Biology Unit 4 Questions Megathread

[nooshnoosh95]

thanks guys

[cricketstar]

Just had a question, what is the difference between genome and genotype cause both the terms seem to have very similar definitions and every commercial exam company seems to define it differently.

Thanks

[Reckoner]

Genome is the sum total of genetic information in an organism, Genotype is the genetic make-up of an organism at particular locus/loci, in other words the allelic combination of that organism. 

[Eloise]

In the NEAP 2010 practice exam, I'm quite confused about Q12 in the multiple choice. Could someone talk it through for me?

"The bread mould, Mucor haemalis, normally produces its own amino acids from raw material through a system of enzymes.

                    gene X              gene Y            gene Z
                        |                        |                     |
                        v                       v                     v
                  enzyme X         enzyme Y        enzyme Z
                        |                        |                     |
                        v                       v                     v
raw materials------>ornithine------>cutrulline------>arginine

The production of arginine is controlled by the following (minimum) number of genes
A. two
B. one
C. four
D. five

The answer is D. five. How does that work? What five genes?

[WhoTookMyUsername]

it's a typo, suggested answers say "so a minimum of 3 genes is need"

[nooshnoosh95]

i dont get it :S
why is it three genes as a minimum wouldn't it just be one (gene Z)?

[Drunk]

i dont get it :S
why is it three genes as a minimum wouldn't it just be one (gene Z)?

It's 3 because you need to have cutrulline to be converted to arginine, which comes about from gene Y, and the same for ornithine. So in short, you're not gonna get any arginine without the other compounds, which are made by the action of the other genes

[simpak]

Alternatively, and the correct answer to your question, is that it is Neap and therefore you will never get it because they cannot phrase questions adequately.

[nooshnoosh95]

so i thought pure breeding meant the it had to be either homozygous receesive or homozygous dominant

but in an exam paper it says which of the genotypes are for pure breeding plants?
and the solutions say
AALL, AAll, aaLL and aall
are AAll, aaLL also considered pure breeding?

ohhhh yea and are the hominids the greater apes or the lesser apes?

[Reckoner]

^Yes, homozygous at all loci being observed.

[stephanieteddy]

Hello everyone I hope studying is going really well for you all,

I was hoping one of you would be able to clear this up for me,

When we want to insert a gene into a plant do we do recombinant plasmids? What part of the plant do we put it in?

And for humans we infect cells with a virus containing recombinant DNA,  culture the cells and then inject into patient? How do we inject the cells? Just a needle?

And have we decided on a clear cut definition of selection pressure?

What is used to combine the two different single strands of DNA in hybridisaton?

Hominin is all bipedal primates and hominid is all humans and human like species?

What does it mean by sloped face, is that protruding or non protruding jaw?

Is the centromere important for anything other than allowing for cell division to occur? When the chromosome splits into two chromatids that move to opposition poles, is that the deactivation of the centromere?

What is more significant to evolution, crossing over or mutations?


THANK YOU!

[Base]

Quick question from STAV 2010 MC.

Correct answers are circled.

Can someone explain how to figure out Question 9?

[earlandcookie]

Quick question from STAV 2010 MC.
(Image removed from quote.)
Correct answers are circled.

Can someone explain how to figure out Question 9?

maybe a bit obvious but it says those children with the deleted chromosome 'only' have the syndrome, only one of those gametes has the unbalanced translocation (gamete 4) so there is a 1/4 or 25% chance of the child inheriting the cri du chat syndrome.

[thushan]

Also, gamete 3, whilst it may have a broken chromosome 5, that but is in chromosome 13 so the child does not criduchat

[Base]

Oh wow I completely missed that so stupid rofl :S