Unit 5 Flashcards
When are Homologous chromosomes present during Meiosis 1?
Interphase-metaphase 1
When does independent assortment occur?
Metaphase 1
homologous chromosomes line up randomly on the sides
When does crossing over occur?
Prophase 1
When are Tetrads present during Meiosis?
Prophase-Metaphase 1
What does 2 large X chromosome’s mean?
It’s a girl
What does a big X chromosome and a small Y one mean?
It’s a boy
What does the equation 2n stand for?
Combinations of unique gametes
independent assortment equation
After Meiosis is complete how many sperm cells are made?
4
What has to happen in order for meiosis to be complete in the female? How many cells are made?
Fertilization, 1 egg cell is created but the remaining three are polar bodies that degrade in the body
Why are Homologous chromosomes all the same?
Because of genes, but alleles are what make them different because they have 2 types of genes
How do the cells at the end of meiosis compare with the parent cell?
They start as Diploids, then increased directly through crossover and independent assortment and end as diploid
Why do we need diversity?
To create Gametes that are haploid. Then they can combine during fertilization producing a diploid egg
Why is genetic diversity produced by meiosis is a good thing for nature?
Helps to maintain health of the population by including alleles that provide variation of traits
Sister Chromatid
Identical copies of a replicated chromosome joined by a centromere
Mitosis traits
Results in 2 diploid (2N) cells
Identical cells result
Somatic
Meiosis traits
Results in 4 haploid (1N) cells
Not identical cells result
Independent assortment and crossing over occurs
What order do these go in?
Random fertilization
Crossing over
Independent assortment
Crossing over
Independent assortment
Random fertilization
Crossing over
Homologous chromosomes exchange genetic info during prophase 1
Independent assortment
Homologous chromosomes arrange randomly during metaphase 1
Random fertilization
The ovum has 8 million possible chromosome’s to combine, so do the sperm cells
Diploid, what process do we see this kind of cell?
Containing 2 complete sets of chromosomes from each parent
Mitosis
Haploid, what process do we see this kind of cell?
A single set if unpaired chromosomes
Meiosis
What are homologous chromosomes? What makes a pair of homologous chromosomes different from each other?
2 sets of each chromosome’s where 1 pair comes from the mother and the other comes from the father (have different alleles)
What is a gene?
Section of DNA that controls the characteristics if an individual through protein production
What is an allele?
1 or more alternate forms of a gene
What is a Tetrad, when is it formed?
A homologous pair of chromosomes each made of 2 chromatids that form in late prophase 1
What does Nondisjunction in Meiosis 1 result as?
The pairs of homologous chromosome’s fail to separate, and 4 cells end up with the incorrect # of chromosomes
What does Nondisjunction in Meiosis 2 result as?
Sister Chromosomes fail to separate and 2 cells end up with the wrong # of chromosomes
What is a karyotype?
Organized profile of a persons chromosomes
Explain the difference between autosomal and sex chromosome’s and how many of each you would find in a human karyotype
Autosomes are the somatic chromosomes that control body characteristics. We have 22 setsC sex chromosome’s determine gender and we have 1 set
Monosomy
Missing a chromosome on a pair
Anuplodiy
Abnormal # of chromosomes in the body
Deletion
Part of a chromosome is missing
ABC-DFG
When does the cell go from diploid to haploid during Meiosis?
Telophase 1 (after cytokinesis)
Trimosy
1 extra chromosome on a pair
Non disjunction
Uneven separation of chromosomes during Anaphase 1 and 2 in Meiosis
Inversion
Letter swaps with another in sequence
Translocation
Letter breaks off of one sequence and gets attached to another
2 sets of chromosomes is a…
Holomongous, diploid
1/2 set of chromosome is a…
Haploid
When are Tetrads formed?
Prophase 1
The reduction division
Meioses
Between meiosis 1 and 2 the chromosomes…?
Duplicate
The longest part of meiosis
Prophase 1
Gamete production is a result of…?
Meiosis
Meiosis 2 looks like…?
Mitosis
At the end of Meosis what does the female produce?
1 egg and 3 polar bodies
Meosis starts with (blank) and ends with (blank)
1 diploid, 4 haploid
When does this happen in meiosis?
Chromosome is shorter and thicker, and the nuclear membrane breaks down and disappears
Prophase
Cell replacement, growth and healing is the result of?
Mitosis
What’s the difference between a haploid and diploid cell?
n-haploid, 1/2 # of chromosomes
2n-diploid, full set
