Exam Flashcards
Does facilitated diffusion require energy?
No
What is source-sink theory?
At the source (e.g. leaves) energy is required to actively pump sugars into the phloem tissue. This is highly concentrated, and creates a region of high pressure. At the sink (e.g. root cells) energy is required to remove the tissues from the phloem tissue. This dilutes the solution which causes the water to leave by osmosis and return to the xylem tissue. This creates a region of low pressure.
What is interstitial fluid?
Fluid found in the spaces around cells
Cell requirements of plants (energy, chemical, waste removal)?
Energy: light
Chemicals: H2O and CO2 for photosynthesis; O2 for cellular respiration; inorganic substances e.g. phosphates, nitrates
Waste removal: in daylight — excess O2 excreted by simple diffusion in cells
Cell requirements of bacteria (energy, chemical, waste removal)?
Energy: may require light or inorganic chemicals
Chemicals: H2O, CO2, O2, Ca2+, K+
Waste removal: excretion carried out by simple diffusion or active transport
Cell requirements of animals (energy, chemical, waste removal)?
Energy: complex carbs
Chemicals: H2O, O2, minerals, vitamins
Waste removal: individual cells excrete CO2 by diffusion,
How can you trace products of photosynthesis through plants?
Giving plants C-14 which is incorporated into sugars
What are the similarities between heterotroph and autograph gas and nutrient requirements?
They both require water and mineral ions are taken from the surroundings
What are the differences between heterotroph and autograph gas and nutrient requirements?
Autotrophs need carbon dioxide gas
Heterotrophs need to ingest organic substances
Autotrophs produce their own oxygen, glucose, proteins and lipids
What is adaptive radiation?
Where organisms diversify rapidly from ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches.
What are microevolutionary changes that caused the evolution of horses?
Changes in horse ancestors include size, jaw size and toe numbers
How do antibiotic-resistant strains of bacteria demonstrate evolutionary change?
Some variations in bacterial populations can recolonise and develop natural resistance to antibiotics and pesticides
What was the cause of the Permian extinction?
The Permian extinction killed about 90% of the species on Earth, and was believed to be caused by global warming.
What is facilitated diffusion?
Facilitated diffusion is the transport of substances across a biological membrane through a concentration gradient by means of a carrier molecule.
How do Aboriginal rock paintings provide evidence for past changes in ecosystems?
Some Aboriginal rock paintings depict extinct species and megafauna such as the Thylacine, and keeps a record the predominant flora and fauna of the past.
How do rock structure and formation provide evidence for past changes in ecosystems?
Banded iron formations contain vast amounts of iron and indicate the appearance of photosynthetic prokaryotes. Fossils, particularly the fossil record, keeps track of the evolution of past species and the transitional species to our modern-day species.
How does ice core drilling provide evidence for past changes in ecosystems?
In an ice core, isotopes can be measured using radiometric dating which allows the absolute dating of layers. This creates a record of climate change and human activity
How does gas analysis provide evidence for past changes in ecosystems?
Scientists can use the data in ice cores to reconstruct atmospheric concentrations of certain gases, particularly carbon dioxide and oxygen.
What are some examples of human-induced selection pressures on the extinction of species?
Some human-induced selection pressures include over-exploitation of resources, introduced species and disruption of ecological relationships
What are some models that humans can use to predict future impacts on biodiversity?
- The equilibrium model (a baseline at some point in the past that has relevance to the ecosystem being managed
- Measurements of change since that point in time
What is the role of changing climate on ecosystems?
The enhanced greenhouse effect by human activity creates climate change which imposes multiple changes on an ecosystem at once, putting greater strain on its resilience.
What are practices used to restore ecosystems damaged by mining?
Removal of infrastructure, properly sealing the mine, removal of contaminated soil, testing of water, control of gas emissions and dust, etc.
What are practices used to restore land degraded from agriculture?
Managing soil erosion, salinisation, eutrophication, introduced species, land clearing and pesticide residues.
How does Oxygen get from the alveoli into the blood?
Diffuses from alveoli into blood capillaries down a concentration gradient
What is the fluid mosaic model?
The fluid mosaic model describes the cell membrane as a lipid bilayer with proteins embedded in the lipid providing flexibility. The hydrophobic tails face each other and the hydrophilic head faces outwards. Proteins either act as pores or form active carrier systems as channels for transport.
