final test genetics.

what happens in mitosis?

-diploid parent cell splits into two identical daughter cells.

abnormal cell division.. what happens?

-happens when u end up with the wrong number of chromosomes in one of the resulting daughter cells. so, in meiosis 1, the result could be one of the two cells have more/less chromosome pairs than it should.

Trisomy 21

-happens when you have an extra copy of chromosome 21.

In meiosis 1, the result could be one of the two cells have more/less chromosome pairs than it should. why does this typically happen?

-normally is happens in anaphase. -the chromosomes are not pulled to the correct side of the cell. -so, all of the 4 cells created in meiosis 2 have all bad chromosome distribution bc of what happened in meiosis 1

what are the types of anewpolidy?

-our body has 2n number of chromosomes in out somatic cells. 2n-1 (menos un single chromosome) - monosomy 2n+1 (plus 1)- trisomy 2n-2 (minus 2)

abnormal cell division in Meisosis 2

-so, meisosis 1 went perfectly. - So, we have 2 cells each half of the chromosomal pairs of the original cell. but, then in meiosis 2.. in anaphase, one chromosomes fails to separate into two sister chromatids. (non-disjunction)

Anewploidy

-the addition or deletion of 1 chromosome to one single pair of the chromosome.. not all pairs that are in the cell. -this can also add 1/2 of a single chromosome. ex: one extra chromosome is added (ex: trisomic 21)

what happens in crossover when inversion loop?

-the problems arise when a crossover occus within the normal chromosome and inverted chromosome during meiosis.

what are the purpose of genes?

-they are segments of DNA that code for certain proteins.

Polyploidy

-when there a chromosome is added to not only one pair of chromosomes but to all of the pairs of chromosomes in the cell. ex: if they all get one more single chromosome to all of the chromosomal pairs.. its called triploidy so, it changes from 2n to 3n.

what are the two parts of meisosis?

1. Homologous recombination - 2. Crossing over

What is aneuploidy?

Abnormal number of chromosomes.

What is nondisjunction?

An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell

Haploid

An organism or cell having only one complete set of chromosomes.

what is trisomy 21?

Down syndrome

Why are crossovers risky?

It's difficult to line up base pairs. -they could lead to viable and inviable gametes.

inversion mutation

Mutation in which a chromosome piece reattaches to original chromosome but in reverse orientation

what is the difference between somatic cells and sex cells?

Somatic cells: -they are all diploid (2 pairs of chromosomes) so, they have 46 chromosomes in total. Sex cells: -they are haploid -they have 23 single chromosomes. -so, they have 23 chromosomes in total.

what happens in meiosis?

The same phases as mitosis but it happens twice. The result is four daughter cells. -== Two parts occur to make diploid parent cell makes 4 different daughter cells that are haploid (once pair of chromosome each) -they each have different genetic variations.

FLIP!!!! ---- ----- -its anewploid

What type of duplication is this? -Anewploid, polyploid or euploid?

trisomy 21, the presence of extra 21st chromosome, result from abnormal meiotic event. During gametogenesis in a trisomic individual, meiosis is predicted to be irregular. Knowing how meiosis might occur in trisomic individual, predict the probability that a trisomic individual will produce aneuploid or normal gamete

aneuploid individual has a chromosome number that is not an exact multiple of the haploid number, like 47, XXY sex trisomy or trisomy 21 it mostly prefer to aneuploid conditin and ratio of probability is Aneuploid: Normal =3:1

what happens if you dont have 22 pairs of chromomes and 1 pair that is XX or XY?

chromosomal abnormality

pair of chromosomes

homologous maternal and paternal chromosomes -thye have two homologous chromosomes (ignore the pic where is says sister chromatids... it should be homologous chromosomes.)

what is the inversion loop? why does it happen.

it happens when there is a inverted chromosome and your body is trying to find the pairs to match it. (in meiosis) -it inverts to be able to match to the correct pairs. -the crossover in the inverted segment

Two types of inversion:

pericentric and paracentric pericentric: -the inverted segment includes the centromere Paracentric: -doesnt include the centromere.

Meiosis

two rounds of cell division. Meiosis 1 parent cells--> 2 cells that have half of the chromosomal pairs and Meiosis 2 - 4 daughter cells wiht only haploid chromatids.