Topic 5

Question 1

Ecosystem

Answer 1

Distinctive features affecting organism living there abiotic (non-living)/biotic (living)

Question 2

Abiotic factors (physical/chemical)

Answer 2

Climate- temperature
Solar energy- light can affect animal behaviour and photosynthesis
Pollution
O2 concentration

Question 3

Biotic factors

Answer 3

Completion- either interspecific (between species) or intraspecific (within species)
Diseases
Predation

Question 4

Succession

Answer 4

Change in species over time
Primary succession- starts in new habitat where no species been before
Secondary succession- occurs where existing species have been cleared

Question 5

Pioneer species (adaptations)

Answer 5

A species that colonises area first
Adaptations: -rapid growth
-short life cycle
-can be spread by wind

Question 6

Deflected succession

Answer 6

Human activity preventing succession from running its course

Question 7

What are autotrophs

Answer 7

Organisms that make their own organic compounds from inorganic compounds

Question 8

Photosynthesis

Answer 8

6CO2 + 6H20———>C6H12O6 + 6O2

In photosynthesis energy from light break C02 and water bonds, so products are at a higher energy than reactants (act as energy store)

Question 9

Photolysis of water

Answer 9

Occurs in granum ,it’s the splitting of OH bonds with light energy into O and H

Question 10

Uses of glucose in plants

Answer 10

Used in aerobic respiration to release energy and C02 and glucose can be stored as starch or cellulose

Question 11

Light dependant reaction

Answer 11

-Uses energy from light and H+ from photolysis of water to produce NADPH, ATP and O2 (waste product). O2 used in respiration or release. Occurs in thykloid membrane.

1)Light raises two electrons in chlorophyll to higher energy level (chlorophyll excited)
2)electrons leave chlorophyll via ETC
3)Photolysis of water to produce O2, electrons and H+ ions
4)Electrons move across ETC
5)Photophoshorylation to produce ATP
6)Reduction of NADP

Question 12

Light independent reaction

Answer 12

Occurs in stroma. Uses ATP are NADPH from LDR to reduce C02 to carbohydrates (glucose)

1)RuBP combines with C02 in Carbon fixation catalysed by RUBISCO
2)Unstable 6 carbon formed breaks down into two molecules of GP
3)NADPH and ATP are used to reduce two GP molecules into GALP
4)2/12 GALP used to make 6-carbon sugar (hexose) which is converted into their compounds (lipids,amino acids)
5)the 10/12 GALP involved to recreate RuBP with ATP (phosphorylation/adding inorganic phosphate) so process can repeats

Question 13

Structure of Chloroplast

Answer 13

Stroma- has enzymes needed for LIDR
DNA loop- contains genes for some proteins
Starch grain- stores product of photosynthesis
Granum- stack of thylakoids
Inner membrane- contains transporter molecules, inner/outer membrane form envelope
Outer membrane- freely preamble to C02 and H20
Thykaloid space- has enzymes for photolysis
Thykaloid membranes- system of flattens sacs, includes photosynthetic pigment chlorophyll and electrons involved in LDR

Question 14

Role of ATP

Answer 14

-Energy carrier molecule
-Moves energy from energy yeilding to energy requiring reactions
-ATP is a nucleotide consisting of Adenine, Ribose and 3 phosphate group. When 3rd group removed ADP is formed and group becomes hydrated forming bonds with water. ATPase catalyses ATP—>ADP
-ATP+inorganic phosphate = ATP (ATP has higher energy in water than ADP)

Question 15

Uses of glucose produced in Calvin cycle

Answer 15

Respiration
Make sucrose to be transported via phloem
Polymerases to form cellulose
Used to make lipids/proteins

Question 16

Heterotrophs

Answer 16

Organisms obtaining energy as organic matter by ingesting material from other organisms

Question 17

Detritivores

Answer 17

Primary consumers feeding on dead organic material

Question 18

Gross primary productivity and Net primary productivity

Answer 18

—>GPP- rate of which energy is incorporated into organisms by ecosystem
—>NPP-rate of which energy is transferred into molecules making up new plant biomass

NPP=GPP-R (respiration)

Question 19

What evidence is there for climate change

Answer 19

Temperature record
Peat bogs
Dendrochronology

Question 20

Peat bogs

Answer 20

Pollen from peat bogs is useful as:
-pollen has outer layer resistant to decay
-plant produce large amount of pollen
-each plant species have distinctive pollen type
-peat forms layers the deeper the older, carbon 14 dating allows age to be determined

Question 21

Tree ring analysis

Answer 21

Each year new xylem vessel produced by cell division, wider vessels in summer/spring and narrower in winter/autumn (little growth)

Question 22

Green house effect

Answer 22

Sun radiates energy and some absorbed by earth and some reflected as infrared radiation. Some energy absorbed by greenhouse gases in atmosphere warming it up

Question 23

Factors affecting global warming

Answer 23

-Increased C02
-other green house gases (methane)
-cloud cover
-degree of reflection
-changes in sun radiation

Question 24

Darwin’s theory’s

Answer 24

-Organism produce more offspring that can survive and reproduce so as populations grow their is a struggle for existence due to environmental factors
-there are huge amounts of variation in species so species with best adaptions will survive (selective adv) and natural selection is occurring

Question 25

How can variation occur in populations

Answer 25

alleles can arise through random mutations creating variation

Question 26

Molecular evidence for DNA

Answer 26

—>DNA hybridisation- heat DNA from both sets to separate strands. Mix two strands to make a hybrid and complementary bases will occur (not all). Heat hybrid to separate stands the higher the temp the more closely related.
—>DNA profiling- using restriction enzymes to cut DNA at specific sequences to provide fragments which can be visualised on profiles. If mutation occurs enzyme can’t cut DNA
—>DNA/protein sequncing- comparing base sequences few differences show close relationships
—>Molecular clock- PCR to produce DNA copies allowing quick determination of sequences, as species evolve they mutate randomly becoming genetically different. Molecular change on clock used to pinpoint evolution events.

Question 27

Speciation

Answer 27

Formation of new species
Allopatric speciation- occurs when there is geographical isolation
Sympatric speciation- populations become reproductively isolated

Question 28

Role of microbes in carbon cycle

Answer 28

They recycle plant biomass via respiration and release C02

Question 29

Other factors affecting C02

Answer 29

-Volcanos release C02
-Increase of acid rain in areas C02
-War, water holds lees C02 (sea water)

Question 30

How to maintain C02 balance

Answer 30

Reforestation
Use of sustainable resources

Controversial: -wind farms produce energy affecting C02
-production of biofueL can reuse C02