.

The result of adaptation is natural selection.

Organisms are made up of cells

All living things are made up of cells – cells are very very small and there are many different kinds of cells within living organisms. (skin cells, brain cells, muscle cells)

Cells are the functional unit of all living things – This means that they are where all the action happens, they process food, give structure and many other things.

The Cell Theory

All organisms are composed of cells (and the products of cells).

All cells come from pre-existing cells.

The cell is the smallest living organisational unit.

Cell Structure

There are many types of cells and each has its own structure and purpose, so each cells has features that help it carry out its purpose. (e.g Nerve cells)

Despite cells having different functions, all cells have some things in common.

• Plasma or Cell membrane.• Cytoplasm • DNA- genetic material•Organelles

Properties of cells

There are many types of cells and each has its own structure and purpose, so each cells has features that help it carry out its purpose.

Despite cells having different functions, all cells have some things in common.

• Plasma or Cell membrane - separates the cell from it’s external environment.

• Cytoplasm – Jelly like holds all the organelles, ions, salt, enzymes, nucleus and is 90% water. Cytosol is the fluid part of the cytoplasm.

• DNA- genetic material that directs the cell’s activities.

•Organelles – Components inside the cells cytoplasm that perform different functions.

Flagella and cilia

Flagella- whip like tailCilia- Hair like structures

http://www.youtube.com/watch?v=gtIz1u8g1F0&feature=related http://www.youtube.com/watch?v=4GTfq2m-SnY&feature=related

Prokaryotes Vs Eukaryotes

Eukaryotes(Eu meaning true)

More primitive cells Lack membrane

bound organelles Smaller than

Eukaryotic cells

Complex cells Have membrane

bound specialised organelles

Larger than prokaryotic cells

Prokaryotes

• Classified in the kingdom Monera• Small and lack membrane bound organelles• Contain a single circular DNA chromosome

found in an irregularly shaped region (nucleoid)

Eukaryotes DNA is located inside the nucleus as thread like chromosomes Specialised organelles each performing a specific function

Eukaryotes

Protists* Mostly single celled

but occasionally multicellular (seaweed)

* Very diverse- include moulds, algae,

protozoan

Funghi

* Some are unicellular but mostly they are

multicellular* Made of thread like filaments

call hyphae* Are

heterotrophs

* Do not have flagella

or cilia

Animals

* Multicellular organisms* Highly Mobile

* Heterotrophi

c

Plants*

Multicellular*

Autotrophic* Have a cell wall made of

cellulose*Large fluid

filled vacuoles

Double Bubble MapComparing and Contrasting

From what you have learnt about Eukaryotes and prokaryotes draw a double bubble map and use it to compare the differences.

Prokaryote Eukaryote

Organelles

Organelles

Cells and Microscopes There are several types of microscopes, each can allow us

to view cells differently and to a different degree.

Iridium or gold platting

Slides and Microscopes experiment Collect a light microscope and a slide from

Layal Place the slide gently under the microscope

and focus in. Draw an image of the cell you are looking at

the highest magnification.

Organic and Inorganic compounds

Compounds are organized into 2 types: Organic compounds –

These are complex chemical compounds which contain Carbon and Hydrogen.

Inorganic compounds- These are all non-organic compounds. e.g. water, oxygen, nitrogen.

Inorganic components

Water- most organisms are 70-90% water Surface tension Heat capacity Cohesiveness

Oxygen and carbon dioxide Oxygen is needed for cells to release energy from food

molecules Carbon is the key molecule in organic molecules.

Nitrogen Nitrogen is needed to make proteins.

Minerals Are needed for the structural part of cells, the body and in

enzymes and vitamins

Organic molecules

Carbohydrates Important source of energy Made of carbon, hydrogen and oxygen

Lipids fats and oils important for energy stores and some

structures.

Proteins Vital for all sorts of functions!

Nucleic Acid Genetic material for all organisms

Vitamins Required for normal functioning.