Nature and Variety of Living Organisms

Question 1

Name the characteristics of living organisms

Answer 1

Require nutrition - Make their own food in plants, to eat other organisms as animals do
Excrete - get rid of toxic waste products
Move - action of muscles and slow growth movements
Grow - increase in size and mass using materials from food
Respire - get energy from their food
Respond to Stimuli - sensitive to changes in their surroundings
Reproduce - produce offspring
Control - internal conditions

Question 2

describe the common features shared by organisms within plants

Answer 2

These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose

Question 3

Give an example of organisms in plants

Answer 3

Flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans)

Question 4

describe the common features shared by organisms within animals

Answer 4

These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen

Question 5

Give an example of organisms in animals

Answer 5

Mammals (for example humans) and insects (for example housefly and mosquito)

Question 6

describe the common features shared by organisms within Fungi

Answer 6

These are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen

Question 7

Give an example of organisms in fungi

Answer 7

Mucor, which has the typical fungal hyphal structure, and yeast, which is single-celled

Question 8

describe the common features shared by organisms within bacteria

Answer 8

These are microscopic single-celled organisms; they have a cell wall, cell membrane, cytoplasm and plasmids; they lack a nucleus but contain a circular chromosome of DNA; some bacteria can carry out photosynthesis but most feed off other living or dead organisms

Question 9

Give an example of organisms in bacteria

Answer 9

Lactobacillus bulgaricus, a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia

Question 10

describe the common features shared by organisms within protoctists

Answer 10

These are microscopic single-celled organisms. Some, like Amoeba, that live in pond water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants.

Question 11

describe the common features shared by organisms within viruses

Answer 11

These are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells; they infect every type of living organism. They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA

Question 12

Give an example of organisms in viruses

Answer 12

Tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza virus that causes ‘flu’ and the HIV virus that causes AIDS

Question 13

Define the term “pathogen”. Name examples

Answer 13

A pathogen is a microorganism (e.g. virus, bacterium, protist, fungi) that causes disease in animals or plants.
Protoctist: Plasmodium - causes disease
Bacterium: Pneumococcus - causes pneumonia
Viruses: Influenza - causes flu, HIV causes AIDS