Variety Of Living Organisms

Question 1

MRS GREN- Living organisms have the following characteristics in common:

Answer 1

Movement - they can change their position

Reproduction – they can make more of the same kind of organism as themselves

Sensitivity – they can detect or sense stimuli and respond to them

Growth - they can permanently increase their size or dry mass by increasing the number or size of their cells.

Respiration – they can create chemical reactions that break down nutrient molecules in living cells to release energy

Excretion – they can excrete toxic materials, waste products of metabolism, and excess substances

Nutrition - they can take in and absorb nutrients such as organic substances and mineral ions

Question 2

Eukaryotic (with nucleus) organisms

Answer 2

Plants, animals, fungi and protoctists

Question 3

Characteristics of plants

Answer 3

• multicellular
• cells contain chloroplasts
• are able to carry out photosynthesis
• cells have cellulose cell walls
• they store carbohydrates like starch and sucrose

Question 4

Characteristics of animals

Answer 4

• multicellular
• cells don’t have chloroplasts and can’t carry out photosynthesis
• they have no cell walls
• have nervous coordination
• store carbohydrate as glycogen

Question 5

Characteristics of fungi

Answer 5

• can’t carry out photosynthesis (Instead they use saprotrophic nutrition. They secrete enzymes onto their food so that digestion happens outside the fungal cells)
• their body is usually organised into a mycelium made from thread like structures called hyphae which contain many nuclei
• cells have walls made of chitin
• they may store carbohydrate as glycogen

Question 6

Characteristics of Protoctists

Answer 6

• they are microscopic single-celled organisms
• some, like Amoeba, have features like an animal cell
• some, like Chlorella, have chloroplasts and are more like plants
• some are pathogens (Plasmodium)

Question 7

What is prokaryotic

Answer 7

Without a nucleus (bacteria)

Question 8

Characteristics of bacteria

Answer 8

• microscopic single-celled organisms
• cell wall made of polysaccharides and proteins
• they have no nucleus but instead a circular chromosome of DNA
• some bacteria can carry out photosynthesis but most feed off other organisms

Question 9

What are pathogens

Answer 9

Pathogens can be fungi, bacteria, protoctists or viruses that carry disease

Question 10

Characteristics of viruses

Answer 10

• they aren’t living organisms but are small particles
• they are parasitic and can reproduce only inside living cells
• virus particles have a variety of shapes
• they have a core of genetic materials surrounded by a protein coat