Ecology

Question 1

Advantage of asexual reproduction?

2 things

Answer 1

Takes less time

Advantageous alleles will be passed down

Question 2

Advantage of sexual reproduction?

Answer 2

Greater gene pool

More genetic diversity

Question 3

How to show that there is a relationship between two variables?
(4 steps)

Answer 3

Plot a scatter graph
Look for correlation
Carry out a statistics test
e.g. Spearman’s Rank Correlation

Question 4

Where does carbon fixation take place in the leaf?

Answer 4

stroma

Question 5

Enzyme involved in carbon fixation?

Answer 5

RUBISCO

Question 6

Molecule Y + CO2 => 2x Molecule Z
(carbon fixation equation)
What is molecules Y and Z

Answer 6

Y - RuBP

Z - GP

Question 7

Properties of Starch

Answer 7

Insoluble (won’t affect osmotic effect of cell)
A polymer made up of alpha glucose monomers
Monomers joined by glycosidic bonds
Glycosidic bonds at 1,4 and 1,6
Contains two chains: amylose and amylopectin
Amylose is straight chained (1,4 bonds)
Amylopectin is branched (1,4 and 1,6 bonds)

Question 8

How does methane, carbon dioxide and water lead to global warming?
(5 points)

Answer 8

They are greenhouse gases
They form a layer in the atmosphere
This layer absorbs IR that has been reflected off the Earth’s surface
Increasing levels of these gases in the atmosphere leads to an increase in the greenhouse effect
This causes the Earth’s surface temperature to increase

Question 9

GPP

Answer 9

Rate of production of organic substances in plants

Question 10

NPP

Answer 10

rate of energy incorporated in organic material in plants

Question 11

Climax Community?

Describe?

Answer 11

Final community that’s self-sustaining

has the most productive group of organisms the environment can support.

Question 12

Niche

Answer 12

role of an organism in its ecosystem

Question 13

Community?

Answer 13

All the populations of different species living in a habitat at any time

Question 14

What is GALP used for?

Answer 14

Producing alpha glucose,
Carbohydrates,
Deoxyribose (sugar in DNA) from glucose,
Amino Acids,
Synthesis of DNA bases (GALP + nitrates)

Question 15

In dendrochronolgy how is growth of measured?

Answer 15

By width of bands/rings

Question 16

How would an increase in temperature affect plant growth? Explain?
(5 points)

Answer 16

Increase temperature => increased growth
Because enzymes work faster (increased KE, increased collisions)
Photosynthesis is also faster
However, above a specific temp (optimum) enzyme begins to denature
Growth rate decreases

Question 17

How do microorganisms decompose organic matter?

Answer 17

Microorganisms involved are bacteria and fungi
They secrete enzymes onto the organic matter
Protein => protease => amino acid (peptide)
Carbohydrate => amylase => glucose (glycosidic)
Monomers produced are soluble
Some of the monomers are taken up by the microorganisms

Question 18

How would pH affect an organism?

Answer 18

pH affects the enzymes
The shape of the active site is changed as R groups are ionised
Respiration/Metabolism is affected
pH may affect cell wall structure/membrane

Question 19

Why are certain phenotypes/alleles selected for in natural selection?

Answer 19

They indicate good health
May provide warning to or protection from predators
Camouflage
Attract a mate
Increase chances of reproduction
Allele is passed onto offspring (allele freq increases)

Question 20

How is oxygen formed in leaf?

Answer 20

In the chloroplasts
Water is split (photolysis)
To form one Oxygen atom and a H+ ion and electrons
Two water molecules are needed

Question 21

Structure of chloroplasts linked to role in photosynthesis

Answer 21

Compartmentalised
Thylakoids are site of light-dependent reactions
Thylakoids contain chlorophyll and photosystems
Thylakoids provide a space for H+ ions to accumulate
Stroma is location of light-independent reactions
Stroma contains RuBP and RUBISCO

Question 22

Where does all the bonding to form the 3D shapes of proteins occur?

Answer 22

Between R groups (hydrophobic interactions)

Question 23

How can we study and compare different proteins?

Answer 23

Proteomics

Question 24

Gel Electrophoresis

Answer 24

DNA fragments placed in wells in agarose gel
Electric Current run through the gel
Longer fragments travel slower through the gel
Bands are formed
Use fluorescent staining so the bands can be seen

Question 25

Describe interferon action

Answer 25

Bind to uninfected host cell receptors
So virus cannot bind to host cell receptor
Therefore virus cannot enter host cell
Therefore virus cannot replicate
Viral Replication Inhibited

Question 26

Describe structure of a lipid

Answer 26

Comprised of C, H and O only
Fatty acids and glycerol joined by ester bonds formed through condensation reactions
There are saturated and unsaturated fatty acids

Question 27

Minerals/ions required for plant growth

5 ions

Answer 27

Magnesium ion - chlorophyll production (photosynthesis)
Nitrates - amino acid production (proteins needed for growth)
Calcium ions - strengthen cell wall
Potassium ions - protein synthesis and photosynthesis
Phosphate - protein synthesis (root growth)

Question 28

Succession

Answer 28

A series of changes of organisms in a community over a period of time

Question 29

How can animals help plant growth/soil development

Answer 29

Carry seeds with them (pollination)
Faeces act as fertiliser
Provide structure to the soil
Faeces add nutrients to the soil
More plants can grow

Question 30

Describe Enzyme structure

Answer 30

Globular proteins
Specific 3D shape due to bonding and interaction of R groups and specific AA chain
Hydrophilic on the outside (charged R groups on outside)
Hydrophobic on the inside