BIOL4 Biology Unit 4 Exam - 13th June 2011

aww same i didnt do well either...i thought that jan's paper was harder than jan 2010 >.<

I got a C....but just a C: 60 ums

what do you need to get into uni?

Looking at the past papers, there are some really random questions such as the 15 marks about a shrew investigation, it wouldn't suprise me if AQA banged in a question about 'the increasing seal population in ethopia' or 'polar bears immigrating into foreign countries' :P

..... you never know with aqa x

Looking at the past papers, there are some really random questions such as the 15 marks about a shrew investigation, it wouldn't suprise me if AQA banged in a question about 'the increasing seal population in ethopia' or 'polar bears immigrating into foreign countries' :P

..... you never know with aqa x

I am doing that shrew question now :P.....thanks to AQA, I now hate shrews....

oh thanks !

whatdid you get last time? or are you not resitting this paper?

theres a much easier way to do this too btw.

births - deaths = 15

then 15/1000 = 1.5%

so you just get the population size which is 107m and do

107 x 1.015 = 108.605m

where did you get 1.015 from @.@

thanks btw

in maths when you are doing percentage increase you times whatever your increasing by 1 + whatever the percentage is in decimal form.

in this case 15/1000 = 1.5% = 0.015 in percentage form. therefore you add that to 1 to get 1.015 ....



however, for many of these questions in biology there are other ways to do it for the non mathematicians (ie, the one that was first shown to you) but that method i just showed you is probably gcse standard maths or lower. its just quicker thats all....

I think for the last week before this exam we should do a thing I've seen in previous threads which is what I call 'rolling question time' .... we ask a question, it gets answered, and the person answering puts forward a question. obviously there will be multiple answers so just all post a question after your answer and people will answer them if they want etc....

I will get the ball rolling with a nice one:

Give 3 methods of species conservation and briefly explain each

Finally done those questions asked earlier ...

5 of them:

1.Conserving fish : fish quotas

Limit on amount of certain fish that fishermen are allowed to catch

The limit is worked out by scientist
---------
2.Conserving animals: Captive breeding programme

Thats for species that are already extinct or endangered

Animals with low population are bred in captivity to increase their population
---------
3.Conserving plants: Using seedbank

Lots of seed of lots of different species are stored and can be used when a plant species

become extinct ( by replanting the extinct plant)
-----
4. Conserving Habitat: Protected areas

National park-coppicing

restricting urban development, industrial development and farming

-----
5. Conserving any organisms: Relocation

Move species with very low population which are directly under threat to new area


Thats all I remember ..
Correct me if am wrong


Here is another one:

Describe and explain factors effecting the rate of photosynthesis (6 marks)

Co2 - Plants need this to for the calvin cycle, the higher the Co2 concentration the more RuBp is turuned into GP which is broken down to TP which produces glucose and other useful organic substances.

Temp - PS will be directly proportional to the temp, between 0 and 25 the rate doubles for ever 10 increase. After that the PS level evens off and declines as the enzymes start to become denature and do not function properly.

Light intensity - Light is used in the depended-reaction, the light excites the chlorophyll which excites electrons and goes down ETC to produce ATP. As the light intensity increases more electrons are excited.

The rate of PS will be limited by the factor that is at its least favorable value.

Correct?

Describe the process of the Electron Transport Chain in the production of ATP (6 marks)

If you're talking bout respiration then.....

Electrons are transfered down the transport chain through various carrier molecules. each carrier molecule is at a lower energy level than the previous one, so energy is lost from the electrons at these stages. this energy is used to transport protons from the mitochondrial matrix into the intermembrane space of the mitochondria. this creates a proton gradient, so protons move back into the mitochondrial matrix through the enzyme ATP synthase. the energy gained from this is used to combine ADP and and an inorganic phosphate molecule to produce ATP.


Question: What are the two main types of selection and what do they mean?

Directional: selection may favour individuals that vary in one directional from the mean of the population and changes the characteristics.

Stabilising: selection favours the average individuals and the the individuals at the 2 extremities eventually die, it preserves characteristics of the population.

What are nitrification, nitrification and nitrogen fixation important in the nitrogen cycle?

Nitrification is the conversion of ammonium ions to nitrite ions and then nitrate ions through an oxidation reaction, which releases energy. Uses nitrifying bacteria
Nitrogen fixation is the fixing of nitrogen gas into nitrogen containing compounds. This can occur naturally e.g. lightening. There are two main types of fixing bacteria, mutualistic nitrogen fixing bacteria and free living bacteria. Free living bacteria reduces gaseous nitrogen into ammonia used to make amino acids, mutualistic bacteria live in the nodules of leguminous plants and the plants acquires amino acids from the bacteria and the bacteria obtains carbohydrates from the plant.

Question: Explain the predator prey cycle

The what cycle? First time I've seen this.

Has anybody got the exam report for this paper? thanks.

Nitrification is the conversion of ammonium ions to nitrite ions and then nitrate ions through an oxidation reaction, which releases energy. Uses nitrifying bacteria
Nitrogen fixation is the fixing of nitrogen gas into nitrogen containing compounds. This can occur naturally e.g. lightening. There are two main types of fixing bacteria, mutualistic nitrogen fixing bacteria and free living bacteria. Free living bacteria reduces gaseous nitrogen into ammonia used to make amino acids, mutualistic bacteria live in the nodules of leguminous plants and the plants acquires amino acids from the bacteria and the bacteria obtains carbohydrates from the plant.

Question: Explain the predator prey cycle