Biology

Question 1

What is an ecosystem?

Answer 1

A community of organisms, their physical environment, and the interaction that happens between them.

Question 2

What is a community?

Answer 2

All of the populations of different species that live in the same area and interact with one another.

Question 3

What is a population?

Answer 3

A group of individuals of the same species living in one area at one time.

Question 4

What is adaptation?

Answer 4

A feature that enhances an organism’s chance of survival.

Question 5

What is symbiosis?

Answer 5

An interspecific interaction in which the different species live together in a long term relationship.

Question 6

What is a disease?

Answer 6

An abnormal condition of an organism which interrupts the normal bodily functions.

Question 7

What is a pathogen?

Answer 7

Biological agents that cause disease (some are living, some are non-living).

Question 8

What is a sign?

Answer 8

Can be detected (seen) or measured by another individual.

Question 9

What is a symptom?

Answer 9

Is experienced or felt by the individual affected by the disease.

Question 10

What is prevention?

Answer 10

Inhibiting the introduction of a disease into an area, population or individual.

Question 11

What is treatment?

Answer 11

The use of an agent or procedure (such as a drug or surgery) in an attempt to cure or mitigate a disease condition.

Question 12

What is an epidemic?

Answer 12

The occurrence of more cases of a disease than would be expected in a community, country or region during a given period.

Question 13

What is a pandemic?

Answer 13

An epidemic of a disease that has spread across a large region (e.g. multiple continents or worldwide).

Question 14

What is vaccination?

Answer 14

Treatment with a vaccine (a substance that contains a weakened or dead pathogen which is injected in order to stimulate the immune response) to produce immunity to a particular infectious disease or pathogen.

Question 15

What is ecology?

Answer 15

The study of the relationships between living things and their environment.

Question 16

What is the environment?

Answer 16

All of the living and non-living factors that affect the survival of an organism in its living place.

Question 17

What is a habitat?

Answer 17

The living place of an organism.

Question 18

What is biodiversity?

Answer 18

The total variety of organisms, habitats, communities and ecological processes.

Question 19

What is a predator?

Answer 19

An organism that consumes other organisms (prey) that they actively hunt.

Question 20

What is a producer?

Answer 20

Organisms that make their own energy-rich molecules (e.g. glucose) by using the Sun’s energy to convert simple molecules into larger energy-rich molecules.

Question 21

What is a consumer?

Answer 21

Organisms that get their energy from the food they eat.

Question 22

What is a decomposer?

Answer 22

Organisms that break down energy-rich molecules (e.g. glucose) in dead organisms and the wastes of organisms into simple molecules and so help to recycle matter.

Question 23

What are the 5 major groups of pathogens? - And a disease caused by each

Answer 23

Viruses - Ebola
Multicellular parasites - Tape worm
Fungi - Ring worm
Protozoa - Malaria
Bacteria - Salmonella

Question 24

Contrast infectious disease and non infectious diseases

Answer 24

Infectious diseases - caused by pathogens, some are contagious
Non infectious diseases - not caused by pathogens, not contagious. Caused by Physiological malfunction
Environmental factors
Heredity
Incorrect nutrition

Question 25

Contrast bacteria and viruses

Answer 25

Bacteria: Unicellular, Small, simple cells without a nucleus Reproduce by attaching to their cells and taking their nutrients Viruses: Non-living, not cells - genetic material in a layer of protein or fat Reproduce by entering cells, causing them to burst and die

Question 26

Strategies to control the spread of infectious diseases?

Answer 26

- Social distancing - Wearing masks - Washing hands

Question 27

Epidemic Vs Pandemic?

Answer 27

Epidemic - The occurrence of more cases of a disease than would be expected in a community, country or region in a give period. Pandemic - An epidemic of a disease that has spread across a large region (e.g. across multiple continents or worldwide)

Question 28

Why are developing countries more susceptible to epidemics and pandemics of infectious diseases?

Answer 28

- Overcrowding - Malnutrition - Inadequate health care systems - Cultural attitudes - Practices

Question 29

Describe the first line of defence:

Answer 29

- Non specific - Made up of physical and chemical barriers 1. Skin: Acts as a barrier; cuts clot quickly to form scabs and stop entry. 2. Nose & Lungs: Mucus and hairs trap pathogens; removed by sneezing, coughing, or swallowing. 3. Eyes: Tears contain a chemical that breaks down bacterial cell walls. 4. Stomach: Acid kills many pathogens, but some (e.g. Salmonella) can survive.

Question 30

Describe the second line of defence:

Answer 30

Non-Specific Immune Response Inflammation occurs when pathogens enter the body. Chemical signals are released from infected tissue. Vasodilation: Blood vessels widen, bringing white blood cells & platelets. Neutrophils kill pathogens with chemicals. Macrophages engulf & destroy pathogens (phagocytosis). Pus forms from dead cells & debris. Fever (above 38°C) may occur to slow or kill pathogens.

Question 31

Describe the third line of defence:

Answer 31

Third Line of Defence – Specific Immune Response Targets specific pathogens using B lymphocytes (B cells). B cells detect antigens (unique markers on pathogens). B cells produce antibodies that attach to antigens and mark pathogens for destruction. Antibodies are specific to each pathogen. After infection, memory B cells remain. On reinfection, memory cells respond faster & stronger, often preventing illness.

