BIOL4 Biology Unit 4 Exam - 13th June 2011

Reply 820

*Rainbow*

Original post by Superlogon

khanacademy on youtube people! works wonders!

He's really good! :eek:

Thanks!

Reply 821

llamalad200

10

someone explain how they mark please your answers please.

say there is a five mark question and you get marks for saying:

1
2
3
4
5

my answer however has points:

1
3
4
5

now, does this mean that i will lose the marks for 3,4,5 because i didn't have a point for 2. resulting in me only getting the mark for 1? so one mark?

Reply 822

SashaLuLu

Original post by llamalad200

someone explain how they mark please your answers please.

say there is a five mark question and you get marks for saying:

1
2
3
4
5

my answer however has points:

1
3
4
5

now, does this mean that i will lose the marks for 3,4,5 because i didn't have a point for 2. resulting in me only getting the mark for 1? so one mark?

No, you would get 4 marks as you've said 4 points. Each point is marked independently from each other.

Reply 823

llamalad200

10

Original post by SashaLuLu

No, you would get 4 marks as you've said 4 points. Each point is marked independently from each other.

oh thank goodness! it always confused me because they put in semi colons making me think that they all had to be related to each other.

Reply 824

dents

can anyone explain jan 11 ques 5 b please??

no idea how to get right answer

Reply 825

Kishanpatel

Original post by dents

can anyone explain jan 11 ques 5 b please??

no idea how to get right answer

It is the value of the medium light intensity at 20 degrees + the value of respiration at the same temp. :

2.4 + 0.35 = 2.75
:smile:

Good luck with the exam today...!!

Reply 826

SK-mar

1

can someone quickly do a 5 mark answer to:

Explain the importance of conservation in an ecosystem...

Reply 827

SK-mar

1

just a quick question. what is the experiment called when you put elodea in water to measure the rate of photosynthesis? and whats the experiment called when u place an organism in one of those tube things where is respires and there is a pressure change, measuring the rate of respiration?

Reply 828

Stratos

15

Original post by tehsponge

Lol but I'm not revising... I'm sitting here just staring at the electron transport chain pages of NT.
How are you relaxed :frown:

That's actually my favourite part :ahee:

All you need to remember is that reduced NAD and reduced FAD carry hydrogen atoms from the krebs cycle, link reaction and glycolysis and then transport the hydrogen protons through carrier proteins don't forget that the hydrogen atoms are reduced before they are transported to replace the electrons in the electron chain, oxygen is the final acceptor of the electron and reacts with protons diffusing out the ATP Synthase protein.

Chemiosmosis is basically the transport of these protons through the carrier proteins against a concentration gradient, so that the protons will move across a diffusion gradient through ATP Synthase which produces energy, ATP Synthase uses this energy for phosphorylation of ADP+Pi to form ATP.

In cases where there is no ATP Synthase such as in brown fat the protons will move through other protein channels and their energy is no longer converted to chemical energy but heat energy which heats the cell up.

NADH and FADH are recycled to be used again, and in anaerobic respiration NADH is recycled by converting pyruvate into lactate, in yeast it produced CO2 which means matter is lost therefore not reversible.

Glycolysis/kreb and link are relatively easy, just need to remember the carbon numbers(is what my book says) although I just went ahead and remembered the names just because I can.

Original post by SK-mar

can someone quickly do a 5 mark answer to:

Explain the importance of conservation in an ecosystem...

1. Conservation is the act of preventing complete succession(deflected succession)
2. If succession isn't deflected the ecosystem reaches a climax community which is similar to other climax communities
3. We want to preserve alleles to maintain diversity
4. diversity is useful because it means that plants are more likely to survive in the case of disruptions in abiotic factors/niches
5. consumers feed on the diversity of plants, therefore more food sources for different organisms, blablabla secondary consumers feed on primary consumers maintaining trophic level or something.
6. humans can use the alleles/genes for medicine, to develop cures and treatments to diseases, can be used for biotechnology, ethical reasons like preserving organisms.

It's not a very confident answer But I guess it will do.

(edited 12 years ago)

Reply 829

Zetsubeau

1

Original post by SK-mar

just a quick question. what is the experiment called when you put elodea in water to measure the rate of photosynthesis? and whats the experiment called when u place an organism in one of those tube things where is respires and there is a pressure change, measuring the rate of respiration?

Respirometer?

Original post by SK-mar

can someone quickly do a 5 mark answer to:

Explain the importance of conservation in an ecosystem...

Wouldn't that be talking about niches and genetic diversity and how it's all so brilliant?

Reply 830

SashaLuLu

can anybody explain what biomass is + dry biomass?

Reply 831

Zetsubeau

1

By the way I posted this in another thread but nobody seems to be posting there anymore.
Correct me if I'm wrong, as usual.

Original post by Zetsubeau

Genes are a section of DNA that is responsible for a characteristic. This is by coding for a protein such as an enzyme, etc. Genes are carried on chromosomes. They can be expressed (exons) or not expressed (introns).
An organisms genetic code is given during reproduction. When the reproduction is asexual: simple! The genetics of the parent are identical to the child/daughter. When it's sexual, the gametes carry half the genetics each and form a zygote which contains a split of genes. This is where expression is slightly more complex.
When a gene (genotype) is expressed, it creates a phenotype (a characteristic, e.g. blue eyes, brown hair, formation of proto-oncogenes, etc.). When a genotype causes a phenotype, it is dominant. Other genes are often carried which also have a phenotype, but may be dominant or recessive. If it is recessive, the dominant gene is expressed and the recessive is not. When a gene is present but not expressed, it's being carried. The organism is a carrier. Sometimes both are expressed, however, causing a co-dominance (such as AB bloodtype). When a gene is sex-linked, it's carried on the Y chromosome, as that's the chromosome that varies between sexes. This means it's only present in one sex.

