Variety of Organisms

Question 1

Define Diffusion :

Answer 1

Net movement of particles from an area of high concentration to an area of low concentration

Question 2

Define Osmosis :

Answer 2

Net movement of water molecules across a semi permeable membrane from an area of high to low concentration

Question 3

Define Active Transport :

Answer 3

Movement of particles against a concentration gradient (area of low to high concentration) using energy released during respiration

Question 4

Characteristics of living organisms :

Answer 4

• Nutrition
• Respire
• Excrete
• Respond to surroundings
• Movement
• Control internal conditions
• Reproduce
• Grow and develop

Question 5

What organelles are found in Plant Cells and what are their functions?

Answer 5

• Chloroplasts- photosynthesis
• Cell wall- Support structure
• Vacuole- Support call
• Ribosomes- Proteins made
• Mitochondria- Reactions for aerobic respiration take place
• Cytoplasm- Chemical reactions happen
• Cell Membrane- Control what goes in & out
• Nucleus- Contain genetic material

Question 6

What organelles are found in Animal Cell and what are their functions?

Answer 6

• Ribosomes- Proteins made
• Mitochondria- Reactions for aerobic respiration take place
• Cytoplasm- Chemical reactions happen
• Cell Membrane- Control what goes in & out
• Nucleus- Contain genetic material

Question 7

Define a Catalyst :

Answer 7

A substance which increases the speed of a reaction without being changed or used up in the reaction

Question 8

How can Temperature and pH affect Enzyme function?

Answer 8

• Higher temperature increases rate, enzymes and substrate have more energy so move more and collide = enzyme-substrate complexes
• If too hot - bonds holding enzyme together break, changing shape of active site, substrate won’t fit = enzyme denatured

Question 9

What is a Substrate?

Answer 9

Molecule that is changed in a reaction

Question 10

What is an Active Site?

Answer 10

Part where a substrate joins on to the enzyme

Question 11

What is a ‘Lock and Key’ model?

Answer 11

Substrate fits into the enzyme just like a key fits into a lock

Question 12

Describe a Protoctists and give an example:

Answer 12

• Single-celled, microscopic
• Some like plant cells and others like animal cells
• E.g. Chlorella (Plant), Amoeba (animal)

Question 13

Describe a Bacteria and give an example:

Answer 13

• Single-celled, microscopic
• No nucleus
• Circular chromosome of DNA
• Feed off other organisms
• Some can photosynthesise
• E.g. Lactobacillus bulgaricus

Question 14

Describe a Virus and give an example:

Answer 14

• Particles, very small
• Reproduce inside living cells
• Infect all types of living organisms
• Loads of different shapes and sizes
• No cellular structure
• E.g.HIV, Tobacco mosaic virus

Question 15

What are Pathogens?

Answer 15

• Organisms that cause disease

* E.g. Fungi, Bacteria, Virus, protoctists

Question 16

Describe a Plant and give an example:

Answer 16

• Multicellular
• Have chloroplasts so can photosynthesise
• Cell walls made of cellulose
• Store carbohydrates as sucrose or starch
• E.g. Cereals - maize

Question 17

Describe an Animal and give an example:

Answer 17

• Multicellular
• Can’t photosynthesise
• No cell wall
• Have nervous coordination
• Move around
• Store carbohydrates as glucose
• E.g. mammals - humans

Question 18

Describe a Fungi and give an example:

Answer 18

• Some are single-celled, others have a body (mycelium) made of hyphae (contains nuclei)
• Can’t photosynthesise
• Have cell walls made of chitin
• Feed by saprotrophic nutrition
• Store carbohydrates as glycogen
• E.g. Yeast (single-celled), mucor (multicellular)