1.1-1.4 Nature and variety of organisms

What does MRS H GREN stand for?

1. Movement

2. Respiration

3. Sensitivity

4. Homeostasis

5. Growth

6. Reproduction

7. Excretion

8. Nutrition

What are three waste products excreted by animals?

Carbon dioxide, water and urea

What does urea contain?

Urea contains nitrogen resulting from the breakdown of proteins

What is respiration?

An exothermic chemical reaction which takes palce within cells and releases energy

What are the four groups of eukaryotic organisms?

1. Protoctists

2. Fungi

3. Plants

4. Animals

What is the common feature of all eukaryotes?

Cells that contain a nucleus with a distinct membrane

Are prokaryotic organisms unicellular or multicellular?

Prokaryotic organisms are always unicellular

Where is the genetic material of prokaryotic cells found?

In the cytoplasm as a single, circular chromosome of DNA

What do animals usually store carbohydrates as?

Glycogen

What do plants usually store carbohydrates as?

Starch or sucrose

What are multicellular fungi made up of [hint: what’s the name of the thread-like structure]?

Hyphae contain many nuclei and are organised into a network known as a mycelium

What is saprotrophic nutrition?

Feeding by secreting extracellular digestive enzymes outside the mycelium onto the decaying organic matter and absorbing digested molecules

What do some fungi store carbohydrates as?

Some fungi store carbohydrates as glycogen

Do yeast cells have a cell wall?

Yes (a cell wall made of chitin)

Are protoctists mainly unicellular or multicellular?

Protoctists are mainly unicellular

Change the word: Protoctists are mainly small.

Protoctists are mainly microscopic

Name a protoctist and the disease it causes

Plasmodium is the protoctist that causes malaria

Name a protoctist that has cell walls and chloroplasts making it more like plant cells:

Chlorella

What four features do bacteria definitely have?

1. Cell wall

2. Cell membrane

3. Cytoplasm

4. Plasmids

What two features do bacteria lack?

1. A nucleus (instead they have a circular chromosome of DNA)

2. Mitochondria

Name a bacteria involved in food production:

Lactobacillus bulgaricus is a rod-shaped bacterium used in production of yoghurt from milk

Name a bacteria which causes a disease:

Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia

Which are smaller: protoctists, or bacteria?

Bacteria are usually 0.5-5 micrometres whereas protoctists are 10-100 micrometres

How many micrometres in a metre?

10⁶

What are the groups of organisms that include pathogens?

1. Bacteria

2. Fungi

3. Protoctists

4. Viruses

What is the name of the protoctist that causes severe forms of malaria in humans?

Plasmodium falciparum

What do viruses have which bacteria don't have?

A protein coat

Describe the effect of a named virus that infects plants

Tobacco mosaic virus (TMV). TMV destroys and infects chloroplast cells, reducing chlorophyll and leaving yellow, discoloured leaves

Which of these substances is a carbohydrate stored in plant cells?

• Chlorophyll

• Glucose

• Glycogen

• Starch

Starch

Does a bacterial cell have a cell wall?

Most bacteria have a cell wall

Does a bacterial cell have ribosomes?

Yes, bacterial cells do have ribosomes

In a bacterial cell, where would you find the DNA plasmids?

Floating free in the cytoplasm

Which microorganism is described in the following sentences? "They are small cells. Their cells do not contain a nucleus but do have a cell wall."

Bacteria

What name is given to the short loops of DNA found only in bacterial cells?

Plasmids

The results of an experiment show that the plants exposed to unidirectional light grow towards the light. Explain how this response benefits the plant. [3 points]

1. Larger SA of the leaf exposed to the light

2. Plants can carry out more photosynthesis

3. Increased production of glucose for respiration/growth

Suggest how students can alter their experiment method to carry out an experiment to find out if the plant response varies with different levels of light intensity.

The students could measure at least three different angles/three different distances to place the light source from the plant to vary the intensity

What do fungi store their glucose as?

Glycogen

Suggest why some types of organisms may need to have adapations to release their glucose faster than other types of organisms. [4]

1. Faster respiration

2. More energy can be released in cells

3. Some organisms are more mobile and require more energy

4. Some organisms require more energy for thermoregulation

Name two types of organisms that contain cellulose in their cells.

Plants and some protoctists

What do viruses lack?

Viruses lack organelles, cytoplasm and plasma membranes