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Biology ­ Common Mark Scheme Answers

PHOTOSYNTHESIS

Light hitting leaf is not used by chloroplasts ­
Due to reflection
Incorrect wavelength
It is transmitted, not hitting the chloroplasts

Structures in a chloroplast involved in light dependent reactions
Thylakoids
Made of membranes
Arranged as stacks of grana
Contains chlorophyll

Oxygen from…

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Losses in respiration in plants
GPP ­
ECOSYSTEMS

Explain what is meant by the term NICHE:
Role/Purpose/Interaction
Of an organism
It is predator ­ controls prey population/it is prey ­ provides food for
other animals
Provides shelter for some animals

GLOBAL WARMING
Global Warming ­
Less greenhouse gases such as…

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Two species from a single population
Original population spreading to a wider diversity of habitats
Mutations may occur
Reproductive isolation may occur
Restriction in gene flow between extremes in populations
Different environmental factors in each region
Plants adapt to the region
Change in allele frequency over time

Genetic Mutation
Change…

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Drop in body temp. is linked to time after death
Factors affect the temp. body size/clothing/environmental temp
Only useful for short period of time after death

State of decomposition ­
Body decomposes in a specific sequence with time
Factors affect decomposition ­ environmental temp/wounds
Not useful if all body has…

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DNA profiling
Assumes every individuals DNA is unique
apart from identical twins
DNA profiling analyses non-coding blocks
There is a large number of non-coding blocks
Many combinations at each locus


MICROORGANISMS & DISEASE

HYDROLYSIS - type of chemical reaction involved in the digestion of
cellulose by enzymes.

GLUCOSE - most…

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Specific response
Antigens are specific to each bacteria
Antibodies need to be complementary to antigens
So binding can take place
Antibodies already present from passive immunity/breast feeding



How organisms are taken up by macrophages
Bacterium recognises it as nonself
Phagocytosis occurs
Vacuole is formed

advantage of using monoclonal antibodies, rather…

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On membrane of lymphocytes
Viral RNA enters the lymphocytes
And is used to produce Viral DNA
Using reverse transcriptase
T killer cells destroy T helper cells


HIV enters through T cells and phagocytic cells
Binds to CD4 receptors
On cells
Fusion of virus with cell membrane
Phagocytosis ­ macrophage

Comments

Ricky Rozay

boss

Katie Hamiton

Do you have Unit 5 by any chance?

Former Member

beaut!

hadgert

you guys are so cute

hadgert

i love hanging out with you

mahir

k.

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