questions, questions, more questions... (1 Viewer)

[mei_ling03]

--> dotpoint: solve problems involving co-dominance and sex linkage

i don't think i've done any co-dominance problems before...does anyone have an example (of a question)?

--> dotpoint: describe the work of morgan that led to the understanding of sex linkage

how in depth do we have to go? could someone please give me an example?

--> dotpoint: proces information from secondary sources to construct a model that demonstrates meosis and the process of crossing over, segregation of chromosomes and the production of haploid gametes

the only part i know if the crossing over bit!... please explain??

--> dotpoint: explain the relationship between the structure and behaviour of chromosomes during meiosis and the inheritance of genes

i have no idea.

many thanks for your help guys!!!

 

[Rosem]

this is how i understand the dot point and i hope this help you

--> dotpoint: describe the work of morgan that led to the understanding of sex linkage

- Morgan breed Drosophilia (fruit fly) and notice that there were some white eye male out of the both parents having red eye
- he breed the white eye male with red eye female, and in f1 generation they all had red eye, he further bread them and in f2 generation some had white and some had red
-he notice that they were certain character that relates to XY(male) and XX(female) chromosome
- X chromosome is larger than Y chromosome and if they is defect in X chromosome of a female than the other X would cover the defect becoz they r the same size
-However if X chromosome of a male is defected than y can not cover it caz Y is smaller
-Therefore male express the disease and female carry them

--> dotpoint: proces information from secondary sources to construct a model that demonstrates meosis and the process of crossing over, segregation of chromosomes and the production of haploid gametes

"model" usually is broad so u can do anything. like if u know the process of meosis and crossing over u can use playdo(fink that how u spell it) and just like create the process

sorry i can't help you with other dot point i am lost as well lol

 

[arls]

okay ill have a go at the last one..

the relationship betwen the structure and behaviour of chroms during meiosis and inheritance of genes:

Im pretty sure this is talking about the process meiosis and how the 4 daughter cells produced will have genes inherited from both parents.

structure and behaviour of chromosomes:

- haploid number of chroms in a sex cell.

- gametes (sex cells) are fromed by the random process of fertilisation, this produces genetic variation.

-during meiosis genes sort themselves randomly and independently which = genetic variation further.

-Linked genes and crossing over are exceptions to random segregation... lead to even more genetic variation. Linked genes are genes for 2 different characteristics found on the same chrom, consequently are often inherited together.

- crossing over occurs (behaviour of chrom) early on in meiosis (just as chroms have replicated into two) and is the swapping of chromatid parts early on in meiosis... this means that there will be even more genetic variation in the offspring.

therefore.... in conclusion... with all these different processes during meiosis that mix up all the chromosomes and genes (random assortment of genes/chroms in meiosis, linked genes, crossing over) the daughter cell that is produced has characteristics of BOTH parents, yet these are completly random (apart from say linked genes which are inherited together) and because of the random nature of this process you will almost NEVER look the same as one of you siblings!

Im not sure if this is answering the dot properly... but its my analogy... if any1 can prove me wrong go ahead.

 

[arls]

btw... there stuff in bio excel.. only a little that may help u understand this dot. pg 39-40. ill post it if u dont have it, tell me!

 

[mei_ling03]

Rosem: with the model thing, i thought they meant we had to create a drawing of some sort cos we're 'processing information from secondary sources'... they won't ask us that in exams, will they?
also, i thought that in sex linked inheritance, the Y chromosome does not carry the specific gene, therefore the recessive faulty gene is displayed in the phenotype?

arls: ciao! yeah i do have excel but it seemed a lil brief... your explanation sounds a lil better so, basically, are we meant to talk about how the behaviour of the chromosomes lead to variation in gene inheritance and therefore variation in individuals? i just thought that all this info was needed in the dotpoint above - something about how gamete formation leads to variation.

thank you both.. feel free to type any more info

 

[arls]

Originally posted by mei_ling03

also, i thought that in sex linked inheritance, the Y chromosome does not carry the specific gene, therefore the recessive faulty gene is displayed in the phenotype?

arls: ciao! yeah i do have excel but it seemed a lil brief... your explanation sounds a lil better so, basically, are we meant to talk about how the behaviour of the chromosomes lead to variation in gene inheritance and therefore variation in individuals? i just thought that all this info was needed in the dotpoint above - something about how gamete formation leads to variation.

thank you both.. feel free to type any more info

rosem is right... and so are you about sex linkeage mei!
umm.../.. just reading dotties now... yeah your right actually the dot below talks about gamete production and variation of offspring..... Im thinking if you understand all of this stuff, even if dot points overlap youll be okay in the exam! the question wont be a direct dot point or anything - it will be very clear and much easier to understand than the dot points (to make marking easier.. and for the stress of the exam situation) i mean look at previous hsc papers... the questions are really clear..

so in answer to ure ques.. i really dont know how to differentiate between these two dot points.. but if understand the main concepts im sure ull be fine!

 

[arls]

meosis and the process of crossing over, segregation of chromosomes and the production of haploid gametes

with this.. i always just use simple diagram that my teacher did at school to explain the whole process.. with descriptions around the diagram of each stage.. this should be fine im sure if you've got one.

if not check a text or bio excel has a great lil diagram u culd copy.

 

[psycho_mushy]

explain the relationship between the structure and behaviour of chromosomes during meiosis and the inheritance of genes

The structure of chromosomes is such that there are 2 of each chromosomes in each cell and in meiosis they double and split so that at fertilisation, one chromosome from each parent is given to the offspring. This enables genes and characteristics from each parent to be passed on

from our clas....

notice the point says "relationship betwen the structure and behaviour of chromosomes[/l]

so all u have to worry about is the chromosome.. nothing else and the process of meiosis

 

[Rosem]

Originally posted by mei_ling03
Rosem: with the model thing, i thought they meant we had to create a drawing of some sort cos we're 'processing information from secondary sources'... they won't ask us that in exams, will they?
also, i thought that in sex linked inheritance, the Y chromosome does not carry the specific gene, therefore the recessive faulty gene is displayed in the phenotype?

arls: ciao! yeah i do have excel but it seemed a lil brief... your explanation sounds a lil better so, basically, are we meant to talk about how the behaviour of the chromosomes lead to variation in gene inheritance and therefore variation in individuals? i just thought that all this info was needed in the dotpoint above - something about how gamete formation leads to variation.

thank you both.. feel free to type any more info

you are right about sex link but mam in my response i didn't say anything about Y carrying specific gene all i said was X being defected