Original post by SashaLuLu

can anybody explain what biomass is + dry biomass?

Biomass the the weight of the organism. Dry is the organism's weight without water.

Reply 832

dents

Original post by Kishanpatel

It is the value of the medium light intensity at 20 degrees + the value of respiration at the same temp. :

2.4 + 0.35 = 2.75
:smile:

Good luck with the exam today...!!

cheers

all i did wrong was in my rush to quickly finish paper kept on looking at the wrong axis but didnt realise, hope i dont do that in exam.

gud luk.

Reply 833

Zetsubeau

1

Original post by Stratos

1. Conservation is the act of preventing complete succession(deflected succession)
2. If succession isn't deflected the ecosystem reaches a climax community which is similar to other climax communities
3. We want to preserve alleles to maintain diversity
4. diversity is useful because it means that plants are more likely to survive in the case of disruptions in abiotic factors/niches
5. consumers feed on the diversity of plants, therefore more food sources for different organisms, blablabla secondary consumers feed on primary consumers maintaining trophic level or something.
6. humans can use the alleles/genes for medicine, to develop cures and treatments to diseases, can be used for biotechnology, ethical reasons like preserving organisms.

It's not a very confident answer But I guess it will do.

That's what I thought. Good.

Side note though: ethics isn't a major point.

Reply 834

Kishanpatel

Original post by SashaLuLu

can anybody explain what biomass is + dry biomass?

According to NT: 'biomass is the total mass of living material in a specific area at a given time. It is usually measured as dry biomass because the amount of water in an organism is very variable'

hope that helped :smile:

Reply 835

Stratos

15

Original post by Zetsubeau

Genes are a section of DNA that is responsible for a characteristic. This is by coding for a protein such as an enzyme, etc. Genes are carried on chromosomes. They can be expressed (exons) or not expressed (introns).
An organisms genetic code is given during reproduction. When the reproduction is asexual: simple! The genetics of the parent are identical to the child/daughter. When it's sexual, the gametes carry half the genetics each and form a zygote which contains a split of genes. This is where expression is slightly more complex.
When a gene (genotype) is expressed, it creates a phenotype (a characteristic, e.g. blue eyes, brown hair, formation of proto-oncogenes, etc.). When a genotype causes a phenotype, it is dominant. Other genes are often carried which also have a phenotype, but may be dominant or recessive. If it is recessive, the dominant gene is expressed and the recessive is not. When a gene is present but not expressed, it's being carried. The organism is a carrier. Sometimes both are expressed, however, causing a co-dominance (such as AB bloodtype). When a gene is sex-linked, it's carried on the Y chromosome, as that's the chromosome that varies between sexes. This means it's only present in one sex.

Firstly exons and introns are merely bases in a mRNA sequence they aren't genes in themselves, a gene contains introns when it hasn't been edited yet basically and a edited gene contains exons only.

And sex-linked genes merely mean that the gene is present on a heterosomal chromosome(X or Y) it and can be present in both genders, but it more likely to be present in males e.g. in colour blindness.

But the rest sounds fine I guess.

(edited 12 years ago)

Reply 836

Zetsubeau

1

Original post by Stratos

Firstly exons and introns are merely bases in a mRNA sequence they aren't genes in themselves, a gene contains introns when it hasn't been edited yet basically and a edited gene contains exons only.

And sex-linked genes merely mean that the gene is present on a heterosomal chromosome(X or Y) it and can be present in both genders, but it more likely to be present in males e.g. in colour blindness.

But the rest sounds fine I guess.

Good enough. Sex-linkage is a bit confusing to me but it's not a big deal, I understand it well enough.

Reply 837

Abby :)

8

Heyyy can someome help me... ive seen this Q a couple of times and i really cant find the answer!

What are the advantages of using a pyramid of biomass/measuring in biomass???

Reply 838

Zetsubeau

1

Original post by Abby :)

Heyyy can someome help me... ive seen this Q a couple of times and i really cant find the answer!

What are the advantages of using a pyramid of biomass/measuring in biomass???

Energy is lost between each consumer? I think.

Reply 839

Stratos

15

Original post by Abby :)

Heyyy can someome help me... ive seen this Q a couple of times and i really cant find the answer!

What are the advantages of using a pyramid of biomass/measuring in biomass???

Pyramid of numbers often misrepresent the energy in a food chain due to primary consumers often being insect which are more numerous than the producer e.g. tree therefore the pyramid isn't shaped as a pyramid whereas in biomass the tree which has more biomass than the insects will have a wider trophic level therefore shaped like a pyramid and representing the transition of energy more accurate however this falls in cases such as crickets which have seasonal spurs in which they are actually of greater biomass than the producer in which case we use the pyramid of energy which records the average energy absorbed by the organism yearly, therefore seasonal spurs which are anomalies are evened out and the shape is always a pyramid as energy cannot be gained only lost across a food chain.

The reasons are fairly obvious e.g. indigestible matter, respiration(includes biosynthesis e.g. growth/reproduction), heat loss in endothermic organisms(warm blooded)

BIOL4 Biology Unit 4 Exam - 13th June 2011

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