1 - The nature and variety of living organisms

Question 1

What characteristics do all living organisms share?

Answer 1

• they require nutrition
• they respire
• they excrete their waste
• they respond to their surroundings
• they move
• they control their internal conditions
• they reproduce
• they grow and develop.

Question 2

What is the ways to describe animals and plants?

Answer 2

Monkeys, Can, Play, Cod Warzone and CreateHappiness

Question 3

What are some features of plants and some examples?

Answer 3

• multicellular organisms
• cells contain chloroplasts
• are able to carry out photosynthesis
• cells have cellulose cell walls
• store carbohydrates as starch or sucrose
• They feed via photosynthesis
• Their cell contains a nucleus with a distinct membrane
• They do not have nervous coordination
• examples include: flowering plants, such as a cereal (eg. maize), and a herbaceous legume (eg. peas or beans

Question 4

What are some features of animals and some examples?

Answer 4

• multicellular organisms
• cells do not contain chloroplasts so not able to carry out photosynthesis
• no cell walls
• store carbohydrates as glycogen
• they feed on organic substances mad of living things
• Their cell contains a nucleus with a distinct membrane
• They usually have nervous coordination
• they are able to move
• examples: mammals (eg. humans) and insects (eg. housefly and mosquito).

Question 5

What are some features of fungi and some examples?

Answer 5

• They are usually multicellular but some are single-celled (e.g. yeast)
• not able to carry out photosynthesis - no chloroplasts in cells
• Multicellular fungi are mainly made up of thread-like structures known as hyphae that contain many nuclei and are organised into a network known as a mycelium
• some examples are single-celled
• their cells have walls made of chitin

-They feed by secreting extracellular digestive enzymes (outside the mycelium) onto the food (usually decaying organic matter) and then absorbing the digested molecules. This method of feeding is known as saprotrophic nutrition

• Some fungi are parasitic and feed on living material
• They do not have nervous coordination
• they store carbohydrate as glycogen
• Their cells contain a nucleus with a distinct membrane

Examples of fungi include: moulds, mushrooms, yeast, mucor

Question 6

What are some features of protoctists and some examples?

Answer 6

• microscopic single-celled organisms
• some aggregate (group together) into larger forms, such as colonies or chains of cells that form filaments
• Their cells contain a nucleus with a distinct membrane
• Some have features making them more like animal cells e.g. Plasmodium (the protoctist that causes malaria)
• Some have features, such as cell walls and chloroplasts, making them more like plant cells e.g. green algae, such as Chlorella
• This means some protoctists photosynthesize and some feed on organic substances made by other living things
• They do not have nervous coordination
• a pathogenic example is Plasmodium, responsible for causing malaria. Chlorella

Question 7

What are Prokaryote cells?

Answer 7

are in a separate kingdom and are different from eukaryotes as they are always single-celled and do not contain a nucleus (instead, the nuclear material of prokaryotic cells is found in the cytoplasm)
Bacteria are prokaryotic organisms
Prokaryotic cells are substantially smaller than eukaryotic cells

Question 8

Is bacteria microscopic?

Answer 8

microscopic single-celled organisms

Question 9

What are some parts of the structure of bacteria?

Answer 9

they have a cell wall, cell membrane, cytoplasm and plasmids

Question 10

Do bacteria have a nucleus?

Answer 10

they don’t have a nucleus but contain a circular chromosome of DNA.

Question 11

Do bacteria carry out photosynthesis?

Answer 11

Some bacteria can carry out photosynthesis but most feed off other living or dead organisms.

Question 12

Are viruses living?

Answer 12

not living as viruses can’t move, grow, convert nutrients into energy or excrete waste products.

Question 13

Examples of viruses:

Answer 13

• examples include the 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 14

Are viruses smaller than bacteria?

Answer 14

small particles, smaller than bacteria

Question 15

Is viruses parasitic?

Answer 15

yes they are parasitic and can reproduce only inside living cells

Question 16

Can viruses infect other living organisms?

Answer 16

yes, they infect every type of living organism

Question 17

What shapes to viruses have?

Answer 17

• have a wide variety of shapes and sizes

Question 18

What is the structure of a virus?

Answer 18

They have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA.

Question 19

What is a pathogen?

Answer 19

A pathogen is any microorganism that causes disease in another organism (e.g. in plants or animals) (its host)

Question 20

What are examples of pathogens?

Answer 20

may include fungi, bacteria, protoctists or viruses however not all of the species within these groups (apart from viruses) are pathogens.

Question 21

What is a eukaryotic organism?

Answer 21

Eukaryotic organisms can be multicellular or single-celled and are made up of cells that contain a nucleus with a distinct membrane

Question 22

What are some examples of eukaryotic organisms?

Answer 22

• Plants
• animals
• fungi
• protoctists

Question 23

What are some examples of prokaryotic organisms?

Answer 23

• bacteria

Question 24

What are some features of bacteria and some examples?

Answer 24

• They are microscopic single-celled organisms
• They have a cell wall (not made of cellulose), cell membrane, cytoplasm and plasmids
• They lack a nucleus but contain a circular chromosome of DNA
• They lack mitochondria and other membrane-bound organelles found in eukaryotic cells

Question 25

What are the 2 different ways bacteria feed?

Answer 25

• Some bacteria can carry out photosynthesis
• Most feed on other living or dead organisms (if they feed on dead organic matter then they are known as saprobionts or decomposers)

Question 26

What are 2 examples of bacteria?

Answer 26

• Lactobacillus (a rod-shaped bacterium used in the production of yogurt from milk)
• Pneumococcus (a spherical bacterium that acts as the pathogen causing pneumonia)

Question 27

Are viruses living and why?

Answer 27

Viruses are not usually included in the classification of living organisms as they are not considered to be alive
This is due to the fact that viruses do not carry out the 8 life processes for themselves

Question 28

What is the only life process viruses display?

Answer 28

In fact, the only life process they seem to display is reproduction but even to carry out this process they must take over a host cell’s metabolic pathways in order to make multiple copies of themselves

Question 29

What are the biological characteristics of viruses?

Answer 29

• They are small particles (always smaller than bacteria)
• They are parasitic and can only reproduce inside living cells
• They infect every type of living organism
• They have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA

Question 30

What are some examples of viruses?

Answer 30

• The tobacco mosaic virus (TMV) causes discolouring of the leaves on tobacco plants by preventing the formation of chloroplasts
• The HIV virus causes AIDS
• The influenza virus causes the ‘flu’