1. the nature and variety of living organisms

Question 1

what characteristics do all living organisms share?

Answer 1

-they move
-they respire
-they respond to their surroundings
-they control their internal conditions
-they grow and develop
-they reproduce
-they excrete their waste
-they require nutrition
(MRS C GREN)

Question 2

describe the common features of a plant cell:

Answer 2

-multicellular
-contain chloroplasts (so are able to carry out photosynthesis)
-cellulose cell wall
-store carbohydrates as starch or sucrose

Question 3

what is an example of a plant organism?

Answer 3

flowering plants, such as cereal (like maize), and a herbaceous legume (like peas or beans)

Question 4

describe the common features of an animal organism:

Answer 4

-multicellular
-do not contain chloroplasts
-no cell walls
-usually have nervous coordination and are able to move from one place to another
-store carbohydrates as glycogen

Question 5

what is an example of an animal organism?

Answer 5

mammals (like humans) and insects (like housefly and mosquito)

Question 6

describe the common features of fungi:

Answer 6

-usually multicellular but some are single celled (like yeast)
-no chloroplasts
-body is usually organised into a mycelium made from thread-like structures called hyphae (which contain many nuclei)
-chitin cell wall
-feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products (known as saprotrophic nutrition)
-store carbohydrates as glycogen

Question 7

what is an example of fungi?

Answer 7

mucor (which has typical fungal hyphal structure) and yeast (which is single celled)

Question 8

describe the common features of protoctists:

Answer 8

-microscopic single celled organisms
-some (like amoeba) live in pond water have features like an animal cell, while others (like chlorella) have chloroplasts and are more like plants

Question 9

what is a pathogenic example of a protoctist?

Answer 9

plasmodium, which is responsible for causing malaria

Question 10

describe the common features of a prokaryotic organism (bacteria):

Answer 10

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

Question 11

what are some examples of bacteria?

Answer 11

-lactobacillus bulgaricus (a rod shaped bacterium used in the production of yoghurt from milk)
-pneumococcus (a spherical bacterium that acts as the pathogen causing pneumonia)

Question 12

what is a pathogen?

Answer 12

any microorganism that causes disease in another organism
can include fungi, bacteria, protoctists or viruses

Question 13

describe the common features of viruses:

Answer 13

-non living organism
-small particles (smaller than bacteria)
-parasitic and can only reproduce inside living cells
-infect every type of living organism
-have a wide variety of shapes and sizes
-no cellular structure, but have a protein coat and contain one type of nucleic acid (either DNA or RNA)

Question 14

what are some examples of viruses?

Answer 14

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