Biology B4 (OCR Gateway)

Why are larger sample sizes good?
Increases the accuracy of an estimation of population size
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What is the equation for population size?
Population size= number in 1st sample x number in 2nd sample/ number in 2nd sample previously marked
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What are the assumptions made by capture- recapture data?
No death, immigration or emigration; identical sampling methods; marking does not affect survival rate.
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What is an ecosystem?
All living things and the surroundings in a particular area.
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What is a habitat?
Where an organism lives
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What is a community?
All organisms living in an ecosystem
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What is a population?
The number of a particular organism in a community
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What is zonation?
A gradual change in the distribution of species across a habitat
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What is biodiversity?
The variety of different species living in a habitat
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Name two natural ecosystems with high biodiversity
Native woodlands and lakes
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Name two artificial ecosystems with low biodiversity
Forestry plantations, fish farms
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State the word equation for photosynthesis.
Carbon dioxide + water ---> glucose + oxygen
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State the symbol equation for photosynthesis.
6CO2 + 6H2O ---> C6H12O6 + 6O2
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State the first stage of photosynthesis
Light energy is used to split water, releasing oxygen gas and hydrogen ions
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State the second stage of photosynthesis
Carbon dioxide gas combines with the hydrogen to make glucose
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How is glucose transported and stored?
Transported as soluble sugars but stored as insoluble starch
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What can glucose and starch be converted to?
Other substances in plants to be used for growth, energy and storage products
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What is glucose used for?
Energy (respiration)
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What process do plants carry out all the time?
Respiration (provides energy for staying alive)
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How does water enter a plant?
Through the root hairs
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What happens in plant stomata?
Carbon dioxide enters and oxygen leaves through the stomata
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What is the role of broad leaves?
Provide a large surface area
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What do thin leaves provide?
A short distance for gases to diffuse
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Name the four pigments in leaves.
Chlorophyll A, B, carotene and xanophyll- these absorb light from different parts of the spectrum
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What is the role of vascular bundles?
A network for support and transport
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What is the role of guard cells?
Open and close the stomata
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What does the epidermis look like?
It is transparent
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Where are most of the chloroplasts contained?
The palisade layer
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What do air spaces in the spongy mesophyll layer do?
Allow diffusion between stomata and photosynthesising cells
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Name a useful feature of leaves
Large internal sa/v ratio allows for efficient diffusion of substances in/ out of cells
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How do molecules move in and out of cells?
Diffusion through the cell membrane
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What is diffusion?
The net movement of particles from a region of high concentration to a region of low concentration as a result of the random movement of particles
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How does water move in and out of cells?
By osmosis through the cell membrane
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What is osmosis?
The movement of water across a partially permeable membrane from an area of high water concentration to an area of low water concentration
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What is osmosis a type of?
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What does the plant cell wall do?
Provide support
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What happens to plants who have a lack of water?
They wilt
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What must healthy plants balance?
Water loss and uptake
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What are xylem vessels?
The site of the transpiration stream: the movement of water and minerals from the shoots to the roots and leaves
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What is phloem?
The site of translocation: movement of food substances (sugar) up and down stems to growing and storage tissues
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What do xylem and phloem have in common?
Form continuous systems in leaves, stems and roots
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What is transpiration?
The evaporation and diffusion of water from inside leaves
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How can transpiration rate be increased?
Increase in light intensity, temperature, air movement or a decrease in humidity
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What is the water provided by transpiration used for?
Cooling, photosynthesis, support, movement of minerals
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What is the purpose of root hairs?
Increase the ability of roots to take up water by osmosis by increasing surface area of roots
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Name four minerals found in magnesium.
Nitrates, phosphates, potassium, magnesium
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What do NPK values show?
The percentage of fertilisers that is nitrates, phosphates and potassium
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What are nitrates used for?
Making amino acids
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What are nitrates needed for?
Cell growth
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What are phosphates used for?
Making DNA and cell membranes
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What are phosphates needed for?
Respiration and growth
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What are potassium compounds used for?
Helping enzymes
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What are potassium compounds needed for?
Respiration and photosynthesis
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What are magnesium compounds used for?
Making chlorophyll
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What are magnesium compounds needed for?
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What does active transport do?
Moves substances from low concentrations to high concentrations across a cell membrane, using energy from respiration
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What is required for the process of decay?
The presence of microbes
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What are microorganisms used for?
Breaking down human and plant waste
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What are detritivores?
Animals that feed on dead and decaying plants
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How do detritivores increase the rate of decay?
Producing a larger surface area
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Give three examples of detritivores.
Earthworms, maggots and woodlice
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What are saprophytes?
Organisms that feed off of dead and decaying material
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How do saprophytes digest material?
Releasing enzymes onto the food to break it into simple, soluble substances
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What happens to the food digested by saprophytes?
It is absorbed
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What are pests?
Any organisms which damage crops
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What do pesticides do?
Kill pests
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What is intensive farming?
Trying to produce as much food as possible from the land, plants and animals available
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What is hydroponics?
Growing plants without soil
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Give examples of hydroponic uses.
Glasshouse tomatoes and plant growth in areas of barren soil
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What is the dilemma of using intensive farming methods?
May be efficient but they raise ethical dilemmas such as animal welfare
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What is organic farming?
Farming that does not use artificial fertilisers or pesticides
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What is biological control?
The use of predators to reduce populations of pests
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Other cards in this set

Card 2


What is the equation for population size?


Population size= number in 1st sample x number in 2nd sample/ number in 2nd sample previously marked

Card 3


What are the assumptions made by capture- recapture data?


Preview of the front of card 3

Card 4


What is an ecosystem?


Preview of the front of card 4

Card 5


What is a habitat?


Preview of the front of card 5
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