AREA OF STUDY 1
Cells in action
VCE Biology- Unit 1
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 dead
Item
Fruit in a bowl
Leaves attached to a tree
Bark on a tree
Paper
Egg
Water
Fish in the ocean
Potato
Living or dead
Explanation
Characteristics of organisms
Movement
Respiration
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 tail
Cilia- Hair like structures
http://www.youtube.com/watch?v=gtIz1u8g
1F0&feature=related
http://www.youtube.com/watch?v=4GTfq2
m-SnY&feature=related
Prokaryotes Vs Eukaryotes



More primitive cells
Lack membrane bound
organelles
Smaller than Eukaryotic
cells



Complex cells
Have membrane bound
specialised organelles
Larger than prokaryotic
cells
Eukaryotes
(Eu meaning true)
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
* Heterotrophic
Plants
* Multicellular
* Autotrophic
* Have a cell wall made of
cellulose
*Large fluid filled vacuoles
Double Bubble Map
Comparing 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.