Exam

Question 1

Does facilitated diffusion require energy?

Answer 1

No

Question 2

What is source-sink theory?

Answer 2

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.

Question 3

What is interstitial fluid?

Answer 3

Fluid found in the spaces around cells

Question 4

Cell requirements of plants (energy, chemical, waste removal)?

Answer 4

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

Question 5

Cell requirements of bacteria (energy, chemical, waste removal)?

Answer 5

Energy: may require light or inorganic chemicals
Chemicals: H2O, CO2, O2, Ca2+, K+
Waste removal: excretion carried out by simple diffusion or active transport

Question 6

Cell requirements of animals (energy, chemical, waste removal)?

Answer 6

Energy: complex carbs
Chemicals: H2O, O2, minerals, vitamins
Waste removal: individual cells excrete CO2 by diffusion,

Question 7

How can you trace products of photosynthesis through plants?

Answer 7

Giving plants C-14 which is incorporated into sugars

Question 8

What are the similarities between heterotroph and autograph gas and nutrient requirements?

Answer 8

They both require water and mineral ions are taken from the surroundings

Question 9

What are the differences between heterotroph and autograph gas and nutrient requirements?

Answer 9

Autotrophs need carbon dioxide gas
Heterotrophs need to ingest organic substances
Autotrophs produce their own oxygen, glucose, proteins and lipids

Question 10

What is adaptive radiation?

Answer 10

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.

Question 11

What are microevolutionary changes that caused the evolution of horses?

Answer 11

Changes in horse ancestors include size, jaw size and toe numbers

Question 12

How do antibiotic-resistant strains of bacteria demonstrate evolutionary change?

Answer 12

Some variations in bacterial populations can recolonise and develop natural resistance to antibiotics and pesticides

Question 13

What was the cause of the Permian extinction?

Answer 13

The Permian extinction killed about 90% of the species on Earth, and was believed to be caused by global warming.

Question 14

What is facilitated diffusion?

Answer 14

Facilitated diffusion is the transport of substances across a biological membrane through a concentration gradient by means of a carrier molecule.

Question 15

How do Aboriginal rock paintings provide evidence for past changes in ecosystems?

Answer 15

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.

Question 16

How do rock structure and formation provide evidence for past changes in ecosystems?

Answer 16

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.

Question 17

How does ice core drilling provide evidence for past changes in ecosystems?

Answer 17

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

Question 18

How does gas analysis provide evidence for past changes in ecosystems?

Answer 18

Scientists can use the data in ice cores to reconstruct atmospheric concentrations of certain gases, particularly carbon dioxide and oxygen.

Question 19

What are some examples of human-induced selection pressures on the extinction of species?

Answer 19

Some human-induced selection pressures include over-exploitation of resources, introduced species and disruption of ecological relationships

Question 20

What are some models that humans can use to predict future impacts on biodiversity?

Answer 20

1. The equilibrium model (a baseline at some point in the past that has relevance to the ecosystem being managed
2. Measurements of change since that point in time

Question 21

What is the role of changing climate on ecosystems?

Answer 21

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.

Question 22

What are practices used to restore ecosystems damaged by mining?

Answer 22

Removal of infrastructure, properly sealing the mine, removal of contaminated soil, testing of water, control of gas emissions and dust, etc.

Question 23

What are practices used to restore land degraded from agriculture?

Answer 23

Managing soil erosion, salinisation, eutrophication, introduced species, land clearing and pesticide residues.

Question 24

How does Oxygen get from the alveoli into the blood?

Answer 24

Diffuses from alveoli into blood capillaries down a concentration gradient

Question 25

What is the fluid mosaic model?

Answer 25

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.