The Nature and Variety of Living Organisms & Level of Organisation & Cell Structure

Question 1

What characteristics do all living organisms have?

Answer 1

• Movement: can change position
• Respiration: can produce energy aerobically/anaerobically
• Sensitivity: can detect stimuli and respond
• Control: can control internal environment
• Growth: can increase in number of cells
• Reproduction: can have offspring sexually/asexually
• Excretion: can remove waste products produced by reactions in the body
• Nutrition: can absorb nutrients in order to use them for growth

Question 2

Which kingdoms are eukaryotic and what do they have in common?

Answer 2

• Kingdoms: plants, animals, fungi and protoctists
• All contain a nucleus and other membrane-bound organelles

Question 3

What is the function of a nucleus?

Answer 3

• Contains the genetic material which codes for a particular protein

Question 4

What is the cytoplasm?

Answer 4

• A liquid substance in which chemical reactions occur
• Contains enzymes
• Organelles are found in the cytoplasm

Question 5

What is the function of the cell membrane?

Answer 5

• Contains the receptor molecules that identify and selectively control what can enter or leave the cell

Question 6

What is the function of the mitochondria?

Answer 6

• Site where aerobic respiration reactions occur
• The ‘powerhouse’ of the cell because its provides energy

Question 7

What is the function of the ribosomes?

Answer 7

• Site of protein synthesis

Question 8

Describe the unique features of plants

Answer 8

• Contains chloroplasts
• Have cellulose cell walls
• Store carbohydrates as starch or sucrose
• Contains a permanent vacuole

Question 9

Give two examples of plants

Answer 9

• Cereals (e.g. maize)
• Herbaceous legume (e.g. peas)

Question 10

Describe the unique features of animals

Answer 10

• Have nervous systems in order to coordinate movement
• Stores carbohydrates as glycogen

Question 11

Give two examples of animals

Answer 11

• Mammals (e.g. humans)
• Insects (e.g. mosquito)

Question 12

Describe the unique features of fungi

Answer 12

• Cannot photosynthesise
• Body is organised into a mycelium, made of hyphae (thread-like structures) which contain many nuclei
• Some fungi are single-celled
• Have cell walls made of chitin
• Feed by saprotrophic nutrition
• Stores carbohydrates as glycogen

Question 13

Give two examples of fungi

Answer 13

• Unicellular (e.g. yeast)
• Multicellular (e.g. Mucor)

Question 14

What is saprotrophic nutrition?

Answer 14

• Feeding by extracellular secretion of digestive enzymes
• Breaks the food into smaller pieces
• Can then be absorbed by the fungi

Question 15

Describe protoctists

Answer 15

• Microscopic
• Can be unicellular/multicellular

Question 16

Give three examples of protoctists

Answer 16

• Amoeba: live in pond water and resemble animal cells
• Chlorella: have chloroplasts and are similar to plants
• Plasmodium: pathogenic example and causes malaria

Question 17

Describe the unique features of bacteria

Answer 17

• Prokaryotic
• Microscopic and unicellular
• Have a cell wall, cell membrane, cytoplasm
• Lack nucleus but have circular chromosomes of DNA
• Some can carry out photosynthesis
• Most feed off living/dead

Question 18

Give two examples of bacteria

Answer 18

• Lactobacillus Bulgaricus: rod shaped, used in the production of yoghurt from milk
• Pneumococcus: spherical, pathogen causing pneumonia

Question 19

What are plasmids?

Answer 19

• Loops of DNA found in the cytoplasm of prokaryotic cells

Question 20

What are pathogens and which kingdoms have pathogenic organisms?

Answer 20

• Microorganisms that cause infectious disease
• Kingdoms: fungi, bacteria, protoctists, viruses

Question 21

Describe the unique features of viruses

Answer 21

• Non-living
• Small particles
• Parasitic
• Can only reproduce within living cells
• Can infect every type of living organisms
• Have a wide variety of shapes and sizes
• Have no cellular structure: only a protein coat and one type of nucleic acid (DNA/RNA)

Question 22

Give three examples of viruses

Answer 22

• Tobacco mosaic virus: discolouring of leaves, prevents chloroplasts formation
• Influenza virus: causes ‘flu’
• HIV virus: weakens immune system, leads to AIDS

Question 23

What are organelles?

Answer 23

• Specialised sub-cellular structures found within living cells

Question 24

What are cells?

Answer 24

• The basic structural unit of a living organism

Question 25

What are tissues?

Answer 25

- A group of cells with similar structures that work together to form the same function

Question 26

What are organs?

Answer 26

- A group of tissues that work together to perform specific functions

Question 27

What are organ systems?

Answer 27

- A group of organs with similar functions that work together to perform body functions

Question 28

What are the sub-cellular structures that are found only in plants?

Answer 28

- Chloroplasts - Permanent Vacuole - Cell Wall

Question 29

What is the function of the chloroplasts?

Answer 29

- Where photosynthesis takes place - Provides food for the plant - Contains chlorophyll pigment (makes it green)

Question 30

What is the function of the permanent vacuole?

Answer 30

- Contains cell sap (which has sugars, amino acids, salt minerals, waste products) - Improves cell's rigidity

Question 31

What is the function of the cell wall?

Answer 31

- Provides strength to the cell

Question 32

What is the difference between protein and virus?

Answer 32

- Protein recognised by immune system - Protein does not have genetic material - Viruses have a protein coat

Question 33

What is a vector?

Answer 33

- An organisms (e.g. mosquito) that transmits pathogens from one host to another