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

Question 1

Explain what characteristics make an organism living (8)

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

It contains the genetic material which codes for a particular protein

Question 4

What is the cytoplasm? (3)

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

It 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? (2)

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

It is the site of protein synthesis

Question 8

Describe the unique features of plants (4)

Answer 8

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

Question 9

Examples of plants (2)

Answer 9

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

Question 10

Describe the unique features of animals (2)

Answer 10

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

Question 11

Examples of animals (2)

Answer 11

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

Question 12

Describe the unique features of fungi (6)

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

Examples of fungi (2)

Answer 13

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

Question 14

Describe saprotrophic nutrition (3)

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 unicellular organisms

Question 16

Examples of protoctists (3)

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 (6)

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

Examples of bacteria (2)

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 (7)

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

Examples of viruses (3)

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

They are 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? (3)

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? (2)

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

It provides strength to the cell