practice exam questions thread

[Smiley_]

could someone please help me with the 2006 exam mc question
3+4

[psyxwar]

Assuming you mean U4:

q3: Three alleles, let's just call them a,b and c.

a,a/ a,b/ a,c/ b,b/ b,c/ c,c

Thus, there are 6 possible genotypes (D)

q4: answer is C, two thirds of the marble offspring are heterozygotes.

3:1 ratio of marbled to spotted, we know then that it is a cross between two heterozygotes, which yields a 1 homozygous dominant: 2 heterozygous: 1 homozygous recessive. Hence, 2/3rds of marbled offspring here are heterozygotes.

[Smiley_]

are cytokines protein or glycoprotein or both ?

[Irving4Prez]

are cytokines protein or glycoprotein or both ?

Glycoproteins are conjugated forms of protein consisting of protein and a carbohydrate component. Cytokines are glycoproteins.

[Smiley_]

Glycoproteins are conjugated forms of protein consisting of protein and a carbohydrate component. Cytokines are glycoproteins.

i dont know why i said and both

[Smiley_]

do we need to know about
the region upstream of the coding sequence
the region downstream of the coding sequence.
I saw this in a practice exam?


also I just did the stav exam today and I want to cry , I found it so hard, anyone else done it?

[Yacoubb]

do we need to know about
the region upstream of the coding sequence
the region downstream of the coding sequence.
I saw this in a practice exam?


also I just did the stav exam today and I want to cry , I found it so hard, anyone else done it?

All you need to know that the promotor region (where RNA Polymerase binds to before transcription), is located in the upstream region, whilst the terminator region, which signals the termination of transcription when reached by RNA Polymerase, is located in the downstream region of a gene.

Also, the upstream and downstream region are called flanking regions.

[Smiley_]

All you need to know that the promotor region (where RNA Polymerase binds to before transcription), is located in the upstream region, whilst the terminator region, which signals the termination of transcription when reached by RNA Polymerase, is located in the downstream region of a gene.

Also, the upstream and downstream region are called flanking regions.

thanks :

[Irving4Prez]

also I just did the stav exam today and I want to cry , I found it so hard, anyone else done it?

Which one? I recall one from Unit 3 that was demoralising

[Smiley_]

the second part , im not to sure on, its from 2009 unit 4

[Yacoubb]

the second part , im not to sure on, its from 2009 unit 4

There are expected phenotypic ratios for a cross between two parents with particular genotypes. This expected ratio is based on the genes being unlinked, and so applying to Mendel's Law of Independent Assortment, where one gene is sorted to a gamete independent of other gametes. If the offspring show more parental phenotypes (i.e. The phenotypes of their parents), relative to recombinant phenotypes (i.e. Breaking parental allele linkages to create new genotypes --> new phenotypes), then the two genes are linked.

[Smiley_]

Which one? I recall one from Unit 3 that was demoralising

3=4

[Shenz0r]

There are expected phenotypic ratios for a cross between two parents with particular genotypes. This expected ratio is based on the genes being unlinked, and so applying to Mendel's Law of Independent Assortment, where one gene is sorted to a gamete independent of other gametes. If the offspring show more parental phenotypes (i.e. The phenotypes of their parents), relative to recombinant phenotypes (i.e. Breaking parental allele linkages to create new genotypes --> new phenotypes), then the two genes are linked.

To put what Yacoubb said more simply, if you do a test cross involving two gene loci (and one of the parents was heterozygous), you would get a 1:1:1:1 phenotypic ratio if there was independent assortment (and for the sake of VCE Bio, that means the gene loci are on separate chromosomes). If the phenotype ratio deviates from that, your gene loci are not assorting independently, meaning that linkage is occurring and your gene loci are on the same chromosomes.

This deviation from the 1:1:1:1 ratio is due to recombination. Parental offspring, which have the parent's phenotypes, will be in higher frequency than the recombinant offspring, which have different phenotypes.

[Smiley_]

thanks

also im having trouble with last years exam mc unit 3 question 5 why is the answer c?

[SocialRhubarb]

A DNA sequence that is 100 nucleotide pairs long has 200 bases, because the nucleotides come in pairs.

There are 25 adenine bases, which means there must also be 25 thymine bases, making a total of 50 bases.

There must be 150 more bases of cytosine and guanine, and since they will appear in equal numbers, there will be 75 bases of guanine.