Question 32

How do vaccines build immunity against pathogens?

Answer 32

Vaccines imitate infection to train the immune system. Traditional vaccines use weakened or dead pathogens, while mRNA vaccines give instructions to make antigens. This activates B cells to produce antibodies and memory cells, allowing the body to respond quickly to future exposure—building immunity without causing illness.

Question 33

Recall public health care measures that can affect disease incidence

Answer 33

Minimising or eliminating exposure to disease agents through: quarantine / social isolation good hygiene such as washing hands or disinfecting food preparation areas sanitation facilities bed nets condoms face masks avoiding travel when you are ill or travel to pandemic areas or any other isolation or barrier method.

Question 34

Describe mutualism and provide and example

Answer 34

Both species benefit - bees and flowers

Question 35

Describe commensalism and provide and example

Answer 35

One benefits, one is not affected - Remora fish and shark

Question 36

Describe parasitism and provide and example

Answer 36

One benefits, the other species is harmed - Tick and a dog

Question 37

Describe competition and provide and example

Answer 37

organisms struggling for the same resources - birds fighting over a worm

Question 38

Describe predation and provide and example

Answer 38

one organism actively hunts and eats another organism, these organisms are not in a long term relationship with each other - lion consuming a zebra

Question 39

Word + Chemical equation for photosynthesis

Answer 39

Word: Carbon Dioxide + Water = Energy rich food (e.g. glucose) + Oxygen Chemical: 6CO2 + 6H2O = C6H12O6 + 6O2

Question 39

Word + Chemical equation for cellular respiration

Answer 39

Word: Energy rich food (e.g. glucose) + Oxygen= Carbon Dioxide + Water + ATP (Energy) Chemical: C6H12O6 + 6O2 = 6CO2 + 6H2O + ATP (energy)

Question 40

Describe the transfer and transformation of matter (Nitrogen) as it cycles through ecosystems.

Answer 40

Ammonification is the production of ammonia (NH3) from proteins in dead organisms and urea in urine. Nitrogen fixation  is the conversion of nitrogen gas into nitrogen compounds e.g., ammonia (NH3) and nitrate (NO3-). Nitrification is the conversion of ammonia (NH3) into nitrites (NO2-) and then into nitrates (NO3-). Denitrification is the conversion of soil nitrates into nitrogen gas (N2).

Question 41

Describe the transfer and transformation of matter (carbon) as it cycles through ecosystems.

Answer 41

Photosynthesis: Carbon is removed from the air and enters food chains via photosynthesis in producers. Consumption and Assimilation: Carbon is then is transferred between organisms (passes along food chains in organic matter (food)) via feeding and assimilation into biomass. Respiration & Decomposition: Carbon leaves organisms and is added to the air as a result of cellular respiration (excreted as CO2) and also during decomposition (CO2 and CH4). Some carbon leaves organisms in the faeces. Combustion: burning wood and fossil fuels adds carbon to air (C02, CO and CH4).

Question 42

Describe and provide examples of prey

Answer 42

Organisms that are actively hunted by predators - zebra

Question 43

Describe and provide example of trophic level

Answer 43

specific trophic (feeding) level or what specific type of food they feed on: Decomposers: Break down energy rich molecules

Question 44

Describe how human activity ( deforestation ) negatively impacts ecosystems.

Answer 44

Loss of biodiversity - Trees serve as habitats for a wide range of organisms. Wide-scale land degradation - loss of nutrients, increased levels of soil erosion,  increased levels of soil salinity. Global warming - trees are a source of oxygen & remove carbon dioxide from the atmosphere.

Question 45

Describe how human activity ( bioaccumilation) negatively impacts ecosystems.

Answer 45

Bioaccumulation is the gradual accumulation of pollutants, such as pesticides, plastics, or other chemicals through the lifetime of an individual organism,  at a rate faster than that at which the substance is lost by excretion.

Question 46

Describe how human activity ( Climate change) negatively impacts ecosystems.

Answer 46

The increase in greenhouse gases like carbon dioxide and methane due to human activities (burning fossil fuels, deforestation) enhances the Earth’s warming effect. This enhanced warming can disrupt the natural balance of ecosystems by changing temperature and climate patterns. Such changes may affect how ecosystems function, potentially harming plants and animals adapted to previous stable conditions.

Question 47

What is biomagnification?

Answer 47

biomagnification is the increase in the concentration of a pollutant from one tropic level to the next. The higher an animal is on the food chain, the greater the concentration which accumulates. 

Question 48

What are the different bacterias involved in cycling nitrogen?

Answer 48

Decomposer bacteria: Breakdown dead material and waste. Nitrogen fixing bacteria: Convert atmospheric nitrogen into ammonia or nitrates. They are located in soil or live symbiotically in the root nodules of some plants. Nitrifying bacteria: Convert  ammonia (NH3) and nitrites (NO2-) into nitrates (NO3-). Denitrifying bacteria: Convert nitrates and nitrites back into atmospheric nitrogen (N2).