Bio: 1, 2

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  • Created by: atta
  • Created on: 08-04-17 06:12

The Nature and Variety of Living Organisms

All living organisms...

Movement: move all or parts of themselves

Respiration: release energy from their food

Sensitivity: respond to their surroundings

Homeostasis: control their internal surroundings

Growth: grow and develop

Reproduction: produce offspring

Excretion: remove toxic waste

Nutrition: require nutrients

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Plants

• Multicellular

• Contain chloroplasts + chlorophyll 

     ↳ can carry out photosynthesis

Cellulose cell walls

• Permanent vacuole

• Store carbohydrates as starch or sucrose

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Animals

• Multicellular

No cell wall

No permanent vacuole

• Usually have a nervous system and can move from one place to another

• Store carbohydrates as glycogen

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Fungi

• Multicellular and unicellular

• Body is organised into a mycelium    

       ↳ made from thread-like structures, hyphae (containing many nuclei)

• Chitin cell walls

• Feed by saprotrophic nutrition 

                        ↳ = secretion of digestive enzymes and absorbing the organic products

• Store carbs as glycogen

Examples: Mucor (multicellular)

                  Yeast (unicellular)

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Bacteria

• Microscopic, unicellular

• Have a cell wall, cell membrane, cytoplasm, and plasmids

No nucleus, but has a circular chromosome of DNA

• Some can carry out photosynthesis, but most are parasitic and feed off others

Examples: Lactobacillus (useful)

                  Pneumococcus (pathogenic)

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Protoctists

• Microscopic, unicellular

• Some (like Amoeba, that live in pond water) have animal cell features

  While others (like Chlorella) have chloroplasts and are more like plants

Example: Plasmodium (pathogenic, causes malaria)

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Viruses

• Teeny tiny organisms, smaller than bacteria

Parasitic - can only reproduce within living cells

• Infect every type of living organism

• No cellular structure, but have a protein coat

  Contain 1 type of nucleic acid - either DNA or RNA

Example: influenza (causes flu)

                 HIV (causes AIDS)

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Pathogens

• Cause diseases

Examples: Plasmodium (Protoctist) - causes malaria 

 Pneumococcus (Bacterium) - causes pneumonia

 Influenza (Virus) - causes 'flu'

 HIV (Virus) - causes AIDS

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Levels of Organisation

Organelles: tiny structures that carry out different functions within a cell

Cells: specialised basic unit, building block of all organisms

Tissues: groups of similar cells that work together to carry out a particular function

Organs: groups of similar tissues that work together to carry out a particular function

Organ Systems: organs work together to form organ systems, carrying out a particular function

Organism: the full functional living unit

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Cell Structure

Functions of Organelles

Nucleus: contains the genetic material that controls the cell's activities

Cytoplasm: responsible for the cell's chemical reactions

Cell membrane: responsible for what enters and leaves the cell

Mitochondrion: responsible for respiration

Vacuole: contains sap (solution of sugars and salts), supports the cell

Cell wall: supports and strengthens the cell

Chloroplast: contains chlorophyll, responsible for photosynthesis

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